from abc import ABC, abstractmethod
from datetime import datetime, timezone
from typing import Optional, Tuple

from sqlalchemy import asc, desc, select, update
from sqlalchemy.ext.asyncio import AsyncSession

from common.database.db_session_manager import DB_SESSION_MNG
from common.database.model.models import chats, items, sessions
from common.enums import ErrorType, SessionStatus
from common.logger import LOG


# 협상 채팅 CRUD. 메시지 로그(negotiation.chats)와 종료 시 세션 입찰 확정(negotiation.sessions)을 다룬다.
# chats / sessions 모두 NEGOTIATION 논리 DB 라 한 트랜잭션(execute_lambda_run)으로 묶을 수 있다.
class IChatCRUD(ABC):
    @abstractmethod
    async def list_by_session(self, cdb: AsyncSession, session_id) -> Tuple[ErrorType, list]:
        pass

    @abstractmethod
    async def get_last(self, cdb: AsyncSession, session_id) -> Tuple[ErrorType, Tuple[int, Optional[int], Optional[dict]]]:
        """마지막 메시지의 (seq, sender, meta). 없으면 (0, None, None).
        동시전송 가드 + seq 채번 + 입력-모드 검증(직전 봇 meta.input_mode)에 사용."""
        pass

    @abstractmethod
    async def insert_message(self, cdb: AsyncSession, message: chats) -> ErrorType:
        pass

    @abstractmethod
    async def soft_delete_message(self, cdb: AsyncSession, chat_id) -> ErrorType:
        pass

    @abstractmethod
    async def get_item_by_id(self, cdb: AsyncSession, item_id) -> Tuple[ErrorType, items]:
        pass

    @abstractmethod
    async def finalize_session(
        self, cdb: AsyncSession, session_id, status: int,
        bid_price: Optional[int] = None, reject_reason: Optional[str] = None, reject_price: Optional[int] = None,
    ) -> ErrorType:
        pass

    @abstractmethod
    async def update_last_offer_price(self, cdb: AsyncSession, session_id, price: int) -> ErrorType:
        pass


class ChatCRUD(IChatCRUD):
    async def list_by_session(self, cdb: AsyncSession, session_id) -> Tuple[ErrorType, list]:
        try:
            # (session_id, seq) 유니크 인덱스가 정렬 스캔을 커버한다.
            query = (
                select(chats)
                .where(chats.session_id == session_id, chats.deleted == False)  # noqa: E712
                .order_by(asc(chats.seq))
            )
            err_type, rows = await DB_SESSION_MNG.execute(cdb, query, "list_by_session failed.")
            if err_type != ErrorType.SUCCESS:
                return err_type, []
            return ErrorType.SUCCESS, rows
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED, []

    async def get_last(self, cdb: AsyncSession, session_id) -> Tuple[ErrorType, Tuple[int, Optional[int], Optional[dict]]]:
        try:
            query = (
                select(chats.seq, chats.sender, chats.meta)
                .where(chats.session_id == session_id, chats.deleted == False)  # noqa: E712
                .order_by(desc(chats.seq))
                .limit(1)
            )
            err_type, rows = await DB_SESSION_MNG.execute(cdb, query, "get_last failed.")
            if err_type != ErrorType.SUCCESS:
                return err_type, (0, None, None)
            if not rows:
                return ErrorType.SUCCESS, (0, None, None)
            return ErrorType.SUCCESS, (rows[0][0], rows[0][1], rows[0][2])
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED, (0, None, None)

    async def insert_message(self, cdb: AsyncSession, message: chats) -> ErrorType:
        try:
            return await DB_SESSION_MNG.insert(cdb, message, raise_error=False)
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED

    async def soft_delete_message(self, cdb: AsyncSession, chat_id) -> ErrorType:
        # agent 실패 시 선점(pre-claim)한 유저 메시지를 되돌린다. 부분 유니크(WHERE deleted=FALSE)라 seq 가 다시 비워진다.
        try:
            query = update(chats).where(chats.chat_id == chat_id).values(deleted=True)
            return await DB_SESSION_MNG.add(cdb, query)
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED

    async def get_item_by_id(self, cdb: AsyncSession, item_id) -> Tuple[ErrorType, items]:
        try:
            query = select(items).where(items.item_id == item_id, items.deleted == False).limit(1)  # noqa: E712
            err_type, row_list = await DB_SESSION_MNG.execute(cdb, query, f"get_item_by_id({item_id}) failed.")
            if err_type != ErrorType.SUCCESS:
                return err_type, None
            if len(row_list) != 1:
                return ErrorType.DB_INVALID_KEY, None
            return ErrorType.SUCCESS, row_list[0]
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED, None

    async def finalize_session(
        self, cdb: AsyncSession, session_id, status: int,
        bid_price: Optional[int] = None, reject_reason: Optional[str] = None, reject_price: Optional[int] = None,
    ) -> ErrorType:
        try:
            values = {"status": status}
            if bid_price is not None:
                values["bid_price"] = bid_price
                values["bid_at"] = datetime.now(timezone.utc)
            if reject_reason is not None:
                values["reject_reason"] = reject_reason[:255]
            if reject_price is not None:
                values["reject_price"] = reject_price
            # 진행중일 때만 전이 — negodata 일괄마감/중복 전송 경합이 종료된 세션을 되살리지 못하게 가드
            query = (
                update(sessions)
                .where(sessions.session_id == session_id, sessions.status == SessionStatus.IN_PROGRESS.value)
                .values(**values)
            )
            return await DB_SESSION_MNG.add(cdb, query)
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED

    async def update_last_offer_price(self, cdb: AsyncSession, session_id, price: int) -> ErrorType:
        """협력사 마지막 제시가 갱신 — 가격 입력 턴의 봇 메시지 저장과 같은 트랜잭션에서 호출.

        진행 중엔 매 가격 입력마다 덮어쓰고 종료 후엔 불변. 앵커링 표본 판정에서
        "가격을 한 번이라도 써낸 협상"을 가르는 기준값(NULL=가격 흔적 없음 → 집계 제외).
        status 가드: 일괄마감 등으로 이미 종료된 세션의 흔적을 사후에 바꾸지 못하게 한다(판정 결정성 보호).
        """
        try:
            query = (
                update(sessions)
                .where(sessions.session_id == session_id, sessions.status == SessionStatus.IN_PROGRESS.value)
                .values(last_offer_price=price)
            )
            return await DB_SESSION_MNG.add(cdb, query)
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED