// @vitest-environment node
import { beforeEach, describe, expect, it, vi } from 'vitest';
import { createLearningAgentClient } from '@electron/services/learning-agent-client';

describe('Learning Agent client', () => {
  const fetchImpl = vi.fn<typeof fetch>();
  const getAccessToken = vi.fn();

  const chunkedStream = (...chunks: string[]) => new Response(new ReadableStream<Uint8Array>({
    start(controller) {
      const encoder = new TextEncoder();
      for (const chunk of chunks) controller.enqueue(encoder.encode(chunk));
      controller.close();
    },
  }), { status: 200, headers: { 'Content-Type': 'text/event-stream' } });

  const mockRun = (stream: Response) => {
    fetchImpl
      .mockResolvedValueOnce(new Response(JSON.stringify({ session_id: 'session-1' }), { status: 201 }))
      .mockResolvedValueOnce(new Response(JSON.stringify({ run_id: 'run-1' }), { status: 202 }))
      .mockResolvedValueOnce(new Response(JSON.stringify({ stream_url: '/api/agents/sessions/session-1/events?ticket=ticket-1' }), { status: 200 }))
      .mockResolvedValueOnce(stream);
  };

  const ask = () => createLearningAgentClient({
    fetchImpl,
    getAccessToken,
    apiBaseUrl: 'https://square.example',
  }).ask({
    courseId: 'course-1',
    contentHash: 'a'.repeat(64),
    message: '为什么要学 Python？',
  });

  beforeEach(() => {
    fetchImpl.mockReset();
    getAccessToken.mockReset();
    getAccessToken.mockResolvedValue('works-token');
  });

  it('binds the exact course hash and collects the Learning Runtime answer', async () => {
    const event = (type: string, payload: Record<string, unknown>) => `event: agent.event\ndata: ${JSON.stringify({ run_id: 'run-1', type, payload })}\n\n`;
    fetchImpl
      .mockResolvedValueOnce(new Response(JSON.stringify({ session_id: 'session-1' }), { status: 201 }))
      .mockResolvedValueOnce(new Response(JSON.stringify({ run_id: 'run-1' }), { status: 202 }))
      .mockResolvedValueOnce(new Response(JSON.stringify({ stream_url: '/api/agents/sessions/session-1/events?ticket=ticket-1' }), { status: 200 }))
      .mockResolvedValueOnce(new Response(
        event('learning.assistant.delta', { delta: 'Python ' })
        + event('learning.assistant.delta', { delta: '很适合入门。' })
        + event('learning.assistant.completed', { sources: [] }),
        { status: 200, headers: { 'Content-Type': 'text/event-stream' } },
      ));
    const client = createLearningAgentClient({ fetchImpl, getAccessToken, apiBaseUrl: 'https://square.example' });

    await expect(client.ask({
      courseId: 'course-1',
      contentHash: 'a'.repeat(64),
      message: '为什么要学 Python？',
      anchor: { sceneId: 'scene-1', sceneOrder: 1 },
    })).resolves.toEqual({ text: 'Python 很适合入门。' });

    expect(JSON.parse(String(fetchImpl.mock.calls[0][1]?.body))).toMatchObject({
      runtime: 'learning',
      runtime_version: 'v1',
      binding: { kind: 'learning-course', key: `course-1:${'a'.repeat(64)}` },
    });
    expect(fetchImpl.mock.calls[3][1]?.headers).toEqual({ Accept: 'text/event-stream' });
    expect(fetchImpl.mock.calls.some((call) => call[1]?.method === 'DELETE')).toBe(false);
  });

