from typing import Annotated

from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.orm import Session

from app.auth import get_current_admin, get_current_user, get_password_hash
from app.database import get_db
from app.models.user import User, UserRole
from app.schemas import AdminUserCreate, UserResponse, UserUpdate
from app.services.user_cleanup import cleanup_user_files

router = APIRouter(prefix="/api/users", tags=["users"])


def _count_admins(db: Session) -> int:
    return db.query(User).filter(User.role == UserRole.admin, User.is_active == True).count()


@router.get("", response_model=list[UserResponse])
def list_users(
    db: Annotated[Session, Depends(get_db)],
    _: Annotated[User, Depends(get_current_admin)],
):
    return db.query(User).order_by(User.created_at).all()


@router.post("", response_model=UserResponse, status_code=status.HTTP_201_CREATED)
def create_user(
    user_data: AdminUserCreate,
    db: Annotated[Session, Depends(get_db)],
    _: Annotated[User, Depends(get_current_admin)],
):
    from app.auth import get_user_by_email, get_user_by_username

    if get_user_by_email(db, user_data.email):
        raise HTTPException(status_code=400, detail="Email already registered")
    if get_user_by_username(db, user_data.username):
        raise HTTPException(status_code=400, detail="Username already taken")

    user = User(
        email=user_data.email,
        username=user_data.username,
        hashed_password=get_password_hash(user_data.password),
        role=user_data.role,
        is_active=True,
    )
    db.add(user)
    db.commit()
    db.refresh(user)
    return user


@router.patch("/{user_id}", response_model=UserResponse)
def update_user(
    user_id: int,
    update: UserUpdate,
    db: Annotated[Session, Depends(get_db)],
    current_user: Annotated[User, Depends(get_current_admin)],
):
    from app.auth import get_user_by_email

    user = db.query(User).filter(User.id == user_id).first()
    if not user:
        raise HTTPException(status_code=404, detail="User not found")

    if user.id == current_user.id:
        if update.role is not None and update.role != UserRole.admin:
            raise HTTPException(status_code=400, detail="Cannot demote yourself")
        if update.is_active is False:
            raise HTTPException(status_code=400, detail="Cannot deactivate yourself")

    if update.role is not None and update.role != UserRole.admin and user.role == UserRole.admin:
        if _count_admins(db) <= 1:
            raise HTTPException(status_code=400, detail="Cannot demote the last admin")

    if update.is_active is False and user.role == UserRole.admin:
        if _count_admins(db) <= 1:
            raise HTTPException(status_code=400, detail="Cannot deactivate the last admin")

    if update.email is not None and update.email != user.email:
        if get_user_by_email(db, update.email):
            raise HTTPException(status_code=400, detail="Email already registered")
        user.email = update.email

    if update.username is not None and update.username != user.username:
        from app.auth import get_user_by_username

        if get_user_by_username(db, update.username):
            raise HTTPException(status_code=400, detail="Username already taken")
        user.username = update.username

    if update.role is not None:
        user.role = update.role
    if update.is_active is not None:
        user.is_active = update.is_active
    if update.password:
        user.hashed_password = get_password_hash(update.password)

    db.commit()
    db.refresh(user)
    return user


@router.delete("/{user_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_user(
    user_id: int,
    db: Annotated[Session, Depends(get_db)],
    current_user: Annotated[User, Depends(get_current_admin)],
):
    user = db.query(User).filter(User.id == user_id).first()
    if not user:
        raise HTTPException(status_code=404, detail="User not found")

    if user.id == current_user.id:
        raise HTTPException(status_code=400, detail="Cannot delete yourself")

    if user.role == UserRole.admin and _count_admins(db) <= 1:
        raise HTTPException(status_code=400, detail="Cannot delete the last admin")

    cleanup_user_files(db, user)
    db.delete(user)
    db.commit()