"""
Test suite for SessionManager.

Tests database creation, CRUD operations, concurrent access, and edge cases.

Author: Claude Code
Created: 2026-02-13
"""

import asyncio
import logging
import os
import tempfile
from pathlib import Path

import pytest

# Add parent directory to path for imports
import sys
sys.path.insert(0, str(Path(__file__).parent.parent))

from claude_coordinator.session_manager import SessionManager


# Configure logging for tests
logging.basicConfig(
    level=logging.DEBUG,
    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s'
)


@pytest.fixture
def temp_db():
    """Create a temporary database file for testing."""
    with tempfile.NamedTemporaryFile(delete=False, suffix='.db') as f:
        db_path = f.name

    yield db_path

    # Cleanup
    try:
        os.unlink(db_path)
        # Also remove WAL and SHM files if they exist
        for ext in ['-wal', '-shm']:
            wal_path = db_path + ext
            if os.path.exists(wal_path):
                os.unlink(wal_path)
    except Exception as e:
        print(f"Warning: Could not clean up test database: {e}")


@pytest.fixture
async def manager(temp_db):
    """Create a SessionManager instance with temporary database."""
    mgr = SessionManager(db_path=temp_db)
    await mgr._initialize_db()
    yield mgr
    await mgr.close()


# Configure pytest-asyncio
pytest_plugins = ('pytest_asyncio',)


class TestSessionManagerInit:
    """Test database initialization and schema creation."""

    @pytest.mark.asyncio
    async def test_database_creation(self, temp_db):
        """
        Test that database file is created and schema is initialized.

        What: Verify database file creation and table schema
        Why: Ensure proper initialization on first use
        """
        async with SessionManager(db_path=temp_db) as manager:
            assert manager._db is not None
            assert Path(temp_db).exists()

            # Verify sessions table exists
            async with manager._db.execute(
                "SELECT name FROM sqlite_master WHERE type='table' AND name='sessions'"
            ) as cursor:
                result = await cursor.fetchone()
                assert result is not None
                assert result[0] == 'sessions'

    @pytest.mark.asyncio
    async def test_indexes_created(self, temp_db):
        """
        Test that database indexes are created for performance.

        What: Check for idx_last_active and idx_project_name indexes
        Why: Indexes are critical for query performance
        """
        async with SessionManager(db_path=temp_db) as manager:
            async with manager._db.execute(
                "SELECT name FROM sqlite_master WHERE type='index'"
            ) as cursor:
                indexes = [row[0] for row in await cursor.fetchall()]

            assert 'idx_last_active' in indexes
            assert 'idx_project_name' in indexes

    @pytest.mark.asyncio
    async def test_default_db_path(self):
        """
        Test that default database path is created in user home directory.

        What: Verify ~/.claude-coordinator/sessions.db creation
        Why: Users should get sensible defaults without configuration
        """
        manager = SessionManager()
        expected_dir = Path.home() / ".claude-coordinator"
        expected_path = expected_dir / "sessions.db"

        assert manager.db_path == str(expected_path)

        # Cleanup if created
        if expected_path.exists():
            expected_path.unlink()
            for ext in ['-wal', '-shm']:
                wal_path = str(expected_path) + ext
                if Path(wal_path).exists():
                    Path(wal_path).unlink()


class TestSessionCRUD:
    """Test Create, Read, Update, Delete operations for sessions."""

    @pytest.mark.asyncio
    async def test_save_new_session(self, manager):
        """
        Test creating a new session.

        What: Save a new session and verify it's stored correctly
        Why: Session creation is core functionality
        """
        await manager.save_session(
            channel_id="123456",
            session_id="sess_abc123",
            project_name="major-domo"
        )

        session = await manager.get_session("123456")
        assert session is not None
        assert session['channel_id'] == "123456"
        assert session['session_id'] == "sess_abc123"
        assert session['project_name'] == "major-domo"
        assert session['message_count'] == 0

    @pytest.mark.asyncio
    async def test_save_session_without_project(self, manager):
        """
        Test creating a session without a project name.

        What: Save session with project_name=None
        Why: Project name should be optional
        """
        await manager.save_session(
            channel_id="789012",
            session_id="sess_xyz789"
        )

        session = await manager.get_session("789012")
        assert session is not None
        assert session['session_id'] == "sess_xyz789"
        assert session['project_name'] is None

    @pytest.mark.asyncio
    async def test_update_existing_session(self, manager):
        """
        Test updating an existing session with new session_id.

