"""
Integration tests for WebSocket communication layer.

Tests the complete WebSocket message flow, error handling, and real-time communication
features of the multi-language chat agent.
"""

import pytest
import json
import time
from datetime import datetime
from unittest.mock import Mock, patch, MagicMock
from uuid import uuid4

from flask import Flask
from flask_socketio import SocketIO, SocketIOTestClient
import redis

from chat_agent.websocket import (
    ChatWebSocketHandler, MessageValidator, ConnectionManager,
    create_chat_websocket_handler, create_message_validator, 
    create_connection_manager, register_websocket_events
)
from chat_agent.services.chat_agent import ChatAgent, ChatAgentError
from chat_agent.services.session_manager import SessionManager, SessionNotFoundError
from chat_agent.models.chat_session import ChatSession


class TestWebSocketIntegration:
    """Integration tests for WebSocket communication."""
    
    @pytest.fixture
    def app(self):
        """Create Flask app for testing."""
        app = Flask(__name__)
        app.config['TESTING'] = True
        app.config['SECRET_KEY'] = 'test-secret-key'
        return app
    
    @pytest.fixture
    def socketio(self, app):
        """Create SocketIO instance for testing."""
        return SocketIO(app, cors_allowed_origins="*")
    
    @pytest.fixture
    def mock_redis(self):
        """Create mock Redis client."""
        mock_redis = Mock(spec=redis.Redis)
        mock_redis.setex = Mock()
        mock_redis.get = Mock(return_value=None)
        mock_redis.delete = Mock()
        mock_redis.sadd = Mock()
        mock_redis.srem = Mock()
        mock_redis.smembers = Mock(return_value=set())
        mock_redis.expire = Mock()
        return mock_redis
    
    @pytest.fixture
    def mock_chat_agent(self):
        """Create mock chat agent."""
        mock_agent = Mock(spec=ChatAgent)
        mock_agent.stream_response = Mock()
        mock_agent.switch_language = Mock()
        mock_agent.get_session_info = Mock()
        return mock_agent
    
    @pytest.fixture
    def mock_session_manager(self):
        """Create mock session manager."""
        mock_manager = Mock(spec=SessionManager)
        mock_manager.get_session = Mock()
        mock_manager.update_session_activity = Mock()
        return mock_manager
    
    @pytest.fixture
    def connection_manager(self, mock_redis):
        """Create connection manager."""
        return create_connection_manager(mock_redis)
    
    @pytest.fixture
    def message_validator(self):
        """Create message validator."""
        return create_message_validator()
    
    @pytest.fixture
    def websocket_handler(self, mock_chat_agent, mock_session_manager, connection_manager):
        """Create WebSocket handler."""
        return create_chat_websocket_handler(
            mock_chat_agent, mock_session_manager, connection_manager
        )
    
    @pytest.fixture
    def client(self, app, socketio, websocket_handler):
        """Create SocketIO test client."""
        register_websocket_events(socketio, websocket_handler)
        return socketio.test_client(app)
    
    @pytest.fixture
    def sample_session(self):
        """Create sample chat session."""
        session = Mock(spec=ChatSession)
        session.id = str(uuid4())
        session.user_id = str(uuid4())
        session.language = 'python'
        session.message_count = 5
        session.is_active = True
        return session
    
    def test_successful_connection(self, client, mock_session_manager, sample_session):
        """Test successful WebSocket connection."""
        # Setup
        mock_session_manager.get_session.return_value = sample_session
        
        auth_data = {
            'session_id': sample_session.id,
            'user_id': sample_session.user_id
        }
        
        # Connect
        assert client.is_connected() == False
        client.connect(auth=auth_data)
        assert client.is_connected() == True
        
        # Verify session validation was called
        mock_session_manager.get_session.assert_called_once_with(sample_session.id)
        mock_session_manager.update_session_activity.assert_called_once_with(sample_session.id)
        
