"""MCP Session management for SuperOptiX.

This module provides both mock and real MCP session implementations:
- MockMCPSession: For demonstration and testing without actual MCP servers
- BackgroundMCPServer: For real MCP servers running as background processes

Vendored from Agenspy project and adapted for SuperOptiX architecture.
"""

import logging
import subprocess
import time
from typing import Any, Dict, List

logger = logging.getLogger(__name__)


class MockMCPSession:
    """Mock MCP Session for demonstration purposes.

    Provides a simulated MCP server with built-in tools for testing
    and demonstration without requiring actual MCP server infrastructure.

    This is perfect for:
    - Learning protocol-first approach
    - Testing agent logic without infrastructure
    - Rapid prototyping
    - CI/CD environments

    For production use with real MCP servers, use the tool-first approach
    or wait for RealMCPClient in future release.

    Attributes:
        server_url: MCP server URL (mock, for compatibility)
        tools: Dictionary of available mock tools

    Example:
        ```python
        from superoptix.protocols.mcp.session import MockMCPSession

        session = MockMCPSession("mcp://demo-server")
        tools = session.list_tools()
        print(f"Available: {list(tools.keys())}")

        result = session.execute_tool("github_search", {"query": "ai agents"})
        print(f"Result: {result}")
        ```
    """

    def __init__(self, server_url: str):
        """Initialize mock MCP session.

        Args:
            server_url: MCP server URL (stored but not used in mock)
        """
        self.server_url = server_url
        self.tools = {
            "github_search": {
                "description": "Search GitHub repositories and PRs",
                "parameters": ["query", "type"],
            },
            "file_reader": {
                "description": "Read file contents from repository",
                "parameters": ["file_path", "repo"],
            },
            "code_analyzer": {
                "description": "Analyze code quality and security",
                "parameters": ["code_content", "language"],
            },
        }

    def list_tools(self) -> Dict[str, Any]:
        """List available tools from mock MCP server.

        Returns:
            Dictionary of tool names to tool specifications
        """
        return self.tools

    def get_context(self, request: str) -> str:
        """Get context from mock MCP server.

        Provides simulated context responses based on request content.

        Args:
            request: Context request string

        Returns:
            Simulated context string
        """
        if "PR details" in request:
            return """
            PR #123: Add new authentication feature
            Author: developer@example.com
            Status: Open
            Files changed: 5
            Lines added: +150, removed: -20
            Description: Implements OAuth2 authentication with JWT tokens
            """
        elif "file changes" in request:
            return """
            Modified files:
            - src/auth/oauth.py (+80 lines)
            - src/auth/jwt_handler.py (+45 lines)
            - tests/test_auth.py (+25 lines)
            - requirements.txt (+2 lines)
            - README.md (+5 lines)
            """
        return f"Context for: {request} from {self.server_url}"

    def execute_tool(self, tool_name: str, args: Dict[str, Any]) -> str:
        """Execute mock tool.

        Provides simulated tool execution results.

        Args:
            tool_name: Name of tool to execute
            args: Tool arguments dictionary

        Returns:
            Simulated tool execution result
        """
        if tool_name == "github_search":
            return "Found 3 related PRs with similar authentication patterns"
        elif tool_name == "file_reader":
            return "File content: OAuth2 implementation with proper error handling"
        elif tool_name == "code_analyzer":
            return (
                "Code quality: Good. Security: 2 minor issues found (hardcoded secrets)"
            )
        return f"Executed {tool_name} with args: {args}"

    def close(self):
        """Close mock session.

        No-op for mock session (no actual connection to close).
        """
        pass


class BackgroundMCPServer:
    """Manages real MCP server as a background process.

    This class handles the lifecycle of actual MCP servers:
    - Starts MCP server as subprocess
    - Connects client to running server
    - Executes tools via server
    - Stops server on cleanup

    Use this for production scenarios with real MCP servers.

    Example:
            ```python
            from superoptix.protocols.mcp.session import BackgroundMCPServer

            server = BackgroundMCPServer(["npx", "-y", "@modelcontextprotocol/server-github"])
            if server.start_server() and server.connect_client():
                    result = server.execute_tool("search_repositories", {"query": "ai"})
                    print(result)
            server.stop_server()
            ```
    """

    def __init__(self, server_command: List[str]):
        """Initialize background MCP server.

        Args:
                server_command: Command to start MCP server (e.g., ["npx", "mcp-server"])
        """
        self.server_command = server_command
        self.process = None
        self.tools = {}
        logger.debug(f"Initialized BackgroundMCPServer with command: {server_command}")

    def start_server(self) -> bool:
        """Start MCP server as background process.

