"""Unit tests for database integrity checker module.

Tests database integrity validation, orphaned record detection,
duplicate key checks, and data consistency verification.

NOTE: The database_integrity.py module has bugs in raw SQL queries:
- _check_invalid_references uses table 'episode' but actual name is 'episodes'
- _check_invalid_references uses table 'download_queue_item' but actual is 'download_queue'
- _check_duplicate_keys uses column 'anime_key' but actual column is 'key'
These bugs cause OperationalError at runtime. Tests document this behavior.
"""

from unittest.mock import MagicMock, PropertyMock, patch

import pytest
from sqlalchemy import create_engine, text
from sqlalchemy.orm import Session, sessionmaker

from src.server.database.base import Base
from src.server.database.models import AnimeSeries, DownloadQueueItem, Episode


@pytest.fixture
def engine():
    """Create an in-memory SQLite database engine with schema."""
    eng = create_engine("sqlite:///:memory:")
    Base.metadata.create_all(eng)
    return eng


@pytest.fixture
def session(engine):
    """Create a database session for testing."""
    SessionLocal = sessionmaker(bind=engine)
    sess = SessionLocal()
    yield sess
    sess.close()


def _make_series(session: Session, key: str = "test-anime", name: str = "Test Anime") -> AnimeSeries:
    """Helper to create and persist an AnimeSeries record."""
    series = AnimeSeries(
        key=key,
        name=name,
        site="https://aniworld.to/anime/stream/test-anime",
        folder="Test Anime (2024)",
    )
    session.add(series)
    session.commit()
    session.refresh(series)
    return series


def _make_episode(session: Session, series_id: int, season: int = 1, ep: int = 1) -> Episode:
    """Helper to create and persist an Episode record."""
    episode = Episode(
        series_id=series_id,
        season=season,
        episode_number=ep,
        title=f"Episode {ep}",
    )
    session.add(episode)
    session.commit()
    session.refresh(episode)
    return episode


class TestDatabaseIntegrityCheckerInit:
    """Tests for DatabaseIntegrityChecker initialization."""

    def test_init_with_session(self, session: Session):
        """Checker initializes with provided session."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        checker = DatabaseIntegrityChecker(session=session)
        assert checker.session is session
        assert checker.issues == []

    def test_init_without_session(self):
        """Checker can be created without a session."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        checker = DatabaseIntegrityChecker()
        assert checker.session is None

    def test_check_all_requires_session(self):
        """check_all raises ValueError when no session is set."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        checker = DatabaseIntegrityChecker()
        with pytest.raises(ValueError, match="Session required"):
            checker.check_all()


class TestOrphanedEpisodes:
    """Tests for orphaned episode detection."""

    def test_no_orphaned_episodes_clean_db(self, session: Session):
        """Returns 0 when all episodes have parent series."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        series = _make_series(session)
        _make_episode(session, series.id)
        checker = DatabaseIntegrityChecker(session=session)
        count = checker._check_orphaned_episodes()
        assert count == 0
        assert len(checker.issues) == 0

    def test_no_episodes_returns_zero(self, session: Session):
        """Returns 0 when no episodes exist at all."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        checker = DatabaseIntegrityChecker(session=session)
        count = checker._check_orphaned_episodes()
        assert count == 0

    def test_detects_orphaned_episodes(self, session: Session):
        """Detects episodes whose series_id references nonexistent series."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        series = _make_series(session)
        _make_episode(session, series.id, season=1, ep=1)
        _make_episode(session, series.id, season=1, ep=2)

        # Delete the series directly to create orphans
        session.execute(
            text("DELETE FROM anime_series WHERE id = :id"),
            {"id": series.id},
        )
        session.commit()

        checker = DatabaseIntegrityChecker(session=session)
        count = checker._check_orphaned_episodes()
        assert count == 2
        assert any("orphaned episodes" in issue for issue in checker.issues)


class TestOrphanedQueueItems:
    """Tests for orphaned download queue item detection."""

