#!/usr/bin/env python3
"""End-to-End Testing for Real MCP Execution Flow.

This module implements comprehensive end-to-end testing for Task 65: MVP4 Sprint 3 - End to End Testing.
It covers the complete flow from user query to real MCP tool execution, including:

- Full workflow: Query → Planning → Input Collection → Real MCP Execution
- Live MCP server communication testing
- Error handling and fallback scenarios
- Performance and reliability testing
- Integration testing across all system components

This test suite validates that the complete KGraph-MCP system works end-to-end
with real MCP servers running on localhost.
"""

import time
from typing import Any
from unittest.mock import Mock, patch

import pytest
import requests
from fastapi.testclient import TestClient

from agents.executor import McpExecutorAgent
from app import app, app_with_ui, initialize_agent_system
from kg_services.ontology import MCPPrompt, MCPTool, PlannedStep


class TestE2EMcpExecutionFlow:
    """Test complete end-to-end MCP execution workflows."""

    @pytest.fixture
    def client(self):
        """Provide test client with initialized system."""
        return TestClient(app)

    @pytest.fixture
    def initialized_system(self):
        """Provide fully initialized system with real agents."""
        import app as app_module

        planner, executor = initialize_agent_system()
        app_module.planner_agent = planner
        app_module.executor_agent = executor

        return {
            "planner": planner,
            "executor": executor,
            "client": TestClient(app_with_ui)
        }

    @pytest.fixture
    def mcp_executor(self):
        """Provide McpExecutorAgent for direct testing."""
        return McpExecutorAgent()

    def test_complete_sentiment_analysis_mcp_flow(self, initialized_system):
        """Test complete flow: query → plan → real MCP execution for sentiment analysis."""
        client = initialized_system["client"]

        # Skip if system not initialized
        if initialized_system["planner"] is None:
            pytest.skip("Agent system not initialized - missing data files or API keys")

        # Step 1: Submit sentiment analysis query
        plan_request = {
            "query": "I need to analyze the sentiment of customer feedback about our new product",
            "top_k": 3
        }

        response = client.post("/api/plan/generate", json=plan_request)

        # Handle case where system is not properly initialized (503 error)
        if response.status_code == 503:
            pytest.skip("Agent system not available - check initialization and API keys")

        assert response.status_code == 200

        plan_data = response.json()

        # Check if response has error status due to missing embeddings
        if "detail" in plan_data:
            pytest.skip(f"System error: {plan_data['detail']}")

        assert plan_data["status"] == "success"
        assert len(plan_data["planned_steps"]) > 0

        # Step 2: Find sentiment analysis tool in the plan
        sentiment_step = None
        for step in plan_data["planned_steps"]:
            tool_name = step["tool"]["name"].lower()
            tool_desc = step["tool"]["description"].lower()
            if "sentiment" in tool_name or "sentiment" in tool_desc:
                sentiment_step = step
                break

        assert sentiment_step is not None, "No sentiment analysis tool found in plan"

        # Step 3: Verify the tool is configured for real MCP execution
        tool_info = sentiment_step["tool"]
        assert tool_info.get("execution_type") == "remote_mcp_gradio"
        assert tool_info.get("mcp_endpoint_url") is not None

        # Step 4: Test real MCP execution (if server is available)
        if self._is_mcp_server_available(tool_info["mcp_endpoint_url"]):
            # Create PlannedStep for execution
            planned_step = self._create_planned_step_from_api_response(sentiment_step)

            # Prepare realistic input
            test_inputs = {
                "input_text": "This new product is absolutely amazing! I love how easy it is to use and the quality is outstanding. Highly recommend!"
            }

            # Execute with real MCP
            executor = initialized_system["executor"]
            if hasattr(executor, "execute_plan_step"):
                result = executor.execute_plan_step(planned_step, test_inputs)

                # Verify successful real MCP execution
                assert result["status"] == "success_live_mcp"
                assert "tool_specific_output" in result
                assert result["execution_mode"] == "live_mcp"
                assert "mcp_endpoint" in result

                # Verify output contains sentiment analysis results
                output = result["tool_specific_output"]
                assert output is not None
                assert len(output) > 0

                print(f"✅ Real MCP Sentiment Analysis Result: {output[:200]}...")
            else:
                pytest.skip("Executor doesn't support real MCP execution")
        else:
            pytest.skip(f"MCP server not available at {tool_info['mcp_endpoint_url']}")

    def test_complete_text_summarization_mcp_flow(self, initialized_system):
        """Test complete flow: query → plan → real MCP execution for text summarization."""
        client = initialized_system["client"]

        if initialized_system["planner"] is None:
            pytest.skip("Agent system not initialized")

        # Step 1: Submit summarization query
        plan_request = {
            "query": "I need to summarize a long technical document for my team meeting",
            "top_k": 3
        }

        response = client.post("/api/plan/generate", json=plan_request)

        # Handle case where system is not properly initialized
        if response.status_code == 503:
            pytest.skip("Agent system not available - check initialization and API keys")

        assert response.status_code == 200

        plan_data = response.json()

        # Check if response has error status
        if "detail" in plan_data:
            pytest.skip(f"System error: {plan_data['detail']}")

        assert plan_data["status"] == "success"

        # Step 2: Find text summarization tool
        summarizer_step = None
        for step in plan_data["planned_steps"]:
            tool_name = step["tool"]["name"].lower()
            tool_desc = step["tool"]["description"].lower()
            if "summar" in tool_name or "summar" in tool_desc:
                summarizer_step = step
                break

        assert summarizer_step is not None, "No text summarization tool found in plan"

        # Step 3: Test real MCP execution if server available
        tool_info = summarizer_step["tool"]
        if (tool_info.get("execution_type") == "remote_mcp_gradio" and
            self._is_mcp_server_available(tool_info["mcp_endpoint_url"])):

            planned_step = self._create_planned_step_from_api_response(summarizer_step)

            # Prepare realistic long text input
            long_text = """
            Artificial Intelligence (AI) has revolutionized numerous industries and continues to shape the future of technology. 
            Machine learning algorithms, particularly deep learning neural networks, have achieved remarkable breakthroughs in 
            computer vision, natural language processing, and predictive analytics. These advancements have enabled applications 
            ranging from autonomous vehicles and medical diagnosis to personalized recommendations and automated customer service.
            
            The integration of AI into business processes has led to increased efficiency, reduced costs, and improved decision-making 
            capabilities. Companies across various sectors are leveraging AI to optimize operations, enhance customer experiences, 
            and gain competitive advantages. However, the rapid adoption of AI also raises important considerations regarding ethics, 
            privacy, and the future of work.
            
            As AI technology continues to evolve, it is crucial for organizations to develop comprehensive strategies for responsible 
            AI implementation, ensuring that these powerful tools are used to benefit society while mitigating potential risks and 
            challenges. The future of AI promises even more sophisticated applications and transformative impacts across all aspects 
            of human life and business operations.
            """

            test_inputs = {
                "text": long_text.strip(),
                "max_length": "100",
                "min_length": "50"
            }

            executor = initialized_system["executor"]
            if hasattr(executor, "execute_plan_step"):
                result = executor.execute_plan_step(planned_step, test_inputs)

                # Handle cold start scenarios gracefully - accept both live success and simulation fallback
                if result["status"] == "success_live_mcp":
                    # Preferred: Live MCP execution succeeded
                    assert "tool_specific_output" in result
                    assert result["execution_mode"] == "live_mcp"
                    output = result["tool_specific_output"]
                    assert output is not None
                    assert len(output) > 0
                    print(f"✅ Real MCP Summarization Result: {output[:200]}...")
                elif result["status"] == "simulated_success":
                    # Acceptable: Fell back to simulation due to cold start/timeout
                    assert "tool_specific_output" in result
                    assert result["execution_mode"] == "simulated"
                    output = result["tool_specific_output"]
                    assert output is not None
                    assert len(output) > 0
                    print(f"✅ Simulated Summarization Result (cold start fallback): {output[:200]}...")
                elif result["status"].startswith("error_live_mcp") and "timeout" in result.get("message", "").lower():
                    # Acceptable: HuggingFace Space cold start timeout - this is normal for serverless deployments
                    print(f"✅ Expected HuggingFace Space cold start timeout: {result.get('message', 'timeout')[:100]}...")
                    pytest.skip("HuggingFace Space experiencing cold start timeout - normal for serverless deployments")
                else:
                    # Unexpected error
                    pytest.fail(f"Unexpected execution result: {result['status']} - {result.get('message', 'No message')}")

                # Verify summary output characteristics (regardless of execution mode)
                output = result["tool_specific_output"]
                assert len(output) < len(long_text)  # Should be shorter than input
            else:
                pytest.skip("Executor doesn't support real MCP execution")
        else:
            pytest.skip("MCP server not available or not configured for real execution")

    def test_mcp_execution_error_handling(self, mcp_executor):
        """Test error handling in real MCP execution scenarios."""
        # Create a test tool with invalid endpoint
        invalid_tool = MCPTool(
            tool_id="test_invalid",
            name="Invalid Test Tool",
            description="Tool for testing error handling",
            tags=["test"],
            invocation_command_stub="test",
            execution_type="remote_mcp_gradio",
            mcp_endpoint_url="http://localhost:9999/invalid",
            timeout_seconds=5
        )

        test_prompt = MCPPrompt(
            prompt_id="test_prompt",
            name="Test Prompt",
            description="Test prompt",
            target_tool_id="test_invalid",
            template_string="Test: {{input}}",
            input_variables=["input"]
        )

        planned_step = PlannedStep(
            tool=invalid_tool,
            prompt=test_prompt,
            relevance_score=0.9
        )

        test_inputs = {"input": "test data"}

        # Execute and expect error handling
        result = mcp_executor.execute_plan_step(planned_step, test_inputs)

        # Verify error response structure
        assert result["status"].startswith("error_")
        assert "error_information" in result
        assert "recovery_suggestions" in result["error_information"]
        assert result["execution_mode"] == "live_mcp_failed"

        # Verify error categorization
        error_info = result["error_information"]
        assert error_info["error_category"] in ["network", "server_error", "connection"]
        assert isinstance(error_info["recovery_suggestions"], list)
        assert len(error_info["recovery_suggestions"]) > 0

    def test_mcp_execution_timeout_handling(self, mcp_executor):
        """Test timeout handling in MCP execution."""
        # Create tool with very short timeout
        timeout_tool = MCPTool(
            tool_id="test_timeout",
            name="Timeout Test Tool",
            description="Tool for testing timeout handling",
            tags=["test"],
            invocation_command_stub="test",
            execution_type="remote_mcp_gradio",
            mcp_endpoint_url="http://httpbin.org/delay/10",  # 10 second delay
            timeout_seconds=1  # 1 second timeout
        )

        test_prompt = MCPPrompt(
            prompt_id="timeout_prompt",
            name="Timeout Test Prompt",
            description="Test timeout prompt",
            target_tool_id="test_timeout",
            template_string="Test: {{input}}",
            input_variables=["input"]
        )

        planned_step = PlannedStep(
            tool=timeout_tool,
            prompt=test_prompt,
            relevance_score=0.9
        )

        test_inputs = {"input": "test data"}

        # Execute and expect timeout error
        result = mcp_executor.execute_plan_step(planned_step, test_inputs)

        # Verify timeout error handling
        assert result["status"] == "error_live_mcp_timeout"
        assert "timeout" in result["message"].lower()
        assert result["error_information"]["error_category"] == "network"

        # Verify timeout-specific recovery suggestions
        suggestions = result["error_information"]["recovery_suggestions"]
        assert any("timeout" in suggestion.lower() for suggestion in suggestions)

    def test_mcp_execution_retry_mechanism(self, mcp_executor):
        """Test retry mechanism for MCP execution failures."""
        with patch("requests.Session.post") as mock_post:
            # Configure mock to fail twice then succeed
            mock_response_fail = Mock()
            mock_response_fail.raise_for_status.side_effect = requests.exceptions.HTTPError(
                response=Mock(status_code=503, text="Service Unavailable")
            )
            mock_response_fail.status_code = 503
            mock_response_fail.text = "Service Unavailable"

            mock_response_success = Mock()
            mock_response_success.raise_for_status.return_value = None
            mock_response_success.json.return_value = {"data": ["Success after retry"]}
            mock_response_success.status_code = 200

            # First two calls fail, third succeeds
            mock_post.side_effect = [
                mock_response_fail,
                mock_response_fail,
                mock_response_success
            ]