        # Check connection status event
        received = client.get_received()
        assert len(received) == 1
        assert received[0]['name'] == 'connection_status'
        assert received[0]['args'][0]['status'] == 'connected'
        assert received[0]['args'][0]['session_id'] == sample_session.id
    
    def test_connection_rejected_missing_auth(self, client):
        """Test connection rejection due to missing auth data."""
        # Try to connect without auth
        client.connect()
        assert client.is_connected() == False
    
    def test_connection_rejected_invalid_session(self, client, mock_session_manager):
        """Test connection rejection due to invalid session."""
        # Setup
        mock_session_manager.get_session.side_effect = SessionNotFoundError("Session not found")
        
        auth_data = {
            'session_id': 'invalid-session',
            'user_id': 'test-user'
        }
        
        # Try to connect
        client.connect(auth=auth_data)
        assert client.is_connected() == False
    
    def test_connection_rejected_user_mismatch(self, client, mock_session_manager, sample_session):
        """Test connection rejection due to user mismatch."""
        # Setup
        mock_session_manager.get_session.return_value = sample_session
        
        auth_data = {
            'session_id': sample_session.id,
            'user_id': 'different-user'  # Different from session.user_id
        }
        
        # Try to connect
        client.connect(auth=auth_data)
        assert client.is_connected() == False
    
    def test_message_processing_success(self, client, mock_session_manager, mock_chat_agent, sample_session):
        """Test successful message processing with streaming response."""
        # Setup connection
        mock_session_manager.get_session.return_value = sample_session
        auth_data = {
            'session_id': sample_session.id,
            'user_id': sample_session.user_id
        }
        client.connect(auth=auth_data)
        
        # Setup streaming response
        mock_response_chunks = [
            {'type': 'start', 'session_id': sample_session.id, 'language': 'python', 'timestamp': datetime.utcnow().isoformat()},
            {'type': 'chunk', 'content': 'Hello', 'timestamp': datetime.utcnow().isoformat()},
            {'type': 'chunk', 'content': ' world!', 'timestamp': datetime.utcnow().isoformat()},
            {'type': 'complete', 'message_id': str(uuid4()), 'total_chunks': 2, 'processing_time': 0.5, 'timestamp': datetime.utcnow().isoformat()}
        ]
        mock_chat_agent.stream_response.return_value = iter(mock_response_chunks)
        
        # Send message
        message_data = {
            'content': 'Hello, how are you?',
            'session_id': sample_session.id
        }
        
        client.emit('message', message_data)
        
        # Verify chat agent was called
        mock_chat_agent.stream_response.assert_called_once_with(
            sample_session.id, 'Hello, how are you?', None
        )
        
        # Check received events
        received = client.get_received()
        
        # Should have: connection_status, message_received, processing_status, response_start, 2x response_chunk, response_complete
        assert len(received) >= 6
        
        # Find specific events
        message_received = next((r for r in received if r['name'] == 'message_received'), None)
        assert message_received is not None
        
        processing_status = next((r for r in received if r['name'] == 'processing_status'), None)
        assert processing_status is not None
        assert processing_status['args'][0]['status'] == 'processing'
        
        response_start = next((r for r in received if r['name'] == 'response_start'), None)
        assert response_start is not None
        
        response_chunks = [r for r in received if r['name'] == 'response_chunk']
        assert len(response_chunks) == 2
        
        response_complete = next((r for r in received if r['name'] == 'response_complete'), None)
        assert response_complete is not None
    
    def test_message_validation_failure(self, client, mock_session_manager, sample_session):
        """Test message validation failure."""
        # Setup connection
        mock_session_manager.get_session.return_value = sample_session
        auth_data = {
            'session_id': sample_session.id,
            'user_id': sample_session.user_id
        }
        client.connect(auth=auth_data)
        
        # Send invalid message (missing content)
        invalid_message = {
            'session_id': sample_session.id
            # Missing 'content' field
        }
        
        client.emit('message', invalid_message)
        
        # Check for error event
        received = client.get_received()
        error_event = next((r for r in received if r['name'] == 'error'), None)
        assert error_event is not None
        assert error_event['args'][0]['code'] == 'INVALID_MESSAGE'
    
    def test_language_switch_success(self, client, mock_session_manager, mock_chat_agent, sample_session):
        """Test successful language switching."""
        # Setup connection
        mock_session_manager.get_session.return_value = sample_session
        auth_data = {
            'session_id': sample_session.id,
            'user_id': sample_session.user_id
        }
        client.connect(auth=auth_data)
        
