"""
Unit tests for DatabaseClient class.
"""

import pytest
import pytest_asyncio
from unittest.mock import Mock, patch, MagicMock
from typing import Dict, Any

from src.database.client import DatabaseClient


class TestDatabaseClient:
    """Test cases for DatabaseClient."""

    @pytest_asyncio.fixture
    async def db_client(self):
        """Create a test database client."""
        client = DatabaseClient(
            database_url="postgresql://test:test@localhost:5432/test",
            min_connections=1,
            max_connections=2
        )
        
        # Mock the connection pool
        client.connection_pool = Mock()
        client.connection_pool.getconn.return_value = Mock()
        client.connection_pool.putconn = Mock()
        
        return client

    @pytest.mark.asyncio
    async def test_connect_success(self, db_client):
        """Test successful database connection."""
        with patch('psycopg2.pool.ThreadedConnectionPool') as mock_pool:
            mock_pool_instance = Mock()
            mock_pool.return_value = mock_pool_instance
            
            mock_conn = MagicMock()
            mock_cursor = MagicMock()
            mock_cursor.fetchone.return_value = {'version': 'PostgreSQL 14.0'}
            mock_conn.cursor.return_value.__enter__.return_value = mock_cursor
            mock_conn.cursor.return_value.__exit__.return_value = None
            
            mock_pool_instance.getconn.return_value = mock_conn
            
            await db_client.connect()
            
            assert db_client.connection_pool is not None
            mock_pool.assert_called_once()

    @pytest.mark.asyncio
    async def test_connect_failure(self, db_client):
        """Test database connection failure."""
        with patch('psycopg2.pool.ThreadedConnectionPool') as mock_pool:
            mock_pool.side_effect = Exception("Connection failed")
            
            with pytest.raises(Exception, match="Connection failed"):
                await db_client.connect()

    def test_execute_query_success(self, db_client):
        """Test successful query execution."""
        # Mock the cursor
        mock_cursor = MagicMock()
        mock_cursor.fetchall.return_value = [{'id': 1, 'name': 'test'}]
        
        # Mock the cursor context manager
        db_client._get_cursor = MagicMock()
        db_client._get_cursor.return_value.__enter__.return_value = mock_cursor
        db_client._get_cursor.return_value.__exit__.return_value = None
        
        result = db_client.execute_query("SELECT * FROM test", (1,))
        
        assert result == [{'id': 1, 'name': 'test'}]
        mock_cursor.execute.assert_called_once_with("SELECT * FROM test", (1,))

    def test_execute_query_failure(self, db_client):
        """Test query execution failure."""
        # Mock the cursor to raise an exception
        mock_cursor = MagicMock()
        mock_cursor.execute.side_effect = Exception("Query failed")
        
        # Mock the cursor context manager
        db_client._get_cursor = MagicMock()
        db_client._get_cursor.return_value.__enter__.return_value = mock_cursor
        db_client._get_cursor.return_value.__exit__.return_value = None
        
        with pytest.raises(Exception, match="Query failed"):
            db_client.execute_query("SELECT * FROM test")

    def test_execute_success(self, db_client):
        """Test successful execute operation."""
        # Mock the cursor
        mock_cursor = MagicMock()
        
        # Mock the cursor context manager
        db_client._get_cursor = MagicMock()
        db_client._get_cursor.return_value.__enter__.return_value = mock_cursor
        db_client._get_cursor.return_value.__exit__.return_value = None
        
        db_client.execute("INSERT INTO test VALUES (%s)", (1,))
        
        mock_cursor.execute.assert_called_once_with("INSERT INTO test VALUES (%s)", (1,))

    def test_health_check_success(self, db_client):
        """Test successful health check."""
        # Mock the cursor
        mock_cursor = MagicMock()
        mock_cursor.fetchone.return_value = {'health_check': 1}
        
        # Mock the cursor context manager
        db_client._get_cursor = MagicMock()
        db_client._get_cursor.return_value.__enter__.return_value = mock_cursor
        db_client._get_cursor.return_value.__exit__.return_value = None
        
        result = db_client.health_check()
        
        assert result is True
        mock_cursor.execute.assert_called_once_with("SELECT 1 as health_check;")

    def test_health_check_failure(self, db_client):
        """Test health check failure."""
        # Mock the cursor to raise an exception
        mock_cursor = MagicMock()
        mock_cursor.execute.side_effect = Exception("Health check failed")
        
        # Mock the cursor context manager
        db_client._get_cursor = MagicMock()
        db_client._get_cursor.return_value.__enter__.return_value = mock_cursor
        db_client._get_cursor.return_value.__exit__.return_value = None
        
        result = db_client.health_check()
        
        assert result is False

    def test_get_connection_stats(self, db_client):
        """Test connection statistics retrieval."""
        stats = db_client.get_connection_stats()
        
        expected = {
            "min_connections": 1,
            "max_connections": 2,
            "pool_status": "active"
        }
        assert stats == expected

    def test_get_connection_stats_no_pool(self):
        """Test connection statistics when pool is not initialized."""
        client = DatabaseClient("test_url")
        stats = client.get_connection_stats()
        
        assert stats == {"status": "pool_not_initialized"}

    @pytest.mark.asyncio
    async def test_disconnect(self, db_client):
        """Test database disconnection."""
        db_client.connection_pool.closeall = Mock()
        
        await db_client.disconnect()
        
        db_client.connection_pool.closeall.assert_called_once()

    @pytest.mark.asyncio
    async def test_disconnect_no_pool(self, db_client):
        """Test disconnection when no pool exists."""
        db_client.connection_pool = None
        
        # Should not raise an exception
        await db_client.disconnect()