import { describe, expect, it, vi, afterEach } from 'vitest';
import { findOpencodeServer, parseModelRef, opencodeBaseUrls, opencodePrompt } from '../opencode';

/**
 * The single most important behaviour under test is the SPA-catch-all trap:
 * `opencode serve` answers 200 with the web UI's index.html for ANY unknown
 * path, so a probe that trusts `res.ok` "verifies" endpoints that do not
 * exist. That is not hypothetical — it is exactly how this integration was
 * first built wrong (against an assumed OpenAI-compatible `/v1/models` that
 * only ever returned HTML).
 */

const HTML_CATCHALL = {
  ok: true,
  headers: new Headers({ 'content-type': 'text/html; charset=utf-8' }),
  json: async () => {
    throw new Error('not json');
  },
};

function jsonResponse(body: unknown) {
  return {
    ok: true,
    headers: new Headers({ 'content-type': 'application/json' }),
    json: async () => body,
  };
}

describe('parseModelRef', () => {
  it('splits providerID/modelID, keeping slashes inside the model id', () => {
    expect(parseModelRef('opencode/deepseek-v4-flash-free')).toEqual({
      providerID: 'opencode',
      modelID: 'deepseek-v4-flash-free',
    });
    // Real provider ids do contain slashes (e.g. openrouter's
    // "anthropic/claude-..."), so only the FIRST slash separates.
    expect(parseModelRef('openrouter/anthropic/claude-sonnet-4.5')).toEqual({
      providerID: 'openrouter',
      modelID: 'anthropic/claude-sonnet-4.5',
    });
  });

  it('rejects malformed refs rather than guessing', () => {
    expect(parseModelRef('noslash')).toBeNull();
    expect(parseModelRef('/leading')).toBeNull();
    expect(parseModelRef('trailing/')).toBeNull();
    expect(parseModelRef('')).toBeNull();
  });
});

describe('opencodeBaseUrls', () => {
  const original = process.env.OPENCODE_BASE_URL;
  afterEach(() => {
    if (original === undefined) delete process.env.OPENCODE_BASE_URL;
    else process.env.OPENCODE_BASE_URL = original;
  });

  it('refuses a non-loopback override — this class must never reach off-machine', () => {
    process.env.OPENCODE_BASE_URL = 'https://evil.example.com';
    const urls = opencodeBaseUrls();
    expect(urls.some((u) => u.includes('evil.example.com'))).toBe(false);
    expect(urls[0]).toMatch(/127\.0\.0\.1|localhost/);
  });

  it('honours a loopback override, trying it first', () => {
    process.env.OPENCODE_BASE_URL = 'http://127.0.0.1:9999/';
    expect(opencodeBaseUrls()[0]).toBe('http://127.0.0.1:9999');
  });
});

describe('findOpencodeServer', () => {
  const originalFetch = global.fetch;
  afterEach(() => {
    global.fetch = originalFetch;
    vi.restoreAllMocks();
  });

  it('does NOT accept the web UI catch-all as a working API (200 + HTML)', async () => {
    global.fetch = vi.fn().mockResolvedValue(HTML_CATCHALL) as unknown as typeof fetch;
    expect(await findOpencodeServer()).toBeNull();
  });

  it('parses the real /api/model shape into providerID/modelID refs', async () => {
    global.fetch = vi.fn().mockResolvedValue(
      jsonResponse({
        data: [
          { id: 'deepseek-v4-flash-free', providerID: 'opencode', name: 'DeepSeek V4 Flash Free' },
          { id: 'deepseek-chat', providerID: 'deepseek' },
          { id: '', providerID: 'broken' },
        ],
      }),
    ) as unknown as typeof fetch;

    const found = await findOpencodeServer();
    expect(found?.models.map((m) => m.ref)).toEqual([
      'opencode/deepseek-v4-flash-free',
      'deepseek/deepseek-chat',
    ]);
    expect(found?.models[0].label).toBe('DeepSeek V4 Flash Free (opencode)');
  });

  it('returns null when the server answers JSON with no models', async () => {
    global.fetch = vi.fn().mockResolvedValue(jsonResponse({ data: [] })) as unknown as typeof fetch;
    expect(await findOpencodeServer()).toBeNull();
  });
});

describe('opencodePrompt', () => {
  const originalFetch = global.fetch;
  afterEach(() => {
    global.fetch = originalFetch;
    vi.restoreAllMocks();
  });

  it('returns only the text parts — never the model\'s private reasoning', async () => {
    global.fetch = vi.fn()
      .mockResolvedValueOnce(jsonResponse({ id: 'ses_abc' }))
      .mockResolvedValueOnce(
        jsonResponse({
          parts: [
            { type: 'step-start' },
            { type: 'reasoning', text: 'SECRET chain of thought that must not be shown' },
            { type: 'text', text: 'The visible answer.' },
            { type: 'step-finish' },
          ],
        }),
      ) as unknown as typeof fetch;

    const result = await opencodePrompt('http://127.0.0.1:4096', { providerID: 'opencode', modelID: 'm' }, 'sys', 'q');
    expect(result).toEqual({ ok: true, answer: 'The visible answer.' });
    if (result.ok) expect(result.answer).not.toContain('SECRET');
  });

  it('fails cleanly when no session can be created', async () => {
    global.fetch = vi.fn().mockResolvedValue(HTML_CATCHALL) as unknown as typeof fetch;
    const result = await opencodePrompt('http://127.0.0.1:4096', { providerID: 'p', modelID: 'm' }, undefined, 'q');
    expect(result.ok).toBe(false);
  });

  it('fails cleanly when the reply carries no text part', async () => {
    global.fetch = vi.fn()
      .mockResolvedValueOnce(jsonResponse({ id: 'ses_abc' }))
      .mockResolvedValueOnce(jsonResponse({ parts: [{ type: 'step-start' }, { type: 'reasoning', text: 'only thinking' }] })) as unknown as typeof fetch;
    const result = await opencodePrompt('http://127.0.0.1:4096', { providerID: 'p', modelID: 'm' }, undefined, 'q');
    expect(result).toEqual({ ok: false, error: 'OpenCode returned no message content' });
  });
});