import fs from 'node:fs';
import { PNG } from 'pngjs';

for (const name of process.argv.slice(2)) {
  const png = PNG.sync.read(fs.readFileSync(name));
  const { width: w, height: h, data } = png;
  let sum = 0, bright = 0, n = 0;
  // 分区域统计
  const zones = { center: 0, left: 0, right: 0 };
  for (let y = 0; y < h; y++) {
    for (let x = 0; x < w; x++) {
      const i = (y * w + x) * 4;
      const lum = 0.299 * data[i] + 0.587 * data[i + 1] + 0.114 * data[i + 2];
      sum += lum; n++;
      if (lum > 40) bright++;
      if (lum > 40) {
        if (x < w / 3) zones.left++;
        else if (x > (2 * w) / 3) zones.right++;
        else zones.center++;
      }
    }
  }
  console.log(`${name}: ${w}x${h} avgLum=${(sum / n).toFixed(1)} brightPct=${((bright / n) * 100).toFixed(1)}% left/center/right=${zones.left}/${zones.center}/${zones.right}`);
}