/**
 * `supportedProtocolVersions`: support a protocol version not yet in the SDK.
 * The first version in the list is the fallback when the client requests an
 * unsupported one. One binary, either transport.
 */
import { serve } from '@hono/node-server';
import { parseExampleArgs } from '@mcp-examples/shared';
import { createMcpHonoApp } from '@modelcontextprotocol/hono';
import { createMcpHandler, McpServer, SUPPORTED_PROTOCOL_VERSIONS } from '@modelcontextprotocol/server';
import { serveStdio } from '@modelcontextprotocol/server/stdio';

// Add support for a newer protocol version (first in list is fallback).
const CUSTOM_VERSIONS = ['2026-01-01', ...SUPPORTED_PROTOCOL_VERSIONS];

function buildServer(): McpServer {
    const server = new McpServer(
        { name: 'custom-protocol-server', version: '1.0.0' },
        { supportedProtocolVersions: CUSTOM_VERSIONS, capabilities: { tools: {} } }
    );

    server.registerTool('get-protocol-info', { description: 'Returns protocol version configuration' }, async () => ({
        content: [{ type: 'text', text: JSON.stringify({ supportedVersions: CUSTOM_VERSIONS }) }]
    }));

    return server;
}

const { transport, port } = parseExampleArgs();

if (transport === 'stdio') {
    void serveStdio(buildServer);
    console.error('[server] serving over stdio');
} else {
    const handler = createMcpHandler(buildServer);
    // `createMcpHonoApp()` binds the endpoint behind localhost host/origin
    // validation by default, matching the framework factories' defaults.
    const app = createMcpHonoApp();
    app.all('/mcp', c => handler.fetch(c.req.raw));
    serve({ fetch: app.fetch, port, hostname: '127.0.0.1' }, () => {
        console.error(`[server] listening on http://127.0.0.1:${port}/mcp`);
    });
}