import puppeteer from 'puppeteer-core';
import { devices } from './devices';
import { createPlugin } from './plugins';
import { render } from './template';

const args = process.argv.slice(2);

if (args.includes('--help') || args.includes('-h')) {
  console.log(`Usage: bun run src/preview.ts [options]

Render a plugin to a local PNG file for testing.

Options:
  --config <path>   Config file (default: config.json)
  --device <id>     Device ID from config (default: first device)
  --output <path>   Output PNG path (default: preview.png)
  --firefox <path>  Firefox executable path (or set FIREFOX env var)
  --dither          Apply e-ink dithering via ImageMagick
  --html            Also save the raw HTML to <output>.html
  -h, --help        Show this help`);
  process.exit(0);
}

function getArg(flag: string, fallback: string): string {
  const idx = args.indexOf(flag);
  return idx !== -1 && args[idx + 1] ? args[idx + 1]! : fallback;
}

const configPath = getArg('--config', Bun.env['CONFIG_FILE'] ?? 'config.json');
const outputPath = getArg('--output', 'preview.png');
const firefoxPath = getArg('--firefox', Bun.env['FIREFOX'] ?? 'firefox');
const dither = args.includes('--dither');
const saveHtml = args.includes('--html');

const config = JSON.parse(await Bun.file(configPath).text());
const deviceEntries = Object.entries(config.devices ?? {});

if (deviceEntries.length === 0) {
  console.error('No devices found in config.');
  process.exit(1);
}

const deviceIdArg = getArg('--device', '');
const [deviceId, deviceConfig] = deviceIdArg
  ? [deviceIdArg, config.devices[deviceIdArg]]
  : (deviceEntries[0] as [string, any]);

if (!deviceConfig) {
  console.error(`Device "${deviceIdArg}" not found. Available: ${deviceEntries.map(([k]) => k).join(', ')}`);
  process.exit(1);
}

const model = devices.find((a) => a.name === (deviceConfig.model ?? 'inkplate_10'));
if (!model) {
  console.error(`Unknown model: ${deviceConfig.model}`);
  process.exit(1);
}

console.log(`Rendering plugin "${deviceConfig.plugin ?? 'calendar'}" for device "${deviceId}" (${model.width}x${model.height})...`);

const plugin = createPlugin(deviceConfig.plugin ?? 'calendar', deviceConfig.settings ?? {});
const html = await render([[plugin, 'full']], model);

if (saveHtml) {
  const htmlPath = outputPath.replace(/\.png$/, '.html');
  await Bun.write(htmlPath, html);
  console.log(`HTML saved to ${htmlPath}`);
}

const browser = await puppeteer.launch({
  browser: 'firefox',
  args: ['--new-instance'],
  executablePath: firefoxPath,
});

const page = await browser.newPage();
await page.setViewport({ width: model.width, height: model.height, deviceScaleFactor: 1 });
await page.setContent(html, { waitUntil: 'networkidle2' });
await Bun.sleep(3000);
const screenshot = await page.screenshot({ encoding: 'binary' });
await page.close();
await browser.close();

if (dither) {
  const colormap = Bun.env['COLORMAP'] ?? './colormap.png';
  const processed = await Bun.spawn(
    ['magick', '-', '-dither', 'FloydSteinberg', '-remap', colormap,
     '-define', 'png:bit-depth=2', '-define', 'png:color-type=0', '-strip', 'png:-'],
    { stdin: screenshot }
  ).stdout.bytes();
  await Bun.write(outputPath, processed);
} else {
  await Bun.write(outputPath, screenshot);
}

console.log(`Preview saved to ${outputPath}`);