const readline = require('node:readline')

const rl = readline.createInterface({ input: process.stdin, crlfDelay: Infinity })

rl.on('line', line => {
  if (!line.trim()) return
  const message = JSON.parse(line)
  if (message.method === 'initialize') {
    process.stdout.write(`${JSON.stringify({
      jsonrpc: '2.0',
      id: message.id,
      result: {
        protocolVersion: '2024-11-05',
        capabilities: { tools: {} },
        serverInfo: { name: 'fake-mcp', version: '0.0.0' },
      },
    })}\n`)
    return
  }
  if (message.method === 'tools/list') {
    process.stdout.write(`${JSON.stringify({
      jsonrpc: '2.0',
      id: message.id,
      result: {
        tools: [
          {
            name: 'fake_echo',
            description: 'Echo a value through fake MCP.',
            inputSchema: {
              type: 'object',
              properties: { text: { type: 'string' } },
              required: ['text'],
              additionalProperties: false,
            },
          },
        ],
      },
    })}\n`)
    return
  }
  if (message.method === 'tools/call') {
    process.stdout.write(`${JSON.stringify({
      jsonrpc: '2.0',
      id: message.id,
      result: {
        content: [{ type: 'text', text: `mcp:${message.params?.arguments?.text || ''}` }],
      },
    })}\n`)
    return
  }
  process.stdout.write(`${JSON.stringify({
    jsonrpc: '2.0',
    id: message.id,
    error: { code: -32601, message: `Method not found: ${message.method}` },
  })}\n`)
})