        What: Save a session, then save again with different session_id
        Why: Sessions need to be updateable when Claude sessions change
        """
        # Create initial session
        await manager.save_session(
            channel_id="123456",
            session_id="sess_old",
            project_name="project-a"
        )

        # Update with new session_id
        await manager.save_session(
            channel_id="123456",
            session_id="sess_new",
            project_name="project-b"
        )

        session = await manager.get_session("123456")
        assert session['session_id'] == "sess_new"
        assert session['project_name'] == "project-b"

    @pytest.mark.asyncio
    async def test_get_nonexistent_session(self, manager):
        """
        Test retrieving a session that doesn't exist.

        What: Call get_session for channel with no session
        Why: Should return None gracefully, not error
        """
        session = await manager.get_session("nonexistent")
        assert session is None

    @pytest.mark.asyncio
    async def test_reset_session(self, manager):
        """
        Test deleting a session.

        What: Create session, reset it, verify it's gone
        Why: /reset command needs to clear sessions
        """
        await manager.save_session(
            channel_id="123456",
            session_id="sess_abc123"
        )

        deleted = await manager.reset_session("123456")
        assert deleted is True

        session = await manager.get_session("123456")
        assert session is None

    @pytest.mark.asyncio
    async def test_reset_nonexistent_session(self, manager):
        """
        Test resetting a session that doesn't exist.

        What: Call reset_session for channel with no session
        Why: Should return False, not error
        """
        deleted = await manager.reset_session("nonexistent")
        assert deleted is False


class TestSessionActivity:
    """Test session activity tracking."""

    @pytest.mark.asyncio
    async def test_update_activity(self, manager):
        """
        Test updating last_active and incrementing message_count.

        What: Create session, update activity multiple times, verify counters
        Why: Activity tracking is essential for monitoring
        """
        await manager.save_session(
            channel_id="123456",
            session_id="sess_abc123"
        )

        # Update activity 3 times
        await manager.update_activity("123456")
        await manager.update_activity("123456")
        await manager.update_activity("123456")

        session = await manager.get_session("123456")
        assert session['message_count'] == 3

    @pytest.mark.asyncio
    async def test_update_activity_updates_timestamp(self, manager):
        """
        Test that update_activity changes last_active timestamp.

        What: Create session, wait, update activity, check timestamp changed
        Why: Timestamp tracking is needed for session management
        """
        await manager.save_session(
            channel_id="123456",
            session_id="sess_abc123"
        )

        session1 = await manager.get_session("123456")
        original_timestamp = session1['last_active']

        # Small delay to ensure timestamp difference
        await asyncio.sleep(0.1)

        await manager.update_activity("123456")

        session2 = await manager.get_session("123456")
        new_timestamp = session2['last_active']

        assert new_timestamp >= original_timestamp


class TestSessionListing:
    """Test listing and querying multiple sessions."""

    @pytest.mark.asyncio
    async def test_list_empty_sessions(self, manager):
        """
        Test listing when no sessions exist.

        What: Call list_sessions on empty database
        Why: Should return empty list, not error
        """
        sessions = await manager.list_sessions()
        assert sessions == []

    @pytest.mark.asyncio
    async def test_list_multiple_sessions(self, manager):
        """
        Test listing multiple sessions.

        What: Create 3 sessions, list them, verify order
        Why: Bot needs to view all active sessions
        """
        await manager.save_session("channel1", "sess1", "project-a")
        await asyncio.sleep(0.01)  # Small delay for timestamp ordering
        await manager.save_session("channel2", "sess2", "project-b")
        await asyncio.sleep(0.01)
        await manager.save_session("channel3", "sess3", "project-c")

        sessions = await manager.list_sessions()
        assert len(sessions) == 3

        # Should be ordered by last_active DESC (most recent first)
        assert sessions[0]['channel_id'] == "channel3"
        assert sessions[1]['channel_id'] == "channel2"
        assert sessions[2]['channel_id'] == "channel1"

    @pytest.mark.asyncio
    async def test_list_sessions_after_activity(self, manager):
        """
        Test that list_sessions ordering changes after activity updates.

