const express = require('express');
const request = require('supertest');

jest.mock('@modelcontextprotocol/sdk/server/streamableHttp.js', () => ({
  StreamableHTTPServerTransport: jest.fn().mockImplementation(() => ({
    handleRequest: jest.fn(async (req, res) => {
      res.status(200).json({ ok: true });
    }),
    close: jest.fn(),
  })),
}));

jest.mock('../src/mcp-server', () => ({
  createWebshareMcpServer: jest.fn(() => ({
    connect: jest.fn(async () => {}),
    close: jest.fn(),
  })),
}));

const { StreamableHTTPServerTransport } = require('@modelcontextprotocol/sdk/server/streamableHttp.js');
const { createWebshareMcpServer } = require('../src/mcp-server');
const { registerMcpHttp } = require('../src/mcp-http');

describe('registerMcpHttp', () => {
  let app;

  beforeEach(() => {
    jest.clearAllMocks();
    createWebshareMcpServer.mockImplementation(() => ({
      connect: jest.fn(async () => {}),
      close: jest.fn(),
    }));
    StreamableHTTPServerTransport.mockImplementation(() => ({
      handleRequest: jest.fn(async (req, res) => {
        res.status(200).json({ ok: true });
      }),
      close: jest.fn(),
    }));
    app = express();
    app.use(express.json());
    registerMcpHttp(app, { username: 'u', password: 'p', path: '/mcp' });
  });

  it('POST /mcp connects transport and handles request', async () => {
    const res = await request(app)
      .post('/mcp')
      .send({ jsonrpc: '2.0', method: 'initialize', id: 1 });
    expect(res.status).toBe(200);
    expect(createWebshareMcpServer).toHaveBeenCalledWith({ username: 'u', password: 'p' });
    expect(StreamableHTTPServerTransport).toHaveBeenCalled();
  });

  it('GET /mcp returns 405 with method-not-allowed body', async () => {
    const res = await request(app).get('/mcp');
    expect(res.status).toBe(405);
    expect(res.body.error.message).toMatch(/Method not allowed/i);
  });

  it('DELETE /mcp returns 405', async () => {
    const res = await request(app).delete('/mcp');
    expect(res.status).toBe(405);
  });

  it('POST /mcp returns 500 JSON-RPC when connect throws and headers not sent', async () => {
    createWebshareMcpServer.mockImplementation(() => ({
      connect: jest.fn(async () => {
        throw new Error('boom');
      }),
      close: jest.fn(),
    }));
    const res = await request(app).post('/mcp').send({});
    expect(res.status).toBe(500);
    expect(res.body.error.code).toBe(-32603);
  });

  it('uses default path /mcp when path option omitted', () => {
    const app2 = express();
    registerMcpHttp(app2, { username: 'a', password: 'b' });
    const layer = app2._router.stack.find(
      (l) => l.route && l.route.path === '/mcp' && l.route.methods.post
    );
    expect(layer).toBeTruthy();
  });

  it('skips 500 body when headers already sent after handler error', async () => {
    StreamableHTTPServerTransport.mockImplementation(() => ({
      handleRequest: jest.fn(async (req, res) => {
        res.status(202).json({ partial: true });
        throw new Error('late failure');
      }),
      close: jest.fn(),
    }));
    const res = await request(app).post('/mcp').send({});
    // first write wins — not overwritten with 500
    expect(res.status).toBe(202);
    expect(res.body).toEqual({ partial: true });
  });
});