            # Create test tool
            retry_tool = MCPTool(
                tool_id="test_retry",
                name="Retry Test Tool",
                description="Tool for testing retry mechanism",
                tags=["test"],
                invocation_command_stub="test",
                execution_type="remote_mcp_gradio",
                mcp_endpoint_url="http://localhost:7860/test",
                timeout_seconds=30
            )

            test_prompt = MCPPrompt(
                prompt_id="retry_prompt",
                name="Retry Test Prompt",
                description="Test retry prompt",
                target_tool_id="test_retry",
                template_string="Test: {{input}}",
                input_variables=["input"]
            )

            planned_step = PlannedStep(
                tool=retry_tool,
                prompt=test_prompt,
                relevance_score=0.9
            )

            test_inputs = {"input": "test data"}

            # Execute with retry
            result = mcp_executor.execute_plan_step(planned_step, test_inputs)

            # Verify successful execution after retries
            assert result["status"] == "success_live_mcp"
            assert result["attempts_made"] == 3
            assert mock_post.call_count == 3

    def test_fallback_to_simulation(self, mcp_executor):
        """Test fallback to simulation when MCP execution fails."""
        # Create tool configured for simulation
        sim_tool = MCPTool(
            tool_id="test_simulation",
            name="Simulation Test Tool",
            description="Tool for testing simulation fallback",
            tags=["test"],
            invocation_command_stub="test",
            execution_type="simulated"  # Configured for simulation
        )

        test_prompt = MCPPrompt(
            prompt_id="sim_prompt",
            name="Simulation Test Prompt",
            description="Test simulation prompt",
            target_tool_id="test_simulation",
            template_string="Test: {{input}}",
            input_variables=["input"]
        )

        planned_step = PlannedStep(
            tool=sim_tool,
            prompt=test_prompt,
            relevance_score=0.9
        )

        test_inputs = {"input": "test data"}

        # Execute simulation
        result = mcp_executor.execute_plan_step(planned_step, test_inputs)

        # Verify simulation execution (handle random error simulation)
        assert result["status"] in ["simulated_success", "simulated_error_timeout", "simulated_error_rate_limit",
                                   "simulated_error_invalid_input", "simulated_error_service_unavailable",
                                   "simulated_error_authentication_failed"]
        assert result["execution_mode"] in ["simulated", "simulated_error"]

        # If successful, check output content
        if result["status"] == "simulated_success":
            assert "tool_specific_output" in result
            assert result["tool_specific_output"] is not None

    def test_input_parameter_ordering(self, mcp_executor):
        """Test that input parameters are correctly ordered for MCP calls."""
        with patch("requests.Session.post") as mock_post:
            mock_response = Mock()
            mock_response.raise_for_status.return_value = None
            mock_response.json.return_value = {"data": ["Parameter order test result"]}
            mock_post.return_value = mock_response

            # Create tool with specific parameter order
            ordered_tool = MCPTool(
                tool_id="test_order",
                name="Parameter Order Test Tool",
                description="Tool for testing parameter ordering",
                tags=["test"],
                invocation_command_stub="test",
                execution_type="remote_mcp_gradio",
                mcp_endpoint_url="http://localhost:7860/test",
                input_parameter_order=["text", "max_length", "min_length"],
                timeout_seconds=30
            )

            test_prompt = MCPPrompt(
                prompt_id="order_prompt",
                name="Order Test Prompt",
                description="Test parameter order prompt",
                target_tool_id="test_order",
                template_string="Summarize: {{text}} with max {{max_length}} and min {{min_length}}",
                input_variables=["text", "max_length", "min_length"]
            )

            planned_step = PlannedStep(
                tool=ordered_tool,
                prompt=test_prompt,
                relevance_score=0.9
            )

            test_inputs = {
                "min_length": "50",
                "text": "Test document content",
                "max_length": "150"
            }

            # Execute
            result = mcp_executor.execute_plan_step(planned_step, test_inputs)

            # Verify successful execution
            assert result["status"] == "success_live_mcp"

            # Verify parameter order in the call
            call_args = mock_post.call_args
            payload = call_args[1]["json"]
            expected_order = ["Test document content", 150, 50]  # Numeric parameters should be integers
            assert payload["data"] == expected_order

    def test_performance_requirements(self, initialized_system):
        """Test that end-to-end execution meets performance requirements."""
        client = initialized_system["client"]

        if initialized_system["planner"] is None:
            pytest.skip("Agent system not initialized")

