// 生成应用图标（build/icon.ico + build/icon.png）：
//   npx electron scripts/make-icons.cjs
// 用 Electron 离屏渲染 build/icon.svg（居中于方形画布、留 9% 边距），
// 输出多尺寸 PNG 并打包为 PNG 内嵌式 ICO（Vista+ 支持）。
const { app, BrowserWindow } = require('electron')
const { readFileSync, writeFileSync } = require('node:fs')
const { join } = require('node:path')

app.commandLine.appendSwitch('disable-gpu')

const SIZES = [16, 24, 32, 48, 64, 128, 256]
const ROOT = join(__dirname, '..')

const sleep = (ms) => new Promise((r) => setTimeout(r, ms))

/** PNG 内嵌式 ICO 打包 */
function buildIco(pngs) {
  const count = pngs.length
  const header = Buffer.alloc(6)
  header.writeUInt16LE(0, 0) // reserved
  header.writeUInt16LE(1, 2) // type: icon
  header.writeUInt16LE(count, 4)
  const entries = Buffer.alloc(16 * count)
  const blobs = []
  let offset = 6 + 16 * count
  pngs.forEach((png, i) => {
    const size = png.size
    entries.writeUInt8(size >= 256 ? 0 : size, i * 16 + 0) // width
    entries.writeUInt8(size >= 256 ? 0 : size, i * 16 + 1) // height
    entries.writeUInt8(0, i * 16 + 2) // palette
    entries.writeUInt8(0, i * 16 + 3) // reserved
    entries.writeUInt16LE(1, i * 16 + 4) // planes
    entries.writeUInt16LE(32, i * 16 + 6) // bpp
    entries.writeUInt32LE(png.data.length, i * 16 + 8)
    entries.writeUInt32LE(offset, i * 16 + 12)
    offset += png.data.length
    blobs.push(png.data)
  })
  return Buffer.concat([header, entries, ...blobs])
}

async function renderSize(win, svgDataUrl, size) {
  await win.loadURL(
    'data:text/html,' +
      encodeURIComponent(
        `<!doctype html><html><body style="margin:0;background:transparent">` +
          `<div style="display:flex;align-items:center;justify-content:center;width:${size}px;height:${size}px">` +
          `<img src="${svgDataUrl}" style="width:${Math.round(size * 0.86)}px;height:auto;display:block"/>` +
          `</div></body></html>`
      )
  )
  await sleep(350)
  const image = await win.webContents.capturePage({ x: 0, y: 0, width: size, height: size })
  return image.toPNG()
}

async function run() {
  const svg = readFileSync(join(ROOT, 'build', 'icon.svg'), 'utf8')
  const svgDataUrl = 'data:image/svg+xml;base64,' + Buffer.from(svg, 'utf8').toString('base64')

  const win = new BrowserWindow({
    width: 256,
    height: 256,
    show: false,
    frame: false,
    transparent: true,
    webPreferences: { paintWhenInitiallyHidden: true, offscreen: true }
  })

  const pngs = []
  for (const size of SIZES) {
    await win.setSize ? win.setSize(size, size) : null
    const png = await renderSize(win, svgDataUrl, size)
    pngs.push({ size, data: png })
    console.log('rendered', size, `${png.length}B`)
  }

  writeFileSync(join(ROOT, 'build', 'icon.png'), pngs.find((p) => p.size === 256).data)
  writeFileSync(join(ROOT, 'build', 'icon.ico'), buildIco(pngs))
  console.log('written build/icon.ico & build/icon.png')
  app.exit(0)
}

app.whenReady().then(run).catch((err) => {
  console.error(err)
  app.exit(1)
})