[ADD] tui: interactive terminal UI for resolving duplicates

The tool could only act on duplicates non-interactively or through a
line-oriented per-group prompt. Add a full-screen terminal UI (--tui) for
browsing and resolving them visually.

The UI is a two-pane master/detail view: a list of duplicate groups and,
for the selected group, its files with per-file deletion marks. Files can
be marked individually or in bulk by a keep-strategy (newest/oldest/first/
last/shortest/shallowest, reused from the resolver) applied to the current
group or to all groups at once. A footer tracks how many files are marked
and how much space would be reclaimed. Deletion is gated behind an explicit
confirmation, a group always keeps at least one file, and the highlighted
file can be opened in the system default application.

The design keeps the interaction logic pure and independently testable: an
App model translates an abstract key event into an outcome, so navigation,
marking, strategy application, and post-deletion model updates are all unit
tested without a terminal. Rendering (ratatui) and the destructive file I/O
live in the event loop, which restores the terminal on both normal exit and
panic so a crash never leaves it broken. --tui is mutually exclusive with
--keep and --interactive.

.github/workflows/release.yml

@@ -1,137 +1,121 @@
-# CI that:
+name: Deduplicator Release Build CI Pipeline
-#
-# * checks for a Git Tag that looks like a release
-# * creates a Github Release™ and fills in its text
-# * builds artifacts with cargo-dist (executable-zips, installers)
-# * uploads those artifacts to the Github Release™
-#
-# Note that the Github Release™ will be created before the artifacts,
-# so there will be a few minutes where the release has no artifacts
-# and then they will slowly trickle in, possibly failing. To make
-# this more pleasant we mark the release as a "draft" until all
-# artifacts have been successfully uploaded. This allows you to
-# choose what to do with partial successes and avoids spamming
-# anyone with notifications before the release is actually ready.
-name: Release
 
-permissions:
-  contents: write
-
-# This task will run whenever you push a git tag that looks like a version
-# like "v1", "v1.2.0", "v0.1.0-prerelease01", "my-app-v1.0.0", etc.
-# The version will be roughly parsed as ({PACKAGE_NAME}-)?v{VERSION}, where
-# PACKAGE_NAME must be the name of a Cargo package in your workspace, and VERSION
-# must be a Cargo-style SemVer Version.
-#
-# If PACKAGE_NAME is specified, then we will create a Github Release™ for that
-# package (erroring out if it doesn't have the given version or isn't cargo-dist-able).
-#
-# If PACKAGE_NAME isn't specified, then we will create a Github Release™ for all
-# (cargo-dist-able) packages in the workspace with that version (this is mode is
-# intended for workspaces with only one dist-able package, or with all dist-able
-# packages versioned/released in lockstep).
-#
-# If you push multiple tags at once, separate instances of this workflow will
-# spin up, creating an independent Github Release™ for each one.
-#
-# If there's a prerelease-style suffix to the version then the Github Release™
-# will be marked as a prerelease.
 on:
   push:
     tags:
-      - '*-?v[0-9]+*'
+      - 'v*.*.*'
 
 jobs:
-  # Create the Github Release™ so the packages have something to be uploaded to
+  lint_test:
-  create-release:
     runs-on: ubuntu-latest
-    outputs:
-      has-releases: ${{ steps.create-release.outputs.has-releases }}
     env:
-      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      RUSTFLAGS: "-C target-feature=+aes,+sse2"
     steps:
-      - uses: actions/checkout@v3
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
       - name: Install Rust
-        run: rustup update 1.71.0 --no-self-update && rustup default 1.71.0
+        uses: dtolnay/rust-toolchain@stable
-      - name: Install cargo-dist
+        with:
-        run: curl --proto '=https' --tlsv1.2 -LsSf https://github.com/axodotdev/cargo-dist/releases/download/v0.0.7/cargo-dist-installer.sh | sh
+          components: clippy
-      - id: create-release
-        run: |
-          cargo dist plan --tag=${{ github.ref_name }} --output-format=json > dist-manifest.json
-          echo "dist plan ran successfully"
-          cat dist-manifest.json
 
-          # Create the Github Release™ based on what cargo-dist thinks it should be
+      - name: Run cargo check
-          ANNOUNCEMENT_TITLE=$(jq --raw-output ".announcement_title" dist-manifest.json)
+        run: cargo check
-          IS_PRERELEASE=$(jq --raw-output ".announcement_is_prerelease" dist-manifest.json)
-          jq --raw-output ".announcement_github_body" dist-manifest.json > new_dist_announcement.md
-          gh release create ${{ github.ref_name }} --draft --prerelease="$IS_PRERELEASE" --title="$ANNOUNCEMENT_TITLE" --notes-file=new_dist_announcement.md
-          echo "created announcement!"
 
-          # Upload the manifest to the Github Release™
+      - name: Run cargo clippy
-          gh release upload ${{ github.ref_name }} dist-manifest.json
+        run: cargo clippy -- -D warnings
-          echo "uploaded manifest!"
 
-          # Disable all the upload-artifacts tasks if we have no actual releases
+      - name: Run tests
-          HAS_RELEASES=$(jq --raw-output ".releases != null" dist-manifest.json)
+        run: cargo test -- --test-threads=1
-          echo "has-releases=$HAS_RELEASES" >> "$GITHUB_OUTPUT"
 
-  # Build and packages all the things
+  build:
-  upload-artifacts:
+    needs: lint_test
-    # Let the initial task tell us to not run (currently very blunt)
+    runs-on: ${{ matrix.os }}
-    needs: create-release
-    if: ${{ needs.create-release.outputs.has-releases == 'true' }}
     strategy:
       matrix:
-        # For these target platforms
         include:
-        - os: macos-11
+          - target: aarch64-unknown-linux-gnu
-          dist-args: --artifacts=local --target=aarch64-apple-darwin --target=x86_64-apple-darwin
+            os: ubuntu-latest
-          install-dist: curl --proto '=https' --tlsv1.2 -LsSf https://github.com/axodotdev/cargo-dist/releases/download/v0.0.7/cargo-dist-installer.sh | sh
+            artifact_name: linux-aarch64
-        - os: ubuntu-20.04
+            rustflags: "-C target-feature=+aes,+neon"
-          dist-args: --artifacts=local --target=x86_64-unknown-linux-gnu
+          - target: x86_64-unknown-linux-gnu
-          install-dist: curl --proto '=https' --tlsv1.2 -LsSf https://github.com/axodotdev/cargo-dist/releases/download/v0.0.7/cargo-dist-installer.sh | sh
+            os: ubuntu-latest
-        - os: windows-2019
+            artifact_name: linux-amd64
-          dist-args: --artifacts=local --target=x86_64-pc-windows-msvc
+            rustflags: "-C target-feature=+aes,+sse2"
-          install-dist: irm  https://github.com/axodotdev/cargo-dist/releases/download/v0.0.7/cargo-dist-installer.ps1 | iex
+          - target: x86_64-apple-darwin
+            os: macos-14
+            artifact_name: macos-amd64
+            rustflags: "-C target-feature=+aes,+sse2"
+          - target: aarch64-apple-darwin
+            os: macos-14
+            artifact_name: macos-arm64
+            rustflags: "-C target-feature=+aes,+neon"
 
-    runs-on: ${{ matrix.os }}
-    env:
-      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
     steps:
-      - uses: actions/checkout@v3
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
       - name: Install Rust
-        run: rustup update 1.71.0 --no-self-update && rustup default 1.71.0
+        uses: dtolnay/rust-toolchain@stable
-      - name: Install cargo-dist
+
-        run: ${{ matrix.install-dist }}
+      - name: Add target
-      - name: Run cargo-dist
+        run: rustup target add ${{ matrix.target }}
-        # This logic is a bit janky because it's trying to be a polyglot between
+
-        # powershell and bash since this will run on windows, macos, and linux!
+      - name: Install cross-compilation toolchain (Linux ARM only)
-        # The two platforms don't agree on how to talk about env vars but they
+        if: matrix.target == 'aarch64-unknown-linux-gnu'
-        # do agree on 'cat' and '$()' so we use that to marshal values between commands.
         run: |
-          # Actually do builds and make zips and whatnot
+          sudo apt-get update
-          cargo dist build --tag=${{ github.ref_name }} --output-format=json ${{ matrix.dist-args }} > dist-manifest.json
+          sudo apt-get install -y gcc-aarch64-linux-gnu
-          echo "dist ran successfully"
-          cat dist-manifest.json
 
-          # Parse out what we just built and upload it to the Github Release™
+      - name: Build release binary
-          jq --raw-output ".artifacts[]?.path | select( . != null )" dist-manifest.json > uploads.txt
+        env:
-          echo "uploading..."
+          RUSTFLAGS: ${{ matrix.rustflags }}
-          cat uploads.txt
+          CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_LINKER: ${{ matrix.target == 'aarch64-unknown-linux-gnu' && 'aarch64-linux-gnu-gcc' || '' }}
-          gh release upload ${{ github.ref_name }} $(cat uploads.txt)
+        run: |
-          echo "uploaded!"
+          if [ "${{ matrix.target }}" = "aarch64-unknown-linux-gnu" ]; then
+            export CARGO_TARGET_AARCH64_UNKNOWN_LINUX_GNU_LINKER=aarch64-linux-gnu-gcc
+          fi
+          cargo build --release --target ${{ matrix.target }}
 
-  # Mark the Github Release™ as a non-draft now that everything has succeeded!
+      - name: Package binary
-  publish-release:
+        run: |
-    # Only run after all the other tasks, but it's ok if upload-artifacts was skipped
+          if [[ "${{ matrix.os }}" == macos* ]]; then
-    needs: [create-release, upload-artifacts]
+            BINARY_NAME=$(find target/${{ matrix.target }}/release -maxdepth 1 -type f -perm +111 -print0 | xargs -0 basename | head -1)
-    if: ${{ always() && needs.create-release.result == 'success' && (needs.upload-artifacts.result == 'skipped' || needs.upload-artifacts.result == 'success') }}
+          else
+            BINARY_NAME=$(find target/${{ matrix.target }}/release -maxdepth 1 -type f -executable -print0 | xargs -0 basename | head -1)
+          fi
+          
+          echo "Packaging binary: $BINARY_NAME"
+          mkdir -p release
+          cp target/${{ matrix.target }}/release/$BINARY_NAME release/$BINARY_NAME
+          tar -C release -czf ${{ matrix.artifact_name }}.tar.gz $BINARY_NAME
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: ${{ matrix.artifact_name }}-binary
+          path: ${{ matrix.artifact_name }}.tar.gz
+
+  create_release:
+    needs: build
     runs-on: ubuntu-latest
-    env:
-      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
     steps:
-      - uses: actions/checkout@v3
+      - name: Checkout repository
-      - name: mark release as non-draft
+        uses: actions/checkout@v4
-        run: |
+
-          gh release edit ${{ github.ref_name }} --draft=false
+      - name: Download all artifacts
+        uses: actions/download-artifact@v4
+        with:
+          path: artifacts
+
+      - name: Create GitHub Release
+        id: create_release
+        uses: softprops/action-gh-release@v1
+        with:
+          tag_name: ${{ github.ref_name }}
+          name: Release ${{ github.ref_name }}
+          body: "Automated release for version ${{ github.ref_name }}"
+          files: |
+            artifacts/*/*.tar.gz
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.gitignore

@@ -1,3 +1,7 @@
 /target
 /Cargo.lock
 /result-bin
+/.bacon-locations
+/docs
+/.claude
+/.superpowers

Cargo.toml

@@ -1,47 +1,60 @@
 [package]
 name = "deduplicator"
-version = "0.2.2"
+version = "0.3.2"
 edition = "2021"
-description = "find,filter,delete Duplicates"
+description = "find,filter and delete duplicate files"
 repository = "https://github.com/sreedevk/deduplicator"
 license = "MIT"
 authors = [
-    "Sreedev Kodichath <sreedevpadmakumar@gmail.com>",
+  "Sreedev Kodichath <sreedevpadmakumar@gmail.com>",
-    "Valentin Bersier <vbersier@gmail.com>",
+  "Valentin Bersier <vbersier@gmail.com>",
-    "Dhruva Sagar <dhruva.sagar@gmail.com>",
+  "Dhruva Sagar <dhruva.sagar@gmail.com>",
 ]
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[[bin]]
+name = "deduplicator"
+path = "src/main.rs"
 
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 [dependencies]
 anyhow = "1.0.68"
-bytesize = "1.1.0"
+bytesize = "2.0.1"
 chrono = "0.4.23"
 clap = { version = "4.0.32", features = ["derive"] }
-colored = "2.0.0"
+dirs = "6.0.0"
-dashmap = { version = "5.4.0", features = ["rayon"] }
+globwalk = "0.9.1"
-globwalk = "0.8.1"
+gxhash = { version = "3.4.1", default-features = false }
-gxhash = "3.4.1"
+indicatif = { version = "0.18.0", features = ["rayon"] }
-indicatif = { version = "0.17.2", features = ["rayon"] }
+memmap2 = "0.9.7"
-itertools = "0.10.5"
+open = "5.4.0"
-memmap2 = "0.5.8"
 pathdiff = "0.2.1"
 prettytable-rs = "0.10.0"
+ratatui = "0.30.2"
 rayon = "1.6.1"
-serde = { version = "1.0.192", features = ["derive"] }
+unicode-segmentation = "1.12.0"
-serde_json = "1.0.108"
-unicode-segmentation = "1.10.0"
 
 [profile.release]
 strip = true
+opt-level = 3
+lto = "thin"
+debug = false
+codegen-units = 1
 
 # generated by 'cargo dist init'
 [profile.dist]
 inherits = "release"
-lto = "thin"
 
 [workspace.metadata.dist]
-rust-toolchain-version = "1.78.0"
+rust-toolchain-version = "1.87.0"
 ci = ["github"]
-targets = ["x86_64-unknown-linux-gnu", "x86_64-apple-darwin", "x86_64-pc-windows-msvc", "aarch64-apple-darwin"]
+targets = [
+  "x86_64-unknown-linux-gnu",
+  "x86_64-apple-darwin",
+  "x86_64-pc-windows-msvc",
+  "aarch64-apple-darwin",
+]
 cargo-dist-version = "0.0.7"
+
+[dev-dependencies]
+tempfile = "3.20.0"
+rand = "0.9.1"

README.md

@@ -7,21 +7,25 @@
 ## Usage
 
 ```bash
+find,filter and delete duplicate files
+
 Usage: deduplicator [OPTIONS] [scan_dir_path]
 
 Arguments:
   [scan_dir_path]  Run Deduplicator on dir different from pwd (e.g., ~/Pictures )
 
 Options:
-  -t, --types <TYPES>          Filetypes to deduplicate [default = all]
+  -T, --exclude-types <EXCLUDE_TYPES>  Exclude Filetypes [default = none]
-  -i, --interactive            Delete files interactively
+  -t, --types <TYPES>                  Filetypes to deduplicate [default = all]
-  -s, --min-size <MIN_SIZE>    Minimum filesize of duplicates to scan (e.g., 100B/1K/2M/3G/4T) [default: 1b]
+  -i, --interactive                    Delete files interactively
-  -d, --max-depth <MAX_DEPTH>  Max Depth to scan while looking for duplicates
+  -m, --min-size <MIN_SIZE>            Minimum filesize of duplicates to scan (e.g., 100B/1K/2M/3G/4T) [default: 1b]
-      --min-depth <MIN_DEPTH>  Min Depth to scan while looking for duplicates
+  -D, --max-depth <MAX_DEPTH>          Max Depth to scan while looking for duplicates
-  -f, --follow-links           Follow links while scanning directories
+  -d, --min-depth <MIN_DEPTH>          Min Depth to scan while looking for duplicates
-  -h, --help                   Print help information
+  -f, --follow-links                   Follow links while scanning directories
-  -V, --version                Print version information
+  -s, --strict                         Guarantees that two files are duplicate (performs a full hash)
-      --json                    
+  -p, --progress                       Show Progress spinners & metrics
+  -h, --help                           Print help
+  -V, --version                        Print version
 ```
 ### Examples
 
@@ -29,6 +33,9 @@ Options:
 # Scan for duplicates recursively from the current dir, only look for png, jpg & pdf file types & interactively delete files
 deduplicator -t pdf,jpg,png -i
 
+# Scan for duplicates recursively from current dir, exclude png and jpg file types
+deduplicator -T jpg,png
+
 # Scan for duplicates recursively from the ~/Pictures dir, only look for png, jpeg, jpg & pdf file types & interactively delete files
 deduplicator ~/Pictures/ -t png,jpeg,jpg,pdf -i
 
@@ -42,88 +49,165 @@ deduplicator ~/.config --follow-links
 deduplicator ~/Media --min-size 100mb
 ```
 
+## Demo
+![demo](https://github.com/user-attachments/assets/bdb95831-542d-4902-a458-4e0f5d171a33)
+
+
+
+
 ## Installation
+Currently, you can only install deduplicator using cargo package manager.
 
-### Cargo Install
+### Cargo
+> GxHash relies on aes hardware acceleration, so please set `RUSTFLAGS` to `"-C target-feature=+aes"` or `"-C target-cpu=native"` before
+> installing.
 
-#### Stable
+#### install from crates.io (stable)
 
 ```bash
-$ cargo install deduplicator
+$ RUSTFLAGS="-C target-cpu=native" cargo install deduplicator
+
+# or
+
+$ RUSTFLAGS="-C target-feature=+aes,+sse2" cargo install deduplicator
 ```
 
-#### Nightly
+#### install from git (nightly)
-
-if you'd like to install with nightly features, you can use
-
 ```bash
-$ cargo install --git https://github.com/sreedevk/deduplicator
+$ RUSTFLAGS="-C target-cpu=native" cargo install deduplicator --git https://github.com/sreedevk/deduplicator
-```
-Please note that if you use a version manager to install rust (like asdf), you need to reshim (`asdf reshim rust`).
 