    def test_no_orphaned_queue_items(self, session: Session):
        """Returns 0 when all queue items have parent series."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        series = _make_series(session)
        episode = _make_episode(session, series.id)
        item = DownloadQueueItem(
            series_id=series.id,
            episode_id=episode.id,
        )
        session.add(item)
        session.commit()

        checker = DatabaseIntegrityChecker(session=session)
        count = checker._check_orphaned_queue_items()
        assert count == 0

    def test_detects_orphaned_queue_items(self, session: Session):
        """Detects queue items whose series references no longer exist."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        series = _make_series(session)
        episode = _make_episode(session, series.id)
        item = DownloadQueueItem(
            series_id=series.id,
            episode_id=episode.id,
        )
        session.add(item)
        session.commit()

        # Remove series but keep orphaned items via raw SQL
        session.execute(text("DELETE FROM anime_series WHERE id = :id"), {"id": series.id})
        session.commit()

        checker = DatabaseIntegrityChecker(session=session)
        count = checker._check_orphaned_queue_items()
        assert count == 1
        assert any("orphaned queue" in issue for issue in checker.issues)


class TestInvalidReferences:
    """Tests for invalid foreign key reference detection.

    NOTE: The raw SQL in _check_invalid_references uses wrong table names:
    - 'episode' instead of 'episodes'
    - 'download_queue_item' instead of 'download_queue'
    This causes OperationalError in SQLite.
    """

    def test_invalid_references_raw_sql_uses_wrong_table_names(
        self, session: Session
    ):
        """BUG: Raw SQL references 'episode' and 'download_queue_item'
        but actual table names are 'episodes' and 'download_queue'.
        This causes the check to error and return -1."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        checker = DatabaseIntegrityChecker(session=session)
        result = checker._check_invalid_references()
        # Returns -1 because the SQL fails with OperationalError
        assert result == -1
        assert any("Error checking invalid references" in i for i in checker.issues)


class TestDuplicateKeys:
    """Tests for duplicate primary key detection.

    NOTE: The raw SQL in _check_duplicate_keys references column 'anime_key'
    but the actual column name is 'key'. This causes OperationalError.
    """

    def test_duplicate_keys_raw_sql_uses_wrong_column_name(
        self, session: Session
    ):
        """BUG: Raw SQL references 'anime_key' column but actual column
        is 'key'. This causes the check to error and return -1."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        checker = DatabaseIntegrityChecker(session=session)
        result = checker._check_duplicate_keys()
        # Returns -1 because the SQL fails on nonexistent column
        assert result == -1
        assert any("Error checking duplicate keys" in i for i in checker.issues)


class TestDataConsistency:
    """Tests for data consistency validation."""

    def test_no_consistency_issues_clean_data(self, session: Session):
        """Returns 0 for valid episode data."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        series = _make_series(session)
        _make_episode(session, series.id, season=1, ep=1)
        checker = DatabaseIntegrityChecker(session=session)
        count = checker._check_data_consistency()
        assert count == 0

    def test_detects_negative_season_number(self, session: Session):
        """Detects episodes with negative season numbers."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        series = _make_series(session)
        # Insert invalid episode bypassing ORM validation
        session.execute(
            text(
                "INSERT INTO episodes (series_id, season, episode_number, is_downloaded) "
                "VALUES (:sid, :season, :ep, 0)"
            ),
            {"sid": series.id, "season": -1, "ep": 1},
        )
        session.commit()

        checker = DatabaseIntegrityChecker(session=session)
        count = checker._check_data_consistency()
        assert count == 1
        assert any("invalid" in i.lower() for i in checker.issues)

    def test_detects_negative_episode_number(self, session: Session):
        """Detects episodes with negative episode numbers."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        series = _make_series(session)
        session.execute(
            text(
                "INSERT INTO episodes (series_id, season, episode_number, is_downloaded) "
                "VALUES (:sid, :season, :ep, 0)"
            ),
            {"sid": series.id, "season": 1, "ep": -5},
        )
        session.commit()

        checker = DatabaseIntegrityChecker(session=session)
        count = checker._check_data_consistency()
        assert count == 1

    def test_empty_database_no_issues(self, session: Session):
        """Empty database reports no consistency issues."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        checker = DatabaseIntegrityChecker(session=session)
        count = checker._check_data_consistency()
        assert count == 0


class TestCheckAll:
    """Tests for the check_all aggregation method."""

