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

from sqlalchemy import and_, select, update
from sqlalchemy.ext.asyncio import AsyncSession

from common.database.db_session_manager import DB_SESSION_MNG
from common.database.model.models import place_facts
from common.enums import ErrorType, FactStatus
from common.logger import LOG
from common.utils.gtime import GTime

# ★ 사이트에 나가는 상태. PUBLISHABLE_FACT_STATUSES 와 같은 집합이어야 한다.
#   유니크 인덱스(uq_facts_published_*)의 조건과도 같아야 한다.
_PUBLISHED = (FactStatus.VERIFIED.value, FactStatus.CORRECTED.value)
# 후보 — 재수집이 올려놓은 확인 대기 항목. 여러 건 공존한다.
_CANDIDATE = (FactStatus.UNVERIFIED.value, FactStatus.PENDING_OWNER.value)
# 화면에 보이는 것 전체(이력 제외).
_ACTIVE = _PUBLISHED + _CANDIDATE


def _unit_cond(unit_id):
    """unit_id 는 NULL 비교라 == 로 걸면 안 된다(사업장 단위 fact 를 못 찾는다)."""
    return place_facts.unit_id.is_(None) if unit_id is None else place_facts.unit_id == unit_id


# fact CRUD. 항상 place_id 로 스코프한다.
class IFactCRUD(ABC):
    @abstractmethod
    async def add_fact(self, cdb: AsyncSession, fact: place_facts) -> ErrorType:
        pass

    @abstractmethod
    async def get_fact(self, cdb: AsyncSession, place_id, fact_id) -> Tuple[ErrorType, place_facts]:
        pass

    @abstractmethod
    async def list_facts(self, cdb: AsyncSession, place_id, unit_id, status, publishable_only, active_only) -> Tuple[ErrorType, list]:
        pass

    @abstractmethod
    async def get_published_fact(self, cdb: AsyncSession, place_id, unit_id, key) -> Tuple[ErrorType, place_facts]:
        pass

    @abstractmethod
    async def get_candidate(self, cdb: AsyncSession, place_id, unit_id, key, source_type) -> Tuple[ErrorType, place_facts]:
        pass

    @abstractmethod
    async def refresh_collected(self, cdb: AsyncSession, fact_id, source_type, source_url, ts) -> Tuple[ErrorType, int]:
        pass

    @abstractmethod
    async def update_candidate(self, cdb: AsyncSession, fact_id, value, source_url, status, ts) -> Tuple[ErrorType, int]:
        pass

    @abstractmethod
    async def transition(self, cdb: AsyncSession, fact_id, from_statuses, to_status, data: dict) -> Tuple[ErrorType, int]:
        pass

    @abstractmethod
    async def expire_published(self, cdb: AsyncSession, place_id, unit_id, key, ts, except_fact_id=None) -> Tuple[ErrorType, int]:
        pass

    @abstractmethod
    async def reject_candidates(self, cdb: AsyncSession, place_id, unit_id, key, ts, except_fact_id=None) -> Tuple[ErrorType, int]:
        pass


class FactCRUD(IFactCRUD):
    async def add_fact(self, cdb: AsyncSession, fact: place_facts) -> ErrorType:
        try:
            return await DB_SESSION_MNG.insert(cdb, fact)
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED

    async def get_fact(self, cdb: AsyncSession, place_id, fact_id) -> Tuple[ErrorType, place_facts]:
        try:
            query = (
                select(place_facts)
                .where(place_facts.fact_id == fact_id, place_facts.place_id == place_id, place_facts.deleted == False)  # noqa: E712
                .limit(1)
            )
            err_type, row_list = await DB_SESSION_MNG.execute(cdb, query)
            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 list_facts(
        self, cdb: AsyncSession, place_id, unit_id=None, status: Optional[int] = None,
        publishable_only: bool = False, active_only: bool = True,
    ) -> Tuple[ErrorType, list]:
        """fact 목록.
        publishable_only=True → ★ VERIFIED·CORRECTED 만 (사이트 렌더·발행 게이트가 쓰는 경로)
        active_only=True      → REJECTED·EXPIRED 이력 제외 (관리 화면 기본: 노출값 + 후보)
        """
        try:
            conditions = [place_facts.place_id == place_id, place_facts.deleted == False]  # noqa: E712
            if unit_id is not None:
                conditions.append(place_facts.unit_id == unit_id)
            if publishable_only:
                conditions.append(place_facts.status.in_(_PUBLISHED))
            elif status is not None:
                conditions.append(place_facts.status == status)
            elif active_only:
                conditions.append(place_facts.status.in_(_ACTIVE))

            # 노출값이 먼저, 그 아래 후보. 같은 key 끼리 붙어 보이게 정렬한다.
            query = select(place_facts).where(and_(*conditions)).order_by(
                place_facts.key.asc(), place_facts.status.desc(), place_facts.collected_at.desc()
            )
            err_type, rows = await DB_SESSION_MNG.execute(cdb, query)
            return (err_type, list(rows) if err_type == ErrorType.SUCCESS else [])
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED, []

    async def get_published_fact(self, cdb: AsyncSession, place_id, unit_id, key) -> Tuple[ErrorType, place_facts]:
        """★ 지금 사이트에 나가고 있는 값. 없으면 (SUCCESS, None).
        유니크 인덱스가 1건만 허용하므로 결과는 0 또는 1건이다."""
        try:
            query = (
                select(place_facts)
                .where(and_(
                    place_facts.place_id == place_id,
                    place_facts.key == key,
                    place_facts.deleted == False,  # noqa: E712
                    place_facts.status.in_(_PUBLISHED),
                    _unit_cond(unit_id),
                ))
                .limit(1)
            )
            err_type, row_list = await DB_SESSION_MNG.execute(cdb, query)
            if err_type != ErrorType.SUCCESS:
                return err_type, None
            return ErrorType.SUCCESS, (row_list[0] if row_list else None)
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED, None

