from datetime import datetime, timedelta
from typing import Optional
from uuid import UUID
from jose import JWTError, jwt
from passlib.context import CryptContext
from fastapi import Depends, HTTPException, status
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from app.config import get_settings
from app.database import get_db
from app.models.models import User

settings = get_settings()
pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
security = HTTPBearer()


def hash_password(password: str) -> str:
    return pwd_context.hash(password)


def verify_password(plain: str, hashed: str) -> bool:
    return pwd_context.verify(plain, hashed)


def create_access_token(user_id: UUID, role: str, expires_delta: Optional[timedelta] = None) -> str:
    expire = datetime.utcnow() + (expires_delta or timedelta(minutes=settings.JWT_EXPIRATION_MINUTES))
    payload = {
        "sub": str(user_id),
        "role": role,
        "exp": expire,
    }
    return jwt.encode(payload, settings.JWT_SECRET, algorithm=settings.JWT_ALGORITHM)


def decode_token(token: str) -> dict:
    try:
        return jwt.decode(token, settings.JWT_SECRET, algorithms=[settings.JWT_ALGORITHM])
    except JWTError:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid token")


async def get_current_user(
    credentials: HTTPAuthorizationCredentials = Depends(security),
    db: AsyncSession = Depends(get_db),
) -> User:
    payload = decode_token(credentials.credentials)
    user_id = payload.get("sub")
    result = await db.execute(select(User).where(User.id == UUID(user_id)))
    user = result.scalar_one_or_none()
    if not user or user.deleted_at:
        raise HTTPException(status_code=401, detail="User not found")
    return user


class RequireRole:
    def __init__(self, *allowed_roles: str):
        self.allowed_roles = allowed_roles

    async def __call__(self, user: User = Depends(get_current_user)) -> User:
        if user.role not in self.allowed_roles:
            raise HTTPException(status_code=403, detail="Insufficient permissions")
        return user


require_admin = RequireRole("admin")
require_editor = RequireRole("admin", "editor")
require_viewer = RequireRole("admin", "editor", "viewer")