import { useState, useEffect, useCallback } from "react";
import { MCPClientService } from "../services/mcpClient";
import type {
  MCPServerConfig,
  MCPClientState,
  ExtendedTool,
} from "../types/mcp";
import type { Tool as OriginalTool } from "../components/ToolItem";

// Singleton instance
let mcpClientInstance: MCPClientService | null = null;

const getMCPClient = (): MCPClientService => {
  if (!mcpClientInstance) {
    mcpClientInstance = new MCPClientService();
  }
  return mcpClientInstance;
};

export const useMCP = () => {
  const [mcpState, setMCPState] = useState<MCPClientState>({
    servers: {},
    isLoading: false,
    error: undefined,
  });

  const mcpClient = getMCPClient();

  // Subscribe to MCP state changes
  useEffect(() => {
    const handleStateChange = (state: MCPClientState) => {
      console.log("MCP state change triggered:", Object.keys(state.servers));
      setMCPState(state);
    };

    mcpClient.addStateListener(handleStateChange);

    // Get initial state
    setMCPState(mcpClient.getState());

    return () => {
      mcpClient.removeStateListener(handleStateChange);
      // Don't cleanup the service itself as it's a singleton used across the app
    };
  }, [mcpClient]);

  // Add a new MCP server
  const addServer = useCallback(
    async (config: MCPServerConfig): Promise<void> => {
      return mcpClient.addServer(config);
    },
    [mcpClient]
  );

  // Remove an MCP server
  const removeServer = useCallback(
    async (serverId: string): Promise<void> => {
      return mcpClient.removeServer(serverId);
    },
    [mcpClient]
  );

  // Connect to a server
  const connectToServer = useCallback(
    async (serverId: string): Promise<void> => {
      return mcpClient.connectToServer(serverId);
    },
    [mcpClient]
  );

  // Disconnect from a server
  const disconnectFromServer = useCallback(
    async (serverId: string): Promise<void> => {
      return mcpClient.disconnectFromServer(serverId);
    },
    [mcpClient]
  );

  // Test connection to a server
  const testConnection = useCallback(
    async (config: MCPServerConfig): Promise<boolean> => {
      return mcpClient.testConnection(config);
    },
    [mcpClient]
  );

  // Call a tool on an MCP server
  const callMCPTool = useCallback(
    async (
      serverId: string,
      toolName: string,
      args: Record<string, unknown>
    ) => {
      console.log("MCP tool called:", {
        serverId,
        toolName,
        args,
        timestamp: new Date().toISOString(),
      });
      console.trace("MCP tool call stack trace:");
      return mcpClient.callTool(serverId, toolName, args);
    },
    [mcpClient]
  );

  // Get all available MCP tools
  const getMCPTools = useCallback((): ExtendedTool[] => {
    console.log(
      "getMCPTools called - checking if this is being called frequently"
    );
    const mcpTools: ExtendedTool[] = [];

    Object.entries(mcpState.servers).forEach(([serverId, connection]) => {
      if (connection.isConnected && connection.config.enabled) {
        connection.tools.forEach((mcpTool) => {
          mcpTools.push({
            id: `${serverId}:${mcpTool.name}`,
            name: mcpTool.name,
            enabled: true,
            isCollapsed: false,
            mcpServerId: serverId,
            mcpTool: mcpTool,
            isRemote: true,
          });
        });
      }
    });

    return mcpTools;
  }, [mcpState.servers]);

  // Convert MCP tools to the format expected by the existing tool system
  const getMCPToolsAsOriginalTools = useCallback((): OriginalTool[] => {
    const mcpTools: OriginalTool[] = [];
    let globalId = 10000; // Start with high numbers to avoid conflicts

    Object.entries(mcpState.servers).forEach(([serverId, connection]) => {
      if (connection.isConnected && connection.config.enabled) {
        connection.tools.forEach((mcpTool) => {
          // Convert tool name to valid JavaScript identifier and include server name for uniqueness
          const serverName = connection.config.name
            .replace(/[-\s]/g, "_")
            .replace(/[^a-zA-Z0-9_]/g, "");
          const toolName = mcpTool.name
            .replace(/[-\s]/g, "_")
            .replace(/[^a-zA-Z0-9_]/g, "");
          const jsToolName = `${serverName}_${toolName}`;

          // Create a JavaScript function that calls the MCP tool
          const code = `/**
 * ${mcpTool.description || `MCP tool from ${connection.config.name}`}
 * Server: ${connection.config.name}
 * ${Object.entries(mcpTool.inputSchema.properties || {})
   .map(([name, prop]) => {
     const p = prop as { type?: string; description?: string };
     return `@param {${p.type || "any"}} ${name} - ${p.description || ""}`;
   })
   .join("\n * ")}
 * @returns {Promise<any>} Tool execution result
 */
export async function ${jsToolName}(${Object.keys(
            mcpTool.inputSchema.properties || {}
          ).join(", ")}) {
  // This is an MCP tool - execution is handled by the MCP client
  return { mcpServerId: "${serverId}", toolName: "${
            mcpTool.name
          }", arguments: arguments };
}

export default (input, output) =>
  React.createElement(
    "div",
    { className: "bg-blue-50 border border-blue-200 rounded-lg p-4" },
    React.createElement(
      "div",
      { className: "flex items-center mb-3" },
      React.createElement(
        "div",
        {
          className:
            "w-8 h-8 bg-blue-100 rounded-full flex items-center justify-center mr-3",
        },
        "🌐",
      ),
      React.createElement(
        "h3",
        { className: "text-blue-900 font-semibold" },
        "${mcpTool.name} (${connection.config.name})"
      ),
    ),
    React.createElement(
      "div",
      { className: "text-sm mb-2" },
      React.createElement(
        "p",
        { className: "text-blue-700 font-medium mb-1" },
        \`Server: ${connection.config.name}\`
      ),
    ),
  );`;

          mcpTools.push({
            id: globalId++,
            name: jsToolName, // Use JavaScript-safe name for function calls
            code: code,
            enabled: true,
            isCollapsed: false,
          });
        });
      }
    });

    return mcpTools;
  }, [mcpState.servers]);

  // Connect to all enabled servers
  const connectAll = useCallback(async (): Promise<void> => {
    return mcpClient.connectAll();
  }, [mcpClient]);

  // Disconnect from all servers
  const disconnectAll = useCallback(async (): Promise<void> => {
    return mcpClient.disconnectAll();
  }, [mcpClient]);

  return {
    mcpState,
    addServer,
    removeServer,
    connectToServer,
    disconnectFromServer,
    testConnection,
    callMCPTool,
    getMCPTools,
    getMCPToolsAsOriginalTools,
    connectAll,
    disconnectAll,
  };
};