// storyboard2.ts
// ported from https://github.com/Dibyakshu/go-video-storyboard-generator/blob/main/main.go

import { existsSync, mkdirSync, readdirSync, rmSync, writeFileSync } from 'fs';
import { join } from 'path';
import { getNanoSpawn } from './nanoSpawn';

// Entry point
(async function main() {
  if (process.argv.length < 5) {
    showUsage();
  }

  const fps = parseInt(process.argv[2], 10);
  const inputFile = process.argv[3];
  const outputDir = process.argv[4];

  if (isNaN(fps) || fps <= 0) {
    console.error('Error: Invalid FPS value. Please provide a positive integer.');
    process.exit(1);
  }

  ensureDirectoryExists(outputDir);

  const startTime = Date.now();
  const thumbnailsDir = join(outputDir, 'thumbnails');
  ensureDirectoryExists(thumbnailsDir);

  generateThumbnails(fps, inputFile, thumbnailsDir);
  const storyboardImage = join(outputDir, 'storyboard.jpg');
  generateStoryboard(thumbnailsDir, storyboardImage);
  const vttFile = join(outputDir, 'storyboard.vtt');
  generateVTT(fps, thumbnailsDir, vttFile);
  cleanup(thumbnailsDir);

  const elapsed = (Date.now() - startTime) / 1000;
  console.log(`Process completed in ${elapsed.toFixed(2)} seconds.`);
})();

function showUsage(): never {
  console.log('Usage: ts-node storyboard.ts <fps> <input_file> <output_dir>');
  console.log('Example: ts-node storyboard.ts 1 example.mp4 ./output');
  process.exit(1);
}

function ensureDirectoryExists(path: string) {
  if (!existsSync(path)) {
    mkdirSync(path, { recursive: true });
  }
}

export async function generateThumbnails(fps: number, inputFile: string, thumbnailsDir: string) {
  const spawn = await getNanoSpawn()
  console.log('Generating thumbnails...');
  try {
    spawn('ffmpeg', [
      '-i', inputFile,
      '-vf', `fps=1/${fps},scale=384:160`,
      join(thumbnailsDir, 'thumb%05d.jpg'),
    ], { stdio: 'inherit' });
    console.log('Thumbnails generated successfully.');
  } catch (err) {
    console.error('Error generating thumbnails:', err);
    process.exit(1);
  }
}

export async function generateStoryboard(thumbnailsDir: string, storyboardImage: string) {
  const spawn = await getNanoSpawn()
  console.log('Creating storyboard.jpg...');
  const thumbnails = readdirSync(thumbnailsDir).filter(f => f.endsWith('.jpg'));
  if (thumbnails.length === 0) {
    console.error('No thumbnails found. Exiting.');
    process.exit(1);
  }

  const columns = 10;
  const rows = Math.ceil(thumbnails.length / columns);
  const tileFilter = `tile=${columns}x${rows}`;

  try {
    await spawn('ffmpeg', [
      '-pattern_type', 'glob',
      '-i', join(thumbnailsDir, '*.jpg'),
      '-filter_complex', tileFilter,
      storyboardImage,
    ], { stdio: 'inherit' });
    console.log('Storyboard image created successfully.');
  } catch (err) {
    console.error('Error creating storyboard image:', err);
    process.exit(1);
  }
}

function generateVTT(fps: number, thumbnailsDir: string, vttFile: string) {
  console.log('Generating storyboard.vtt...');
  const thumbnails = readdirSync(thumbnailsDir).filter(f => f.startsWith('thumb') && f.endsWith('.jpg'));
  const durationPerThumb = fps;
  let vttContent = 'WEBVTT\n\n';

  for (let i = 0; i < thumbnails.length; i++) {
    const start = i * durationPerThumb * 1000;
    const end = start + durationPerThumb * 1000;

    const x = (i % 10) * 384;
    const y = Math.floor(i / 10) * 160;

    vttContent += `${formatDuration(start)} --> ${formatDuration(end)}\n`;
    vttContent += `https://insertlinkhere.com/storyboard.jpg#xywh=${x},${y},384,160\n\n`;
  }

  try {
    writeFileSync(vttFile, vttContent, 'utf8');
    console.log('Storyboard VTT file generated successfully.');
  } catch (err) {
    console.error('Error writing VTT file:', err);
    process.exit(1);
  }
}

function cleanup(thumbnailsDir: string) {
  console.log('Cleaning up temporary files...');
  try {
    rmSync(thumbnailsDir, { recursive: true, force: true });
  } catch (err) {
    console.error('Error cleaning up thumbnails:', err);
    process.exit(1);
  }
}

function formatDuration(ms: number): string {
  const totalSeconds = Math.floor(ms / 1000);
  const hours = Math.floor(totalSeconds / 3600);
  const minutes = Math.floor((totalSeconds % 3600) / 60);
  const seconds = totalSeconds % 60;
  const milliseconds = ms % 1000;
  return `${pad(hours)}:${pad(minutes)}:${pad(seconds)}.${pad(milliseconds, 3)}`;
}

function pad(n: number, width = 2): string {
  return n.toString().padStart(width, '0');
}