#!/usr/bin/env bash
# =============================================================================
# Hook: Protect System Files (PreToolUse on Write/Edit)
# =============================================================================
# Prevents agents from accidentally overwriting core crew files at runtime.
# Custom agents in the platform agents directory are allowed (the Architect
# creates them). User-mutable references (agents-registry.md, agents.md) are
# also allowed.
#
# Reads platform_dir and dispatcher_name from the neutral JSON input to
# determine which paths to protect. Falls back to .claude / CLAUDE.md if
# the fields are missing (backward compatibility).
#
# Exit codes:
#   0 = allow the operation
#   2 = block the operation (hard reject)
# =============================================================================

INPUT=$(cat)
FILE=$(echo "$INPUT" | jq -r '.args.file_path // .args.command // ""' 2>/dev/null)

# If we can't extract a file path, allow the operation
[[ -z "$FILE" ]] && exit 0

BASENAME=$(basename "$FILE")
PLATFORM_DIR=$(echo "$INPUT" | jq -r '.platform_dir // ".claude"' 2>/dev/null)
DISPATCHER_NAME=$(echo "$INPUT" | jq -r '.dispatcher_name // "CLAUDE.md"' 2>/dev/null)

# ── Dispatcher file: never modify at runtime ──────────────────────────────
if [[ "$BASENAME" == "$DISPATCHER_NAME" && "$FILE" != *"$PLATFORM_DIR/"* ]]; then
  echo "BLOCKED: $DISPATCHER_NAME is a system file. Update it in the repo and run updateme.sh."
  exit 2
fi

# ── Core agent definitions: never modify at runtime ─────────────────────────
CORE_AGENTS="architect.md scribe.md sorter.md seeker.md connector.md librarian.md transcriber.md postman.md"
if [[ "$FILE" == *"$PLATFORM_DIR/agents/"* ]]; then
  for core in $CORE_AGENTS; do
    if [[ "$BASENAME" == "$core" ]]; then
      echo "BLOCKED: $BASENAME is a core agent definition. Update it in the repo and run updateme.sh."
      exit 2
    fi
  done
  # Custom agents are allowed through
  exit 0
fi

# ── Skills: never modify at runtime ─────────────────────────────────────────
if [[ "$FILE" == *"$PLATFORM_DIR/skills/"* ]]; then
  echo "BLOCKED: Skill files are managed by the repo. Update them in the repo and run updateme.sh."
  exit 2
fi

# ── Core references: block all except user-mutable ones ─────────────────────
if [[ "$FILE" == *"$PLATFORM_DIR/references/"* ]]; then
  USER_MUTABLE="agents-registry.md agents.md"
  for allowed in $USER_MUTABLE; do
    [[ "$BASENAME" == "$allowed" ]] && exit 0
  done
  echo "BLOCKED: $BASENAME is a core reference file. Update it in the repo and run updateme.sh."
  exit 2
fi

# Everything else is allowed
exit 0