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

// 颜色分类预览：G=金, R=红, B=蓝, E=绿, P=纸(亮), .=暗
// 用于检查地球上的弧线(G)与标记(R/B/E)
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 = 90, rows = 36;
  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 R = 0, G = 0, B = 0, n = 0;
      for (let y = y0; y < y1; y += 2) {
        for (let x = x0; x < x1; x += 2) {
          const i = (y * w + x) * 4;
          R += data[i]; G += data[i + 1]; B += data[i + 2]; n++;
        }
      }
      R /= n; G /= n; B /= n;
      const lum = 0.299 * R + 0.587 * G + 0.114 * B;
      let ch = '.';
      if (lum > 150) ch = 'P';
      else if (R > 150 && G > 110 && B < 120) ch = 'G'; // 金
      else if (R > 110 && G < 90 && B < 90) ch = 'R';   // 红
      else if (B > 90 && R < 90 && G < 110) ch = 'B';   // 蓝
      else if (G > 70 && R < 110 && B < 110) ch = 'E';  // 绿
      else if (lum > 60) ch = ':';
      else if (lum > 30) ch = '-';
      line += ch;
    }
    console.log(line);
  }
}