-### Linux (Pre-built Binary)
+# or
 
-you can download the pre-built binary from the [Releases](https://github.com/sreedevk/deduplicator/releases) page.
+$ RUSTFLAGS="-C target-feature=+aes,+sse2" cargo install --git https://github.com/sreedevk/deduplicator
-download the `deduplicator-x86_64-unknown-linux-gnu.tar.gz` for linux. Once you have the tarball file with the executable,
-you can follow these steps to install:
-
-```bash
-$ tar -zxvf deduplicator-x86_64-unknown-linux-gnu.tar.gz
-$ sudo mv deduplicator /usr/bin/
 ```
 
-### Mac OS (Pre-built Binary)
+### Manual Installation
-
+- Download the right pre-compiled binary archive for your platform from [github release page](https://github.com/sreedevk/deduplicator/releases/tag/latest).
-you can download the pre-build binary from the [Releases](https://github.com/sreedevk/deduplicator/releases) page.
+- Decompress it using `tar -zxvf <archive>.tar.gz` 
-download the `deduplicator-x86_64-apple-darwin.tar.gz` tarball for mac os. Once you have the tarball file with the executable, you can follow these steps to install:
+- Move it to a directory included in `$PATH`. 
-
+    - ideally `/usr/local/bin/`.
-```bash
-$ tar -zxvf deduplicator-x86_64-unknown-linux-gnu.tar.gz
-$ sudo mv deduplicator /usr/bin/
-```
-
-### Windows (Pre-built Binary)
-
-you can download the pre-build binary from the [Releases](https://github.com/sreedevk/deduplicator/releases) page.
-download the `deduplicator-x86_64-pc-windows-msvc.zip` zip file for windows. unzip the `zip`  file & move the `deduplicator.exe` to a location in the PATH system environment variable.
-
-Note: If you Run into an msvc error, please install MSCV from [here](https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist?view=msvc-170)
 
 ## Performance
+Deduplicator uses size comparison and [GxHash](https://docs.rs/gxhash/latest/gxhash/) to quickly check a large number of files to find duplicates. its also heavily parallelized. The default behavior of deduplicator is to only hash the first page (4K) of the file. This is to ensure that performance is the default priority. You can modify this behavior by using the `--strict` flag which will hash the whole file and ensure that 2 files are indeed duplicates. I'll add benchmarks in future versions.
 
-Deduplicator uses size comparison and fxhash (a non non-cryptographic hashing algo) to quickly scan through large number of files to find duplicates. its also highly parallel (uses rayon and dashmap). I was able to scan through 120GB of files (Videos, PDFs, Images) in ~300ms. checkout the benchmarks
+### Benchmarks
-
+I've used hyperfine to run deduplicator on files generated by the rake file at `rakelib/benchmark.rake`. The Benchmarking accuracy can further be improved by isolating runs inside restricted docker containers. I'll include that in the future. For now, here's the hyperfine output on my i7-12800H laptop with 32G of RAM.
-## benchmarks
-
-| Command | Dirsize | Filecount | Mean [ms] | Min [ms] | Max [ms] | Relative |
-|:---|:---|---:|---:|---:|---:|---:|
-| `deduplicator ~/Data/tmp` | (~120G) | 721 files | 33.5 ± 28.6 | 25.3 | 151.5 | 1.87 ± 1.60 |
-| `deduplicator ~/Data/books` | (~8.6G) | 1419 files | 24.5 ± 1.0 | 22.9 | 28.1 | 1.37 ± 0.08 |
-| `deduplicator ~/Data/books --min-size 10M` | (~8.6G) | 1419 files | 17.9 ± 0.7 | 16.8 | 20.0 | 1.00 |
-| `deduplicator ~/Data/ --types pdf,jpg,png,jpeg` | (~290G) | 104222 files | 1207.2 ± 37.0 | 1172.2 | 1287.7 | 67.27 ± 3.33 |
-
-* The last entry is lower because of the number of files deduplicator had to go through (~660895 Files). The average size of the files rarely affect the performance of deduplicator.
-
-These benchmarks were run using [hyperfine](https://github.com/sharkdp/hyperfine). Here are the specs of the machine used to benchmark deduplicator:
 
+#### Fewer Large Files
 ```
-OS: Arch Linux x86_64 
+# hyperfine -N --warmup 80 './target/release/deduplicator bench_artifacts'
-Host: Precision 5540
+Benchmark 1: ./target/release/deduplicator bench_artifacts
-Kernel: 5.15.89-1-lts 
+  Time (mean ± σ):       2.2 ms ±   0.4 ms    [User: 2.2 ms, System: 4.4 ms]
-Uptime: 4 hours, 44 mins 
+  Range (min … max):     1.3 ms …   7.1 ms    1522 runs
-Shell: zsh 5.9                        
+
-Terminal: kitty 
+dust 'bench_artifacts'
-CPU: Intel i9-9880H (16) @ 4.800GHz 
+
-GPU: NVIDIA Quadro T2000 Mobile / Max-Q 
+ 54M   ┌── file_0_fwds.bin   │████                                                               │   2%
-GPU: Intel CoffeeLake-H GT2 [UHD Graphics 630] 
+122M   ├── file_1_fwds.bin   │████████                                                           │   5%
-Memory: 31731MiB (~32GiB)
+390M   ├── file_0_fwdcbss.bin│██████████████████████████                                         │  15%
+390M   ├── file_0_fwscas.bin │██████████████████████████                                         │  15%
+390M   ├── file_0_fwss.bin   │██████████████████████████                                         │  15%
+390M   ├── file_1_fwdcbss.bin│██████████████████████████                                         │  15%
+390M   ├── file_1_fwscas.bin │██████████████████████████                                         │  15%
+390M   ├── file_1_fwss.bin   │██████████████████████████                                         │  15%
+2.5G ┌─┴ bench_artifacts     │██████████████████████████████████████████████████████████████████ │ 100%
 ```
 
-## Screenshots
+#### Many Small Files
+```
+# hyperfine --warmup 20 './target/release/deduplicator bench_artifacts'
+Benchmark 1: ./target/release/deduplicator bench_artifacts
+  Time (mean ± σ):      40.1 ms ±   2.3 ms    [User: 251.0 ms, System: 277.3 ms]
+  Range (min … max):    35.0 ms …  45.9 ms    72 runs
 
-![](https://user-images.githubusercontent.com/36154121/213618143-e5182e39-731e-4817-87dd-1a6a0f38a449.gif)
+dust 'bench_artifacts'
+3.9M   ┌── file_992_fwscas.bin │█                                                                │   0%
+3.9M   ├── file_992_fwss.bin   │█                                                                │   0%
+3.9M   ├── file_993_fwdcbss.bin│█                                                                │   0%
+3.9M   ├── file_993_fwscas.bin │█                                                                │   0%
+3.9M   ├── file_993_fwss.bin   │█                                                                │   0%
+3.9M   ├── file_994_fwdcbss.bin│█                                                                │   0%
+3.9M   ├── file_994_fwscas.bin │█                                                                │   0%
+3.9M   ├── file_994_fwss.bin   │█                                                                │   0%
+3.9M   ├── file_995_fwdcbss.bin│█                                                                │   0%
+3.9M   ├── file_995_fwscas.bin │█                                                                │   0%
+3.9M   ├── file_995_fwss.bin   │█                                                                │   0%
+3.9M   ├── file_996_fwdcbss.bin│█                                                                │   0%
+3.9M   ├── file_996_fwscas.bin │█                                                                │   0%
+3.9M   ├── file_996_fwss.bin   │█                                                                │   0%
+3.9M   ├── file_997_fwdcbss.bin│█                                                                │   0%
+3.9M   ├── file_997_fwscas.bin │█                                                                │   0%
+3.9M   ├── file_997_fwss.bin   │█                                                                │   0%
+3.9M   ├── file_998_fwdcbss.bin│█                                                                │   0%
+3.9M   ├── file_998_fwscas.bin │█                                                                │   0%
+3.9M   ├── file_998_fwss.bin   │█                                                                │   0%
+3.9M   ├── file_999_fwdcbss.bin│█                                                                │   0%
+3.9M   ├── file_999_fwscas.bin │█                                                                │   0%
+3.9M   ├── file_999_fwss.bin   │█                                                                │   0%
+3.9M   ├── file_99_fwdcbss.bin │█                                                                │   0%
+3.9M   ├── file_99_fwscas.bin  │█                                                                │   0%
+3.9M   ├── file_99_fwss.bin    │█                                                                │   0%
+3.9M   ├── file_9_fwdcbss.bin  │█                                                                │   0%
+3.9M   ├── file_9_fwscas.bin   │█                                                                │   0%
+3.9M   ├── file_9_fwss.bin     │█                                                                │   0%
+ 11G ┌─┴ bench_artifacts       │████████████████████████████████████████████████████████████████ │ 100%
+```
 
-## Roadmap
+## proposed
-    - Tree format output for duplicate file listing
+- [ ] parallelization
-    - GUI
+    - [ ] scanning + processing sw + processing hw + formatting + printing
-    - Packages for different operating system repositories (currently only installable via cargo) 
+- [ ] user supplied cache file path for faster re-runs
+- [ ] hardlinks / symlinks support
+- [ ] max file path size should use the last set of duplicates
+- [ ] add more unit tests
+    - [ ] test against different filesystems
+    - [ ] test against different file name encodings
+- [ ] restore json output (was removed in 0.3 due to quality issues)
+- [ ] fix memory leak on very large filesystems
+    - [ ] maybe use a bloom filter
+    - [ ] reduce FileInfo size
+- [ ] tui
+- [ ] change the default hashing method to include the first & last page of a file (8K)
+- [ ] provide option to localize duplicate detection to arbitrary levels relative to current directory
+- [ ] localize file meta store locks to sub path levels to avoid global lock contention from multiple threads.
+- [ ] bulk operations
+    - [ ] --keep-latest
+    - [ ] --keep-oldest
+    - [ ] --keep-last-modified
+    - [ ] --keep-first-modified
+
+- [ ] fix: partial hash collision - a file full of null bytes ("\0") and an empty file. This is a known trade off in gxhash.
+    - [ ] include initial pages and final pages of the file 
+    - [ ] append the offset between the last initial page hashed and the first final page hashed in the content passed to the hasher.
+- [ ] potential optimizations
+    -  [ ] lookup the memory efficiency gains if instead of directly inserting into a hashmap, deduplicator looksup the file in a bloom filter. this way, the duplicate store hashmap does
+       not require to be locked for every single file. The bloom filter can be stored in an atomically updateable type to improve performance as well.
+
+## v0.3.2
+- [x] fix: single file groups are printed to screen
+- [x] fix: --exclude-types and --types flag behave identically.
+
+## v0.3.1
+- [x] parallelization
+    - [x] (scanning + processing sw + processing hw) & formatting & printing
+- [x] remove formatting step and write directly to stdout
+- [x] simplify output to improve performance
+- [x] increase the number of pages hashed in partial hashing
+- [x] updated dependencies
+- [x] fix: full file hash collision between a file full of null bytes ("\0") and an empty file. This is a known trade off in gxhash.
+    - [x] appending the file size at the end of content before hashing.
+- [x] created an automated release pipeline
+
+## v0.3.0
+- [x] parallelization
+    - [x] (scanning) + (processing sw & processing hw & formatting & printing)
+- [x] reduce cloning values on the heap
+- [x] add a partial hashing mode (--strict)
+- [x] add unit tests
+- [x] add silent mode
+- [x] update documentation
+- [x] remove color output
+- [x] progress bar improvements
+    - [x] use progress bar groups
+- [x] remove broken json rendering
+- [x] add benchmarks

Rakefile

@@ -0,0 +1 @@
+# tasks are contained in the `rakelib` directory

rakelib/benchmark.rake

@@ -0,0 +1,102 @@
+require 'tempfile'
+require 'fileutils'
+require 'securerandom'
+
+namespace :benchmark do
+  file 'target/release/deduplicator' do
+    sh "cargo build --release"
+  end
+
+  task :few_large_files => 'target/release/deduplicator' do
+    # Benchmark 1: ./target/release/deduplicator bench_artifacts
+    # Time (mean ± σ):       2.5 ms ±   0.6 ms    [User: 2.4 ms, System: 4.8 ms]
+    # Range (min … max):     1.8 ms …   9.7 ms    1474 runs
+
+    root = "bench_artifacts"
+    FileUtils.rm_rf(root)
+    Dir.mkdir(root)
+
+    # files with same size
+    puts "generating files of same size ..."
+    2.times.map do |i|
+      File.open(File.join(root, "file_#{i}_fwss.bin"), 'wb') do |f|
+        f.write(SecureRandom.bytes(4096 * 100_000))
+      end
+    end
+
+    # files with different sizes
+    puts "generating files of different sizes ..."
+    2.times.map do |i|
+      File.open(File.join(root, "file_#{i}_fwds.bin"), 'wb') do |f|
+        f.write(SecureRandom.bytes(4096 * (rand * 100_000).ceil))
+      end
+    end
+
+    # files with same content & size
+    puts "generating files of same content and sizes ..."
+    2.times.each do |i|
+      File.open(File.join(root, "file_#{i}_fwscas.bin"), 'wb') do |f|
+        f.write("\0" * (4096 * 100_000))
+      end
+    end
+
+    # files with different content but same size
+    puts "generating files of different content but same sizes ..."
+    2.times.each do |i|
+      File.open(File.join(root, "file_#{i}_fwdcbss.bin"), 'wb') do |f|
+        f.write(SecureRandom.bytes(4096 * 100_000))
+      end
+    end
+
+    sh("hyperfine -N --warmup 80 './target/release/deduplicator #{root}'")
+    sh("dust '#{root}'")
+
+    FileUtils.rm_rf(root)
+  end
+
+  task :many_small_files => 'target/release/deduplicator' do
+    # Benchmark 1: ./target/release/deduplicator bench_artifacts
+    # Time (mean ± σ):      10.6 ms ±   1.0 ms    [User: 20.0 ms, System: 22.5 ms]
+    # Range (min … max):     8.4 ms …  14.2 ms    235 runs
+
+    root = "bench_artifacts"
+    Dir.mkdir(root)
+
+    # files with same size
+    puts "generating 1000 files of the same size ... "
+    1000.times.each do |i|
+      File.open(File.join(root, "file_#{i}_fwss.bin"), 'wb') do |f|
+        f.write(SecureRandom.bytes(4096 * 1000))
+      end
+    end
+
+    # files with different sizes
+    puts "generating 1000 files of different sizes ... "
+    1000.times.each do |i|
+      File.open(File.join(root, "file_#{i}_fwds.bin"), 'wb') do |f|
+        f.write(SecureRandom.bytes(4096 * (rand * 100).ceil))
+      end
+    end
+
+    # files with same content & size
+    puts "generating files of same content and sizes ..."
+    1000.times.each do |i|
+      File.open(File.join(root, "file_#{i}_fwscas.bin"), 'wb') do |f|
+        f.write("\0" * (4096 * 1000))
+      end
+    end
+
+    # files with different content but same size
+    puts "generating files of different content but same sizes ..."
+    1000.times.each do |i|
+      File.open(File.join(root, "file_#{i}_fwdcbss.bin"), 'wb') do |f|
+        f.write(SecureRandom.bytes(4096 * 1000))
+      end
+    end
+
+    sh("hyperfine --warmup 20 './target/release/deduplicator #{root}'")
