import uuid
from typing import Annotated

from fastapi import Cookie, Depends, HTTPException, status
from sqlalchemy.ext.asyncio import AsyncSession

from src.auth.session import decode_session_cookie
from src.config import Settings
from src.database import SessionLocal
from src.models.project import Project
from src.models.user import User


async def get_db_session():
    async with SessionLocal() as session:
        yield session


async def get_current_user_id(
    session_cookie: Annotated[str | None, Cookie(alias="session")] = None,
) -> uuid.UUID:
    if not session_cookie:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="missing session")

    settings = Settings()
    try:
        payload = decode_session_cookie(settings=settings, cookie_value=session_cookie)
        return uuid.UUID(str(payload["user_id"]))
    except ValueError:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="invalid session")


async def get_current_user(
    session_cookie: Annotated[str | None, Cookie(alias="session")] = None,
    db_session: AsyncSession = Depends(get_db_session),
) -> User:
    if not session_cookie:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="missing session")

    settings = Settings()
    try:
        payload = decode_session_cookie(settings=settings, cookie_value=session_cookie)
        user_id = uuid.UUID(str(payload["user_id"]))
    except ValueError:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="invalid session")

    user = await db_session.get(User, user_id)
    if user is None:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="user not found")
    return user


async def _get_user(session: AsyncSession, user_id: uuid.UUID) -> User:
    """Fetch a user by ID or raise 401 if not found."""
    user = await session.get(User, user_id)
    if user is None:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="user not found")
    return user


async def _get_owned_project(
    project_id: uuid.UUID,
    user_id: uuid.UUID,
    session: AsyncSession,
) -> "Project":
    """Fetch a project and verify ownership.

    Args:
        project_id: UUID of the project.
        user_id: ID of the authenticated user.
        session: Database session.

    Returns:
        The project if found and owned by the user.

    Raises:
        HTTPException: 404 if project not found, 403 if user is not the owner.
    """
    from src.models.project import Project

    project = await session.get(Project, project_id)
    if project is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="project not found")
    if project.owner_id != user_id:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="not project owner")
    return project