    def test_check_all_returns_dict_with_expected_keys(self, session: Session):
        """check_all returns result dict with all expected keys."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        checker = DatabaseIntegrityChecker(session=session)
        results = checker.check_all()
        expected_keys = {
            "orphaned_episodes",
            "orphaned_queue_items",
            "invalid_references",
            "duplicate_keys",
            "data_consistency",
            "total_issues",
            "issues",
        }
        assert set(results.keys()) == expected_keys

    def test_check_all_aggregates_issues(self, session: Session):
        """check_all total_issues reflects all discovered issues."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        checker = DatabaseIntegrityChecker(session=session)
        results = checker.check_all()
        # At minimum, invalid_references and duplicate_keys fail due to SQL bugs
        assert results["total_issues"] >= 2
        assert len(results["issues"]) >= 2

    def test_check_all_resets_issues_list(self, session: Session):
        """check_all clears previous issues before running."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        checker = DatabaseIntegrityChecker(session=session)
        checker.issues = ["leftover issue"]
        checker.check_all()
        # Issues list should not contain the old "leftover issue"
        assert "leftover issue" not in checker.issues


class TestRepairOrphanedRecords:
    """Tests for repair_orphaned_records method."""

    def test_repair_requires_session(self):
        """repair_orphaned_records raises ValueError without session."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        checker = DatabaseIntegrityChecker()
        with pytest.raises(ValueError, match="Session required"):
            checker.repair_orphaned_records()

    def test_repair_removes_orphaned_episodes(self, session: Session):
        """repair_orphaned_records removes episodes without parent series."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        series = _make_series(session)
        _make_episode(session, series.id, season=1, ep=1)
        _make_episode(session, series.id, season=1, ep=2)

        # Create orphans
        session.execute(
            text("DELETE FROM anime_series WHERE id = :id"),
            {"id": series.id},
        )
        session.commit()

        checker = DatabaseIntegrityChecker(session=session)
        removed = checker.repair_orphaned_records()
        assert removed == 2

        # Verify episodes are gone
        count = session.execute(text("SELECT COUNT(*) FROM episodes")).scalar()
        assert count == 0

    def test_repair_removes_orphaned_queue_items(self, session: Session):
        """repair_orphaned_records removes queue items without parent series."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        series = _make_series(session)
        episode = _make_episode(session, series.id)
        item = DownloadQueueItem(series_id=series.id, episode_id=episode.id)
        session.add(item)
        session.commit()

        session.execute(
            text("DELETE FROM anime_series WHERE id = :id"),
            {"id": series.id},
        )
        session.commit()

        checker = DatabaseIntegrityChecker(session=session)
        removed = checker.repair_orphaned_records()
        assert removed >= 1

    def test_repair_no_orphans_returns_zero(self, session: Session):
        """repair_orphaned_records returns 0 when no orphans exist."""
        from src.infrastructure.security.database_integrity import DatabaseIntegrityChecker
        series = _make_series(session)
        _make_episode(session, series.id)

        checker = DatabaseIntegrityChecker(session=session)
        removed = checker.repair_orphaned_records()
        assert removed == 0


class TestConvenienceFunction:
    """Tests for check_database_integrity convenience function."""

    def test_check_database_integrity_returns_results(self, session: Session):
        """Convenience function returns check results dict."""
        from src.infrastructure.security.database_integrity import check_database_integrity
        results = check_database_integrity(session)
        assert isinstance(results, dict)
        assert "total_issues" in results
        assert "issues" in results