        # Setup language switch response
        switch_result = {
            'success': True,
            'previous_language': 'python',
            'new_language': 'javascript',
            'message': 'Language switched to JavaScript',
            'timestamp': datetime.utcnow().isoformat()
        }
        mock_chat_agent.switch_language.return_value = switch_result
        
        # Send language switch request
        switch_data = {
            'language': 'javascript',
            'session_id': sample_session.id
        }
        
        client.emit('language_switch', switch_data)
        
        # Verify chat agent was called
        mock_chat_agent.switch_language.assert_called_once_with(sample_session.id, 'javascript')
        
        # Check for language_switched event
        received = client.get_received()
        language_switched = next((r for r in received if r['name'] == 'language_switched'), None)
        assert language_switched is not None
        assert language_switched['args'][0]['new_language'] == 'javascript'
        assert language_switched['args'][0]['previous_language'] == 'python'
    
    def test_language_switch_invalid_language(self, client, mock_session_manager, sample_session):
        """Test language switch with invalid language."""
        # Setup connection
        mock_session_manager.get_session.return_value = sample_session
        auth_data = {
            'session_id': sample_session.id,
            'user_id': sample_session.user_id
        }
        client.connect(auth=auth_data)
        
        # Send invalid language switch request
        switch_data = {
            'language': 'invalid-language',
            'session_id': sample_session.id
        }
        
        client.emit('language_switch', switch_data)
        
        # Check for error event
        received = client.get_received()
        error_event = next((r for r in received if r['name'] == 'error'), None)
        assert error_event is not None
        assert error_event['args'][0]['code'] == 'INVALID_LANGUAGE_SWITCH'
    
    def test_typing_indicators(self, client, mock_session_manager, sample_session):
        """Test typing indicator functionality."""
        # Setup connection
        mock_session_manager.get_session.return_value = sample_session
        auth_data = {
            'session_id': sample_session.id,
            'user_id': sample_session.user_id
        }
        client.connect(auth=auth_data)
        
        # Send typing start
        client.emit('typing_start', {})
        
        # Send typing stop
        client.emit('typing_stop', {})
        
        # Note: typing events are broadcast to room excluding sender,
        # so we won't see them in our own client's received events
        # This test mainly verifies no errors occur
        received = client.get_received()
        error_events = [r for r in received if r['name'] == 'error']
        assert len(error_events) == 0
    
    def test_ping_pong(self, client, mock_session_manager, sample_session):
        """Test ping/pong for connection health checks."""
        # Setup connection
        mock_session_manager.get_session.return_value = sample_session
        auth_data = {
            'session_id': sample_session.id,
            'user_id': sample_session.user_id
        }
        client.connect(auth=auth_data)
        
        # Send ping
        ping_timestamp = datetime.utcnow().isoformat()
        client.emit('ping', {'timestamp': ping_timestamp})
        
        # Check for pong response
        received = client.get_received()
        pong_event = next((r for r in received if r['name'] == 'pong'), None)
        assert pong_event is not None
        assert pong_event['args'][0]['client_timestamp'] == ping_timestamp
    
    def test_session_info_request(self, client, mock_session_manager, mock_chat_agent, sample_session):
        """Test session info request."""
        # Setup connection
        mock_session_manager.get_session.return_value = sample_session
        auth_data = {
            'session_id': sample_session.id,
            'user_id': sample_session.user_id
        }
        client.connect(auth=auth_data)
        
        # Setup session info response
        session_info = {
            'session': {
                'id': sample_session.id,
                'user_id': sample_session.user_id,
                'language': 'python',
                'message_count': 5
            },
            'language_context': {'current_language': 'python'},
            'statistics': {'total_messages': 5},
            'supported_languages': ['python', 'javascript', 'java']
        }
        mock_chat_agent.get_session_info.return_value = session_info
        
