import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
import { buildServer } from '../src/server';
import { FastifyInstance } from 'fastify';
import fs from 'fs';
import path from 'path';
import { config } from '../src/config';

describe('vLLM Proxy Integration Test', () => {
  let server: FastifyInstance;

  beforeEach(() => {
    // Mutate the loaded config instance
    config.proxyMode = 'vllm';
    
    server = buildServer();
    global.fetch = vi.fn();
  });

  afterEach(async () => {
    await server.close();
    vi.restoreAllMocks();
  });

  it('proxies request and rewrites XML response to tool_calls for vLLM', async () => {
    const requestFixturePath = path.join(__dirname, 'fixtures', 'vllm-like-request.json');
    const responseFixturePath = path.join(__dirname, 'fixtures', 'vllm-xml-response.json');
    
    const requestJson = JSON.parse(fs.readFileSync(requestFixturePath, 'utf8'));
    const responseJson = JSON.parse(fs.readFileSync(responseFixturePath, 'utf8'));

    (global.fetch as any).mockResolvedValue({
      ok: true,
      json: async () => responseJson
    });

    const response = await server.inject({
      method: 'POST',
      url: '/v1/chat/completions',
      payload: requestJson
    });

    expect(response.statusCode).toBe(200);
    const body = JSON.parse(response.payload);

    // Verify proxy forwarded it
    expect(global.fetch).toHaveBeenCalledTimes(1);
    const fetchArgs = (global.fetch as any).mock.calls[0];
    expect(fetchArgs[0]).toContain('/v1/chat/completions');
    
    const upstreamBody = JSON.parse(fetchArgs[1].body);
    expect(upstreamBody.model).toBe('Qwen3.5-27B');
    
    // Verify response was rewritten
    expect(body.choices[0].message.content).toBe("");
    expect(body.choices[0].message.tool_calls).toBeDefined();
    expect(body.choices[0].message.tool_calls).toHaveLength(1);
    expect(body.choices[0].message.tool_calls[0].function.name).toBe('read');
    expect(JSON.parse(body.choices[0].message.tool_calls[0].function.arguments)).toEqual({
      path: "/tmp/test.txt"
    });
  });
});