import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import {
  CallToolRequestSchema,
  ListToolsRequestSchema,
} from "@modelcontextprotocol/sdk/types.js";

// 1. 创建 MCP Server
const server = new Server(
  {
    name: "weather-server",
    version: "1.0.0",
  },
  {
    capabilities: {
      tools: {},
    },
  }
);

// 2. 定义工具列表
server.setRequestHandler(ListToolsRequestSchema, async () => {
  return {
    tools: [
      {
        name: "get_weather",
        description: "获取指定城市的当前天气",
        inputSchema: {
          type: "object",
          properties: {
            city: {
              type: "string",
              description: "城市名称，例如：北京、上海、广州",
            },
            unit: {
              type: "string",
              enum: ["celsius", "fahrenheit"],
              description: "温度单位",
              default: "celsius",
            },
          },
          required: ["city"],
        },
      },
      {
        name: "get_forecast",
        description: "获取指定城市的未来天气预报",
        inputSchema: {
          type: "object",
          properties: {
            city: {
              type: "string",
              description: "城市名称",
            },
            days: {
              type: "number",
              description: "预报天数（1-7）",
              default: 3,
            },
          },
          required: ["city"],
        },
      },
    ],
  };
});

// 3. 处理工具调用
server.setRequestHandler(CallToolRequestSchema, async (request) => {
  const { name, arguments: args } = request.params;

  switch (name) {
    case "get_weather": {
      const city = args?.city as string;
      const unit = (args?.unit as string) || "celsius";

      // 这里可以调用真实的天气 API
      const weather = await fetchWeather(city);

      return {
        content: [
          {
            type: "text",
            text: JSON.stringify(
              {
                city: weather.city,
                temperature:
                  unit === "celsius"
                    ? `${weather.temp_c}°C`
                    : `${weather.temp_f}°F`,
                condition: weather.condition,
                humidity: `${weather.humidity}%`,
                wind: `${weather.wind_kph} km/h`,
              },
              null,
              2
            ),
          },
        ],
      };
    }

    case "get_forecast": {
      const city = args?.city as string;
      const days = (args?.days as number) || 3;

      const forecast = await fetchForecast(city, days);

      return {
        content: [
          {
            type: "text",
            text: JSON.stringify(forecast, null, 2),
          },
        ],
      };
    }

    default:
      throw new Error(`Unknown tool: ${name}`);
  }
});

// 4. 辅助函数：调用天气 API
async function fetchWeather(city: string) {
  // 示例：使用 wttr.in API
  const response = await fetch(
    `https://wttr.in/${encodeURIComponent(city)}?format=j1`
  );
  const data = await response.json();
  const current = data.current_condition[0];

  return {
    city: city,
    temp_c: parseInt(current.temp_C),
    temp_f: parseInt(current.temp_F),
    condition: current.weatherDesc[0].value,
    humidity: parseInt(current.humidity),
    wind_kph: parseInt(current.windspeedKmph),
  };
}

async function fetchForecast(city: string, days: number) {
  const response = await fetch(
    `https://wttr.in/${encodeURIComponent(city)}?format=j1`
  );
  const data = await response.json();

  return data.weather.slice(0, days).map((day: any) => ({
    date: day.date,
    max_temp: `${day.maxtempC}°C`,
    min_temp: `${day.mintempC}°C`,
    condition: day.hourly[4].weatherDesc[0].value,
  }));
}

// 5. 启动服务器
async function main() {
  const transport = new StdioServerTransport();
  await server.connect(transport);
  console.error("Weather MCP Server running on stdio");
}

main().catch(console.error);

// 示例：限制文件访问范围
const ALLOWED_PATHS = ["/home/user/documents", "/home/user/projects"];

server.setRequestHandler(CallToolRequestSchema, async (request) => {
  if (request.params.name === "read_file") {
    const path = request.params.arguments?.path as string;
    
    // 检查路径是否在允许范围内
    if (!ALLOWED_PATHS.some(p => path.startsWith(p))) {
      throw new Error("Access denied: path not allowed");
    }
    
    // 执行读取操作
    return await readFile(path);
  }
});

// 使用 JSON Schema 验证输入
const schema = {
  type: "object",
  properties: {
    sql: {
      type: "string",
      pattern: "^(SELECT|select)",  // 只允许 SELECT 查询
    },
  },
  required: ["sql"],
};