import { EventEmitter } from 'node:events';
import { access, readFile, writeFile } from 'node:fs/promises';
import { beforeEach, describe, expect, it, vi } from 'vitest';

const spawn = vi.hoisted(() => vi.fn());

vi.mock('node:child_process', () => ({
  spawn,
}));

const { renderPdf } = await import('../src/pdf/render.js');

function child() {
  const proc = new EventEmitter();
  proc.stderr = new EventEmitter();
  proc.kill = vi.fn();
  return proc;
}

describe('renderPdf', () => {
  beforeEach(() => {
    spawn.mockReset();
  });

  it('returns the PDF and removes the temp files', async () => {
    spawn.mockImplementation((_bin, args) => {
      const proc = child();
      queueMicrotask(async () => {
        await writeFile(args[1], Buffer.from('%PDF-1.4'));
        proc.emit('close', 0);
      });
      return proc;
    });

    const pdf = await renderPdf('<html><body>Agreement</body></html>');

    expect(pdf.subarray(0, 5).toString()).toBe('%PDF-');
    expect(spawn).toHaveBeenCalledWith(
      'weasyprint',
      expect.any(Array),
      expect.objectContaining({
        stdio: ['ignore', 'ignore', 'pipe'],
        cwd: expect.any(String),
      }),
    );
    const htmlPath = spawn.mock.calls[0][1][0];
    await expect(access(htmlPath)).rejects.toThrow();
  });

  it('writes data-URI images beside the HTML for WeasyPrint', async () => {
    /** @type {string | undefined} */
    let writtenHtml;

    spawn.mockImplementation((_bin, args) => {
      const proc = child();
      queueMicrotask(async () => {
        writtenHtml = await readFile(args[0], 'utf8');
        await writeFile(args[1], Buffer.from('%PDF-1.4'));
        proc.emit('close', 0);
      });
      return proc;
    });

    const tiny =
      'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg==';
    await renderPdf(
      `<html><body><img src="data:image/png;base64,${tiny}" alt="sig" /></body></html>`,
    );

    expect(writtenHtml).toContain('src="embed-0.png"');
    expect(writtenHtml).not.toContain('data:image/png;base64');
  });

  it('reports a missing WeasyPrint binary', async () => {
    spawn.mockImplementation(() => {
      const proc = child();
      queueMicrotask(() => {
        const error = new Error('spawn weasyprint ENOENT');
        error.code = 'ENOENT';
        proc.emit('error', error);
      });
      return proc;
    });

    await expect(renderPdf('<html></html>')).rejects.toThrow('WeasyPrint is not installed');
  });
});