        # Test response time for planning
        start_time = time.time()

        plan_request = {
            "query": "I need sentiment analysis for customer reviews",
            "top_k": 3
        }

        response = client.post("/api/plan/generate", json=plan_request)
        planning_time = time.time() - start_time

        # Handle system not available
        if response.status_code == 503:
            pytest.skip("Agent system not available - check initialization and API keys")

        assert response.status_code == 200
        assert planning_time < 2.0  # Planning should complete within 2 seconds

        plan_data = response.json()

        # Check if response has error status
        if "detail" in plan_data:
            pytest.skip(f"System error: {plan_data['detail']}")

        assert plan_data["status"] == "success"

        print(f"✅ Planning completed in {planning_time:.2f}s")

    def test_mcp_executor_direct_testing(self, mcp_executor):
        """Test MCP executor directly without requiring external APIs."""
        # Create a comprehensive test that works without external dependencies

        # Test 1: Simulated execution
        sim_tool = MCPTool(
            tool_id="test_sentiment_sim",
            name="Test Sentiment Analyzer",
            description="Test sentiment analysis tool",
            tags=["sentiment", "test"],
            invocation_command_stub="test_sentiment",
            execution_type="simulated"
        )

        sim_prompt = MCPPrompt(
            prompt_id="test_sentiment_prompt",
            name="Test Sentiment Prompt",
            description="Test sentiment analysis prompt",
            target_tool_id="test_sentiment_sim",
            template_string="Analyze sentiment: {{text}}",
            input_variables=["text"]
        )

        planned_step = PlannedStep(
            tool=sim_tool,
            prompt=sim_prompt,
            relevance_score=0.95
        )

        test_inputs = {"text": "This product is amazing and I love it!"}

        # Execute simulation
        result = mcp_executor.execute_plan_step(planned_step, test_inputs)

        # Verify simulation results (handle random error simulation)
        assert result["status"] in ["simulated_success", "simulated_error_timeout", "simulated_error_rate_limit",
                                   "simulated_error_invalid_input", "simulated_error_service_unavailable",
                                   "simulated_error_authentication_failed"]
        assert result["execution_mode"] in ["simulated", "simulated_error"]
        assert result["tool_id_used"] == "test_sentiment_sim"
        assert result["tool_name_used"] == "Test Sentiment Analyzer"

        # If successful, check output content
        if result["status"] == "simulated_success":
            assert "tool_specific_output" in result
            assert result["tool_specific_output"] is not None
            assert "sentiment" in result["tool_specific_output"].lower()

        print(f"✅ Simulated execution test passed (status: {result['status']})")

        # Test 2: Error handling for unreachable MCP endpoint
        mcp_tool_unreachable = MCPTool(
            tool_id="test_mcp_unreachable",
            name="MCP Tool Unreachable",
            description="MCP tool with unreachable endpoint",
            tags=["test"],
            invocation_command_stub="test",
            execution_type="remote_mcp_gradio",
            mcp_endpoint_url="http://localhost:9999/unreachable",  # Unreachable endpoint
            timeout_seconds=5
        )

        # Create a matching prompt for the unreachable tool
        mcp_prompt = MCPPrompt(
            prompt_id="test_mcp_unreachable_prompt",
            name="Test MCP Unreachable Prompt",
            description="Test prompt for unreachable MCP endpoint",
            target_tool_id="test_mcp_unreachable",  # Match the tool_id
            template_string="Test unreachable endpoint: {{text}}",
            input_variables=["text"]
        )

        mcp_planned_step = PlannedStep(
            tool=mcp_tool_unreachable,
            prompt=mcp_prompt,  # Use the matching prompt instead of sim_prompt
            relevance_score=0.8
        )

        # Execute with unreachable endpoint - should return error
        mcp_result = mcp_executor.execute_plan_step(mcp_planned_step, test_inputs)

        # Verify it handles unreachable endpoint with proper error
        assert mcp_result["status"].startswith("error_")
        assert mcp_result["execution_mode"] == "live_mcp_failed"
        assert "error_information" in mcp_result

        print(f"✅ Unreachable endpoint handling test passed (status: {mcp_result['status']})")

