from typing import List, Optional, Tuple
from sqlalchemy.orm import Session

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


def get_todo(db: Session, todo_id: int) -> Optional[Todo]:
    return db.query(Todo).filter(Todo.id == todo_id).first()


def get_todos(
    db: Session,
    skip: int = 0,
    limit: int = 100,
    completed: Optional[bool] = None,
    priority: Optional[Priority] = None,
    search: Optional[str] = None,
) -> Tuple[List[Todo], int]:
    query = db.query(Todo)

    # Apply filters
    if completed is not None:
        query = query.filter(Todo.completed == completed)
    if priority is not None:
        query = query.filter(Todo.priority == priority)
    if search:
        query = query.filter(
            Todo.title.contains(search) | Todo.description.contains(search)
        )

    # Get total count before pagination
    total = query.count()

    # Apply pagination and ordering
    todos = query.order_by(Todo.created_at.desc()).offset(skip).limit(limit).all()

    return todos, total


def create_todo(db: Session, todo: TodoCreate) -> Todo:
    db_todo = Todo(**todo.model_dump())
    db.add(db_todo)
    db.commit()
    db.refresh(db_todo)
    return db_todo


def update_todo(db: Session, todo_id: int, todo_update: TodoUpdate) -> Optional[Todo]:
    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if db_todo:
        update_data = todo_update.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) -> bool:
    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if db_todo:
        db.delete(db_todo)
        db.commit()
        return True
    return False