#!/usr/bin/env node
/**
 * Scroll-driven animation capture
 * Interpolates scrollProgress from 0 to 1 across frames
 */

import puppeteer from 'puppeteer';
import { execSync } from 'child_process';
import path from 'path';
import { fileURLToPath } from 'url';
import fs from 'fs';

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const outputDir = path.join(__dirname, 'output/scroll-frames');
const htmlFile = path.join(__dirname, 'output/stripe-scroll.html');

// Clean and create output dir
fs.rmSync(outputDir, { recursive: true, force: true });
fs.mkdirSync(outputDir, { recursive: true });

async function captureFrames() {
  const browser = await puppeteer.launch({ 
    headless: true,
    executablePath: '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome',
    args: ['--no-sandbox']
  });
  
  const page = await browser.newPage();
  await page.setViewport({ width: 1920, height: 1080 });
  
  // 12 seconds at 30fps = 360 frames
  const fps = 30;
  const duration = 12;
  const totalFrames = fps * duration;
  
  console.log(`Capturing ${totalFrames} frames...`);
  
  // Load page and wait for fonts
  await page.goto(`file://${htmlFile}`, { waitUntil: 'networkidle0' });
  await new Promise(r => setTimeout(r, 500));
  
  for (let i = 0; i < totalFrames; i++) {
    // Calculate scroll progress (0 to 1)
    // Add a small ease to the overall progression for smoother feel
    const linearProgress = i / (totalFrames - 1);
    const scrollProgress = linearProgress; // Keep linear for now, easing is in the HTML
    
    // Update the scene
    await page.evaluate((progress) => {
      window.updateScene(progress);
    }, scrollProgress);
    
    // Small delay to let CSS transitions settle
    await new Promise(r => setTimeout(r, 16));
    
    const frameNum = String(i + 1).padStart(4, '0');
    await page.screenshot({ 
      path: path.join(outputDir, `frame-${frameNum}.png`),
      type: 'png'
    });
    
    if (i % 30 === 0) console.log(`Frame ${i + 1}/${totalFrames} (${Math.round(linearProgress * 100)}%)`);
  }
  
  await browser.close();
  
  // Create MP4
  console.log('Creating MP4...');
  const mp4Path = path.join(__dirname, 'output/stripe-scroll.mp4');
  
  try {
    execSync(`ffmpeg -y -framerate ${fps} -i "${outputDir}/frame-%04d.png" -c:v libx264 -pix_fmt yuv420p -crf 18 "${mp4Path}"`, { stdio: 'inherit' });
    console.log(`\n✓ MP4 created: ${mp4Path}`);
  } catch (e) {
    console.error('FFmpeg error:', e.message);
  }
}

captureFrames().catch(console.error);