const { app, nativeImage } = require('electron')
const { writeFileSync } = require('node:fs')
const path = require('node:path')

const projectRoot = path.join(__dirname, '..')
const sizes = [16, 24, 32, 48, 64, 128, 256]

function insideRoundedRect(x, y, left, top, right, bottom, radius) {
  const nearestX = Math.max(left + radius, Math.min(x, right - radius))
  const nearestY = Math.max(top + radius, Math.min(y, bottom - radius))
  return Math.hypot(x - nearestX, y - nearestY) <= radius
}

function createSourceImage() {
  const size = 512
  const bitmap = Buffer.alloc(size * size * 4)
  const bars = [
    [120, 124, 196, 388, 38, 255],
    [218, 188, 294, 388, 38, 224],
    [316, 252, 392, 388, 38, 173],
  ]

  for (let y = 0; y < size; y += 1) {
    for (let x = 0; x < size; x += 1) {
      const offset = (y * size + x) * 4
      if (insideRoundedRect(x + 0.5, y + 0.5, 32, 32, 480, 480, 120)) {
        bitmap[offset] = 246
        bitmap[offset + 1] = 87
        bitmap[offset + 2] = 49
        bitmap[offset + 3] = 255
      }

      const bar = bars.find(([left, top, right, bottom, radius]) => (
        insideRoundedRect(x + 0.5, y + 0.5, left, top, right, bottom, radius)
      ))
      if (bar) {
        const opacity = bar[5] / 255
        bitmap[offset] = Math.round(246 + (255 - 246) * opacity)
        bitmap[offset + 1] = Math.round(87 + (255 - 87) * opacity)
        bitmap[offset + 2] = Math.round(49 + (255 - 49) * opacity)
        bitmap[offset + 3] = 255
      }
    }
  }

  return nativeImage.createFromBitmap(bitmap, { width: size, height: size, scaleFactor: 1 })
}

function generateIcon() {
  const source = createSourceImage()
  const images = sizes.map((size) => source.resize({ width: size, height: size, quality: 'best' }).toPNG())
  const headerSize = 6 + images.length * 16
  const header = Buffer.alloc(headerSize)
  header.writeUInt16LE(0, 0)
  header.writeUInt16LE(1, 2)
  header.writeUInt16LE(images.length, 4)

  let imageOffset = headerSize
  images.forEach((image, index) => {
    const entryOffset = 6 + index * 16
    const size = sizes[index]
    header.writeUInt8(size === 256 ? 0 : size, entryOffset)
    header.writeUInt8(size === 256 ? 0 : size, entryOffset + 1)
    header.writeUInt8(0, entryOffset + 2)
    header.writeUInt8(0, entryOffset + 3)
    header.writeUInt16LE(1, entryOffset + 4)
    header.writeUInt16LE(32, entryOffset + 6)
    header.writeUInt32LE(image.length, entryOffset + 8)
    header.writeUInt32LE(imageOffset, entryOffset + 12)
    imageOffset += image.length
  })

  writeFileSync(path.join(projectRoot, 'build', 'icon-preview.png'), images.at(-1))
  writeFileSync(path.join(projectRoot, 'build', 'icon.ico'), Buffer.concat([header, ...images]))
}

app.whenReady()
  .then(generateIcon)
  .then(() => app.quit())
  .catch((error) => {
    console.error(error)
    app.exit(1)
  })