+    sh("dust '#{root}'")
+
+    FileUtils.rm_rf(root)
+  end
+end

src/cache.rs

@@ -0,0 +1,249 @@
+use std::collections::HashMap;
+use std::fs;
+use std::path::{Path, PathBuf};
+use std::time::{SystemTime, UNIX_EPOCH};
+
+const MAGIC: &[u8; 4] = b"DDUP";
+const VERSION: u8 = 1;
+const RECORD_FIXED_LEN: usize = 45;
+
+pub const CACHE_TTL_DAYS: u64 = 30;
+
+pub struct CacheEntry {
+    pub size: u64,
+    pub mtime: u64,
+    pub strict: bool,
+    pub hash: u128,
+    pub last_seen: u64,
+}
+
+pub struct Cache {
+    entries: HashMap<PathBuf, CacheEntry>,
+    enabled: bool,
+}
+
+pub fn mtime_nanos(modified: SystemTime) -> u64 {
+    modified
+        .duration_since(UNIX_EPOCH)
+        .map(|d| d.as_nanos() as u64)
+        .unwrap_or(0)
+}
+
+impl Cache {
+    pub fn disabled() -> Self {
+        Self {
+            entries: HashMap::new(),
+            enabled: false,
+        }
+    }
+
+    fn empty_enabled() -> Self {
+        Self {
+            entries: HashMap::new(),
+            enabled: true,
+        }
+    }
+
+    pub fn load(path: &Path) -> Self {
+        match fs::read(path) {
+            Ok(bytes) => Self::parse(&bytes).unwrap_or_else(Self::empty_enabled),
+            Err(_) => Self::empty_enabled(),
+        }
+    }
+
+    fn parse(bytes: &[u8]) -> Option<Self> {
+        if bytes.len() < 5 || &bytes[0..4] != MAGIC || bytes[4] != VERSION {
+            return None;
+        }
+
+        let mut entries = HashMap::new();
+        let mut cur = &bytes[5..];
+
+        while cur.len() >= RECORD_FIXED_LEN {
+            let hash = u128::from_le_bytes(cur[0..16].try_into().ok()?);
+            let size = u64::from_le_bytes(cur[16..24].try_into().ok()?);
+            let mtime = u64::from_le_bytes(cur[24..32].try_into().ok()?);
+            let last_seen = u64::from_le_bytes(cur[32..40].try_into().ok()?);
+            let strict = cur[40] != 0;
+            let path_len = u32::from_le_bytes(cur[41..45].try_into().ok()?) as usize;
+
+            let rest = &cur[RECORD_FIXED_LEN..];
+            if rest.len() < path_len {
+                break;
+            }
+
+            match std::str::from_utf8(&rest[..path_len]) {
+                Ok(s) => {
+                    entries.insert(
+                        PathBuf::from(s),
+                        CacheEntry {
+                            size,
+                            mtime,
+                            strict,
+                            hash,
+                            last_seen,
+                        },
+                    );
+                }
+                Err(_) => {}
+            }
+
+            cur = &rest[path_len..];
+        }
+
+        Some(Self {
+            entries,
+            enabled: true,
+        })
+    }
+
+    pub fn lookup(&self, path: &Path, size: u64, mtime: u64, strict: bool) -> Option<u128> {
+        let entry = self.entries.get(path)?;
+        match entry.size == size && entry.mtime == mtime && entry.strict == strict {
+            true => Some(entry.hash),
+            false => None,
+        }
+    }
+
+    pub fn record(
+        &mut self,
+        path: &Path,
+        size: u64,
+        mtime: u64,
+        strict: bool,
+        hash: u128,
+        now_secs: u64,
+    ) {
+        if path.to_str().is_none() {
+            return;
+        }
+
+        self.entries.insert(
+            path.to_path_buf(),
+            CacheEntry {
+                size,
+                mtime,
+                strict,
+                hash,
+                last_seen: now_secs,
+            },
+        );
+    }
+
+    pub fn save(&self, path: &Path, ttl_secs: u64, now_secs: u64) {
+        if !self.enabled {
+            return;
+        }
+
+        let mut buf: Vec<u8> = Vec::new();
+        buf.extend_from_slice(MAGIC);
+        buf.push(VERSION);
+
+        for (entry_path, entry) in &self.entries {
+            if now_secs.saturating_sub(entry.last_seen) > ttl_secs {
+                continue;
+            }
+            let path_str = match entry_path.to_str() {
+                Some(s) => s,
+                None => continue,
+            };
+
+            buf.extend_from_slice(&entry.hash.to_le_bytes());
+            buf.extend_from_slice(&entry.size.to_le_bytes());
+            buf.extend_from_slice(&entry.mtime.to_le_bytes());
+            buf.extend_from_slice(&entry.last_seen.to_le_bytes());
+            buf.push(entry.strict as u8);
+            buf.extend_from_slice(&(path_str.len() as u32).to_le_bytes());
+            buf.extend_from_slice(path_str.as_bytes());
+        }
+
+        if let Some(parent) = path.parent() {
+            let _ = fs::create_dir_all(parent);
+        }
+
+        if let Err(err) = fs::write(path, &buf) {
+            eprintln!("warning: failed to write cache to {}: {err}", path.display());
+        }
+    }
+
+    pub fn default_path() -> Option<PathBuf> {
+        dirs::cache_dir().map(|dir| dir.join("deduplicator").join("cache.bin"))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::path::Path;
+    use std::time::{Duration, UNIX_EPOCH};
+    use tempfile::TempDir;
+
+    #[test]
+    fn lookup_hits_on_exact_match() {
+        let mut c = Cache::disabled();
+        c.record(Path::new("/a/b"), 100, 200, false, 42, 1000);
+        assert_eq!(c.lookup(Path::new("/a/b"), 100, 200, false), Some(42));
+    }
+
+    #[test]
+    fn lookup_misses_on_any_field_change_or_absent() {
+        let mut c = Cache::disabled();
+        c.record(Path::new("/a/b"), 100, 200, false, 42, 1000);
+        assert_eq!(c.lookup(Path::new("/a/b"), 101, 200, false), None);
+        assert_eq!(c.lookup(Path::new("/a/b"), 100, 201, false), None);
+        assert_eq!(c.lookup(Path::new("/a/b"), 100, 200, true), None);
+        assert_eq!(c.lookup(Path::new("/a/x"), 100, 200, false), None);
+    }
+
+    #[test]
+    fn save_then_load_roundtrips_entries() {
+        let dir = TempDir::new().unwrap();
+        let file = dir.path().join("cache.bin");
+        let mut c = Cache::load(&file);
+        c.record(Path::new("/a/b"), 100, 200, false, 42, 1000);
+        c.record(Path::new("/c/d"), 5, 6, true, 99, 1000);
+        c.save(&file, 86_400, 1000);
+
+        let loaded = Cache::load(&file);
+        assert_eq!(loaded.lookup(Path::new("/a/b"), 100, 200, false), Some(42));
+        assert_eq!(loaded.lookup(Path::new("/c/d"), 5, 6, true), Some(99));
+    }
+
+    #[test]
+    fn load_returns_empty_on_corrupt_file() {
+        let dir = TempDir::new().unwrap();
+        let file = dir.path().join("cache.bin");
+        std::fs::write(&file, b"not a valid cache file at all").unwrap();
+        let c = Cache::load(&file);
+        assert_eq!(c.lookup(Path::new("/a/b"), 100, 200, false), None);
+    }
+
+    #[test]
+    fn load_returns_empty_on_version_mismatch() {
+        let dir = TempDir::new().unwrap();
+        let file = dir.path().join("cache.bin");
+        std::fs::write(&file, b"DDUP\x02").unwrap();
+        let c = Cache::load(&file);
+        assert_eq!(c.lookup(Path::new("/a/b"), 100, 200, false), None);
+    }
+
+    #[test]
+    fn save_prunes_entries_older_than_ttl() {
+        let dir = TempDir::new().unwrap();
+        let file = dir.path().join("cache.bin");
+        let mut c = Cache::load(&file);
+        c.record(Path::new("/old"), 1, 2, false, 10, 1000);
+        c.record(Path::new("/new"), 3, 4, false, 20, 5000);
+        c.save(&file, 1000, 5000);
+
+        let loaded = Cache::load(&file);
+        assert_eq!(loaded.lookup(Path::new("/old"), 1, 2, false), None);
+        assert_eq!(loaded.lookup(Path::new("/new"), 3, 4, false), Some(20));
+    }
+
+    #[test]
+    fn mtime_nanos_converts_systemtime() {
+        let t = UNIX_EPOCH + Duration::from_nanos(1234);
+        assert_eq!(mtime_nanos(t), 1234);
+    }
+}

src/fileinfo.rs

@@ -1,43 +1,85 @@
 use anyhow::Result;
-use gxhash::GxHasher;
+use gxhash::gxhash128;
 use memmap2::Mmap;
-use serde::Serialize;
+use std::{
-use std::fs;
+    fs,
-use std::hash::Hasher;
+    io::Read,
-use std::{fs::Metadata, path::PathBuf};
+    path::{Path, PathBuf},
+    time::SystemTime,
+};
 
-#[derive(Debug, Clone, Serialize)]
+#[derive(Debug, Clone)]
 pub struct FileInfo {
-    pub path: PathBuf,
+    pub path: Box<Path>,
-    pub hash: Option<String>,
     pub size: u64,
-    #[serde(skip)]
+    pub modified: SystemTime,
-    pub filemeta: Metadata,
 }
 
 impl FileInfo {
-    pub fn hash(&self) -> Result<Self> {
+    pub fn hash(&self, seed: i64) -> Result<u128> {
-        let file = fs::File::open(self.path.clone())?;
+        if self.size == 0 {
+            return Ok(0u128);
+        };
+
+        let file = fs::File::open(&self.path)?;
         let mapper = unsafe { Mmap::map(&file)? };
-        let mut primhasher = GxHasher::default();
+        let content_hash = mapper
+            .chunks(4096)
+            .fold(0u128, |acc, chunk: &[u8]| acc ^ gxhash128(chunk, seed));
 
-        mapper
+        // NOTE: avoids collision bw an empty file & a file full of null bytes.
-            .chunks(1_000_000)
+        Ok(content_hash ^ gxhash128(&self.size.to_ne_bytes(), seed))
-            .for_each(|chunk| primhasher.write(chunk));
+    }
 
-        Ok(Self {
+    pub fn initpages_hash(&self, seed: i64) -> Result<u128> {
-            hash: Some(primhasher.finish().to_string()),
+        let mut file = fs::File::open(&self.path)?;
-            ..self.clone()
+        let mut buffer = [0; 16384];
-        })
+        let bytes_read = file.read(&mut buffer)?;
+
+        Ok(gxhash128(&buffer[..bytes_read], seed))
     }
 
     pub fn new(path: PathBuf) -> Result<Self> {
-        let filemeta = std::fs::metadata(path.clone())?;
+        let filemeta = std::fs::metadata(&path)?;
         Ok(Self {
-            path,
+            path: path.into_boxed_path(),
-            filemeta: filemeta.clone(),
-            hash: None,
             size: filemeta.len(),
+            modified: filemeta.modified()?,
         })
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use tempfile::TempDir;
+    use std::fs::File;
+    use std::io::Write;
+    use anyhow::Result;
+
+    fn generate_null_bytes(size: usize) -> Vec<u8> {
+        (0..size).map(|_| 0).collect::<Vec<u8>>()
+    }
+
+    #[test]
+    fn hash_differentiates_between_a_file_of_null_bytes_vs_an_empty_file() -> Result<()> {
+        let root = TempDir::new()?;
+        let empty_file_name = root.path().join("empty_file.bin");
+
+        File::create_new(&empty_file_name)?;
+
+        let file_with_null_bytes_name = root.path().join("file_with_null_bytes.bin");
+        let mut file_with_null_bytes = File::create_new(&file_with_null_bytes_name)?;
+
+        file_with_null_bytes.write_all(&generate_null_bytes(1000 * 4096))?;
+
+        let empty_file_info = FileInfo::new(empty_file_name)?;
+        let file_with_empty_bytes_info = FileInfo::new(file_with_null_bytes_name)?;
+
+        let seed: i64 = 246910456374;
+
+        assert_ne!(empty_file_info.hash(seed)?, file_with_empty_bytes_info.hash(seed)?);
+
+        Ok(())
+    }
+}

src/formatter.rs

@@ -1,33 +1,23 @@
-pub struct Formatter;
+use crate::{fileinfo::FileInfo, params::Params, pipeline::DedupReport};
-use crate::fileinfo::FileInfo;
-use crate::params::Params;
 use anyhow::Result;
 use chrono::{DateTime, Utc};
-use colored::Colorize;
-use dashmap::DashMap;
-use indicatif::{
-    ParallelProgressIterator, ProgressBar, ProgressFinish, ProgressIterator, ProgressStyle,
-};
 use pathdiff::diff_paths;
-use prettytable::{format, row, Table};
 use rayon::prelude::*;
-use std::borrow::Cow;
 use std::path::PathBuf;
-use std::time::Duration;
 
+const YELLOW: &str = "\x1b[33m";
+const RESET: &str = "\x1b[0m";
+
+pub struct Formatter;
 impl Formatter {
-    pub fn human_path(
+    pub fn human_path(file: &FileInfo, aargs: &Params, max_path_length: usize) -> Result<String> {
-        file: &FileInfo,
+        let base_directory: PathBuf = aargs.get_directory()?;
-        app_args: &Params,
+        let relative_path = diff_paths(&file.path, base_directory).unwrap_or_default();
-        min_path_length: usize,
-    ) -> Result<String> {
-        let base_directory: PathBuf = app_args.get_directory()?;
-        let relative_path = diff_paths(file.path.clone(), base_directory).unwrap_or_default();
 
         let formatted_path = format!(
             "{:<0width$}",
             relative_path.to_str().unwrap_or_default().to_string(),
-            width = min_path_length
+            width = max_path_length
         );
 
         Ok(formatted_path)
@@ -38,97 +28,43 @@ impl Formatter {
     }
 
     pub fn human_mtime(file: &FileInfo) -> Result<String> {
-        let modified_time: DateTime<Utc> = file.filemeta.modified()?.into();
+        let modified_time: DateTime<Utc> = file.modified.into();
         Ok(modified_time.format("%Y-%m-%d %H:%M:%S").to_string())
     }
 
-    pub fn generate_table(raw: Vec<FileInfo>, app_args: &Params) -> Result<Table> {
+    pub fn print(report: &DedupReport, aargs: &Params) {
-        let basepath_length = app_args.get_directory()?.to_str().unwrap_or_default().len();
+        print!("{}", "\n".repeat(if aargs.progress { 2 } else { 1 }));
-        let max_filepath_length = raw
-            .iter()
-            .map(|file| file.path.to_str().unwrap_or_default().len())
-            .max()
-            .unwrap_or_default();
 
-        let min_path_length = if max_filepath_length > basepath_length {
+        if report.groups.is_empty() {
-            max_filepath_length - basepath_length
+            println!("No duplicates found matching your search criteria.");
-        } else {
+            return;
-            0
-        };
-
-        let progress_style = ProgressStyle::with_template(
-            "[{elapsed_precise}] {bar:40.cyan/blue} {pos:>7}/{len:7} {msg}",
-        )?;
-        let progress_bar = ProgressBar::new(raw.len() as u64);
-        progress_bar.set_style(progress_style);
-        progress_bar.enable_steady_tick(Duration::from_millis(50));
-        progress_bar.set_message("reconciling data");
-
-        let duplicates_table: DashMap<String, Vec<FileInfo>> = DashMap::new();
-        raw.into_par_iter()
-            .progress_with(progress_bar)
-            .with_finish(ProgressFinish::WithMessage(Cow::from("data reconciled")))
-            .map(|file| file.hash())
-            .filter_map(Result::ok)
-            .for_each(|file| {
-                duplicates_table
-                    .entry(file.hash.clone().unwrap_or_default())
-                    .and_modify(|fileset| fileset.push(file.clone()))
-                    .or_insert_with(|| vec![file]);
-            });
-
-        let mut output_table = Table::new();
-        output_table.set_titles(row!["hash", "duplicates"]);
-
-        let progress_style = ProgressStyle::with_template(
-            "[{elapsed_precise}] {bar:40.cyan/blue} {pos:>7}/{len:7} {msg}",
-        )?;
-
-        let progress_bar = ProgressBar::new(duplicates_table.len() as u64);
-        progress_bar.set_style(progress_style);
-        progress_bar.enable_steady_tick(Duration::from_millis(50));
-        progress_bar.set_message("generating output");
-
-        duplicates_table
-            .into_iter()
-            .progress_with(progress_bar)
-            .with_finish(ProgressFinish::WithMessage(Cow::from("output generated")))