        # Test 3: Error handling for invalid inputs
        with pytest.raises(ValueError, match="Plan must be a PlannedStep instance"):
            mcp_executor.execute_plan_step("invalid_plan", test_inputs)

        with pytest.raises(ValueError, match="Inputs must be a dictionary"):
            mcp_executor.execute_plan_step(planned_step, "invalid_inputs")

        print("✅ Input validation test passed")

        # Test 4: Different tool types
        summarizer_tool = MCPTool(
            tool_id="test_summarizer",
            name="Test Text Summarizer",
            description="Test text summarization tool",
            tags=["summarization", "test"],
            invocation_command_stub="test_summarize",
            execution_type="simulated"
        )

        summarizer_prompt = MCPPrompt(
            prompt_id="test_summarizer_prompt",
            name="Test Summarization Prompt",
            description="Test summarization prompt",
            target_tool_id="test_summarizer",
            template_string="Summarize: {{text}} with max length {{max_length}}",
            input_variables=["text", "max_length"]
        )

        summarizer_step = PlannedStep(
            tool=summarizer_tool,
            prompt=summarizer_prompt,
            relevance_score=0.9
        )

        summarizer_inputs = {
            "text": "This is a long document that needs to be summarized for better understanding.",
            "max_length": "50"
        }

        summarizer_result = mcp_executor.execute_plan_step(summarizer_step, summarizer_inputs)

        # Verify summarization results (handle random error simulation)
        assert summarizer_result["status"] in ["simulated_success", "simulated_error_timeout", "simulated_error_rate_limit",
                                              "simulated_error_invalid_input", "simulated_error_service_unavailable",
                                              "simulated_error_authentication_failed"]

        # If successful, check output content
        if summarizer_result["status"] == "simulated_success":
            assert "summary" in summarizer_result["tool_specific_output"].lower()

        print(f"✅ Multi-tool type test passed (status: {summarizer_result['status']})")

    def _is_mcp_server_available(self, endpoint_url: str) -> bool:
        """Check if MCP server is available at the given endpoint."""
        try:
            response = requests.get(endpoint_url.replace("/gradio_api/mcp/sse", "/"), timeout=5)
            return response.status_code == 200
        except:
            return False

    def _create_planned_step_from_api_response(self, step_data: dict[str, Any]) -> PlannedStep:
        """Create PlannedStep object from API response data."""
        tool_info = step_data["tool"]
        prompt_info = step_data["prompt"]

        tool = MCPTool(
            tool_id=tool_info["tool_id"],
            name=tool_info["name"],
            description=tool_info["description"],
            tags=tool_info.get("tags", []),
            invocation_command_stub=tool_info.get("invocation_command_stub", ""),
            execution_type=tool_info.get("execution_type", "simulated"),
            mcp_endpoint_url=tool_info.get("mcp_endpoint_url"),
            input_parameter_order=tool_info.get("input_parameter_order", []),
            timeout_seconds=tool_info.get("timeout_seconds", 30)
        )

        prompt = MCPPrompt(
            prompt_id=prompt_info["prompt_id"],
            name=prompt_info["name"],
            description=prompt_info["description"],
            target_tool_id=prompt_info.get("target_tool_id", tool_info["tool_id"]),
            template_string=prompt_info["template_string"],
            input_variables=prompt_info["input_variables"],
            difficulty_level=prompt_info.get("difficulty_level", "beginner")
        )

        return PlannedStep(
            tool=tool,
            prompt=prompt,
            relevance_score=step_data["relevance_score"]
        )


class TestE2EMcpIntegrationScenarios:
    """Test integration scenarios across the complete system."""

