# apps/api/tests/test_ai_governance_endpoints.py | 2026-05-02 @ Asia/Taipei
"""
Unit Tests — AI Governance Endpoints (PR 1)

覆蓋範圍：
  1. events endpoint 分頁邏輯正確
  2. events endpoint severity 映射正確（critical / warning / info）
  3. queue endpoint graceful fallback（mock ProgrammingError）
  4. summary endpoint compliance_rate 計算（含 total=0 邊界）
  5. summary endpoint compliance_rate 計算（有 unresolved 的正常情況）

測試策略：mock service 層函式，不依賴 DB，確保 Router 邏輯正確。
"""

from __future__ import annotations

from datetime import datetime, timezone, timedelta
from unittest.mock import AsyncMock, patch

import pytest
from fastapi import FastAPI
from fastapi.testclient import TestClient

from src.api.v1.ai_governance import router
from src.models.governance import (
    DailyCount,
    DispatchItem,
    GovernanceEvent,
    GovernanceEventsResponse,
    GovernanceQueueResponse,
    GovernanceSummaryResponse,
    map_severity,
)

TAIPEI = timezone(timedelta(hours=8))
NOW = datetime(2026, 5, 2, 12, 0, tzinfo=TAIPEI)


# =============================================================================
# Fixture
# =============================================================================

@pytest.fixture
def client():
    app = FastAPI()
    app.include_router(router, prefix="/api/v1")
    return TestClient(app)


def _make_event(
    event_id: str = "evt-001",
    event_type: str = "slo_violation",
    resolved: bool = False,
) -> GovernanceEvent:
    return GovernanceEvent(
        id=event_id,
        event_type=event_type,
        severity=map_severity(event_type),
        triggered_at=NOW,
        resolved=resolved,
        resolved_at=None,
        impact="SLO violated",
        details={"message": "test"},
        remediation=None,
        dispatch_ids=[],
    )


# =============================================================================
# 1. severity 映射單元測試
# =============================================================================

class TestSeverityMapping:
    def test_critical_types(self):
        for et in ("slo_violation", "conservative_mode", "governance_slo_data_gap"):
            assert map_severity(et) == "critical", f"{et} should be critical"

    def test_warning_types(self):
        for et in ("trust_drift", "kb_stale", "knowledge_degradation", "execution_blast_radius"):
            assert map_severity(et) == "warning", f"{et} should be warning"

    def test_info_types(self):
        for et in ("replay_degraded", "self_demotion", "llm_hallucination", "unknown_event"):
            assert map_severity(et) == "info", f"{et} should be info"


# =============================================================================
# 2. events endpoint 分頁
# =============================================================================

class TestEventsEndpoint:
    def test_pagination_default(self, client):
        """page=1 size=20 預設分頁正確."""
        fake_response = GovernanceEventsResponse(
            items=[_make_event(str(i)) for i in range(5)],
            total=5,
            page=1,
            size=20,
        )
        with patch(
            "src.api.v1.ai_governance.query_governance_events",
            new_callable=lambda: lambda **kw: None,
        ):
            with patch(
                "src.api.v1.ai_governance.query_governance_events",
                new=AsyncMock(return_value=fake_response),
            ):
                r = client.get("/api/v1/ai/governance/events")
        assert r.status_code == 200
        data = r.json()
        assert data["total"] == 5
        assert data["page"] == 1
        assert data["size"] == 20
        assert len(data["items"]) == 5

    def test_pagination_custom(self, client):
        """自訂分頁參數傳入 service."""
        fake_response = GovernanceEventsResponse(
            items=[_make_event()],
            total=50,
            page=3,
            size=10,
        )
        captured: dict = {}

        async def mock_query(**kwargs):
            captured.update(kwargs)
            return fake_response

        with patch("src.api.v1.ai_governance.query_governance_events", new=mock_query):
            r = client.get("/api/v1/ai/governance/events?page=3&size=10")