-            .for_each(|(hash, group)| {
-                let mut inner_table = Table::new();
-                inner_table.set_format(*format::consts::FORMAT_NO_BORDER_LINE_SEPARATOR);
-                group.iter().for_each(|file| {
-                    inner_table.add_row(row![
-                        Self::human_path(file, app_args, min_path_length)
-                            .unwrap_or_default()
-                            .blue(),
-                        Self::human_filesize(file).unwrap_or_default().red(),
-                        Self::human_mtime(file).unwrap_or_default().yellow()
-                    ]);
-                });
-
-                output_table.add_row(row![hash.green(), inner_table]);
-            });
-
-        Ok(output_table)
-    }
-
-    pub fn print(raw: Vec<FileInfo>, app_args: &Params) -> Result<()> {
-        if raw.is_empty() {
-            println!(
-                "\n\n{}\n",
-                "No duplicates found matching your search criteria.".green()
-            );
-            return Ok(());
         }
 
-        if app_args.json {
+        report.groups.par_iter().for_each(|group| {
-            let output_json = serde_json::to_string_pretty(&raw)?;
+            let mut ostring = format!("{}{:32x}{}\n", YELLOW, group.hash, RESET);
-            println!("{}", output_json);
+            let subfields = group
-        } else {
+                .files
-            let output_table = Self::generate_table(raw, app_args)?;
+                .par_iter()
-            output_table.printstd();
+                .enumerate()
-        }
+                .map(|(i, finfo)| {
+                    let nodechar = if i == group.files.len() - 1 {
+                        "└─"
+                    } else {
+                        "├─"
+                    };
+                    format!(
+                        "{}\t{}\t{}\t{}\n",
+                        nodechar,
+                        Self::human_path(finfo, aargs, report.max_path_len)
+                            .expect("path formatting failed."),
+                        Self::human_filesize(finfo).expect("filesize formatting failed."),
+                        Self::human_mtime(finfo).expect("modified time formatting failed.")
+                    )
+                })
+                .collect::<String>();
 
-        Ok(())
+            ostring.push_str(&subfields);
+            println!("{ostring}");
+        });
     }
 }

src/interactive.rs

@@ -1,154 +1,122 @@
-use crate::formatter::Formatter;
+use crate::{fileinfo::FileInfo, formatter::Formatter, params::Params, pipeline::DuplicateGroup};
-use crate::{fileinfo::FileInfo, params::Params};
 use anyhow::Result;
-use colored::Colorize;
-use dashmap::DashMap;
-use indicatif::{ParallelProgressIterator, ProgressBar, ProgressFinish, ProgressStyle};
 use prettytable::{format, row, Table};
-use rayon::prelude::*;
+use std::io::{self, Write};
-use std::{
+use unicode_segmentation::UnicodeSegmentation;
-    borrow::Cow,
-    io::{self, Write},
-    time::Duration,
-};
 
-pub fn scan_group_confirmation() -> Result<bool> {
+pub struct Interactive;
-    print!("\nconfirm? [y/N]: ");
-    std::io::stdout().flush()?;
-    let mut user_input = String::new();
-    io::stdin().read_line(&mut user_input)?;
 
-    match user_input.trim() {
+impl Interactive {
-        "Y" | "y" => Ok(true),
+    pub fn init(groups: &[DuplicateGroup], app_args: &Params) -> Result<()> {
-        _ => Ok(false),
+        if groups.is_empty() {
-    }
+            println!("No duplicates found matching your search criteria.");
-}
+            return Ok(());
+        }
 
-pub fn scan_group_instruction() -> Result<String> {
+        groups.iter().enumerate().for_each(|(gindex, group)| {
-    println!("\nEnter the indices of the files you want to delete.");
+            let files = &group.files;
-    println!("You can enter multiple files using commas to seperate file indices.");
-    println!("example: 1,2");
-    print!("\n> ");
-    std::io::stdout().flush()?;
-    let mut user_input = String::new();
-    io::stdin().read_line(&mut user_input)?;
-
-    Ok(user_input)
-}
-
-pub fn init(result: Vec<FileInfo>, app_args: &Params) -> Result<()> {
-    let basepath_length = app_args.get_directory()?.to_str().unwrap_or_default().len();
-    let max_filepath_length = result
-        .iter()
-        .map(|file| file.path.to_str().unwrap_or_default().len())
-        .max()
-        .unwrap_or_default();
-
-    let min_path_length = if max_filepath_length > basepath_length {
-        max_filepath_length - basepath_length
-    } else {
-        0
-    };
-
-    let progress_style = ProgressStyle::with_template(
-        "[{elapsed_precise}] {bar:40.cyan/blue} {pos:>7}/{len:7} {msg}",
-    )?;
-    let progress_bar = ProgressBar::new(result.len() as u64);
-    progress_bar.set_style(progress_style);
-    progress_bar.enable_steady_tick(Duration::from_millis(50));
-    progress_bar.set_message("reconciling data");
-
-    let duplicates: DashMap<String, Vec<FileInfo>> = DashMap::new();
-    result
-        .into_par_iter()
-        .progress_with(progress_bar)
-        .with_finish(ProgressFinish::WithMessage(Cow::from("data reconciled")))
-        .map(|file| file.hash())
-        .filter_map(Result::ok)
-        .for_each(|file| {
-            duplicates
-                .entry(file.hash.clone().unwrap_or_default())
-                .and_modify(|fileset| fileset.push(file.clone()))
-                .or_insert_with(|| vec![file]);
-        });
-
-    duplicates
-        .clone()
-        .into_iter()
-        .enumerate()
-        .for_each(|(gindex, (_, group))| {
             let mut itable = Table::new();
             itable.set_format(*format::consts::FORMAT_NO_BORDER_LINE_SEPARATOR);
             itable.set_titles(row!["index", "filename", "size", "updated_at"]);
-            group.iter().enumerate().for_each(|(index, file)| {
+
+            let max_path_size = files
+                .iter()
+                .map(|f| f.path.to_string_lossy().graphemes(true).count())
+                .max()
+                .unwrap_or_default();
+
+            files.iter().enumerate().for_each(|(index, file)| {
                 itable.add_row(row![
                     index,
-                    Formatter::human_path(file, app_args, min_path_length)
+                    Formatter::human_path(file, app_args, max_path_size).unwrap_or_default(),
-                        .unwrap_or_default()
+                    Formatter::human_filesize(file).unwrap_or_default(),
-                        .blue(),
+                    Formatter::human_mtime(file).unwrap_or_default()
-                    Formatter::human_filesize(file).unwrap_or_default().red(),
-                    Formatter::human_mtime(file).unwrap_or_default().yellow()
                 ]);
             });
 
-            process_group_action(&group, gindex, duplicates.len(), itable);
+            Self::process_group_action(files, gindex, groups.len(), itable);
         });
 
-    Ok(())
+        Ok(())
-}
-
-pub fn process_group_action(
-    duplicates: &Vec<FileInfo>,
-    dup_index: usize,
-    dup_size: usize,
-    table: Table,
-) {
-    println!("\nDuplicate Set {} of {}\n", dup_index + 1, dup_size);
-    table.printstd();
-    let files_to_delete = scan_group_instruction().unwrap_or_default();
-    let parsed_file_indices = files_to_delete
-        .trim()
-        .split(',')
-        .filter(|element| !element.is_empty())
-        .map(|index| index.parse::<usize>().unwrap_or_default())
-        .collect::<Vec<usize>>();
-
-    if parsed_file_indices
-        .clone()
-        .into_iter()
-        .any(|index| index > (duplicates.len() - 1))
-    {
-        println!("{}", "Err: File Index Out of Bounds!".red());
-        return process_group_action(duplicates, dup_index, dup_size, table);
     }
 
-    print!("{esc}[2J{esc}[1;1H", esc = 27 as char);
+    pub fn scan_group_confirmation() -> Result<bool> {
+        print!("\nconfirm? [y/N]: ");
+        std::io::stdout().flush()?;
+        let mut user_input = String::new();
+        io::stdin().read_line(&mut user_input)?;
 
-    if parsed_file_indices.is_empty() {
+        match user_input.trim() {
-        return;
+            "Y" | "y" => Ok(true),
-    }
+            _ => Ok(false),
-
+        }
-    let files_to_delete = parsed_file_indices
+    }
-        .into_iter()
+
-        .map(|index| duplicates[index].clone());
+    pub fn scan_group_instruction() -> Result<String> {
-
+        println!("\nEnter the indices of the files you want to delete.");
-    println!("\n{}", "The following files will be deleted:".red());
+        println!("You can enter multiple files using commas to seperate file indices.");
-    files_to_delete
+        println!("example: 1,2");
-        .clone()
+        print!("\n> ");
-        .enumerate()
+        std::io::stdout().flush()?;
-        .for_each(|(index, file)| {
+        let mut user_input = String::new();
-            println!("{}: {}", index.to_string().blue(), file.path.display());
+        io::stdin().read_line(&mut user_input)?;
-        });
+
-
+        Ok(user_input)
-    match scan_group_confirmation().unwrap() {
+    }
-        true => {
+
-            files_to_delete.into_iter().for_each(|file| {
+    pub fn process_group_action(
-                match std::fs::remove_file(file.path.clone()) {
+        duplicates: &Vec<FileInfo>,
-                    Ok(_) => println!("{}: {}", "DELETED".green(), file.path.display()),
+        dup_index: usize,
-                    Err(_) => println!("{}: {}", "FAILED".red(), file.path.display()),
+        dup_size: usize,
-                }
+        table: Table,
-            });
+    ) {
+        println!("\nDuplicate Set {} of {}\n", dup_index + 1, dup_size);
+        table.printstd();
+        let files_to_delete = Self::scan_group_instruction().unwrap_or_default();
+        let parsed_file_indices = files_to_delete
+            .trim()
+            .split(',')
+            .filter(|element| !element.is_empty())
+            .map(|index| index.parse::<usize>().unwrap_or_default())
+            .collect::<Vec<usize>>();
+
+        if parsed_file_indices
+            .clone()
+            .into_iter()
+            .any(|index| index > (duplicates.len() - 1))
+        {
+            println!("Err: File Index Out of Bounds!");
+            return Self::process_group_action(duplicates, dup_index, dup_size, table);
+        }
+
+        print!("{esc}[2J{esc}[1;1H", esc = 27 as char);
+
+        if parsed_file_indices.is_empty() {
+            return;
+        }
+
+        let files_to_delete = parsed_file_indices
+            .into_iter()
+            .map(|index| duplicates[index].clone());
+
+        println!("\nThe following files will be deleted:");
+        files_to_delete
+            .clone()
+            .enumerate()
+            .for_each(|(index, file)| {
+                println!("{}: {}", index, file.path.display());
+            });
+
+        match Self::scan_group_confirmation().unwrap() {
+            true => {
+                files_to_delete.into_iter().for_each(|file| {
+                    match std::fs::remove_file(file.path.clone()) {
+                        Ok(_) => println!("DELETED: {}", file.path.display()),
+                        Err(_) => println!("FAILED: {}", file.path.display()),
+                    }
+                });
+            }
+            false => println!("\nCancelled Delete Operation."),
         }
-        false => println!("{}", "\nCancelled Delete Operation.".red()),
     }
 }

src/main.rs

@@ -1,30 +1,28 @@
+mod cache;
 mod fileinfo;
 mod formatter;
 mod interactive;
 mod params;
+mod pipeline;
 mod processor;
+mod resolver;
 mod scanner;
+mod tui;
 
+use self::{formatter::Formatter, interactive::Interactive};
 use anyhow::Result;
 use clap::Parser;
-use formatter::Formatter;
 use params::Params;
-use processor::Processor;
-use scanner::Scanner;
 
 fn main() -> Result<()> {
-    let app_args = Params::parse();
+    let params = Params::parse();
-    let scan_results = Scanner::build(&app_args)?.scan()?;
+    let report = pipeline::run(&params)?;
-    let processor = Processor::new(scan_results);
-    let results = processor.sizewise()?.hashwise()?;
 
-    match app_args.interactive {
+    match (params.tui, params.keep, params.interactive) {
-        false => {
+        (true, _, _) => tui::run(report, &params)?,
-            Formatter::print(results.files, &app_args)?;
+        (false, Some(strategy), _) => resolver::run(&report, strategy, params.force, &params)?,
-        }
+        (false, None, true) => Interactive::init(&report.groups, &params)?,
-        true => {
+        (false, None, false) => Formatter::print(&report, &params),
-            interactive::init(results.files, &app_args)?;
-        }
     }
 
     Ok(())

src/params.rs

@@ -3,9 +3,12 @@ use std::{fs, path::PathBuf};
 use anyhow::Result;
 use clap::{Parser, ValueHint};
 
-#[derive(Parser, Debug, Clone)]
+#[derive(Parser, Debug, Default, Clone)]
 #[command(author, version, about, long_about = None)]
 pub struct Params {
+    /// Exclude Filetypes [default = none]
+    #[arg(short = 'T', long)]
+    pub exclude_types: Option<String>,
     /// Filetypes to deduplicate [default = all]
     #[arg(short, long)]
     pub types: Option<String>,
@@ -15,21 +18,39 @@ pub struct Params {
     /// Delete files interactively
     #[arg(long, short)]
     pub interactive: bool,
+    /// Keep one file per duplicate group by this rule and remove the rest
+    #[arg(long, conflicts_with = "interactive")]
+    pub keep: Option<crate::resolver::KeepStrategy>,
+    /// Actually delete the duplicates (without this, --keep only previews)
+    #[arg(long, visible_alias = "yes", requires = "keep")]
+    pub force: bool,
     /// Minimum filesize of duplicates to scan (e.g., 100B/1K/2M/3G/4T).
-    #[arg(long, short = 's', default_value = "1b")]
+    #[arg(long, short = 'm', default_value = "1b")]
     pub min_size: Option<String>,
     /// Max Depth to scan while looking for duplicates
-    #[arg(long, short = 'd')]
+    #[arg(long, short = 'D')]
     pub max_depth: Option<usize>,
     /// Min Depth to scan while looking for duplicates
-    #[arg(long)]
+    #[arg(long, short = 'd')]
     pub min_depth: Option<usize>,
     /// Follow links while scanning directories
     #[arg(long, short)]
     pub follow_links: bool,
-    /// print json output
+    /// Guarantees that two files are duplicate (performs a full hash)
+    #[arg(long, short = 's', default_value = "false")]
+    pub strict: bool,
+    /// Show Progress spinners & metrics
+    #[arg(long, short = 'p', default_value = "false")]
+    pub progress: bool,
+    /// Disable the on-disk hash cache
     #[arg(long)]
-    pub json: bool,
+    pub no_cache: bool,
+    /// Use a specific cache file instead of the default location
+    #[arg(long, value_name = "PATH")]
+    pub cache_file: Option<PathBuf>,
+    /// Browse and resolve duplicates in an interactive terminal UI
+    #[arg(long, conflicts_with_all = ["keep", "interactive"])]
+    pub tui: bool,
 }
 
 impl Params {
@@ -49,8 +70,4 @@ impl Params {
         let dir = fs::canonicalize(dir_path)?;
         Ok(dir)
     }
-
-    pub fn get_types(&self) -> Option<String> {
-        self.types.clone()
-    }
 }

src/pipeline.rs

