# app/services/task_service.py

from datetime import datetime
from typing import List, Optional

from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select


from app.utils.search import apply_keyword_search_stmt
from app.utils.pagination import paginate
from app.core.queue_manager import queue_manager
from app.core.biz_exception import NotFoundError,BizLogicError
from app.models.vas_task import VasTask
from app.models.order import VasOrder
from app.schemas.vas_task import VasTaskCreate, VasTaskUpdate


class VasTaskService:

    @staticmethod
    async def create(db: AsyncSession, data: VasTaskCreate) -> VasTask:
        rec = VasTask(
            **data.dict(),
            status="pending",
            created_at=datetime.utcnow(),
        )
        db.add(rec)
        await db.commit()
        await db.refresh(rec)
        
        queue_manager.put(
            queue_name=rec.routing_key,
            task_id=task.id,
            priority=task.priority
        )
        return rec

    @staticmethod
    async def list_task(
        db: AsyncSession,
        status: Optional[str] = None,
        routing_key: Optional[str] = None,
        script_version: Optional[str] = None,
        keyword: Optional[str] = None,
        page: int = 0,
        size: int = 10,
    ):
        stmt = select(VasTask)

        if status:
            stmt = stmt.where(VasTask.status == status)

        if routing_key:
            stmt = stmt.where(VasTask.routing_key == routing_key)

        if script_version:
            stmt = stmt.where(VasTask.script_version == script_version)

        stmt = apply_keyword_search_stmt(
            stmt=stmt,
            model=VasTask,
            keyword=keyword,
            fields=["order_id", "routing_key", "user_inputs"],
        )

        stmt = stmt.order_by(
            VasTask.priority.desc(),
            VasTask.id.asc(),
        )

        return await paginate(db, stmt, page, size)

    @staticmethod
    async def update(
        db: AsyncSession,
        id: int,
        payload: VasTaskUpdate,
    ) -> VasTask:
        stmt = select(VasTask).where(VasTask.id == id)
        result = await db.execute(stmt)
        obj = result.scalar_one_or_none()

        if not obj:
            raise NotFoundError("Task not exist")

        data = payload.dict(exclude_unset=True)

        for key, value in data.items():
            setattr(obj, key, value)

        await db.commit()
        await db.refresh(obj)
        return obj

    @staticmethod
    async def get_active_task_by_order_id(
        db: AsyncSession,
        order_id: str,
    ) -> List[VasTask]:
        stmt = select(VasTask).where(
            VasTask.status == "pending",
            VasTask.order_id == order_id,
        )
        result = await db.execute(stmt)
        return result.scalars().all()

    @staticmethod
    async def return_to_queue(db: AsyncSession, id: int) -> VasTask:
        stmt = select(VasTask).where(VasTask.id == id)
        result = await db.execute(stmt)
        rec = result.scalar_one_or_none()

        if not rec:
            raise NotFoundError("Task not exist")
        
        if rec.status == "pending":
            raise BizLogicError("Task is in queue already")
        
        rec.status = "pending"
        if rec.status == "grabbed":
            rec.attempt_count = (rec.attempt_count or 0) + 1

        await db.commit()
        await db.refresh(rec)
        
        queue_manager.put(
            queue_name=rec.routing_key,
            task_id=rec.id,
            priority= max(0, rec.priority - rec.attempt_count),
        )
        return rec

    @staticmethod
    async def manual_confirm(db: AsyncSession, id: int) -> VasTask:
        stmt = select(VasTask).where(VasTask.id == id)
        result = await db.execute(stmt)
        task = result.scalar_one_or_none()

        if not task:
            raise NotFoundError("Task not exist")

        task.status = "completed"

        order_stmt = select(VasOrder).where(VasOrder.id == task.order_id)
        order_result = await db.execute(order_stmt)
        order = order_result.scalar_one_or_none()

        if not order:
            raise NotFoundError("Order not exist")

        order.status = "completed"

        await db.commit()
        await db.refresh(task)
        return task