  it('reuses one course-bound Works Agent session across multiple turns', async () => {
    const stream = (runId: string, answer: string) => new Response(
      `data: ${JSON.stringify({ run_id: runId, type: 'learning.assistant.delta', payload: { delta: answer } })}\n\n`
      + `data: ${JSON.stringify({ run_id: runId, type: 'learning.assistant.completed', payload: {} })}\n\n`,
      { status: 200, headers: { 'Content-Type': 'text/event-stream' } },
    );
    fetchImpl
      .mockResolvedValueOnce(new Response(JSON.stringify({ session_id: 'session-shared' }), { status: 201 }))
      .mockResolvedValueOnce(new Response(JSON.stringify({ run_id: 'run-1' }), { status: 202 }))
      .mockResolvedValueOnce(new Response(JSON.stringify({ stream_url: '/api/agents/sessions/session-shared/events?ticket=1' }), { status: 200 }))
      .mockResolvedValueOnce(stream('run-1', '第一轮'))
      .mockResolvedValueOnce(new Response(JSON.stringify({ run_id: 'run-2' }), { status: 202 }))
      .mockResolvedValueOnce(new Response(JSON.stringify({ stream_url: '/api/agents/sessions/session-shared/events?ticket=2' }), { status: 200 }))
      .mockResolvedValueOnce(stream('run-2', '第二轮'));
    const client = createLearningAgentClient({ fetchImpl, getAccessToken, apiBaseUrl: 'https://square.example' });
    const binding = { courseId: 'course-1', contentHash: 'a'.repeat(64) };

    await expect(client.ask({ ...binding, message: '第一问' })).resolves.toEqual({ text: '第一轮' });
    await expect(client.ask({ ...binding, message: '追问' })).resolves.toEqual({ text: '第二轮' });

    const urls = fetchImpl.mock.calls.map(([url]) => String(url));
    expect(urls.filter((url) => url === 'https://square.example/api/agents/sessions')).toHaveLength(1);
    expect(urls.filter((url) => url.endsWith('/sessions/session-shared/commands'))).toHaveLength(2);
    expect(fetchImpl.mock.calls.some((call) => call[1]?.method === 'DELETE')).toBe(false);
  });

  it('parses production CRLF-delimited SSE frames', async () => {
    const event = (type: string, payload: Record<string, unknown>) => (
      `id: 1\r\nevent: agent.event\r\ndata: ${JSON.stringify({ run_id: 'run-1', type, payload })}\r\n\r\n`
    );
    mockRun(chunkedStream(
      event('learning.assistant.delta', { delta: 'CRLF 正常。' }),
      event('learning.assistant.completed', {}),
    ));

    await expect(ask()).resolves.toEqual({ text: 'CRLF 正常。' });
  });

  it('parses a CRLF frame delimiter split across stream chunks', async () => {
    const delta = JSON.stringify({
      run_id: 'run-1',
      type: 'learning.assistant.delta',
      payload: { delta: '跨块正常。' },
    });
    const completed = JSON.stringify({
      run_id: 'run-1',
      type: 'learning.assistant.completed',
      payload: {},
    });
    mockRun(chunkedStream(
      `data: ${delta}\r\n\r`,
      `\ndata: ${completed}\r`,
      '\n\r',
      '\n',
    ));

    await expect(ask()).resolves.toEqual({ text: '跨块正常。' });
  });

  it('joins multiple data lines and ignores other SSE fields and comments', async () => {
    const delta = JSON.stringify({
      run_id: 'run-1',
      type: 'learning.assistant.delta',
      payload: { delta: '多行正常。' },
    });
    const split = delta.indexOf(',"type"');
    const completed = JSON.stringify({
      run_id: 'run-1',
      type: 'learning.assistant.completed',
      payload: {},
    });
    mockRun(chunkedStream(
      ': keep-alive\r\nid: 9\r\nevent: agent.event\r\nretry: 3000\r\n',
      `data: ${delta.slice(0, split)},\r\ndata: ${delta.slice(split + 1)}\r\n\r\n`,
      `data: ${completed}\r\n\r\n`,
    ));

    await expect(ask()).resolves.toEqual({ text: '多行正常。' });
  });

  it('stops before the network for an invalid package hash', async () => {
    const client = createLearningAgentClient({ fetchImpl, getAccessToken });
    await expect(client.ask({ courseId: 'course-1', contentHash: 'bad', message: '你好' })).rejects.toThrow('助教请求无效');
    expect(fetchImpl).not.toHaveBeenCalled();
  });
});