@@ -0,0 +1,182 @@
+use anyhow::Result;
+use indicatif::{ProgressBar, ProgressStyle};
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
+use unicode_segmentation::UnicodeSegmentation;
+
+use crate::cache::{mtime_nanos, Cache, CACHE_TTL_DAYS};
+use crate::fileinfo::FileInfo;
+use crate::params::Params;
+use crate::processor;
+use crate::scanner::Scanner;
+
+const HASH_SEED: i64 = 0x00DE_D0CA_C4E5_EED1;
+
+fn now_secs() -> u64 {
+    SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|d| d.as_secs())
+        .unwrap_or(0)
+}
+
+pub struct DuplicateGroup {
+    pub hash: u128,
+    pub files: Vec<FileInfo>,
+}
+
+pub struct DedupReport {
+    pub groups: Vec<DuplicateGroup>,
+    pub max_path_len: usize,
+}
+
+pub(crate) fn spinner(enabled: bool, message: &'static str) -> ProgressBar {
+    let bar = if enabled {
+        ProgressBar::new_spinner()
+    } else {
+        ProgressBar::hidden()
+    };
+
+    let style = ProgressStyle::with_template("[{elapsed_precise}] {pos:>7} {msg}")
+        .expect("valid progress template");
+
+    bar.set_style(style);
+    bar.enable_steady_tick(Duration::from_millis(50));
+    bar.set_message(message);
+    bar
+}
+
+pub fn run(params: &Params) -> Result<DedupReport> {
+    let seed = HASH_SEED;
+
+    let cache_path = match params.no_cache {
+        true => None,
+        false => params.cache_file.clone().or_else(Cache::default_path),
+    };
+
+    let mut cache = match (params.no_cache, &cache_path) {
+        (false, Some(path)) => Cache::load(path),
+        _ => Cache::disabled(),
+    };
+
+    let files = Scanner::new(params)?.scan()?;
+    let size_groups = processor::group_by_size(files, params.progress);
+
+    let candidates: Vec<FileInfo> = size_groups
+        .into_iter()
+        .filter(|group| group.len() > 1)
+        .flatten()
+        .collect();
+
+    let max_path_len = candidates
+        .iter()
+        .map(|file| file.path.to_string_lossy().graphemes(true).count())
+        .max()
+        .unwrap_or(0);
+
+    let hashed = processor::hash_candidates(candidates, params.strict, seed, params.progress, &cache);
+
+    let now = now_secs();
+    for (hash, file) in &hashed {
+        let mtime = mtime_nanos(file.modified);
+        cache.record(&file.path, file.size, mtime, params.strict, *hash, now);
+    }
+
+    let groups = processor::group_hashed(hashed);
+
+    if let Some(path) = &cache_path {
+        cache.save(path, CACHE_TTL_DAYS * 86_400, now);
+    }
+
+    Ok(DedupReport {
+        groups,
+        max_path_len,
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::run;
+    use crate::params::Params;
+    use anyhow::Result;
+    use std::fs::File;
+    use std::io::Write;
+    use tempfile::TempDir;
+
+    #[test]
+    fn run_finds_a_single_group_of_identical_files() -> Result<()> {
+        let root = TempDir::new()?;
+
+        let duplicate = vec![7u8; 200_000];
+        for name in ["a.bin", "b.bin"] {
+            let mut file = File::create_new(root.path().join(name))?;
+            file.write_all(&duplicate)?;
+        }
+
+        let mut unique = File::create_new(root.path().join("c.bin"))?;
+        unique.write_all(&vec![9u8; 100_000])?;
+
+        let params = Params {
+            dir: Some(root.path().into()),
+            ..Default::default()
+        };
+
+        let report = run(&params)?;
+
+        assert_eq!(report.groups.len(), 1);
+        assert_eq!(report.groups[0].files.len(), 2);
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod cache_tests {
+    use super::run;
+    use crate::params::Params;
+    use std::fs::File;
+    use std::io::Write;
+    use tempfile::TempDir;
+
+    fn make_tree(root: &TempDir) {
+        for name in ["a.bin", "b.bin"] {
+            let mut f = File::create_new(root.path().join(name)).unwrap();
+            f.write_all(&vec![7u8; 200_000]).unwrap();
+        }
+        let mut u = File::create_new(root.path().join("c.bin")).unwrap();
+        u.write_all(&vec![9u8; 100_000]).unwrap();
+    }
+
+    #[test]
+    fn run_twice_with_cache_is_identical_and_writes_the_file() {
+        let root = TempDir::new().unwrap();
+        make_tree(&root);
+        let cache_file = root.path().join("dd.cache");
+        let params = Params {
+            dir: Some(root.path().into()),
+            cache_file: Some(cache_file.clone()),
+            ..Default::default()
+        };
+
+        let first = run(&params).unwrap();
+        assert!(cache_file.exists());
+
+        let second = run(&params).unwrap();
+        assert_eq!(first.groups.len(), second.groups.len());
+        assert_eq!(first.groups.len(), 1);
+        assert_eq!(second.groups[0].files.len(), 2);
+    }
+
+    #[test]
+    fn no_cache_does_not_write_a_cache_file() {
+        let root = TempDir::new().unwrap();
+        make_tree(&root);
+        let cache_file = root.path().join("dd.cache");
+        let params = Params {
+            dir: Some(root.path().into()),
+            no_cache: true,
+            cache_file: Some(cache_file.clone()),
+            ..Default::default()
+        };
+
+        run(&params).unwrap();
+        assert!(!cache_file.exists());
+    }
+}

src/processor.rs

@@ -1,107 +1,214 @@
-use anyhow::Result;
+use std::collections::HashMap;
-use dashmap::DashMap;
+
-use indicatif::{ParallelProgressIterator, ProgressBar, ProgressStyle, ProgressFinish};
 use rayon::prelude::{IntoParallelIterator, ParallelIterator};
-use std::{time::Duration, borrow::Cow};
 
+use crate::cache::{mtime_nanos, Cache};
 use crate::fileinfo::FileInfo;
+use crate::pipeline::{spinner, DuplicateGroup};
 
-#[derive(Debug, Clone)]
+pub fn group_by_size(files: Vec<FileInfo>, progress: bool) -> Vec<Vec<FileInfo>> {
-pub enum State {
+    let bar = spinner(progress, "files grouped by size");
-    Initial,
-    SizeWise,
-    HashWise,
-}
 
-#[derive(Debug, Clone)]
+    let mut buckets: HashMap<u64, Vec<FileInfo>> = HashMap::new();
-pub struct Processor {
+    for file in files {
-    pub files: Vec<FileInfo>,
+        bar.inc(1);
-    pub state: State,
+        buckets.entry(file.size).or_default().push(file);
-}
-
-impl Processor {
-    pub fn new(files: Vec<FileInfo>) -> Self {
-        Self {
-            files,
-            state: State::Initial,
-        }
     }
 
-    pub fn hashwise(&self) -> Result<Self> {
+    bar.finish_with_message("files grouped by size");
-        if self.files.is_empty() {
+    buckets.into_values().collect()
-            return Ok(self.clone());
+}
-        }
 
-        let progress_style = ProgressStyle::with_template("[{elapsed_precise}] {bar:40.cyan/blue} {pos:>7}/{len:7} {msg}")?;
+pub fn hash_candidates(
-        let progress_bar = ProgressBar::new(self.files.len() as u64);
+    candidates: Vec<FileInfo>,
-        progress_bar.set_style(progress_style);
+    strict: bool,
-        progress_bar.enable_steady_tick(Duration::from_millis(50));
+    seed: i64,
-        progress_bar.set_message("indexing file hashes");
+    progress: bool,
+    cache: &Cache,
+) -> Vec<(u128, FileInfo)> {
+    let bar = spinner(progress, "files grouped by hash");
 
-        let duplicates_table: DashMap<String, Vec<FileInfo>> = DashMap::new();
+    let hashed: Vec<(u128, FileInfo)> = candidates
-        self.files
+        .into_par_iter()
-            .clone()
+        .map(|file| {
-            .into_par_iter()
+            bar.inc(1);
-            .progress_with(progress_bar)
+            let mtime = mtime_nanos(file.modified);
-            .with_finish(ProgressFinish::WithMessage(Cow::from("indexed files hashes")))
+            let hash = match cache.lookup(&file.path, file.size, mtime, strict) {
-            .map(|file| file.hash())
+                Some(cached) => cached,
-            .filter_map(Result::ok)
+                None => match strict {
-            .for_each(|file| {
+                    true => file.hash(seed).expect("hashing file failed."),
-                duplicates_table
+                    false => file.initpages_hash(seed).expect("hashing file failed."),
-                    .entry(file.hash.clone().unwrap_or_default())
+                },
-                    .and_modify(|fileset| fileset.push(file.clone()))
+            };
-                    .or_insert_with(|| vec![file]);
+            (hash, file)
-            });
-
-        let files = duplicates_table
-            .into_read_only()
-            .values()
-            .cloned()
-            .filter(|subfiles| subfiles.len() > 1)
-            .flatten()
-            .collect::<Vec<FileInfo>>();
-
-        Ok(Self {
-            files,
-            state: State::HashWise,
         })
+        .collect();
+
+    bar.finish_with_message("files grouped by hash.");
+    hashed
+}
+
+pub fn group_hashed(hashed: Vec<(u128, FileInfo)>) -> Vec<DuplicateGroup> {
+    let mut buckets: HashMap<u128, Vec<FileInfo>> = HashMap::new();
+    for (hash, file) in hashed {
+        buckets.entry(hash).or_default().push(file);
     }
 
-    pub fn sizewise(&self) -> Result<Self> {
+    buckets
-        if self.files.is_empty() {
+        .into_iter()
-            return Ok(self.clone());
+        .filter(|(_, files)| files.len() > 1)
-        }
+        .map(|(hash, files)| DuplicateGroup { hash, files })
+        .collect()
+}
 
-        let progress_style = ProgressStyle::with_template("[{elapsed_precise}] {bar:40.cyan/blue} {pos:>7}/{len:7} {msg}")?;
+#[cfg(test)]
-        let progress_bar = ProgressBar::new(self.files.len() as u64);
+mod staged_tests {
-        progress_bar.set_style(progress_style);
+    use anyhow::Result;
-        progress_bar.enable_steady_tick(Duration::from_millis(50));
+    use rand::Rng;
-        progress_bar.set_message("indexing file sizes");
+    use std::fs::File;
+    use std::io::Write;
+    use tempfile::TempDir;
 
-        let duplicates_table: DashMap<u64, Vec<FileInfo>> = DashMap::new();
+    use crate::fileinfo::FileInfo;
-        self.files
-            .clone()
-            .into_par_iter()
-            .progress_with(progress_bar)
-            .with_finish(ProgressFinish::WithMessage(Cow::from("indexed files sizes")))
-            .for_each(|file| {
-                duplicates_table
-                    .entry(file.size)
-                    .and_modify(|fileset| fileset.push(file.clone()))
-                    .or_insert_with(|| vec![file]);
-            });
 
-        let files = duplicates_table
+    fn generate_bytes(size: usize) -> Vec<u8> {
-            .into_read_only()
+        let mut rng = rand::rng();
-            .values()
+        (0..size).map(|_| rng.random::<u8>()).collect::<Vec<u8>>()
-            .cloned()
+    }
-            .filter(|subfiles| subfiles.len() > 1)
-            .flatten()
-            .collect::<Vec<FileInfo>>();
 
-        Ok(Self {
+    fn write_files(root: &TempDir, specs: Vec<(&str, Vec<u8>)>) -> Result<Vec<FileInfo>> {
-            files,
+        specs
-            state: State::SizeWise,
+            .into_iter()
-        })
+            .map(|(name, content)| {
+                let path = root.path().join(name);
+                let mut file = File::create_new(&path)?;
+                file.write_all(&content)?;
+                FileInfo::new(path)
+            })
+            .collect()
+    }
+
+    #[test]
+    fn group_by_size_separates_files_of_different_sizes() -> Result<()> {
+        let root = TempDir::new()?;
+        let files = write_files(
+            &root,
+            vec![
+                ("fileone.bin", generate_bytes(282624)),
+                ("filetwo.bin", generate_bytes(1720320)),
+            ],
+        )?;
+
+        let groups = super::group_by_size(files, false);
+        assert_eq!(groups.len(), 2);
+        Ok(())
+    }
+
+    #[test]
+    fn group_by_size_buckets_same_size_files_together() -> Result<()> {
+        let root = TempDir::new()?;
+        let files = write_files(
+            &root,
+            vec![
+                ("fileone.bin", generate_bytes(282624)),
+                ("filetwo.bin", generate_bytes(282624)),
+            ],
+        )?;
+
+        let groups = super::group_by_size(files, false);
+        assert_eq!(groups.len(), 1);
+        Ok(())
+    }
+
+    #[test]
+    fn group_by_hash_fast_mode_matches_identical_init_pages() -> Result<()> {
+        let root = TempDir::new()?;
+        let shared = generate_bytes(16384);
+
+        let mut content_x = shared.clone();
+        let mut content_y = shared.clone();
+        content_x.extend(generate_bytes(1720320));
+        content_y.extend(generate_bytes(1720320));
+
+        let files = write_files(
+            &root,
+            vec![("fileone.bin", content_x), ("filetwo.bin", content_y)],
+        )?;
+
+        let groups = super::group_hashed(super::hash_candidates(files, false, 300, false, &crate::cache::Cache::disabled()));
+        assert_eq!(groups.len(), 1);
+        Ok(())
+    }
+
+    #[test]
+    fn group_by_hash_strict_mode_rejects_different_tails() -> Result<()> {
+        let root = TempDir::new()?;
+        let shared = generate_bytes(16384);
+
+        let mut content_x = shared.clone();
+        let mut content_y = shared.clone();
+        content_x.extend(generate_bytes(1720320));
+        content_y.extend(generate_bytes(1720320));
+
+        let files = write_files(
+            &root,
+            vec![("fileone.bin", content_x), ("filetwo.bin", content_y)],
+        )?;
+
+        let groups = super::group_hashed(super::hash_candidates(files, true, 300, false, &crate::cache::Cache::disabled()));
+        assert_eq!(groups.len(), 0);
+        Ok(())
+    }
+
+    #[test]
+    fn group_by_hash_matches_identical_files() -> Result<()> {
+        let root = TempDir::new()?;
+        let content = generate_bytes(282624);
+
+        let files = write_files(
+            &root,
+            vec![
+                ("fileone.bin", content.clone()),
+                ("filetwo.bin", content.clone()),
+            ],
+        )?;
+
+        let groups = super::group_hashed(super::hash_candidates(files, false, 300, false, &crate::cache::Cache::disabled()));
+        assert_eq!(groups.len(), 1);
+        Ok(())
+    }
+
+    #[test]
+    fn hash_candidates_uses_cached_hash_when_valid() {
+        let root = TempDir::new().unwrap();
+        let path = root.path().join("f.bin");
+        let mut f = File::create_new(&path).unwrap();
+        f.write_all(b"real content for cache hit test").unwrap();
+        let info = FileInfo::new(path.clone()).unwrap();
+        let mtime = crate::cache::mtime_nanos(info.modified);
+
+        let mut cache = crate::cache::Cache::disabled();
+        cache.record(&path, info.size, mtime, false, 0xDEAD_BEEF, 0);
+
+        let hashed = super::hash_candidates(vec![info], false, 300, false, &cache);
+        assert_eq!(hashed[0].0, 0xDEAD_BEEF);
+    }
+
+    #[test]
+    fn hash_candidates_recomputes_when_mtime_differs() {
+        let root = TempDir::new().unwrap();
+        let path = root.path().join("f.bin");
+        let mut f = File::create_new(&path).unwrap();
+        f.write_all(b"real content for cache miss test").unwrap();
+        let info = FileInfo::new(path.clone()).unwrap();
+        let mtime = crate::cache::mtime_nanos(info.modified);
+        let real = info.initpages_hash(300).unwrap();
+
+        let mut cache = crate::cache::Cache::disabled();