        What: Create sessions, update activity on older one, verify reordering
        Why: Most active sessions should appear first
        """
        await manager.save_session("channel1", "sess1")
        await asyncio.sleep(1.1)  # SQLite CURRENT_TIMESTAMP has 1-second precision
        await manager.save_session("channel2", "sess2")

        # Update activity on channel1 (older session)
        await asyncio.sleep(1.1)  # SQLite CURRENT_TIMESTAMP has 1-second precision
        await manager.update_activity("channel1")

        sessions = await manager.list_sessions()

        # channel1 should now be first (most recent activity)
        assert sessions[0]['channel_id'] == "channel1"
        assert sessions[1]['channel_id'] == "channel2"


class TestSessionStats:
    """Test session statistics and analytics."""

    @pytest.mark.asyncio
    async def test_stats_empty_database(self, manager):
        """
        Test statistics on empty database.

        What: Get stats when no sessions exist
        Why: Should return zeros/nulls, not error
        """
        stats = await manager.get_stats()

        assert stats['total_sessions'] == 0
        assert stats['total_messages'] == 0
        assert stats['active_projects'] == 0
        assert stats['most_active_channel'] is None
        assert stats['oldest_session'] is None
        assert stats['newest_session'] is None

    @pytest.mark.asyncio
    async def test_stats_with_sessions(self, manager):
        """
        Test statistics calculation with multiple sessions.

        What: Create sessions with varying activity, check stats
        Why: Stats are used for monitoring and debugging
        """
        await manager.save_session("channel1", "sess1", "project-a")
        await manager.save_session("channel2", "sess2", "project-b")
        await manager.save_session("channel3", "sess3", "project-a")  # Same project
        await manager.save_session("channel4", "sess4")  # No project

        # Add some message activity
        for _ in range(5):
            await manager.update_activity("channel1")

        for _ in range(3):
            await manager.update_activity("channel2")

        stats = await manager.get_stats()

        assert stats['total_sessions'] == 4
        assert stats['total_messages'] == 8  # 5 + 3 + 0 + 0
        assert stats['active_projects'] == 2  # project-a and project-b (not counting None)
        assert stats['most_active_channel'] == "channel1"

    @pytest.mark.asyncio
    async def test_stats_oldest_newest(self, manager):
        """
        Test oldest and newest session tracking.

        What: Create sessions in sequence, verify oldest/newest detection
        Why: Useful for session lifecycle management
        """
        await manager.save_session("channel1", "sess1")
        await asyncio.sleep(1.1)  # SQLite CURRENT_TIMESTAMP has 1-second precision
        await manager.save_session("channel2", "sess2")
        await asyncio.sleep(1.1)  # SQLite CURRENT_TIMESTAMP has 1-second precision
        await manager.save_session("channel3", "sess3")

        stats = await manager.get_stats()

        assert stats['oldest_session'] == "channel1"
        assert stats['newest_session'] == "channel3"


class TestConcurrentAccess:
    """Test concurrent access and thread safety."""

    @pytest.mark.asyncio
    async def test_concurrent_reads(self, manager):
        """
        Test multiple concurrent read operations.

        What: Create session, then read it from multiple coroutines simultaneously
        Why: Bot handles multiple channels concurrently
        """
        await manager.save_session("channel1", "sess1", "project-a")

        # Launch 10 concurrent reads
        tasks = [manager.get_session("channel1") for _ in range(10)]
        results = await asyncio.gather(*tasks)

        # All reads should succeed
        assert all(r is not None for r in results)
        assert all(r['session_id'] == "sess1" for r in results)

    @pytest.mark.asyncio
    async def test_concurrent_writes(self, manager):
        """
        Test multiple concurrent write operations.

        What: Create multiple sessions concurrently
        Why: Multiple channels may save sessions simultaneously
        """
        tasks = [
            manager.save_session(f"channel{i}", f"sess{i}", "project-a")
            for i in range(10)
        ]

        await asyncio.gather(*tasks)

        # Verify all sessions were created
        sessions = await manager.list_sessions()
        assert len(sessions) == 10

    @pytest.mark.asyncio
    async def test_concurrent_updates_same_channel(self, manager):
        """
        Test concurrent activity updates on the same channel.

