from __future__ import annotations

from collections.abc import Generator
from datetime import datetime
from decimal import Decimal
from unittest.mock import MagicMock, patch

import pytest
from sqlalchemy import create_engine
from sqlalchemy.orm import Session, sessionmaker
from sqlalchemy.pool import StaticPool

from app.db.base import Base
from app.models.agent_asset import AgentAsset, AgentAssetTestRun
from app.models.employee import Employee
from app.models.financial_record import ExpenseClaim
from app.models.golden_case import GoldenCase
from app.services.risk_rule_golden_evaluator import (
    GoldenEvalReport,
    RiskRuleGoldenEvaluator,
    _aggregate,
    _run_single_case,
)


def _build_session() -> Session:
    engine = create_engine(
        "sqlite+pysqlite:///:memory:",
        connect_args={"check_same_thread": False},
        poolclass=StaticPool,
    )
    Base.metadata.create_all(bind=engine)
    factory = sessionmaker(bind=engine, autoflush=False, autocommit=False)
    return factory()


def _keyword_manifest() -> dict:
    """一个简单的 keyword_match_v1 manifest：reason 含"虚假"则命中。"""

    return {
        "rule_code": "risk.test.keyword",
        "template_key": "keyword_match_v1",
        "inputs": {
            "fields": [
                {"key": "claim.reason", "label": "事由", "type": "text", "source": "claim"},
            ]
        },
        "params": {
            "keywords": ["虚假"],
            "field_keys": ["claim.reason"],
            "search_fields": ["claim.reason"],
        },
        "outcomes": {"fail": {"severity": "high", "risk_score": 80}},
    }


def _golden_case(
    case_key: str,
    *,
    reason: str,
    expected_hit: bool,
    rule_code: str = "risk.test.keyword",
) -> GoldenCase:
    return GoldenCase(
        case_key=case_key,
        rule_code=rule_code,
        name=f"case-{case_key}",
        values_json={"claim.reason": reason},
        expected_hit=expected_hit,
        status="active",
    )


def test_run_single_case_hit_matches() -> None:
    result = _run_single_case(
        _keyword_manifest(),
        values={"claim.reason": "虚假发票报销"},
        expected_hit=True,
        expected_severity="high",
    )
    assert result.actual_hit is True
    assert result.passed is True
    assert result.actual_severity == "high"


def test_run_single_case_no_hit_matches() -> None:
    result = _run_single_case(
        _keyword_manifest(),
        values={"claim.reason": "正常差旅报销"},
        expected_hit=False,
        expected_severity="",
    )
    assert result.actual_hit is False
    assert result.passed is True


def test_run_single_case_mismatch_fails() -> None:
    result = _run_single_case(
        _keyword_manifest(),
        values={"claim.reason": "虚假发票"},
        expected_hit=False,  # 期望不命中，但实际命中
        expected_severity="",
    )
    assert result.actual_hit is True
    assert result.passed is False


def test_run_single_case_severity_mismatch_fails() -> None:
    result = _run_single_case(
        _keyword_manifest(),
        values={"claim.reason": "虚假发票"},
        expected_hit=True,
        expected_severity="critical",  # 实际是 high
    )
    assert result.passed is False


def test_aggregate_empty_returns_passed() -> None:
    report = _aggregate([])
    assert report.total == 0
    assert report.all_passed is True
    assert report.accuracy == 0.0


def test_aggregate_all_passed() -> None:
    from app.services.risk_rule_golden_evaluator import GoldenCaseResult

    results = [
        GoldenCaseResult("1", "a", True, True, "high", "high", True),
        GoldenCaseResult("2", "b", False, False, "", "none", True),
    ]
    report = _aggregate(results)
    assert report.total == 2
    assert report.passed_count == 2
    assert report.accuracy == 1.0
    assert report.all_passed is True


def test_aggregate_with_failure() -> None:
    from app.services.risk_rule_golden_evaluator import GoldenCaseResult

    results = [
        GoldenCaseResult("1", "a", True, True, "high", "high", True),
        GoldenCaseResult("2", "b", True, False, "high", "none", False),  # FP
    ]
    report = _aggregate(results)
    assert report.passed_count == 1
    assert report.failed_count == 1
    assert report.accuracy == 0.5
    assert report.all_passed is False
    assert report.precision == 0.5  # 1/(1+1)