        # Request session info
        client.emit('get_session_info', {})
        
        # Verify chat agent was called
        mock_chat_agent.get_session_info.assert_called_once_with(sample_session.id)
        
        # Check for session_info event
        received = client.get_received()
        session_info_event = next((r for r in received if r['name'] == 'session_info'), None)
        assert session_info_event is not None
        assert session_info_event['args'][0]['session']['id'] == sample_session.id
    
    def test_disconnect_cleanup(self, client, mock_session_manager, sample_session, connection_manager):
        """Test proper cleanup on disconnect."""
        # Setup connection
        mock_session_manager.get_session.return_value = sample_session
        auth_data = {
            'session_id': sample_session.id,
            'user_id': sample_session.user_id
        }
        client.connect(auth=auth_data)
        
        # Verify connection was added
        connections = connection_manager.get_all_connections()
        assert len(connections) > 0
        
        # Disconnect
        client.disconnect()
        
        # Verify cleanup
        mock_session_manager.update_session_activity.assert_called()
    
    def test_error_handling_chat_agent_error(self, client, mock_session_manager, mock_chat_agent, sample_session):
        """Test error handling when chat agent fails."""
        # Setup connection
        mock_session_manager.get_session.return_value = sample_session
        auth_data = {
            'session_id': sample_session.id,
            'user_id': sample_session.user_id
        }
        client.connect(auth=auth_data)
        
        # Setup chat agent to raise error
        mock_chat_agent.stream_response.side_effect = ChatAgentError("Processing failed")
        
        # Send message
        message_data = {
            'content': 'Hello',
            'session_id': sample_session.id
        }
        
        client.emit('message', message_data)
        
        # Check for error event
        received = client.get_received()
        error_event = next((r for r in received if r['name'] == 'error'), None)
        assert error_event is not None
        assert error_event['args'][0]['code'] == 'CHAT_AGENT_ERROR'


class TestMessageValidator:
    """Tests for message validation functionality."""
    
    @pytest.fixture
    def validator(self):
        """Create message validator."""
        return create_message_validator()
    
    def test_valid_message(self, validator):
        """Test validation of valid message."""
        message_data = {
            'content': 'Hello, how can I help you with Python?',
            'session_id': 'test-session-123'
        }
        
        result = validator.validate_message(message_data)
        
        assert result['valid'] == True
        assert result['errors'] == []
        assert result['sanitized_content'] == 'Hello, how can I help you with Python?'
    
    def test_message_missing_content(self, validator):
        """Test validation failure for missing content."""
        message_data = {
            'session_id': 'test-session-123'
        }
        
        result = validator.validate_message(message_data)
        
        assert result['valid'] == False
        assert 'Message content is required' in result['errors']
    
    def test_message_too_long(self, validator):
        """Test validation failure for message too long."""
        long_content = 'x' * (validator.MAX_MESSAGE_LENGTH + 1)
        message_data = {
            'content': long_content,
            'session_id': 'test-session-123'
        }
        
        result = validator.validate_message(message_data)
        
        assert result['valid'] == False
        assert any('too long' in error for error in result['errors'])
    
    def test_message_sanitization(self, validator):
        """Test message content sanitization."""
        malicious_content = '<script>alert("xss")</script>Hello world'
        message_data = {
            'content': malicious_content,
            'session_id': 'test-session-123'
        }
        
        result = validator.validate_message(message_data)
        
        # Should be rejected due to malicious content
        assert result['valid'] == False
    
    def test_valid_language_switch(self, validator):
        """Test validation of valid language switch."""
        switch_data = {
            'language': 'javascript',
            'session_id': 'test-session-123'
        }
        
        result = validator.validate_language_switch(switch_data)
        
        assert result['valid'] == True
        assert result['errors'] == []
        assert result['language'] == 'javascript'
    
    def test_invalid_language_switch(self, validator):
        """Test validation failure for invalid language."""
        switch_data = {
            'language': 'invalid-language',
            'session_id': 'test-session-123'
        }
        
        result = validator.validate_language_switch(switch_data)
        
        assert result['valid'] == False
        assert any('Unsupported language' in error for error in result['errors'])
    
    def test_rate_limiting(self, validator):
        """Test rate limiting functionality."""
        session_id = 'test-session-rate-limit'
        
