#!/usr/bin/env node

import {writeFileSync} from 'node:fs';
import {basename, dirname, extname, join} from 'node:path';

import imageSize from 'image-size';

const tileset = process.argv[2];
let w = parseInt(process.argv[3] || '0');
let h = parseInt(process.argv[4] || '0');

const {width, height} = imageSize(tileset);

if (0 === w) {
  w = width;
}
if (0 === h) {
  h = height;
}

const total = (width / w) * (height / h);

const json = {
  frames: {},
  meta: {
    format: 'RGBA8888',
    image: ['.', basename(tileset)].join('/'),
    scale: 1,
    size: {w: width, h: height},
  },
};

const extlessPath = join(dirname(tileset), basename(tileset, extname(tileset)));

let i = 0;
for (let y = 0; y < height; y += h) {
  for (let x = 0; x < width; x += w) {
    json.frames[1 === total ? '' : join(extlessPath, `${i++}`)] = {
      frame: {x, y, w, h},
      spriteSourceSize: {x: 0, y: 0, w, h},
      sourceSize: {w, h},
    };
  }
}

writeFileSync(
  `${extlessPath}.json`,
  JSON.stringify(json),
);