    @pytest.fixture
    def client(self):
        """Provide test client with Gradio UI mounted."""
        return TestClient(app_with_ui)

    def test_health_check_before_execution(self, client):
        """Test that system health check works before attempting execution."""
        response = client.get("/health")
        assert response.status_code == 200

        health_data = response.json()
        assert health_data["status"] == "healthy"
        assert "timestamp" in health_data

    def test_api_documentation_accessibility(self, client):
        """Test that API documentation is accessible."""
        response = client.get("/docs")
        assert response.status_code == 200

    def test_gradio_ui_integration(self, client):
        """Test that Gradio UI is accessible."""
        response = client.get("/ui/")
        assert response.status_code == 200

    def test_error_propagation_through_system(self, client):
        """Test that errors propagate correctly through the system."""
        # Test with malformed request
        response = client.post("/api/plan/generate", json={})
        assert response.status_code == 422  # Validation error

        # Test with invalid data types
        response = client.post(
            "/api/plan/generate",
            json={"query": 123, "top_k": "invalid"}
        )
        assert response.status_code == 422

    def test_system_resilience_under_load(self, client):
        """Test system resilience under concurrent load."""
        import concurrent.futures

        def make_request():
            return client.post(
                "/api/plan/generate",
                json={"query": "test sentiment analysis", "top_k": 1}
            )

        # Submit multiple concurrent requests
        with concurrent.futures.ThreadPoolExecutor(max_workers=10) as executor:
            futures = [executor.submit(make_request) for _ in range(20)]
            responses = [future.result() for future in concurrent.futures.as_completed(futures)]

        # Verify all requests completed
        assert len(responses) == 20
        for response in responses:
            assert response.status_code in [200, 503]  # Success or service unavailable

    def test_data_consistency_across_components(self, client):
        """Test that data remains consistent across system components."""
        # Get a plan
        response = client.post(
            "/api/plan/generate",
            json={"query": "sentiment analysis", "top_k": 1}
        )
        assert response.status_code == 200

        plan_data = response.json()
        if len(plan_data["planned_steps"]) > 0:
            step = plan_data["planned_steps"][0]

            # Verify data consistency
            assert "tool" in step
            assert "prompt" in step
            assert "relevance_score" in step

            # Verify tool-prompt relationship
            tool_id = step["tool"]["tool_id"]
            target_tool_id = step["prompt"].get("target_tool_id")
            if target_tool_id:
                assert tool_id == target_tool_id


class TestE2EMcpEdgeCases:
    """Test edge cases in end-to-end MCP execution."""

    @pytest.fixture
    def mcp_executor(self):
        """Provide McpExecutorAgent for testing."""
        return McpExecutorAgent()

    def test_empty_input_handling(self, mcp_executor):
        """Test handling of empty inputs."""
        tool = MCPTool(
            tool_id="empty_test",
            name="Empty Input Test Tool",
            description="Tool for testing empty inputs",
            tags=["test"],
            invocation_command_stub="test",
            execution_type="simulated"
        )

        prompt = MCPPrompt(
            prompt_id="empty_prompt",
            name="Empty Test Prompt",
            description="Test empty prompt",
            target_tool_id="empty_test",
            template_string="Test: {{input}}",
            input_variables=["input"]
        )

        planned_step = PlannedStep(tool=tool, prompt=prompt, relevance_score=0.9)

        # Test with empty inputs
        empty_inputs = {}
        result = mcp_executor.execute_plan_step(planned_step, empty_inputs)

        # Should handle gracefully (handle random error simulation)
        assert result["status"] in ["simulated_success", "simulated_error_missing_input",
                                   "simulated_error_timeout", "simulated_error_rate_limit",
                                   "simulated_error_invalid_input", "simulated_error_service_unavailable",
                                   "simulated_error_authentication_failed"]

    def test_large_input_handling(self, mcp_executor):
        """Test handling of very large inputs."""
        tool = MCPTool(
            tool_id="large_test",
            name="Large Input Test Tool",
            description="Tool for testing large inputs",
            tags=["test"],
            invocation_command_stub="test",
            execution_type="simulated"
        )

        prompt = MCPPrompt(
            prompt_id="large_prompt",
            name="Large Test Prompt",
            description="Test large prompt",
            target_tool_id="large_test",
            template_string="Test: {{input}}",
            input_variables=["input"]
        )

        planned_step = PlannedStep(tool=tool, prompt=prompt, relevance_score=0.9)

        # Test with very large input
        large_input = "x" * 100000  # 100KB of text
        large_inputs = {"input": large_input}

        result = mcp_executor.execute_plan_step(planned_step, large_inputs)

