import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
import { LlamaCppClient } from './llamacpp.js';
import type { ChatStreamEvent } from '../types.js';

describe('LlamaCppClient', () => {
  const mockFetch = vi.fn();

  beforeEach(() => {
    vi.stubGlobal('fetch', mockFetch);
  });

  afterEach(() => {
    vi.unstubAllGlobals();
  });

  it('sends messages and returns response', async () => {
    mockFetch.mockResolvedValue({
      ok: true,
      json: () => Promise.resolve({
        choices: [{ message: { content: 'Hello from llama.cpp!' } }],
        usage: { prompt_tokens: 10, completion_tokens: 5 },
      }),
    });

    const client = new LlamaCppClient({
      endpoint: 'http://localhost:8080',
    });

    const response = await client.chat({
      messages: [{ role: 'user', content: 'Hello' }],
    });

    expect(response.content).toBe('Hello from llama.cpp!');
    expect(response.usage.inputTokens).toBe(10);
    expect(response.usage.outputTokens).toBe(5);
  });

  it('streams responses via SSE', async () => {
    const chunks = [
      'data: {"choices":[{"delta":{"content":"Hello"}}]}\n\n',
      'data: {"choices":[{"delta":{"content":" world"}}]}\n\n',
      'data: {"choices":[{}],"usage":{"prompt_tokens":5,"completion_tokens":2}}\n\n',
      'data: [DONE]\n\n',
    ];

    const encoder = new TextEncoder();
    let chunkIndex = 0;

    const mockStream = new ReadableStream({
      pull(controller) {
        if (chunkIndex < chunks.length) {
          controller.enqueue(encoder.encode(chunks[chunkIndex]));
          chunkIndex++;
        } else {
          controller.close();
        }
      },
    });

    mockFetch.mockResolvedValue({
      ok: true,
      body: mockStream,
    });

    const client = new LlamaCppClient({
      endpoint: 'http://localhost:8080',
    });

    const events: ChatStreamEvent[] = [];
    for await (const event of client.chatStream({
      messages: [{ role: 'user', content: 'Hi' }],
    })) {
      events.push(event);
    }

    expect(events).toHaveLength(3);
    expect(events[0]).toEqual({ type: 'content', content: 'Hello' });
    expect(events[1]).toEqual({ type: 'content', content: ' world' });
    expect(events[2]).toEqual({
      type: 'done',
      usage: { inputTokens: 5, outputTokens: 2 },
    });
  });
});