+        cache.record(&path, info.size, mtime + 1, false, 0xDEAD_BEEF, 0);
+
+        let hashed = super::hash_candidates(vec![info], false, 300, false, &cache);
+        assert_eq!(hashed[0].0, real);
+        assert_ne!(hashed[0].0, 0xDEAD_BEEF);
     }
 }

src/resolver.rs

@@ -0,0 +1,283 @@
+use std::cmp::Ordering;
+
+use unicode_segmentation::UnicodeSegmentation;
+use anyhow::{bail, Result};
+use bytesize::ByteSize;
+
+use crate::fileinfo::FileInfo;
+use crate::formatter::Formatter;
+use crate::params::Params;
+use crate::pipeline::DedupReport;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, clap::ValueEnum)]
+pub enum KeepStrategy {
+    Newest,
+    Oldest,
+    First,
+    Last,
+    Shortest,
+    Shallowest,
+}
+
+fn path_string(file: &FileInfo) -> String {
+    file.path.to_string_lossy().into_owned()
+}
+
+fn path_len(file: &FileInfo) -> usize {
+    file.path.to_string_lossy().graphemes(true).count()
+}
+
+fn depth(file: &FileInfo) -> usize {
+    file.path.iter().count()
+}
+
+fn compare_keep(a: &FileInfo, b: &FileInfo, strategy: KeepStrategy) -> Ordering {
+    match strategy {
+        KeepStrategy::Newest => b
+            .modified
+            .cmp(&a.modified)
+            .then_with(|| path_string(a).cmp(&path_string(b))),
+        KeepStrategy::Oldest => a
+            .modified
+            .cmp(&b.modified)
+            .then_with(|| path_string(a).cmp(&path_string(b))),
+        KeepStrategy::First => path_string(a).cmp(&path_string(b)),
+        KeepStrategy::Last => path_string(b).cmp(&path_string(a)),
+        KeepStrategy::Shortest => path_len(a)
+            .cmp(&path_len(b))
+            .then_with(|| path_string(a).cmp(&path_string(b))),
+        KeepStrategy::Shallowest => depth(a)
+            .cmp(&depth(b))
+            .then_with(|| path_len(a).cmp(&path_len(b)))
+            .then_with(|| path_string(a).cmp(&path_string(b))),
+    }
+}
+
+pub fn select_keeper(files: &[FileInfo], strategy: KeepStrategy) -> usize {
+    files
+        .iter()
+        .enumerate()
+        .min_by(|(_, a), (_, b)| compare_keep(a, b, strategy))
+        .map(|(index, _)| index)
+        .unwrap_or(0)
+}
+
+pub fn run(
+    report: &DedupReport,
+    strategy: KeepStrategy,
+    force: bool,
+    params: &Params,
+) -> Result<()> {
+    if report.groups.is_empty() {
+        println!("No duplicates found matching your search criteria.");
+        return Ok(());
+    }
+
+    let group_count = report.groups.len();
+    let mut victim_count: u64 = 0;
+    let mut victim_bytes: u64 = 0;
+    let mut freed_bytes: u64 = 0;
+    let mut failures: u64 = 0;
+
+    for group in &report.groups {
+        let keeper = select_keeper(&group.files, strategy);
+
+        if !force {
+            println!(
+                "KEEP    {}",
+                Formatter::human_path(&group.files[keeper], params, report.max_path_len)
+                    .unwrap_or_default()
+            );
+        }
+
+        for (index, file) in group.files.iter().enumerate() {
+            if index == keeper {
+                continue;
+            }
+
+            victim_count += 1;
+            victim_bytes += file.size;
+
+            match force {
+                false => println!(
+                    "DELETE  {}  {}",
+                    Formatter::human_path(file, params, report.max_path_len).unwrap_or_default(),
+                    Formatter::human_filesize(file).unwrap_or_default()
+                ),
+                true => match std::fs::remove_file(&file.path) {
+                    Ok(_) => {
+                        freed_bytes += file.size;
+                        println!("deleted {}", file.path.display());
+                    }
+                    Err(_) => {
+                        failures += 1;
+                        println!("FAILED  {}", file.path.display());
+                    }
+                },
+            }
+        }
+    }
+
+    match force {
+        false => println!(
+            "\n{group_count} groups, would free {}. Re-run with --force to delete.",
+            ByteSize::b(victim_bytes)
+        ),
+        true => println!(
+            "\ndeleted {} files, freed {} across {group_count} groups.",
+            victim_count - failures,
+            ByteSize::b(freed_bytes)
+        ),
+    }
+
+    if failures > 0 {
+        bail!("{failures} deletion(s) failed");
+    }
+
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::fileinfo::FileInfo;
+    use std::path::PathBuf;
+    use std::time::{Duration, SystemTime};
+    use crate::params::Params;
+    use crate::pipeline::{DedupReport, DuplicateGroup};
+    use std::fs::File;
+    use std::io::Write;
+    use tempfile::TempDir;
+
+    fn file(path: &str, mtime_secs: u64) -> FileInfo {
+        FileInfo {
+            path: PathBuf::from(path).into_boxed_path(),
+            size: 0,
+            modified: SystemTime::UNIX_EPOCH + Duration::from_secs(mtime_secs),
+        }
+    }
+
+    #[test]
+    fn newest_keeps_greatest_mtime() {
+        let files = vec![file("/a/x", 10), file("/a/y", 30), file("/a/z", 20)];
+        assert_eq!(select_keeper(&files, KeepStrategy::Newest), 1);
+    }
+
+    #[test]
+    fn oldest_keeps_least_mtime() {
+        let files = vec![file("/a/x", 10), file("/a/y", 30), file("/a/z", 20)];
+        assert_eq!(select_keeper(&files, KeepStrategy::Oldest), 0);
+    }
+
+    #[test]
+    fn first_keeps_lexicographically_smallest_path() {
+        let files = vec![file("/a/y", 10), file("/a/x", 10), file("/a/z", 10)];
+        assert_eq!(select_keeper(&files, KeepStrategy::First), 1);
+    }
+
+    #[test]
+    fn last_keeps_lexicographically_greatest_path() {
+        let files = vec![file("/a/y", 10), file("/a/x", 10), file("/a/z", 10)];
+        assert_eq!(select_keeper(&files, KeepStrategy::Last), 2);
+    }
+
+    #[test]
+    fn shortest_keeps_fewest_chars() {
+        let files = vec![file("/aaa/bbb", 10), file("/a/b", 10), file("/aa/bb", 10)];
+        assert_eq!(select_keeper(&files, KeepStrategy::Shortest), 1);
+    }
+
+    #[test]
+    fn shallowest_keeps_fewest_components() {
+        let files = vec![file("/a/b/c/d", 10), file("/a/b", 10), file("/a/b/c", 10)];
+        assert_eq!(select_keeper(&files, KeepStrategy::Shallowest), 1);
+    }
+
+    #[test]
+    fn newest_tiebreak_is_smallest_path_regardless_of_order() {
+        let forward = vec![file("/a/y", 30), file("/a/x", 30)];
+        let reversed = vec![file("/a/x", 30), file("/a/y", 30)];
+        assert_eq!(
+            forward[select_keeper(&forward, KeepStrategy::Newest)].path,
+            reversed[select_keeper(&reversed, KeepStrategy::Newest)].path
+        );
+        assert_eq!(
+            forward[select_keeper(&forward, KeepStrategy::Newest)]
+                .path
+                .to_string_lossy(),
+            "/a/x"
+        );
+    }
+
+    fn write_dup_report(root: &TempDir, names: &[&str]) -> DedupReport {
+        let files = names
+            .iter()
+            .map(|name| {
+                let path = root.path().join(name);
+                let mut f = File::create_new(&path).unwrap();
+                f.write_all(b"identical duplicate payload").unwrap();
+                FileInfo::new(path).unwrap()
+            })
+            .collect::<Vec<_>>();
+
+        DedupReport {
+            groups: vec![DuplicateGroup { hash: 0, files }],
+            max_path_len: 0,
+        }
+    }
+
+    #[test]
+    fn force_deletes_victims_and_keeps_the_keeper() {
+        let root = TempDir::new().unwrap();
+        let report = write_dup_report(&root, &["a.bin", "b.bin"]);
+        let params = Params {
+            dir: Some(root.path().into()),
+            ..Default::default()
+        };
+
+        super::run(&report, KeepStrategy::First, true, &params).unwrap();
+
+        assert!(root.path().join("a.bin").exists());
+        assert!(!root.path().join("b.bin").exists());
+    }
+
+    #[test]
+    fn dry_run_deletes_nothing() {
+        let root = TempDir::new().unwrap();
+        let report = write_dup_report(&root, &["a.bin", "b.bin"]);
+        let params = Params {
+            dir: Some(root.path().into()),
+            ..Default::default()
+        };
+
+        super::run(&report, KeepStrategy::First, false, &params).unwrap();
+
+        assert!(root.path().join("a.bin").exists());
+        assert!(root.path().join("b.bin").exists());
+    }
+
+    #[test]
+    fn force_reports_error_when_a_deletion_fails() {
+        let root = TempDir::new().unwrap();
+        let report = write_dup_report(&root, &["a.bin", "b.bin"]);
+        let params = Params {
+            dir: Some(root.path().into()),
+            ..Default::default()
+        };
+
+        std::fs::remove_file(root.path().join("b.bin")).unwrap();
+
+        let result = super::run(&report, KeepStrategy::First, true, &params);
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn empty_report_is_ok() {
+        let params = Params::default();
+        let report = DedupReport {
+            groups: vec![],
+            max_path_len: 0,
+        };
+        assert!(super::run(&report, KeepStrategy::First, false, &params).is_ok());
+    }
+}

src/scanner.rs

@@ -1,118 +1,48 @@
-#![allow(unused)]
+use crate::{fileinfo::FileInfo, params::Params, pipeline::spinner};
-use crate::{fileinfo::FileInfo, params::Params};
 use anyhow::Result;
-use indicatif::{ProgressBar, ProgressStyle};
+use std::path::Path;
-use std::{fs, path::PathBuf, time::Duration};
-
 use globwalk::{GlobWalker, GlobWalkerBuilder};
 
-#[derive(Debug, Clone)]
 pub struct Scanner {
-    pub directory: Option<PathBuf>,
+    pub directory: Box<Path>,
-    pub filetypes: Option<String>,
     pub min_depth: Option<usize>,
     pub max_depth: Option<usize>,
+    pub include_types: Option<String>,
+    pub exclude_types: Option<String>,
     pub min_size: Option<u64>,
     pub follow_links: bool,
+    pub progress: bool,
 }
 
 impl Scanner {
-    pub fn new() -> Self {
+    pub fn new(app_args: &Params) -> Result<Self> {
-        Self {
+        Ok(Self {
-            directory: None,
+            directory: app_args.get_directory()?.into_boxed_path(),
-            filetypes: None,
+            include_types: app_args.types.clone(),
-            min_depth: None,
+            exclude_types: app_args.exclude_types.clone(),
-            max_depth: None,
+            min_depth: app_args.min_depth,
-            min_size: None,
+            max_depth: app_args.max_depth,
-            follow_links: true,
+            min_size: app_args.get_min_size(),
-        }
+            follow_links: app_args.follow_links,
-    }
+            progress: app_args.progress,
-
-    pub fn build(app_args: &Params) -> Result<Self> {
-        let scan_directory = app_args.get_directory()?;
-        Ok(Scanner::new())
-            .map(|scanner| scanner.directory(scan_directory))
-            .map(|scanner| match app_args.get_min_size() {
-                Some(min_size) => scanner.min_size(min_size),
-                None => scanner,
-            })
-            .map(|scanner| match app_args.get_types() {
-                Some(ftypes) => scanner.filetypes(ftypes),
-                None => scanner,
-            })
-            .map(|scanner| match app_args.min_depth {
-                Some(min_depth) => scanner.min_depth(min_depth),
-                None => scanner,
-            })
-            .map(|scanner| match app_args.max_depth {
-                Some(max_depth) => scanner.max_depth(max_depth),
-                None => scanner,
-            })
-    }
-
-    pub fn min_size(&self, min_size: u64) -> Self {
-        Self {
-            min_size: Some(min_size),
-            ..self.clone()
-        }
-    }
-
-    pub fn min_depth(&self, min_depth: usize) -> Self {
-        Self {
-            min_depth: Some(min_depth),
-            ..self.clone()
-        }
-    }
-
-    pub fn max_depth(&self, max_depth: usize) -> Self {
-        Self {
-            max_depth: Some(max_depth),
-            ..self.clone()
-        }
-    }
-
-    pub fn directory(&self, dir: PathBuf) -> Self {
-        Self {
-            directory: Some(dir),
-            ..self.clone()
-        }
-    }
-
-    pub fn filetypes(&self, patterns: String) -> Self {
-        Self {
-            filetypes: Some(patterns),
-            ..self.clone()
-        }
-    }
-
-    pub fn ignore_links(&self) -> Self {
-        Self {
-            follow_links: false,
-            ..self.clone()
-        }
-    }
-
-    pub fn follow_links(&self) -> Self {
-        Self {
-            follow_links: true,
-            ..self.clone()
-        }
-    }
-
-    fn scan_patterns(&self) -> Result<String> {
-        Ok(match self.filetypes.clone() {
-            Some(ftypes) => format!("**/*{{{ftypes}}}"),
-            None => "**/*".to_string(),
         })
     }
 
-    fn scan_dir(&self) -> Result<PathBuf> {
+    fn scan_patterns(&self) -> Result<Vec<String>> {
-        let scan_dir = match self.directory.clone() {
+        let include_types = match &self.include_types {
-            Some(path) => path,
+            Some(ftypes) => Some(format!("**/*.{{{ftypes}}}")),
-            None => std::env::current_dir()?,
+            None => Some("**/*".to_string()),
         };
 
-        Ok(fs::canonicalize(scan_dir)?)
+        let exclude_types = self
+            .exclude_types
+            .as_ref()
+            .map(|ftypes| format!("!**/*.{{{ftypes}}}"));
+
+        Ok(vec![include_types, exclude_types]
+            .into_iter()
+            .flatten()
+            .collect())
     }
 
     fn attach_link_opts(&self, walker: GlobWalkerBuilder) -> Result<GlobWalkerBuilder> {
@@ -132,10 +62,11 @@ impl Scanner {
             None => Ok(walker),
         }
     }
+
     fn build_walker(&self) -> Result<GlobWalker> {
         let walker = Ok(GlobWalkerBuilder::from_patterns(
-            self.scan_dir()?,
+            self.directory.clone(),
-            &[self.scan_patterns()?],
+            &self.scan_patterns()?,
         ))
         .and_then(|walker| self.attach_walker_min_depth(walker))
         .and_then(|walker| self.attach_walker_max_depth(walker))
@@ -145,29 +76,141 @@ impl Scanner {
     }
 
     pub fn scan(&self) -> Result<Vec<FileInfo>> {
-        let progress_style = ProgressStyle::with_template("[{elapsed_precise}] {pos:>7} {msg}")?;
+        let bar = spinner(self.progress, "paths mapped");
-        let progress_bar = ProgressBar::new_spinner();
+        let min_size = self.min_size.unwrap_or(0);
-        progress_bar.set_style(progress_style);
-        progress_bar.enable_steady_tick(Duration::from_millis(50));
-        progress_bar.set_message("paths mapped");
-        let min_size = self.min_size.unwrap_or_default();
 
-        let results = self
+        let files: Vec<FileInfo> = self
             .build_walker()?
             .filter_map(Result::ok)
             .map(|entity| entity.into_path())
-            .map(|path| {
+            .inspect(|_path| bar.inc(1))
-                progress_bar.inc(1);
-                path
-            })
             .filter(|path| path.is_file())
             .map(FileInfo::new)
             .filter_map(Result::ok)
-            .filter(|file| file.size > min_size)
+            .filter(|file| file.size >= min_size)
-            .collect::<Vec<FileInfo>>();
+            .collect();
 