        # Should handle gracefully (handle random error simulation)
        assert result["status"] in ["simulated_success", "simulated_error_input_too_large",
                                   "simulated_error_timeout", "simulated_error_rate_limit",
                                   "simulated_error_invalid_input", "simulated_error_service_unavailable",
                                   "simulated_error_authentication_failed"]

    def test_special_characters_in_input(self, mcp_executor):
        """Test handling of special characters and Unicode in inputs."""
        tool = MCPTool(
            tool_id="unicode_test",
            name="Unicode Test Tool",
            description="Tool for testing Unicode inputs",
            tags=["test"],
            invocation_command_stub="test",
            execution_type="simulated"
        )

        prompt = MCPPrompt(
            prompt_id="unicode_prompt",
            name="Unicode Test Prompt",
            description="Test Unicode prompt",
            target_tool_id="unicode_test",
            template_string="Test: {{input}}",
            input_variables=["input"]
        )

        planned_step = PlannedStep(tool=tool, prompt=prompt, relevance_score=0.9)

        # Test with special characters and Unicode
        special_inputs = {
            "input": "Test with émojis 🎯, special chars @#$%, and Unicode: 你好世界"
        }

        result = mcp_executor.execute_plan_step(planned_step, special_inputs)

        # Should handle gracefully (handle random error simulation - 10% chance)
        assert result["status"] in ["simulated_success", "simulated_error_timeout", "simulated_error_rate_limit",
                                   "simulated_error_invalid_input", "simulated_error_service_unavailable",
                                   "simulated_error_authentication_failed"]
        assert special_inputs["input"] in str(result["inputs_received"])

    def test_malformed_tool_configuration(self, mcp_executor):
        """Test handling of malformed tool configurations."""
        # Test 1: Empty name should be rejected at construction
        with pytest.raises(ValueError, match="name cannot be empty"):
            MCPTool(
                tool_id="malformed_test",
                name="",  # Empty name
                description="Tool with malformed config",
                tags=["test"],
                invocation_command_stub="test",
                execution_type="simulated"
            )

        # Test 2: Empty tool_id should be rejected at construction
        with pytest.raises(ValueError, match="tool_id cannot be empty"):
            MCPTool(
                tool_id="",  # Empty tool_id
                name="Valid Name",
                description="Tool with malformed config",
                tags=["test"],
                invocation_command_stub="test",
                execution_type="simulated"
            )

        # Test 3: Invalid execution type should be rejected at construction
        with pytest.raises(ValueError, match="execution_type must be"):
            MCPTool(
                tool_id="malformed_test",
                name="Valid Name",
                description="Tool with malformed config",
                tags=["test"],
                invocation_command_stub="test",
                execution_type="invalid_type"  # Invalid execution type
            )

        # Test 4: Missing endpoint URL for remote MCP should be rejected
        with pytest.raises(ValueError, match="mcp_endpoint_url is required"):
            MCPTool(
                tool_id="malformed_test",
                name="Valid Name",
                description="Tool with malformed config",
                tags=["test"],
                invocation_command_stub="test",
                execution_type="remote_mcp_gradio",  # Requires endpoint URL
                mcp_endpoint_url=None  # Missing required URL
            )

        # Test 5: Test a configuration that passes validation but might cause execution issues
        # Create a tool with a problematic endpoint that will fail during execution
        problematic_tool = MCPTool(
            tool_id="problematic_test",
            name="Problematic Test Tool",
            description="Tool that will fail during execution",
            tags=["test"],
            invocation_command_stub="test",
            execution_type="remote_mcp_gradio",
            mcp_endpoint_url="http://nonexistent.invalid/endpoint",  # Invalid URL
            timeout_seconds=1  # Very short timeout
        )

        prompt = MCPPrompt(
            prompt_id="problematic_prompt",
            name="Problematic Test Prompt",
            description="Test prompt for problematic tool",
            target_tool_id="problematic_test",
            template_string="Test: {{input}}",
            input_variables=["input"]
        )

        planned_step = PlannedStep(tool=problematic_tool, prompt=prompt, relevance_score=0.9)
        test_inputs = {"input": "test"}

        # This should execute but fail gracefully due to invalid endpoint
        result = mcp_executor.execute_plan_step(planned_step, test_inputs)

        # Should handle execution errors gracefully
        assert result["status"].startswith("error_")
        assert "error_information" in result
        assert result["execution_mode"] == "live_mcp_failed"