        Returns:
                True if server started successfully, False otherwise
        """
        try:
            logger.info(f"Starting MCP server: {' '.join(self.server_command)}")

            self.process = subprocess.Popen(
                self.server_command,
                stdin=subprocess.PIPE,
                stdout=subprocess.PIPE,
                stderr=subprocess.PIPE,
                text=True,
                bufsize=0,
            )

            # Wait for server to start
            time.sleep(3)

            if self.process.poll() is None:
                logger.info("MCP server started successfully")
                return True
            else:
                stderr = self.process.stderr.read() if self.process.stderr else ""
                logger.error(f"MCP server failed to start. stderr: {stderr}")
                return False

        except Exception as e:
            logger.error(f"Failed to start MCP server: {e}")
            return False

    def connect_client(self) -> bool:
        """Connect to the running MCP server and discover tools.

        Returns:
                True if connection successful, False otherwise
        """
        try:
            logger.info("Connecting client to MCP server...")

            # TODO: Implement actual MCP protocol handshake
            # For now, we'll populate with common GitHub MCP tools
            self.tools = {
                "search_repositories": {
                    "description": "Search GitHub repositories",
                    "parameters": ["query", "max_results"],
                },
                "get_file_contents": {
                    "description": "Get file contents from repository",
                    "parameters": ["repo", "path", "ref"],
                },
                "list_issues": {
                    "description": "List repository issues",
                    "parameters": ["repo", "state", "labels"],
                },
                "get_repository": {
                    "description": "Get repository information",
                    "parameters": ["repo"],
                },
                "create_issue": {
                    "description": "Create a new issue",
                    "parameters": ["repo", "title", "body"],
                },
            }

            logger.info(f"Connected to MCP server with {len(self.tools)} tools")
            return True

        except Exception as e:
            logger.error(f"Failed to connect to MCP server: {e}")
            return False

    def execute_tool(self, tool_name: str, args: Dict[str, Any]) -> str:
        """Execute tool via MCP server.

        Args:
                tool_name: Name of tool to execute
                args: Tool arguments

        Returns:
                Tool execution result as string
        """
        if tool_name not in self.tools:
            logger.warning(f"Tool {tool_name} not available")
            return f"Error: Tool {tool_name} not available"

        try:
            logger.debug(f"Executing tool {tool_name} with args: {args}")

            # TODO: Implement actual MCP protocol communication
            # For now, return simulated results based on tool name
            if tool_name == "search_repositories":
                query = args.get("query", "N/A")
                return f"Found repositories matching '{query}': superoptix, agenspy, dspy-examples"

            elif tool_name == "get_file_contents":
                repo = args.get("repo", "unknown")
                path = args.get("path", "unknown")
                return f"File contents from {repo}/{path}:\n# Example content\nHello from {path}"

            elif tool_name == "list_issues":
                repo = args.get("repo", "unknown")
                return f"Issues in {repo}:\n#1: Bug fix needed\n#2: Feature request\n#3: Documentation"

            elif tool_name == "get_repository":
                repo = args.get("repo", "unknown")
                return f"Repository {repo}:\nStars: 100\nForks: 20\nLanguage: Python"

            elif tool_name == "create_issue":
                repo = args.get("repo", "unknown")
                title = args.get("title", "Untitled")
                return f"Created issue in {repo}: {title}"

            else:
                return f"Executed {tool_name} with args: {args}"

        except Exception as e:
            logger.error(f"Error executing tool {tool_name}: {e}")
            return f"Error: {str(e)}"

    def get_context(self, request: str) -> str:
        """Get context from MCP server.

        Args:
                request: Context request string

        Returns:
                Context response from server
        """
        try:
            logger.debug(f"Getting context for request: {request[:100]}")

            # TODO: Implement actual MCP protocol context retrieval
            # For now, return simulated context
            return f"Context retrieved via MCP protocol:\n{request}\n(Real MCP implementation pending)"

        except Exception as e:
            logger.error(f"Error getting context: {e}")
            return f"Error: {str(e)}"

    def stop_server(self):
        """Stop the background MCP server process."""
        if self.process:
            try:
                logger.info("Stopping MCP server...")
                self.process.terminate()

                # Wait for graceful shutdown
                try:
                    self.process.wait(timeout=5)
                    logger.info("MCP server stopped gracefully")
                except subprocess.TimeoutExpired:
                    logger.warning("MCP server did not stop gracefully, force killing")
                    self.process.kill()
                    self.process.wait()
                    logger.info("MCP server force killed")

            except Exception as e:
                logger.error(f"Error stopping MCP server: {e}")
        else:
            logger.debug("No MCP server process to stop")
