#!/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];
const w = parseInt(process.argv[3]);
const h = parseInt(process.argv[4]);

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

const json = {
  frames: {},
  meta: {
    format: 'RGBA8888',
    image: tileset,
    scale: 1,
    size: {w: width, h: height},
  },
};

let i = 0;
for (let y = 0; y < height; y += h) {
  for (let x = 0; x < width; x += w) {
    json.frames[i++] = {
      frame: {x, y, w, h},
      spriteSourceSize: {x: 0, y: 0, w, h},
      sourceSize: {w, h},
    };
  }
}

writeFileSync(
  `${join(dirname(tileset), basename(tileset, extname(tileset)))}.json`,
  JSON.stringify(json),
);