-        progress_bar.finish_with_message("paths mapped");
+        bar.finish_with_message("paths mapped");
-
+        Ok(files)
-        Ok(results)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::params::Params;
+    use std::fs::File;
+    use tempfile::TempDir;
+    use super::Scanner;
+
+    #[test]
+    fn ensure_file_include_type_filter_includes_expected_file_types() {
+        let root =
+            TempDir::with_prefix("deduplicator_test_root").expect("unable to create tempdir");
+        [
+            "this-is-a-js-file.js",
+            "this-is-a-css-file.css",
+            "this-is-a-csv-file.csv",
+            "this-is-a-rust-file.rs",
+        ]
+        .iter()
+        .for_each(|path| {
+            File::create_new(root.path().join(path)).unwrap_or_else(|_| {
+                panic!("unable to create file {path}");
+            });
+        });
+
+        let params = Params {
+            types: Some(String::from("js,csv")),
+            dir: Some(root.path().into()),
+            ..Default::default()
+        };
+
+        let scanner = Scanner::new(&params).expect("scanner initialization failed");
+        let files = scanner.scan().expect("scanning failed.");
+
+        assert!(files.iter().any(|f| f.path.to_str().unwrap()
+            == root.path().join("this-is-a-js-file.js").to_str().unwrap()));
+        assert!(files.iter().any(|f| f.path.to_str().unwrap()
+            == root.path().join("this-is-a-csv-file.csv").to_str().unwrap()));
+        assert!(files.iter().all(|f| f.path.to_str().unwrap()
+            != root.path().join("this-is-a-css-file.css").to_str().unwrap()));
+        assert!(files.iter().all(|f| f.path.to_str().unwrap()
+            != root.path().join("this-is-a-rust-file.rs").to_str().unwrap()));
+    }
+
+    #[test]
+    fn ensure_file_exclude_type_filter_excludes_expected_file_types() {
+        let root =
+            TempDir::with_prefix("deduplicator_test_root").expect("unable to create tempdir");
+        [
+            "this-is-a-js-file.js",
+            "this-is-a-css-file.css",
+            "this-is-a-csv-file.csv",
+            "this-is-a-rust-file.rs",
+        ]
+        .iter()
+        .for_each(|path| {
+            File::create_new(root.path().join(path)).unwrap_or_else(|_| {
+                panic!("unable to create file {path}");
+            });
+        });
+
+        let params = Params {
+            exclude_types: Some(String::from("js,csv")),
+            dir: Some(root.path().into()),
+            ..Default::default()
+        };
+
+        let scanner = Scanner::new(&params).expect("scanner initialization failed");
+        let files = scanner.scan().expect("scanning failed.");
+
+        assert!(files.iter().all(|f| f.path.to_str().unwrap()
+            != root.path().join("this-is-a-js-file.js").to_str().unwrap()));
+
+        assert!(files.iter().all(|f| f.path.to_str().unwrap()
+            != root.path().join("this-is-a-csv-file.csv").to_str().unwrap()));
+
+        assert!(files.iter().any(|f| f.path.to_str().unwrap()
+            == root.path().join("this-is-a-css-file.css").to_str().unwrap()));
+
+        assert!(files.iter().any(|f| f.path.to_str().unwrap()
+            == root.path().join("this-is-a-rust-file.rs").to_str().unwrap()));
+    }
+
+    #[test]
+    fn complex_file_type_params() {
+        let root =
+            TempDir::with_prefix("deduplicator_test_root").expect("unable to create tempdir");
+        [
+            "this-is-a-js-file.js",
+            "this-is-a-css-file.css",
+            "this-is-a-csv-file.csv",
+            "this-is-a-rust-file.rs",
+        ]
+        .iter()
+        .for_each(|path| {
+            File::create_new(root.path().join(path)).unwrap_or_else(|_| {
+                panic!("unable to create file {path}");
+            });
+        });
+
+        let params = Params {
+            types: Some(String::from("js,csv,rs")),
+            exclude_types: Some(String::from("csv")),
+            dir: Some(root.path().into()),
+            ..Default::default()
+        };
+
+        let scanner = Scanner::new(&params).expect("scanner initialization failed");
+        let files = scanner.scan().expect("scanning failed.");
+
+        assert!(files.iter().any(|f| f.path.to_str().unwrap()
+            == root.path().join("this-is-a-js-file.js").to_str().unwrap()));
+
+        assert!(files.iter().all(|f| f.path.to_str().unwrap()
+            != root.path().join("this-is-a-csv-file.csv").to_str().unwrap()));
+
+        assert!(files.iter().any(|f| f.path.to_str().unwrap()
+            == root.path().join("this-is-a-rust-file.rs").to_str().unwrap()));
     }
 }

src/tui/app.rs

@@ -0,0 +1,499 @@
+use std::path::PathBuf;
+
+use crate::fileinfo::FileInfo;
+use crate::pipeline::DuplicateGroup;
+use crate::resolver::{select_keeper, KeepStrategy};
+
+pub const STRATEGIES: [KeepStrategy; 6] = [
+    KeepStrategy::Newest,
+    KeepStrategy::Oldest,
+    KeepStrategy::First,
+    KeepStrategy::Last,
+    KeepStrategy::Shortest,
+    KeepStrategy::Shallowest,
+];
+
+pub fn strategy_label(strategy: KeepStrategy) -> &'static str {
+    match strategy {
+        KeepStrategy::Newest => "newest",
+        KeepStrategy::Oldest => "oldest",
+        KeepStrategy::First => "first",
+        KeepStrategy::Last => "last",
+        KeepStrategy::Shortest => "shortest",
+        KeepStrategy::Shallowest => "shallowest",
+    }
+}
+
+#[derive(Clone, Copy, PartialEq)]
+pub enum Focus {
+    Groups,
+    Files,
+}
+
+#[derive(Clone, Copy, PartialEq)]
+pub enum StrategyScope {
+    CurrentGroup,
+    AllGroups,
+}
+
+#[derive(Clone, Copy, PartialEq)]
+pub enum Popup {
+    None,
+    Strategy { scope: StrategyScope },
+    ConfirmDelete,
+}
+
+pub enum Key {
+    Up,
+    Down,
+    Tab,
+    Space,
+    Enter,
+    Esc,
+    Char(char),
+}
+
+pub enum Outcome {
+    Continue,
+    Quit,
+    Delete,
+    Open(PathBuf),
+}
+
+pub struct Group {
+    pub files: Vec<FileInfo>,
+    pub marked: Vec<bool>,
+}
+
+impl Group {
+    pub fn size(&self) -> u64 {
+        self.files.first().map(|f| f.size).unwrap_or(0)
+    }
+}
+
+pub struct App {
+    pub groups: Vec<Group>,
+    pub group_cursor: usize,
+    pub file_cursor: usize,
+    pub focus: Focus,
+    pub popup: Popup,
+    pub strategy_cursor: usize,
+    pub status: Option<String>,
+    pub should_quit: bool,
+}
+
+fn clamp_add(cur: usize, delta: isize, max: usize) -> usize {
+    (cur as isize + delta).clamp(0, max as isize) as usize
+}
+
+impl App {
+    pub fn from_groups(groups: Vec<DuplicateGroup>) -> Self {
+        let groups = groups
+            .into_iter()
+            .map(|g| Group {
+                marked: vec![false; g.files.len()],
+                files: g.files,
+            })
+            .collect();
+
+        Self {
+            groups,
+            group_cursor: 0,
+            file_cursor: 0,
+            focus: Focus::Files,
+            popup: Popup::None,
+            strategy_cursor: 0,
+            status: None,
+            should_quit: false,
+        }
+    }
+
+    pub fn move_group(&mut self, delta: isize) {
+        if self.groups.is_empty() {
+            return;
+        }
+        self.group_cursor = clamp_add(self.group_cursor, delta, self.groups.len() - 1);
+        let len = self.groups[self.group_cursor].files.len();
+        self.file_cursor = self.file_cursor.min(len.saturating_sub(1));
+    }
+
+    pub fn move_file(&mut self, delta: isize) {
+        if let Some(g) = self.groups.get(self.group_cursor) {
+            self.file_cursor = clamp_add(self.file_cursor, delta, g.files.len().saturating_sub(1));
+        }
+    }
+
+    pub fn toggle_mark(&mut self) {
+        let fc = self.file_cursor;
+        if let Some(g) = self.groups.get_mut(self.group_cursor) {
+            if fc >= g.marked.len() {
+                return;
+            }
+            if !g.marked[fc] && g.marked.iter().filter(|m| !**m).count() <= 1 {
+                return;
+            }
+            g.marked[fc] = !g.marked[fc];
+        }
+    }
+
+    pub fn apply_strategy(&mut self, strategy: KeepStrategy, scope: StrategyScope) {
+        let indices: Vec<usize> = match scope {
+            StrategyScope::CurrentGroup => vec![self.group_cursor],
+            StrategyScope::AllGroups => (0..self.groups.len()).collect(),
+        };
+        for gi in indices {
+            if let Some(g) = self.groups.get_mut(gi) {
+                if g.files.len() < 2 {
+                    continue;
+                }
+                let keeper = select_keeper(&g.files, strategy);
+                for i in 0..g.marked.len() {
+                    g.marked[i] = i != keeper;
+                }
+            }
+        }
+    }
+
+    pub fn marked_count(&self) -> usize {
+        self.groups
+            .iter()
+            .flat_map(|g| g.marked.iter())
+            .filter(|m| **m)
+            .count()
+    }
+
+    pub fn reclaimable_bytes(&self) -> u64 {
+        self.groups
+            .iter()
+            .flat_map(|g| g.files.iter().zip(&g.marked))
+            .filter(|(_, m)| **m)
+            .map(|(f, _)| f.size)
+            .sum()
+    }
+
+    pub fn marked_paths(&self) -> Vec<PathBuf> {
+        self.groups
+            .iter()
+            .flat_map(|g| g.files.iter().zip(&g.marked))
+            .filter(|(_, m)| **m)
+            .map(|(f, _)| f.path.to_path_buf())
+            .collect()
+    }
+
+    pub fn apply_deletion(&mut self, deleted: &[PathBuf]) {
+        use std::collections::HashSet;
+        let removed: HashSet<&std::path::Path> = deleted.iter().map(|p| p.as_path()).collect();
+
+        for g in &mut self.groups {
+            let mut files = Vec::new();
+            let mut marked = Vec::new();
+            for (i, f) in g.files.iter().enumerate() {
+                if !removed.contains(&*f.path) {
+                    files.push(f.clone());
+                    marked.push(g.marked[i]);
+                }
+            }
+            g.files = files;
+            g.marked = marked;
+        }
+
+        self.groups.retain(|g| g.files.len() >= 2);
+
+        if self.groups.is_empty() {
+            self.should_quit = true;
+            self.group_cursor = 0;
+            self.file_cursor = 0;
+            return;
+        }
+
+        self.group_cursor = self.group_cursor.min(self.groups.len() - 1);
+        let len = self.groups[self.group_cursor].files.len();
+        self.file_cursor = self.file_cursor.min(len.saturating_sub(1));
+    }
+
+    pub fn handle_key(&mut self, key: Key) -> Outcome {
+        match self.popup {
+            Popup::Strategy { scope } => self.handle_strategy_key(key, scope),
+            Popup::ConfirmDelete => self.handle_confirm_key(key),
+            Popup::None => self.handle_main_key(key),
+        }
+    }
+
+    fn handle_main_key(&mut self, key: Key) -> Outcome {
+        self.status = None;
+        match key {
+            Key::Char('q') | Key::Esc => {
+                self.should_quit = true;
+                Outcome::Quit
+            }
+            Key::Tab => {
+                self.focus = match self.focus {
+                    Focus::Groups => Focus::Files,
+                    Focus::Files => Focus::Groups,
+                };
+                Outcome::Continue
+            }
+            Key::Up | Key::Char('k') => {
+                self.move_in_focus(-1);
+                Outcome::Continue
+            }
+            Key::Down | Key::Char('j') => {
+                self.move_in_focus(1);
+                Outcome::Continue
+            }
+            Key::Space => {
+                if self.focus == Focus::Files {
+                    self.toggle_mark();
+                }
+                Outcome::Continue
+            }
+            Key::Char('s') => {
+                self.open_strategy(StrategyScope::CurrentGroup);
+                Outcome::Continue
+            }
+            Key::Char('S') => {
+                self.open_strategy(StrategyScope::AllGroups);
+                Outcome::Continue
+            }
+            Key::Char('o') => self.open_current(),
+            Key::Char('d') => {
+                if self.marked_count() > 0 {
+                    self.popup = Popup::ConfirmDelete;
+                } else {
+                    self.status = Some("nothing marked".to_string());
+                }
+                Outcome::Continue
+            }
+            _ => Outcome::Continue,
+        }
+    }
+
+    fn handle_strategy_key(&mut self, key: Key, scope: StrategyScope) -> Outcome {
+        match key {
+            Key::Up | Key::Char('k') => {
+                self.strategy_cursor = self.strategy_cursor.saturating_sub(1);
+            }
+            Key::Down | Key::Char('j') => {
+                self.strategy_cursor = (self.strategy_cursor + 1).min(STRATEGIES.len() - 1);
+            }
+            Key::Enter => {
+                let strategy = STRATEGIES[self.strategy_cursor];
+                self.apply_strategy(strategy, scope);
+                self.popup = Popup::None;
+            }
+            Key::Esc => self.popup = Popup::None,
+            _ => {}
+        }
+        Outcome::Continue
+    }
+
+    fn handle_confirm_key(&mut self, key: Key) -> Outcome {
+        match key {
+            Key::Char('y') => {
+                self.popup = Popup::None;
+                Outcome::Delete
+            }
+            Key::Char('n') | Key::Esc => {
+                self.popup = Popup::None;
+                Outcome::Continue
+            }
+            _ => Outcome::Continue,
+        }
+    }
+
+    fn move_in_focus(&mut self, delta: isize) {
+        match self.focus {
+            Focus::Groups => self.move_group(delta),
+            Focus::Files => self.move_file(delta),
+        }
+    }
+
+    fn open_strategy(&mut self, scope: StrategyScope) {
+        self.strategy_cursor = 0;
+        self.popup = Popup::Strategy { scope };
+    }
+
+    fn open_current(&self) -> Outcome {
+        match self.groups.get(self.group_cursor).and_then(|g| g.files.get(self.file_cursor)) {
+            Some(f) => Outcome::Open(f.path.to_path_buf()),
+            None => Outcome::Continue,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::fileinfo::FileInfo;
+    use crate::pipeline::DuplicateGroup;
+    use std::path::PathBuf;
+    use std::time::{Duration, UNIX_EPOCH};
+
+    fn file(path: &str, size: u64, mtime_secs: u64) -> FileInfo {
+        FileInfo {
+            path: PathBuf::from(path).into_boxed_path(),
+            size,
+            modified: UNIX_EPOCH + Duration::from_secs(mtime_secs),
+        }
+    }
+
+    fn group(files: Vec<FileInfo>) -> DuplicateGroup {
+        DuplicateGroup { hash: 0, files }
+    }
+
+    fn sample() -> App {
+        App::from_groups(vec![
+            group(vec![file("/a/x", 10, 100), file("/a/y", 10, 200)]),
+            group(vec![file("/b/p", 5, 50), file("/b/q", 5, 60), file("/b/r", 5, 70)]),
+        ])
+    }
+
+    #[test]
+    fn move_group_clamps_at_bounds() {
+        let mut app = sample();
+        app.move_group(-1);
+        assert_eq!(app.group_cursor, 0);
+        app.move_group(1);
+        assert_eq!(app.group_cursor, 1);
+        app.move_group(5);
+        assert_eq!(app.group_cursor, 1);
+    }
+
+    #[test]
+    fn move_group_reclamps_file_cursor() {
+        let mut app = sample();