    async def get_candidate(self, cdb: AsyncSession, place_id, unit_id, key, source_type) -> Tuple[ErrorType, place_facts]:
        """같은 출처가 이미 올려둔 후보. 재수집이 같은 후보를 계속 쌓지 않도록 갱신 대상을 찾는다."""
        try:
            query = (
                select(place_facts)
                .where(and_(
                    place_facts.place_id == place_id,
                    place_facts.key == key,
                    place_facts.source_type == source_type,
                    place_facts.deleted == False,  # noqa: E712
                    place_facts.status.in_(_CANDIDATE),
                    _unit_cond(unit_id),
                ))
                .order_by(place_facts.collected_at.desc())
                .limit(1)
            )
            err_type, row_list = await DB_SESSION_MNG.execute(cdb, query)
            if err_type != ErrorType.SUCCESS:
                return err_type, None
            return ErrorType.SUCCESS, (row_list[0] if row_list else None)
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED, None

    async def refresh_collected(self, cdb: AsyncSession, fact_id, source_type, source_url, ts) -> Tuple[ErrorType, int]:
        """★ 재수집했는데 값이 그대로일 때 — 검증 상태를 건드리지 않고 '언제 다시 확인했는지'만 갱신한다.

        이게 없으면 값이 안 바뀌었는데도 재수집마다 검증이 초기화돼 사이트에서 사실이 사라진다."""
        try:
            values = {"collected_at": ts, "updated_at": ts}
            if source_url:
                values["source_url"] = source_url
            query = update(place_facts).where(place_facts.fact_id == fact_id, place_facts.deleted == False).values(**values)  # noqa: E712
            return await DB_SESSION_MNG.add_with_rowcount(cdb, query)
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED, 0

    async def update_candidate(self, cdb: AsyncSession, fact_id, value, source_url, status: int, ts) -> Tuple[ErrorType, int]:
        """기존 후보를 새 수집값으로 갱신. 같은 출처의 후보가 계속 쌓이는 것을 막는다."""
        try:
            query = (
                update(place_facts)
                .where(place_facts.fact_id == fact_id, place_facts.status.in_(_CANDIDATE), place_facts.deleted == False)  # noqa: E712
                .values(value=value, source_url=source_url, status=status, collected_at=ts, updated_at=ts)
            )
            return await DB_SESSION_MNG.add_with_rowcount(cdb, query)
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED, 0

    async def transition(self, cdb: AsyncSession, fact_id, from_statuses, to_status: int, data: dict) -> Tuple[ErrorType, int]:
        """검증 상태 전이 — **출발 상태를 WHERE 에 걸어** 조건부로만 바꾼다.

        적용행수 0 = 그 사이 다른 사람이 이미 상태를 바꿨다는 뜻(동시 처리 가드).
        허용 전이 판정 자체는 service 가 FACT_STATUS_TRANSITIONS 로 먼저 한다."""
        try:
            query = (
                update(place_facts)
                .where(
                    place_facts.fact_id == fact_id,
                    place_facts.status.in_(tuple(from_statuses)),
                    place_facts.deleted == False,  # noqa: E712
                )
                .values(status=to_status, updated_at=GTime.UTC(), **data)
            )
            return await DB_SESSION_MNG.add_with_rowcount(cdb, query)
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED, 0

    async def expire_published(self, cdb: AsyncSession, place_id, unit_id, key, ts, except_fact_id=None) -> Tuple[ErrorType, int]:
        """현재 노출값을 EXPIRED 로 내려 자리를 비운다(후보 승격·직접 교체 직전에 호출).

        지우지 않고 이력으로 남긴다 — 예전에 뭐가 나갔는지 추적할 수 있어야 한다."""
        try:
            conditions = [
                place_facts.place_id == place_id,
                place_facts.key == key,
                place_facts.deleted == False,  # noqa: E712
                place_facts.status.in_(_PUBLISHED),
                _unit_cond(unit_id),
            ]
            if except_fact_id is not None:
                conditions.append(place_facts.fact_id != except_fact_id)
            query = update(place_facts).where(and_(*conditions)).values(status=FactStatus.EXPIRED.value, updated_at=ts)
            return await DB_SESSION_MNG.add_with_rowcount(cdb, query)
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED, 0

    async def reject_candidates(self, cdb: AsyncSession, place_id, unit_id, key, ts, except_fact_id=None) -> Tuple[ErrorType, int]:
        """남은 후보를 REJECTED 로 정리한다(하나를 승격시켰으니 나머지는 판정된 셈).

        후보를 그대로 두면 사람 확인 큐에 이미 처리된 항목이 계속 남는다."""
        try:
            conditions = [
                place_facts.place_id == place_id,
                place_facts.key == key,
                place_facts.deleted == False,  # noqa: E712
                place_facts.status.in_(_CANDIDATE),
                _unit_cond(unit_id),
            ]
            if except_fact_id is not None:
                conditions.append(place_facts.fact_id != except_fact_id)
            query = update(place_facts).where(and_(*conditions)).values(status=FactStatus.REJECTED.value, updated_at=ts)
            return await DB_SESSION_MNG.add_with_rowcount(cdb, query)
        except Exception as ex:
            LOG.e_no_callstack(ex)
            return ErrorType.DB_RUN_FAILED, 0