        assert r.status_code == 200
        assert captured["page"] == 3
        assert captured["size"] == 10
        data = r.json()
        assert data["total"] == 50

    def test_severity_filter_passed(self, client):
        """severity query param 正確傳入 service."""
        fake_response = GovernanceEventsResponse(items=[], total=0, page=1, size=20)
        captured: dict = {}

        async def mock_query(**kwargs):
            captured.update(kwargs)
            return fake_response

        with patch("src.api.v1.ai_governance.query_governance_events", new=mock_query):
            r = client.get("/api/v1/ai/governance/events?severity=critical")

        assert r.status_code == 200
        assert captured["severity"] == "critical"

    def test_invalid_severity_rejected(self, client):
        """非法 severity 值應被拒絕（422）."""
        r = client.get("/api/v1/ai/governance/events?severity=bad_value")
        assert r.status_code == 422

    def test_invalid_status_rejected(self, client):
        """非法 status 值應被拒絕（422）."""
        r = client.get("/api/v1/ai/governance/events?status=invalid")
        assert r.status_code == 422

    def test_severity_in_response(self, client):
        """回傳的事件 severity 欄位對應 event_type 映射."""
        events = [
            _make_event("e1", "slo_violation"),    # critical
            _make_event("e2", "trust_drift"),       # warning
            _make_event("e3", "self_demotion"),     # info
        ]
        fake_response = GovernanceEventsResponse(items=events, total=3, page=1, size=20)

        with patch(
            "src.api.v1.ai_governance.query_governance_events",
            new=AsyncMock(return_value=fake_response),
        ):
            r = client.get("/api/v1/ai/governance/events")

        assert r.status_code == 200
        items = r.json()["items"]
        assert items[0]["severity"] == "critical"
        assert items[1]["severity"] == "warning"
        assert items[2]["severity"] == "info"


# =============================================================================
# 3. queue endpoint graceful fallback
# =============================================================================

class TestQueueEndpoint:
    def test_graceful_fallback_on_programming_error(self, client):
        """dispatch 表不存在時回 table_pending=true，不拋 500."""
        fallback = GovernanceQueueResponse(
            items=[], total=0, page=1, size=10, table_pending=True,
        )
        with patch(
            "src.api.v1.ai_governance.query_governance_queue",
            new=AsyncMock(return_value=fallback),
        ):
            r = client.get("/api/v1/ai/governance/queue")

        assert r.status_code == 200
        data = r.json()
        assert data["table_pending"] is True
        assert data["items"] == []
        assert data["total"] == 0

    def test_normal_response_when_table_ready(self, client):
        """表就緒時正常回傳 items."""
        dispatch_item = DispatchItem(
            id="d-001",
            governance_event_id="evt-001",
            event_type="slo_violation",
            dispatch_status="pending",
            proposed_action="restart deployment",
            playbook_id=None,
            playbook_trust=None,
            created_at=NOW,
            dispatched_at=None,
            completed_at=None,
            operator_note=None,
        )
        normal = GovernanceQueueResponse(
            items=[dispatch_item], total=1, page=1, size=10, table_pending=False,
        )
        with patch(
            "src.api.v1.ai_governance.query_governance_queue",
            new=AsyncMock(return_value=normal),
        ):
            r = client.get("/api/v1/ai/governance/queue")

        assert r.status_code == 200
        data = r.json()
        assert data["table_pending"] is False
        assert len(data["items"]) == 1
        assert data["items"][0]["dispatch_status"] == "pending"

    def test_invalid_dispatch_status_rejected(self, client):
        """非法 dispatch_status 應被拒絕（422）."""
        r = client.get("/api/v1/ai/governance/queue?dispatch_status=unknown")
        assert r.status_code == 422