        # Send messages up to the limit
        for i in range(validator.MAX_MESSAGES_PER_MINUTE):
            message_data = {
                'content': f'Message {i}',
                'session_id': session_id
            }
            result = validator.validate_message(message_data)
            assert result['valid'] == True
        
        # Next message should be rate limited
        message_data = {
            'content': 'Rate limited message',
            'session_id': session_id
        }
        result = validator.validate_message(message_data)
        
        assert result['valid'] == False
        assert any('Rate limit exceeded' in error for error in result['errors'])


class TestConnectionManager:
    """Tests for connection management functionality."""
    
    @pytest.fixture
    def mock_redis(self):
        """Create mock Redis client."""
        mock_redis = Mock(spec=redis.Redis)
        mock_redis.setex = Mock()
        mock_redis.get = Mock(return_value=None)
        mock_redis.delete = Mock()
        mock_redis.sadd = Mock()
        mock_redis.srem = Mock()
        mock_redis.smembers = Mock(return_value=set())
        mock_redis.expire = Mock()
        return mock_redis
    
    @pytest.fixture
    def connection_manager(self, mock_redis):
        """Create connection manager."""
        return create_connection_manager(mock_redis)
    
    def test_add_connection(self, connection_manager, mock_redis):
        """Test adding a connection."""
        client_id = 'test-client-123'
        connection_info = {
            'client_id': client_id,
            'session_id': 'test-session-123',
            'user_id': 'test-user-123',
            'connected_at': datetime.utcnow().isoformat(),
            'language': 'python'
        }
        
        connection_manager.add_connection(client_id, connection_info)
        
        # Verify connection was added to memory
        retrieved_info = connection_manager.get_connection(client_id)
        assert retrieved_info is not None
        assert retrieved_info['session_id'] == 'test-session-123'
        
        # Verify Redis calls
        mock_redis.setex.assert_called()
        mock_redis.sadd.assert_called()
    
    def test_remove_connection(self, connection_manager):
        """Test removing a connection."""
        client_id = 'test-client-123'
        connection_info = {
            'client_id': client_id,
            'session_id': 'test-session-123',
            'user_id': 'test-user-123',
            'connected_at': datetime.utcnow().isoformat(),
            'language': 'python'
        }
        
        # Add connection
        connection_manager.add_connection(client_id, connection_info)
        
        # Remove connection
        removed_info = connection_manager.remove_connection(client_id)
        
        assert removed_info is not None
        assert removed_info['session_id'] == 'test-session-123'
        
        # Verify connection is gone
        retrieved_info = connection_manager.get_connection(client_id)
        assert retrieved_info is None
    
    def test_update_connection_activity(self, connection_manager):
        """Test updating connection activity."""
        client_id = 'test-client-123'
        connection_info = {
            'client_id': client_id,
            'session_id': 'test-session-123',
            'user_id': 'test-user-123',
            'connected_at': datetime.utcnow().isoformat(),
            'language': 'python'
        }
        
        # Add connection
        connection_manager.add_connection(client_id, connection_info)
        
        # Update activity
        success = connection_manager.update_connection_activity(client_id)
        assert success == True
        
        # Verify last_activity was added
        updated_info = connection_manager.get_connection(client_id)
        assert 'last_activity' in updated_info
    
    def test_get_connection_stats(self, connection_manager):
        """Test getting connection statistics."""
        # Add multiple connections
        for i in range(3):
            client_id = f'client-{i}'
            connection_info = {
                'client_id': client_id,
                'session_id': f'session-{i}',
                'user_id': f'user-{i % 2}',  # 2 unique users
                'connected_at': datetime.utcnow().isoformat(),
                'language': 'python' if i % 2 == 0 else 'javascript'
            }
            connection_manager.add_connection(client_id, connection_info)
        
        stats = connection_manager.get_connection_stats()
        
        assert stats['total_connections'] == 3
        assert stats['unique_sessions'] == 3
        assert stats['unique_users'] == 2
        assert 'python' in stats['languages']
        assert 'javascript' in stats['languages']


if __name__ == '__main__':
    pytest.main([__file__])