        What: Update activity on one channel from multiple coroutines
        Why: Ensures atomicity and prevents race conditions
        """
        await manager.save_session("channel1", "sess1")

        # Update activity 20 times concurrently
        tasks = [manager.update_activity("channel1") for _ in range(20)]
        await asyncio.gather(*tasks)

        session = await manager.get_session("channel1")
        assert session['message_count'] == 20

    @pytest.mark.asyncio
    async def test_concurrent_mixed_operations(self, manager):
        """
        Test mixed concurrent operations (reads, writes, updates).

        What: Perform saves, gets, updates, and lists concurrently
        Why: Real-world usage has mixed concurrent operations
        """
        # Create initial session
        await manager.save_session("channel1", "sess1")

        # Mix of operations
        tasks = [
            manager.get_session("channel1"),
            manager.update_activity("channel1"),
            manager.save_session("channel2", "sess2"),
            manager.list_sessions(),
            manager.get_session("channel2"),
            manager.update_activity("channel1"),
        ]

        # All should complete without error
        await asyncio.gather(*tasks)

        # Verify final state
        session1 = await manager.get_session("channel1")
        session2 = await manager.get_session("channel2")

        assert session1 is not None
        assert session2 is not None
        assert session1['message_count'] == 2


class TestContextManager:
    """Test async context manager usage."""

    @pytest.mark.asyncio
    async def test_context_manager_cleanup(self, temp_db):
        """
        Test that context manager properly closes database connection.

        What: Use SessionManager with async context manager, verify cleanup
        Why: Proper resource cleanup prevents database lock issues
        """
        manager = SessionManager(db_path=temp_db)

        async with manager:
            await manager.save_session("channel1", "sess1")
            assert manager._db is not None

        # Connection should be closed after exiting context
        assert manager._db is None

    @pytest.mark.asyncio
    async def test_context_manager_exception_handling(self, temp_db):
        """
        Test that context manager closes connection even on exception.

        What: Raise exception inside context, verify cleanup still happens
        Why: Resources must be cleaned up even on errors
        """
        manager = SessionManager(db_path=temp_db)

        try:
            async with manager:
                await manager.save_session("channel1", "sess1")
                raise ValueError("Test exception")
        except ValueError:
            pass

        # Connection should still be closed
        assert manager._db is None


class TestEdgeCases:
    """Test edge cases and error conditions."""

    @pytest.mark.asyncio
    async def test_empty_channel_id(self, manager):
        """
        Test handling of empty channel_id.

        What: Save/get session with empty string channel_id
        Why: Should handle edge case gracefully
        """
        await manager.save_session("", "sess1", "project-a")
        session = await manager.get_session("")
        assert session is not None
        assert session['channel_id'] == ""

    @pytest.mark.asyncio
    async def test_very_long_ids(self, manager):
        """
        Test handling of very long channel and session IDs.

        What: Save session with 1000-character IDs
        Why: Ensure no unexpected length limits
        """
        long_channel = "c" * 1000
        long_session = "s" * 1000

        await manager.save_session(long_channel, long_session)
        session = await manager.get_session(long_channel)

        assert session is not None
        assert session['channel_id'] == long_channel
        assert session['session_id'] == long_session

    @pytest.mark.asyncio
    async def test_special_characters_in_ids(self, manager):
        """
        Test handling of special characters in IDs.

        What: Use IDs with quotes, newlines, unicode
        Why: Ensure proper SQL escaping
        """
        special_channel = "channel'with\"quotes\nand\ttabs"
        special_session = "sess🎉with📊unicode"

        await manager.save_session(special_channel, special_session)
        session = await manager.get_session(special_channel)

        assert session is not None
        assert session['channel_id'] == special_channel
        assert session['session_id'] == special_session


# Performance test (optional, can be slow)
class TestPerformance:
    """Test performance characteristics (can be skipped for quick tests)."""

    @pytest.mark.asyncio
    @pytest.mark.slow
    async def test_large_number_of_sessions(self, manager):
        """
        Test handling of large number of sessions.

        What: Create 1000 sessions and verify operations remain fast
        Why: Bot may accumulate many sessions over time
        """
        # Create 1000 sessions
        for i in range(1000):
            await manager.save_session(f"channel{i}", f"sess{i}", f"project{i % 10}")

        # List should still be reasonably fast
        sessions = await manager.list_sessions()
        assert len(sessions) == 1000

        # Stats should work
        stats = await manager.get_stats()
        assert stats['total_sessions'] == 1000


if __name__ == "__main__":
    # Run tests with pytest
    import pytest
    pytest.main([__file__, "-v", "-s"])