from typing import List, Optional

from sqlalchemy.orm import Session

from app.models.todo import Todo
from app.schemas.todo import TodoCreate, TodoUpdate


def get_todos(db: Session, user_id: int, skip: int = 0, limit: int = 100) -> List[Todo]:
    """
    Get all todo items for a specific user with pagination
    """
    return db.query(Todo).filter(Todo.owner_id == user_id).offset(skip).limit(limit).all()


def get_todo(db: Session, todo_id: int, user_id: int = None) -> Optional[Todo]:
    """
    Get a specific todo item by ID, optionally filtering by user_id
    """
    query = db.query(Todo).filter(Todo.id == todo_id)
    if user_id is not None:
        query = query.filter(Todo.owner_id == user_id)
    return query.first()


def create_todo(db: Session, todo: TodoCreate, user_id: int) -> Todo:
    """
    Create a new todo item
    """
    db_todo = Todo(
        title=todo.title,
        description=todo.description,
        completed=todo.completed,
        owner_id=user_id,
    )
    db.add(db_todo)
    db.commit()
    db.refresh(db_todo)
    return db_todo


def update_todo(db: Session, todo_id: int, todo: TodoUpdate, user_id: int = None) -> Optional[Todo]:
    """
    Update a todo item, optionally checking owner
    """
    db_todo = get_todo(db, todo_id, user_id)
    if not db_todo:
        return None

    update_data = todo.model_dump(exclude_unset=True)

    for field, value in update_data.items():
        setattr(db_todo, field, value)

    db.commit()
    db.refresh(db_todo)
    return db_todo


def delete_todo(db: Session, todo_id: int, user_id: int = None) -> bool:
    """
    Delete a todo item, optionally checking owner
    """
    db_todo = get_todo(db, todo_id, user_id)
    if not db_todo:
        return False

    db.delete(db_todo)
    db.commit()
    return True