import path from 'node:path'
import { fileURLToPath } from 'node:url'
import sharp from 'sharp'

const __dirname = path.dirname(fileURLToPath(import.meta.url))
const rootDir = path.resolve(__dirname, '..')
const animalDir = path.join(rootDir, 'src/assets/animal')
const lightAnimalDir = path.join(rootDir, 'src/assets/light-animal')

const columns = 6
const rows = 6
const cellWidth = 446
const cellHeight = 224
const quality = 82

async function generateSprite(sourceDir, outputFileName) {
  const outputPath = path.join(sourceDir, outputFileName)
  const composites = await Promise.all(
    Array.from({ length: columns * rows }, async (_, index) => {
      const id = index + 1
      const input = path.join(sourceDir, `${id}.webp`)
      const left = (index % columns) * cellWidth
      const top = Math.floor(index / columns) * cellHeight

      const buffer = await sharp(input)
        .resize(cellWidth, cellHeight, {
          fit: 'cover',
          position: 'center',
        })
        .webp({ quality })
        .toBuffer()

      return {
        input: buffer,
        left,
        top,
      }
    }),
  )

  await sharp({
    create: {
      width: columns * cellWidth,
      height: rows * cellHeight,
      channels: 4,
      background: { r: 0, g: 0, b: 0, alpha: 0 },
    },
  })
    .composite(composites)
    .webp({ quality })
    .toFile(outputPath)

  console.log(
    `Generated ${path.relative(rootDir, outputPath)} (${columns}x${rows}, ${cellWidth}x${cellHeight})`,
  )
}

await generateSprite(animalDir, 'animal-sprite.webp')
await generateSprite(lightAnimalDir, 'light-animal-sprite.webp')