#!/usr/bin/env node
/**
 * MCP Client - Core client for interacting with MCP servers
 */

import { Client } from '@modelcontextprotocol/sdk/client/index.js';
import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js';
import { readFile } from 'fs/promises';
import { resolve } from 'path';

interface MCPConfig {
  mcpServers: {
    [key: string]: {
      command: string;
      args: string[];
      env?: Record<string, string>;
    };
  };
}

interface ToolInfo {
  serverName: string;
  name: string;
  description: string;
  inputSchema: any;
  outputSchema?: any;
}

interface PromptInfo {
  serverName: string;
  name: string;
  description: string;
  arguments?: any[];
}

interface ResourceInfo {
  serverName: string;
  uri: string;
  name: string;
  description?: string;
  mimeType?: string;
}

export class MCPClientManager {
  private config: MCPConfig | null = null;
  private clients: Map<string, Client> = new Map();

  async loadConfig(configPath: string = '.claude/.mcp.json'): Promise<MCPConfig> {
    const fullPath = resolve(process.cwd(), configPath);
    const content = await readFile(fullPath, 'utf-8');
    const config = JSON.parse(content) as MCPConfig;
    this.config = config;
    return config;
  }

  async connectToServer(serverName: string): Promise<Client> {
    if (!this.config?.mcpServers[serverName]) {
      throw new Error(`Server ${serverName} not found in config`);
    }

    const serverConfig = this.config.mcpServers[serverName];
    const transport = new StdioClientTransport({
      command: serverConfig.command,
      args: serverConfig.args,
      env: serverConfig.env
    });

    const client = new Client({
      name: `mcp-manager-${serverName}`,
      version: '1.0.0'
    }, { capabilities: {} });

    await client.connect(transport);
    this.clients.set(serverName, client);
    return client;
  }

  async connectAll(): Promise<void> {
    if (!this.config) {
      throw new Error('Config not loaded. Call loadConfig() first.');
    }

    const connections = Object.keys(this.config.mcpServers).map(name =>
      this.connectToServer(name)
    );
    await Promise.all(connections);
  }

  async getAllTools(): Promise<ToolInfo[]> {
    const allTools: ToolInfo[] = [];
    for (const [serverName, client] of this.clients.entries()) {
      const response = await client.listTools({}, { timeout: 300000 });
      for (const tool of response.tools) {
        allTools.push({
          serverName,
          name: tool.name,
          description: tool.description || '',
          inputSchema: tool.inputSchema,
          outputSchema: (tool as any).outputSchema
        });
      }
    }
    return allTools;
  }

  async getAllPrompts(): Promise<PromptInfo[]> {
    const allPrompts: PromptInfo[] = [];
    for (const [serverName, client] of this.clients.entries()) {
      const response = await client.listPrompts({}, { timeout: 300000 });
      for (const prompt of response.prompts) {
        allPrompts.push({
          serverName,
          name: prompt.name,
          description: prompt.description || '',
          arguments: prompt.arguments
        });
      }
    }
    return allPrompts;
  }

  async getAllResources(): Promise<ResourceInfo[]> {
    const allResources: ResourceInfo[] = [];
    for (const [serverName, client] of this.clients.entries()) {
      const response = await client.listResources({}, { timeout: 300000 });
      for (const resource of response.resources) {
        allResources.push({
          serverName,
          uri: resource.uri,
          name: resource.name,
          description: resource.description,
          mimeType: resource.mimeType
        });
      }
    }
    return allResources;
  }

  async callTool(serverName: string, toolName: string, args: any): Promise<any> {
    const client = this.clients.get(serverName);
    if (!client) throw new Error(`Not connected to server: ${serverName}`);
    return await client.callTool({ name: toolName, arguments: args }, { timeout: 300000 });
  }

  async getPrompt(serverName: string, promptName: string, args?: any): Promise<any> {
    const client = this.clients.get(serverName);
    if (!client) throw new Error(`Not connected to server: ${serverName}`);
    return await client.getPrompt({ name: promptName, arguments: args }, { timeout: 300000 });
  }

  async readResource(serverName: string, uri: string): Promise<any> {
    const client = this.clients.get(serverName);
    if (!client) throw new Error(`Not connected to server: ${serverName}`);
    return await client.readResource({ uri }, { timeout: 300000 });
  }

  async cleanup(): Promise<void> {
    for (const client of this.clients.values()) {
      await client.close();
    }
    this.clients.clear();
  }
}