def test_evaluate_for_rule_empty_returns_passed() -> None:
    with _build_session() as db:
        report = RiskRuleGoldenEvaluator().evaluate_for_rule(db, _keyword_manifest(), "risk.test.keyword")
        assert report.total == 0
        assert report.all_passed is True


def test_evaluate_for_rule_all_pass() -> None:
    with _build_session() as db:
        db.add(_golden_case("g1", reason="虚假发票", expected_hit=True))
        db.add(_golden_case("g2", reason="正常报销", expected_hit=False))
        db.commit()
        report = RiskRuleGoldenEvaluator().evaluate_for_rule(db, _keyword_manifest(), "risk.test.keyword")
        assert report.total == 2
        assert report.all_passed is True
        assert report.accuracy == 1.0


def test_evaluate_for_rule_with_failure() -> None:
    with _build_session() as db:
        db.add(_golden_case("g1", reason="虚假发票", expected_hit=False))  # 期望不命中但实际命中
        db.add(_golden_case("g2", reason="正常报销", expected_hit=True))   # 期望命中但实际不命中
        db.commit()
        report = RiskRuleGoldenEvaluator().evaluate_for_rule(db, _keyword_manifest(), "risk.test.keyword")
        assert report.total == 2
        assert report.all_passed is False
        assert report.failed_count == 2


def _asset(asset_id: str, code: str) -> AgentAsset:
    return AgentAsset(
        id=asset_id,
        code=code,
        name=code,
        asset_type="rule",
        domain="expense",
        owner="tester",
        status="review",
        working_version="v1",
    )


def test_require_pass_passes_when_all_green() -> None:
    with _build_session() as db:
        asset = _asset("a1", "R1")
        db.add(asset)
        db.add(_golden_case("g1", reason="虚假", expected_hit=True))
        db.commit()
        report = RiskRuleGoldenEvaluator().require_pass(
            db, asset, "v1", _keyword_manifest(), "risk.test.keyword", actor="tester"
        )
        assert report.all_passed is True
        # 应写一条 test_type='golden' 记录
        run = db.query(AgentAssetTestRun).filter_by(asset_id="a1", test_type="golden").one()
        assert run.passed is True


def test_require_pass_raises_on_failure() -> None:
    with _build_session() as db:
        asset = _asset("a2", "R2")
        db.add(asset)
        db.add(_golden_case("g1", reason="虚假", expected_hit=False))  # 会失败
        db.commit()
        with pytest.raises(PermissionError):
            RiskRuleGoldenEvaluator().require_pass(
                db, asset, "v1", _keyword_manifest(), "risk.test.keyword", actor="tester"
            )
        run = db.query(AgentAssetTestRun).filter_by(asset_id="a2", test_type="golden").one()
        assert run.passed is False


def test_require_pass_empty_golden_set_passes() -> None:
    with _build_session() as db:
        asset = _asset("a3", "R3")
        db.add(asset)
        db.commit()
        report = RiskRuleGoldenEvaluator().require_pass(
            db, asset, "v1", _keyword_manifest(), "risk.test.keyword", actor="tester"
        )
        assert report.total == 0
        assert report.all_passed is True


def test_require_pass_respects_feature_flag(monkeypatch: pytest.MonkeyPatch) -> None:
    monkeypatch.setenv("GOLDEN_SET_GATE_ENABLED", "false")
    with _build_session() as db:
        asset = _asset("a4", "R4")
        db.add(asset)
        db.add(_golden_case("g1", reason="虚假", expected_hit=False))  # 本应失败
        db.commit()
        # 门禁关闭，应放行不抛异常
        report = RiskRuleGoldenEvaluator().require_pass(
            db, asset, "v1", _keyword_manifest(), "risk.test.keyword", actor="tester"
        )
        assert report.total == 0


def test_require_pass_swallows_evaluator_exception() -> None:
    with _build_session() as db:
        asset = _asset("a5", "R5")
        db.add(asset)
        db.commit()
        evaluator = RiskRuleGoldenEvaluator()
        with patch.object(evaluator, "evaluate_for_rule", side_effect=RuntimeError("boom")):
            report = evaluator.require_pass(
                db, asset, "v1", _keyword_manifest(), "risk.test.keyword", actor="tester"
            )
        assert report.total == 0
        assert report.all_passed is True  # 降级放行