+        app.group_cursor = 1;
+        app.file_cursor = 2;
+        app.move_group(-1);
+        assert_eq!(app.group_cursor, 0);
+        assert_eq!(app.file_cursor, 1);
+    }
+
+    #[test]
+    fn move_file_clamps() {
+        let mut app = sample();
+        app.move_file(-1);
+        assert_eq!(app.file_cursor, 0);
+        app.move_file(10);
+        assert_eq!(app.file_cursor, 1);
+    }
+
+    #[test]
+    fn toggle_mark_blocks_marking_the_last_survivor() {
+        let mut app = sample();
+        app.group_cursor = 0;
+        app.file_cursor = 0;
+        app.toggle_mark();
+        assert!(app.groups[0].marked[0]);
+        app.file_cursor = 1;
+        app.toggle_mark();
+        assert!(!app.groups[0].marked[1]);
+    }
+
+    #[test]
+    fn toggle_mark_allows_unmark() {
+        let mut app = sample();
+        app.file_cursor = 0;
+        app.toggle_mark();
+        app.toggle_mark();
+        assert!(!app.groups[0].marked[0]);
+    }
+
+    #[test]
+    fn apply_strategy_current_group_marks_all_but_keeper() {
+        let mut app = sample();
+        app.group_cursor = 0;
+        app.apply_strategy(KeepStrategy::Newest, StrategyScope::CurrentGroup);
+        assert_eq!(app.groups[0].marked, vec![true, false]);
+        assert_eq!(app.groups[1].marked, vec![false, false, false]);
+    }
+
+    #[test]
+    fn apply_strategy_all_groups() {
+        let mut app = sample();
+        app.apply_strategy(KeepStrategy::Oldest, StrategyScope::AllGroups);
+        assert_eq!(app.groups[0].marked, vec![false, true]);
+        assert_eq!(app.groups[1].marked, vec![false, true, true]);
+    }
+
+    #[test]
+    fn totals_sum_marked_only() {
+        let mut app = sample();
+        app.apply_strategy(KeepStrategy::Newest, StrategyScope::AllGroups);
+        assert_eq!(app.marked_count(), 3);
+        assert_eq!(app.reclaimable_bytes(), 20);
+    }
+
+    #[test]
+    fn marked_paths_lists_marked_files() {
+        let mut app = sample();
+        app.group_cursor = 0;
+        app.file_cursor = 0;
+        app.toggle_mark();
+        assert_eq!(app.marked_paths(), vec![PathBuf::from("/a/x")]);
+    }
+
+    #[test]
+    fn apply_deletion_removes_files_and_drops_small_groups() {
+        let mut app = sample();
+        app.apply_deletion(&[PathBuf::from("/a/x")]);
+        assert_eq!(app.groups.len(), 1);
+        assert_eq!(app.groups[0].files.len(), 3);
+    }
+
+    #[test]
+    fn apply_deletion_emptying_everything_sets_quit() {
+        let mut app = App::from_groups(vec![group(vec![file("/a/x", 1, 1), file("/a/y", 1, 2)])]);
+        app.apply_deletion(&[PathBuf::from("/a/x")]);
+        assert!(app.groups.is_empty());
+        assert!(app.should_quit);
+    }
+
+    #[test]
+    fn handle_key_quits_on_q() {
+        let mut app = sample();
+        assert!(matches!(app.handle_key(Key::Char('q')), Outcome::Quit));
+        assert!(app.should_quit);
+    }
+
+    #[test]
+    fn handle_key_space_marks_in_files_focus() {
+        let mut app = sample();
+        app.focus = Focus::Files;
+        app.handle_key(Key::Space);
+        assert!(app.groups[0].marked[0]);
+    }
+
+    #[test]
+    fn handle_key_strategy_popup_apply_flow() {
+        let mut app = sample();
+        app.handle_key(Key::Char('S'));
+        assert!(matches!(app.popup, Popup::Strategy { .. }));
+        app.handle_key(Key::Enter);
+        assert!(matches!(app.popup, Popup::None));
+        assert_eq!(app.groups[0].marked, vec![true, false]);
+    }
+
+    #[test]
+    fn handle_key_delete_requires_marks_then_confirms() {
+        let mut app = sample();
+        app.handle_key(Key::Char('d'));
+        assert!(matches!(app.popup, Popup::None));
+        app.focus = Focus::Files;
+        app.handle_key(Key::Space);
+        app.handle_key(Key::Char('d'));
+        assert!(matches!(app.popup, Popup::ConfirmDelete));
+        assert!(matches!(app.handle_key(Key::Char('y')), Outcome::Delete));
+        assert!(matches!(app.popup, Popup::None));
+    }
+
+    #[test]
+    fn handle_key_open_returns_path() {
+        let mut app = sample();
+        app.focus = Focus::Files;
+        match app.handle_key(Key::Char('o')) {
+            Outcome::Open(p) => assert_eq!(p, PathBuf::from("/a/x")),
+            _ => panic!("expected Open"),
+        }
+    }
+}

src/tui/mod.rs

@@ -0,0 +1,129 @@
+pub mod app;
+mod ui;
+
+use std::io::{self, Stdout};
+
+use anyhow::Result;
+use ratatui::backend::CrosstermBackend;
+use ratatui::crossterm::event::{self, Event, KeyCode, KeyEvent, KeyEventKind};
+use ratatui::crossterm::execute;
+use ratatui::crossterm::terminal::{
+    disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen,
+};
+use ratatui::Terminal;
+
+use crate::params::Params;
+use crate::pipeline::DedupReport;
+use app::{App, Key, Outcome};
+
+type Tui = Terminal<CrosstermBackend<Stdout>>;
+
+pub fn run(report: DedupReport, params: &Params) -> Result<()> {
+    if report.groups.is_empty() {
+        println!("No duplicates found matching your search criteria.");
+        return Ok(());
+    }
+
+    let mut app = App::from_groups(report.groups);
+    let mut terminal = setup_terminal()?;
+    let result = event_loop(&mut terminal, &mut app, params);
+    restore_terminal(&mut terminal)?;
+    result
+}
+
+fn setup_terminal() -> Result<Tui> {
+    install_panic_hook();
+    enable_raw_mode()?;
+    let mut stdout = io::stdout();
+    execute!(stdout, EnterAlternateScreen)?;
+    Ok(Terminal::new(CrosstermBackend::new(stdout))?)
+}
+
+fn restore_terminal(terminal: &mut Tui) -> Result<()> {
+    let _ = disable_raw_mode();
+    let _ = execute!(terminal.backend_mut(), LeaveAlternateScreen);
+    let _ = terminal.show_cursor();
+    Ok(())
+}
+
+fn install_panic_hook() {
+    let original = std::panic::take_hook();
+    std::panic::set_hook(Box::new(move |info| {
+        let _ = disable_raw_mode();
+        let _ = execute!(io::stdout(), LeaveAlternateScreen);
+        original(info);
+    }));
+}
+
+fn event_loop(terminal: &mut Tui, app: &mut App, params: &Params) -> Result<()> {
+    loop {
+        terminal.draw(|frame| ui::draw(frame, app, params))?;
+        if app.should_quit {
+            break;
+        }
+
+        if let Event::Key(key) = event::read()? {
+            if key.kind != KeyEventKind::Press {
+                continue;
+            }
+            if let Some(translated) = translate(key) {
+                match app.handle_key(translated) {
+                    Outcome::Quit => {}
+                    Outcome::Continue => {}
+                    Outcome::Delete => perform_deletion(app),
+                    Outcome::Open(path) => {
+                        if let Err(err) = open::that(&path) {
+                            app.status = Some(format!("open failed: {err}"));
+                        }
+                    }
+                }
+            }
+        }
+
+        if app.should_quit {
+            break;
+        }
+    }
+    Ok(())
+}
+
+fn translate(key: KeyEvent) -> Option<Key> {
+    Some(match key.code {
+        KeyCode::Up => Key::Up,
+        KeyCode::Down => Key::Down,
+        KeyCode::Tab => Key::Tab,
+        KeyCode::Enter => Key::Enter,
+        KeyCode::Esc => Key::Esc,
+        KeyCode::Char(' ') => Key::Space,
+        KeyCode::Char(c) => Key::Char(c),
+        _ => return None,
+    })
+}
+
+fn perform_deletion(app: &mut App) {
+    let paths = app.marked_paths();
+    let mut deleted = Vec::new();
+    let mut freed: u64 = 0;
+    let mut failures: u64 = 0;
+
+    for path in &paths {
+        let size = std::fs::metadata(path).map(|m| m.len()).unwrap_or(0);
+        match std::fs::remove_file(path) {
+            Ok(_) => {
+                deleted.push(path.clone());
+                freed += size;
+            }
+            Err(_) => failures += 1,
+        }
+    }
+
+    app.apply_deletion(&deleted);
+    app.status = Some(match failures {
+        0 => format!("deleted {}, freed {}", deleted.len(), bytesize::ByteSize::b(freed)),
+        _ => format!(
+            "deleted {}, {failures} failed, freed {}",
+            deleted.len(),
+            bytesize::ByteSize::b(freed)
+        ),
+    });
+}

src/tui/ui.rs

@@ -0,0 +1,211 @@
+use ratatui::layout::{Constraint, Direction, Layout, Rect};
+use ratatui::style::Style;
+use ratatui::text::Line;
+use ratatui::widgets::{Block, Borders, Clear, List, ListItem, ListState, Paragraph};
+use ratatui::Frame;
+
+use crate::params::Params;
+use crate::formatter::Formatter;
+
+use super::app::{strategy_label, App, Focus, Popup, StrategyScope, STRATEGIES};
+
+pub fn draw(frame: &mut Frame, app: &App, params: &Params) {
+    let rows = Layout::default()
+        .direction(Direction::Vertical)
+        .constraints([Constraint::Min(1), Constraint::Length(1)])
+        .split(frame.area());
+
+    let panes = Layout::default()
+        .direction(Direction::Horizontal)
+        .constraints([Constraint::Percentage(35), Constraint::Percentage(65)])
+        .split(rows[0]);
+
+    draw_groups(frame, app, panes[0]);
+    draw_files(frame, app, params, panes[1]);
+    draw_footer(frame, app, rows[1]);
+
+    match app.popup {
+        Popup::Strategy { scope } => draw_strategy_popup(frame, app, scope),
+        Popup::ConfirmDelete => draw_confirm_popup(frame, app),
+        Popup::None => {}
+    }
+}
+
+fn pane_block(title: &str, focused: bool) -> Block<'_> {
+    let block = Block::default().borders(Borders::ALL).title(title.to_string());
+    match focused {
+        true => block.border_style(Style::new().yellow()),
+        false => block,
+    }
+}
+
+fn draw_groups(frame: &mut Frame, app: &App, area: Rect) {
+    let items: Vec<ListItem> = app
+        .groups
+        .iter()
+        .enumerate()
+        .map(|(i, g)| {
+            ListItem::new(format!(
+                "{:>3}  {} files  {}",
+                i + 1,
+                g.files.len(),
+                bytesize::ByteSize::b(g.size())
+            ))
+        })
+        .collect();
+
+    let list = List::new(items)
+        .block(pane_block("Groups", app.focus == Focus::Groups))
+        .highlight_style(Style::new().reversed());
+
+    let mut state = ListState::default();
+    state.select(Some(app.group_cursor));
+    frame.render_stateful_widget(list, area, &mut state);
+}
+
+fn draw_files(frame: &mut Frame, app: &App, params: &Params, area: Rect) {
+    let title = format!(
+        "Group {}/{}",
+        (app.group_cursor + 1).min(app.groups.len().max(1)),
+        app.groups.len()
+    );
+
+    let items: Vec<ListItem> = match app.groups.get(app.group_cursor) {
+        Some(g) => g
+            .files
+            .iter()
+            .enumerate()
+            .map(|(i, f)| {
+                let box_char = if g.marked[i] { "[x]" } else { "[ ]" };
+                let path = Formatter::human_path(f, params, 0).unwrap_or_default();
+                let size = Formatter::human_filesize(f).unwrap_or_default();
+                let mtime = Formatter::human_mtime(f).unwrap_or_default();
+                let line = format!("{box_char} {}  {}  {}", path.trim_end(), size.trim_start(), mtime);
+                match g.marked[i] {
+                    true => ListItem::new(Line::from(line).style(Style::new().red())),
+                    false => ListItem::new(line),
+                }
+            })
+            .collect(),
+        None => Vec::new(),
+    };
+
+    let list = List::new(items)
+        .block(pane_block(&title, app.focus == Focus::Files))
+        .highlight_style(Style::new().reversed());
+
+    let mut state = ListState::default();
+    state.select(Some(app.file_cursor));
+    frame.render_stateful_widget(list, area, &mut state);
+}
+
+fn draw_footer(frame: &mut Frame, app: &App, area: Rect) {
+    let hints = "[Tab]pane [Space]mark [s]group [S]all [o]pen [d]elete [q]uit";
+    let left = match &app.status {
+        Some(s) => s.clone(),
+        None => format!(
+            "marked {} · reclaim {}",
+            app.marked_count(),
+            bytesize::ByteSize::b(app.reclaimable_bytes())
+        ),
+    };
+    let text = format!("{left}   {hints}");
+    frame.render_widget(Paragraph::new(text), area);
+}
+
+fn centered_rect(width: u16, height: u16, area: Rect) -> Rect {
+    let x = area.x + area.width.saturating_sub(width) / 2;
+    let y = area.y + area.height.saturating_sub(height) / 2;
+    Rect {
+        x,
+        y,
+        width: width.min(area.width),
+        height: height.min(area.height),
+    }
+}
+
+fn draw_strategy_popup(frame: &mut Frame, app: &App, scope: StrategyScope) {
+    let title = match scope {
+        StrategyScope::CurrentGroup => "Keep in this group",
+        StrategyScope::AllGroups => "Keep in ALL groups",
+    };
+    let items: Vec<ListItem> = STRATEGIES
+        .iter()
+        .map(|s| ListItem::new(strategy_label(*s)))
+        .collect();
+
+    let area = centered_rect(28, (STRATEGIES.len() as u16) + 2, frame.area());
+    frame.render_widget(Clear, area);
+
+    let list = List::new(items)
+        .block(Block::default().borders(Borders::ALL).title(title))
+        .highlight_style(Style::new().reversed());
+
+    let mut state = ListState::default();
+    state.select(Some(app.strategy_cursor));
+    frame.render_stateful_widget(list, area, &mut state);
+}
+
+fn draw_confirm_popup(frame: &mut Frame, app: &App) {
+    let area = centered_rect(48, 3, frame.area());
+    frame.render_widget(Clear, area);
+    let text = format!(
+        "Delete {} files, reclaim {}? [y/N]",
+        app.marked_count(),
+        bytesize::ByteSize::b(app.reclaimable_bytes())
+    );
+    frame.render_widget(
+        Paragraph::new(text).block(Block::default().borders(Borders::ALL).title("Confirm")),
+        area,
+    );
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::fileinfo::FileInfo;
+    use crate::pipeline::DuplicateGroup;
+    use crate::tui::app::App;
+    use ratatui::backend::TestBackend;
+    use ratatui::Terminal;
+    use std::path::PathBuf;
+    use std::time::{Duration, UNIX_EPOCH};
+
+    fn sample_app() -> App {
+        let files = vec![
+            FileInfo {
+                path: PathBuf::from("/tmp/report.pdf").into_boxed_path(),
+                size: 4_000_000,
+                modified: UNIX_EPOCH + Duration::from_secs(1_700_000_000),
+            },
+            FileInfo {
+                path: PathBuf::from("/tmp/report-copy.pdf").into_boxed_path(),
+                size: 4_000_000,
+                modified: UNIX_EPOCH + Duration::from_secs(1_700_100_000),
+            },
+        ];
+        App::from_groups(vec![DuplicateGroup { hash: 0, files }])
+    }
+
+    #[test]
+    fn draw_renders_without_panic_and_shows_content() {
+        let app = sample_app();
+        let params = crate::params::Params::default();
+        let backend = TestBackend::new(100, 24);
+        let mut terminal = Terminal::new(backend).unwrap();
+
+        terminal.draw(|f| draw(f, &app, &params)).unwrap();
+
+        let text: String = terminal
+            .backend()
+            .buffer()
+            .content()
+            .iter()
+            .map(|cell| cell.symbol())
+            .collect();
+
+        assert!(text.contains("Groups"));
+        assert!(text.contains("report"));
+        assert!(text.contains("marked"));
+    }
+}