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

// 以 ASCII 字符打印截图的亮度分布，粗略预览构图
for (const name of process.argv.slice(2)) {
  const png = PNG.sync.read(fs.readFileSync(name));
  const { width: w, height: h, data } = png;
  const cols = 72, rows = 26;
  const chars = ' .:-=+*#%@';
  console.log(`\n=== ${name} ===`);
  for (let r = 0; r < rows; r++) {
    let line = '';
    for (let c = 0; c < cols; c++) {
      const x0 = Math.floor((c / cols) * w), x1 = Math.floor(((c + 1) / cols) * w);
      const y0 = Math.floor((r / rows) * h), y1 = Math.floor(((r + 1) / rows) * h);
      let sum = 0, n = 0;
      for (let y = y0; y < y1; y += 3) {
        for (let x = x0; x < x1; x += 3) {
          const i = (y * w + x) * 4;
          sum += 0.299 * data[i] + 0.587 * data[i + 1] + 0.114 * data[i + 2];
          n++;
        }
      }
      const lum = sum / n;
      line += chars[Math.min(chars.length - 1, Math.floor((lum / 255) * chars.length))];
    }
    console.log(line);
  }
}