"""Dependency injection utilities."""

from typing import Annotated
from uuid import UUID

from fastapi import Depends, HTTPException, status
from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer

# For backwards compatibility with synchronous code
from sqlalchemy import create_engine, select
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.orm import Session, sessionmaker

from app.auth.jwt import decode_access_token
from app.core.config import settings
from app.database.models.user import User
from app.database.session import get_db

# Sync engine for synchronous endpoints
_sync_engine = create_engine(
    str(settings.DATABASE_URL),
    pool_size=settings.DATABASE_POOL_SIZE,
    max_overflow=settings.DATABASE_MAX_OVERFLOW,
    pool_pre_ping=True,
)
_SyncSessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=_sync_engine)


def get_db_sync():
    """Synchronous database session dependency."""
    db = _SyncSessionLocal()
    try:
        yield db
    finally:
        db.close()


# Database session dependency (async)
DatabaseSession = Annotated[AsyncSession, Depends(get_db)]

# Security scheme for JWT Bearer token
security = HTTPBearer()


def get_current_user(
    credentials: HTTPAuthorizationCredentials = Depends(security), db: Session = Depends(get_db_sync)
) -> User:
    """
    Get current authenticated user from JWT token (synchronous version).

    Args:
        credentials: HTTP Authorization Bearer token
        db: Database session

    Returns:
        Current authenticated user

    Raises:
        HTTPException: If token is invalid or user not found
    """
    # Decode token
    token = credentials.credentials
    payload = decode_access_token(token)

    if payload is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid authentication credentials",
            headers={"WWW-Authenticate": "Bearer"},
        )

    # Extract user ID from token
    user_id_str: str = payload.get("sub")
    if user_id_str is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid token payload",
            headers={"WWW-Authenticate": "Bearer"},
        )

    try:
        user_id = UUID(user_id_str)
    except ValueError:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid user ID in token",
            headers={"WWW-Authenticate": "Bearer"},
        ) from None

    # Get user from database (sync)
    user = db.query(User).filter(User.id == user_id).first()

    if user is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="User not found",
            headers={"WWW-Authenticate": "Bearer"},
        )

    if not user.is_active:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="User account is deactivated")

    return user


async def get_current_user_async(
    credentials: HTTPAuthorizationCredentials = Depends(security), db: AsyncSession = Depends(get_db)
) -> User:
    """
    Get current authenticated user from JWT token (asynchronous version).

    Args:
        credentials: HTTP Authorization Bearer token
        db: Async database session

    Returns:
        Current authenticated user

    Raises:
        HTTPException: If token is invalid or user not found
    """
    # Decode token
    token = credentials.credentials
    payload = decode_access_token(token)

    if payload is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid authentication credentials",
            headers={"WWW-Authenticate": "Bearer"},
        )

    # Extract user ID from token
    user_id_str: str = payload.get("sub")
    if user_id_str is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid token payload",
            headers={"WWW-Authenticate": "Bearer"},
        )

    try:
        user_id = UUID(user_id_str)
    except ValueError:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid user ID in token",
            headers={"WWW-Authenticate": "Bearer"},
        ) from None

    # Get user from database (async)
    result = await db.execute(select(User).where(User.id == user_id))
    user = result.scalar_one_or_none()

    if user is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="User not found",
            headers={"WWW-Authenticate": "Bearer"},
        )

    if not user.is_active:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="User account is deactivated")

    return user