import json
from sqlalchemy.orm import Session
from typing import List, Optional
from app.core.biz_exception import NotFoundError, PermissionDeniedError, BizLogicError
from app.models.task import Task
from app.schemas.task import TaskCreate, TaskUpdate


class TaskService:
    @staticmethod
    def create(db: Session, obj_in: TaskCreate) -> Task:
        db_obj = Task(
            command=obj_in.command,
            args=obj_in.args,
            status=obj_in.status or 0,
        )
        db.add(db_obj)
        db.commit()
        db.refresh(db_obj)
        return db_obj

    @staticmethod
    def get_by_id(db: Session, task_id: int) -> Optional[Task]:
        obj = db.query(Task).filter(Task.id == task_id).first()
        if not obj:
            raise NotFoundError("Task not exist")
        return obj

    @staticmethod
    def update(db: Session, task_id: int, obj_in: TaskUpdate) -> Optional[Task]:
        db_obj = db.query(Task).filter(Task.id == task_id).first()
        if not db_obj:
            raise NotFoundError("Task not exist")

        if obj_in.result is not None:
            db_obj.result = obj_in.result
        if obj_in.status is not None:
            db_obj.status = obj_in.status

        db.add(db_obj)
        db.commit()
        db.refresh(db_obj)
        return db_obj

    @staticmethod
    def get_pending(db: Session, command: str, page: int, size: int) -> List[Task]:
        offset = page * size
        return (
            db.query(Task)
            .filter(Task.command == command, Task.status == 0)
            .order_by(Task.create_at.asc())
            .offset(offset)
            .limit(size)
            .all()
        )