from typing import List, Optional
from sqlalchemy.orm import Session
from app.models.task import Task
from app.schemas.task import TaskCreate, TaskUpdate


def get_task(db: Session, task_id: int) -> Optional[Task]:
    return db.query(Task).filter(Task.id == task_id).first()


def get_tasks(db: Session, skip: int = 0, limit: int = 100) -> List[Task]:
    return db.query(Task).offset(skip).limit(limit).all()


def create_task(db: Session, task: TaskCreate) -> Task:
    db_task = Task(
        title=task.title,
        description=task.description,
        status=task.status,
        priority=task.priority,
    )
    db.add(db_task)
    db.commit()
    db.refresh(db_task)
    return db_task


def update_task(db: Session, task_id: int, task_update: TaskUpdate) -> Optional[Task]:
    db_task = db.query(Task).filter(Task.id == task_id).first()
    if db_task is None:
        return None

    update_data = task_update.model_dump(exclude_unset=True)
    for field, value in update_data.items():
        setattr(db_task, field, value)

    db.commit()
    db.refresh(db_task)
    return db_task


def delete_task(db: Session, task_id: int) -> bool:
    db_task = db.query(Task).filter(Task.id == task_id).first()
    if db_task is None:
        return False

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


def get_tasks_by_status(
    db: Session, status: str, skip: int = 0, limit: int = 100
) -> List[Task]:
    return db.query(Task).filter(Task.status == status).offset(skip).limit(limit).all()


def get_tasks_by_priority(
    db: Session, priority: str, skip: int = 0, limit: int = 100
) -> List[Task]:
    return (
        db.query(Task).filter(Task.priority == priority).offset(skip).limit(limit).all()
    )