import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StreamableHTTPServerTransport } from "@modelcontextprotocol/sdk/server/streamableHttp.js";
import { toFetchResponse, toReqRes } from "fetch-to-node";
import {serve} from "@hono/node-server";
import { Hono } from 'hono'
import { z } from "zod";


const BASE_URL = "";
const app = new Hono().basePath(BASE_URL)
function getServer() {
    const server = new McpServer({
        name: "add-tool-server",
        version: "1.0.0",
        description: 'An MCP service for getting the sum of two numbers',
    });
    server.tool(
        "add-tool",
        "Get the sum of two numbers",
        {
            a: z.number(),
            b: z.number()
        },
        async ({ a, b }) => ({
            content: [{
                type: "text",
                text: String(a + b)
            }]
        })
    );

    return server;
}

app.post('/mcp', async (ctx) => {
    try{
        const { req, res } = toReqRes(ctx.req.raw);
        const transport: StreamableHTTPServerTransport = new StreamableHTTPServerTransport({
            sessionIdGenerator: undefined, // set to undefined for stateless servers
        });
        const server = getServer();
        await server.connect(transport);
        await transport.handleRequest(req, res, await ctx.req.json());
        res.on('close', () => {
            console.log('Request closed');
            transport.close();
            server.close();
        });
        return toFetchResponse(res);
    }catch(err: any){
        return ctx.json(
            {
                jsonrpc: "2.0",
                error: {
                    code: -32603,
                    message: "Internal server error",
                },
                id: null,
            },
            { status: 500 }
        );
    }
})


serve({
    fetch: app.fetch,
    port: 3000,
}, (info) => {
    console.log(`Server is running on http://localhost:${info.port}`)
})