const fs = require('fs/promises');
const path = require('path');
const { chromium } = require('playwright');

const input = process.argv[2];
const outputDir = process.argv[3];
const presenterNames = ['Zhihao Zhao', 'Zipeng Wang', 'Jiuqi Feng', 'Siyuan Zhang'];

function baseWithoutHash(url) {
  const hashIndex = url.indexOf('#');
  return hashIndex >= 0 ? url.slice(0, hashIndex) : url;
}

async function applyRequestedEdits(page) {
  await page.evaluate((names) => {
    const visible = Array.from(document.querySelectorAll('section')).find((section) => {
      const style = getComputedStyle(section);
      return style.visibility !== 'hidden' && style.opacity !== '0';
    });
    if (!visible) return;

    if ((visible.getAttribute('data-label') || '').startsWith('01')) {
      for (const el of Array.from(visible.querySelectorAll('div'))) {
        const text = (el.innerText || '').replace(/\s+/g, ' ').trim();
        if (text === 'PRESENTED [ Presentation Date ] 4-person team walkthrough · ~10 min') {
          el.style.display = 'none';
        }
      }
    }

    if ((visible.getAttribute('data-label') || '').startsWith('15')) {
      const placeholders = Array.from(visible.querySelectorAll('div'))
        .filter((el) => (el.innerText || '').trim() === '[ name ]');
      placeholders.forEach((el, index) => {
        if (names[index]) {
          el.textContent = names[index];
        }
      });
    }
  }, presenterNames);
}

(async () => {
  if (!input || !outputDir) {
    throw new Error('Usage: node html_to_ppt_capture.js <file-url> <output-dir>');
  }

  await fs.mkdir(outputDir, { recursive: true });

  const launchOptions = { headless: true };
  if (process.env.BROWSER_EXE) {
    launchOptions.executablePath = process.env.BROWSER_EXE;
  }

  const browser = await chromium.launch(launchOptions);
  const firstPage = await browser.newPage({
    viewport: { width: 1920, height: 1080 },
    deviceScaleFactor: 1,
  });

  const baseUrl = baseWithoutHash(input);
  await firstPage.goto(`${baseUrl}#1`, { waitUntil: 'load', timeout: 30000 });
  await firstPage.waitForSelector('section', { state: 'attached', timeout: 10000 });
  await firstPage.evaluate(() => document.fonts && document.fonts.ready);
  await firstPage.waitForTimeout(500);

  const slideCount = await firstPage.evaluate(() => document.querySelectorAll('section').length);
  await firstPage.close();
  const labels = [];

  for (let i = 1; i <= slideCount; i += 1) {
    const page = await browser.newPage({
      viewport: { width: 1920, height: 1080 },
      deviceScaleFactor: 1,
    });
    await page.goto(`${baseUrl}#${i}`, { waitUntil: 'load', timeout: 30000 });
    await page.waitForSelector('section', { state: 'attached', timeout: 10000 });
    await page.evaluate(() => document.fonts && document.fonts.ready);
    await page.waitForTimeout(900);
    await applyRequestedEdits(page);
    await page.waitForTimeout(100);

    const { label, clip } = await page.evaluate(() => {
      const visible = Array.from(document.querySelectorAll('section')).find((section) => {
        const style = getComputedStyle(section);
        return style.visibility !== 'hidden' && style.opacity !== '0';
      });
      const rect = visible?.getBoundingClientRect();
      return {
        label: visible?.getAttribute('data-label') || document.body.innerText.split('\n')[0] || '',
        clip: rect
          ? {
              x: Math.max(0, Math.round(rect.x)),
              y: Math.max(0, Math.round(rect.y)),
              width: Math.round(rect.width),
              height: Math.round(rect.height),
            }
          : null,
      };
    });
    labels.push({ index: i, label });

    const file = path.join(outputDir, `slide_${String(i).padStart(2, '0')}.png`);
    await page.screenshot({ path: file, fullPage: false, clip: clip || undefined });
    console.log(`captured ${i}/${slideCount}: ${label}`);
    await page.close();
  }

  await fs.writeFile(path.join(outputDir, 'slides.json'), JSON.stringify(labels, null, 2), 'utf8');
  await browser.close();
})().catch((err) => {
  console.error(err);
  process.exit(1);
});