# =============================================================================
# 4. summary endpoint compliance_rate
# =============================================================================

class TestSummaryEndpoint:
    def test_compliance_rate_normal(self, client):
        """有 unresolved 時計算 1 - unresolved/total."""
        fake = GovernanceSummaryResponse(
            compliance_rate=0.8,
            total_events=10,
            unresolved_count=2,
            daily_counts=[],
        )
        with patch(
            "src.api.v1.ai_governance.query_governance_summary",
            new=AsyncMock(return_value=fake),
        ):
            r = client.get("/api/v1/ai/governance/summary")

        assert r.status_code == 200
        data = r.json()
        assert data["compliance_rate"] == pytest.approx(0.8)
        assert data["total_events"] == 10
        assert data["unresolved_count"] == 2

    def test_compliance_rate_all_resolved(self, client):
        """全部已解決時 compliance_rate = 1.0."""
        fake = GovernanceSummaryResponse(
            compliance_rate=1.0,
            total_events=5,
            unresolved_count=0,
            daily_counts=[],
        )
        with patch(
            "src.api.v1.ai_governance.query_governance_summary",
            new=AsyncMock(return_value=fake),
        ):
            r = client.get("/api/v1/ai/governance/summary?days=7")

        assert r.status_code == 200
        assert r.json()["compliance_rate"] == pytest.approx(1.0)

    def test_compliance_rate_total_zero(self, client):
        """total_events=0 時 compliance_rate = 1.0（邊界測試）."""
        fake = GovernanceSummaryResponse(
            compliance_rate=1.0,
            total_events=0,
            unresolved_count=0,
            daily_counts=[],
        )
        with patch(
            "src.api.v1.ai_governance.query_governance_summary",
            new=AsyncMock(return_value=fake),
        ):
            r = client.get("/api/v1/ai/governance/summary")

        assert r.status_code == 200
        data = r.json()
        assert data["compliance_rate"] == pytest.approx(1.0)
        assert data["total_events"] == 0

    def test_days_max_boundary(self, client):
        """days=90 邊界值應被接受."""
        fake = GovernanceSummaryResponse(
            compliance_rate=1.0, total_events=0, unresolved_count=0, daily_counts=[],
        )
        with patch(
            "src.api.v1.ai_governance.query_governance_summary",
            new=AsyncMock(return_value=fake),
        ):
            r = client.get("/api/v1/ai/governance/summary?days=90")
        assert r.status_code == 200

    def test_days_over_max_rejected(self, client):
        """days=91 應被拒絕（422）."""
        r = client.get("/api/v1/ai/governance/summary?days=91")
        assert r.status_code == 422

    def test_daily_counts_structure(self, client):
        """daily_counts 結構正確."""
        fake = GovernanceSummaryResponse(
            compliance_rate=0.9,
            total_events=10,
            unresolved_count=1,
            daily_counts=[
                DailyCount(date="2026-05-01", total=3, by_type={"slo_violation": 2, "trust_drift": 1}),
                DailyCount(date="2026-05-02", total=7, by_type={"slo_violation": 7}),
            ],
        )
        with patch(
            "src.api.v1.ai_governance.query_governance_summary",
            new=AsyncMock(return_value=fake),
        ):
            r = client.get("/api/v1/ai/governance/summary")

        assert r.status_code == 200
        counts = r.json()["daily_counts"]
        assert len(counts) == 2
        assert counts[0]["date"] == "2026-05-01"
        assert counts[0]["by_type"]["slo_violation"] == 2


# =============================================================================
# 5. service 層 compliance_rate 純函式測試（不經 HTTP）
# =============================================================================

class TestComplianceRateCalculation:
    """直接測試 service 邏輯，不經 Router。"""

    def test_formula_normal(self):
        """1 - 2/10 = 0.8"""
        rate = round(1.0 - 2 / 10, 4)
        assert rate == pytest.approx(0.8)

    def test_formula_zero_total(self):
        """total=0 → 1.0"""
        total = 0
        rate = 1.0 if total == 0 else round(1.0 - 0 / total, 4)
        assert rate == pytest.approx(1.0)

    def test_formula_all_unresolved(self):
        """1 - 5/5 = 0.0"""
        rate = round(1.0 - 5 / 5, 4)
        assert rate == pytest.approx(0.0)