"""双时态事实仓储：写入与"按历史时点回放"查询。

对应需求 R3 / ADR-0002：
- 业务有效期 valid_from/valid_to（应用时间）
- 系统记录期 system_from/system_to（事务时间）
回放 = 给定 (as_of_valid, as_of_system) 在两条时间线上各取"包含该时点"的记录。
"""

from __future__ import annotations

import datetime as dt
import uuid

from sqlalchemy import or_
from sqlalchemy.orm import Session

from app.datahub.models import BitemporalFact


def record_fact(
    session: Session,
    entity_id: uuid.UUID,
    attr_name: str,
    attr_value: dict,
    valid_from: dt.datetime,
    valid_to: dt.datetime | None = None,
    data_version_id: uuid.UUID | None = None,
) -> BitemporalFact:
    """记录一条双时态事实（system_from 自动取当前事务时间）。"""
    fact = BitemporalFact(
        entity_id=entity_id,
        attr_name=attr_name,
        attr_value=attr_value,
        valid_from=valid_from,
        valid_to=valid_to,
        data_version_id=data_version_id,
    )
    session.add(fact)
    session.flush()
    return fact


def as_of(
    session: Session,
    entity_id: uuid.UUID,
    attr_name: str,
    as_of_valid: dt.datetime,
    as_of_system: dt.datetime | None = None,
) -> BitemporalFact | None:
    """回放：返回在给定业务时点且按给定系统时点可见的事实。

    - 业务时间线：valid_from <= as_of_valid < valid_to(或为空表示至今)
    - 系统时间线：system_from <= as_of_system < system_to(或为空表示当前可见)
    """
    as_of_system = as_of_system or dt.datetime.now(dt.UTC)

    q = (
        session.query(BitemporalFact)
        .filter(BitemporalFact.entity_id == entity_id)
        .filter(BitemporalFact.attr_name == attr_name)
        .filter(BitemporalFact.valid_from <= as_of_valid)
        .filter(
            or_(BitemporalFact.valid_to.is_(None), BitemporalFact.valid_to > as_of_valid)
        )
        .filter(BitemporalFact.system_from <= as_of_system)
        .filter(
            or_(
                BitemporalFact.system_to.is_(None),
                BitemporalFact.system_to > as_of_system,
            )
        )
        .order_by(BitemporalFact.system_from.desc())
    )
    return q.first()


def close_fact(
    session: Session, fact: BitemporalFact, system_to: dt.datetime | None = None
) -> None:
    """逻辑关闭一条事实的系统可见期（用于更正/失效，而非物理删除）。"""
    fact.system_to = system_to or dt.datetime.now(dt.UTC)
    session.add(fact)
    session.flush()