/**
 * 生成 YCode 应用图标资产。
 *
 * 输入：build/icon.svg（唯一矢量源）
 * 输出：build/icon.ico、build/icon.png、resources/icon.png、build/icon-preview.png
 *
 * 图案是深红旗面 + 按国旗制式排布的五颗金星（一大四小，3:1），
 * 星群坐标由 scripts/star-layout.mjs 算出，这里只负责栅格化与打包。
 *
 * 用法：node scripts/gen-icon.mjs
 */
import { Resvg } from '@resvg/resvg-js'
import { readFileSync, writeFileSync, mkdirSync } from 'node:fs'
import { dirname, join } from 'node:path'
import { fileURLToPath } from 'node:url'

const root = join(dirname(fileURLToPath(import.meta.url)), '..')
const buildDir = join(root, 'build')
const resourcesDir = join(root, 'resources')

const masterSvg = readFileSync(join(buildDir, 'icon.svg'), 'utf8')

const ICO_SIZES = [16, 24, 32, 48, 64, 128, 256]

function render(svg, size) {
  return new Resvg(svg, { fitTo: { mode: 'width', value: size } }).render().asPng()
}

function pick() {
  return masterSvg
}

/** 组装 Windows ICO：每个尺寸内嵌一张 PNG（Vista 及以后支持）。 */
function buildIco(entries) {
  const header = Buffer.alloc(6)
  header.writeUInt16LE(0, 0)
  header.writeUInt16LE(1, 2)
  header.writeUInt16LE(entries.length, 4)

  const dirEntries = []
  let offset = 6 + 16 * entries.length
  for (const { size, png } of entries) {
    const entry = Buffer.alloc(16)
    entry.writeUInt8(size >= 256 ? 0 : size, 0)
    entry.writeUInt8(size >= 256 ? 0 : size, 1)
    entry.writeUInt8(0, 2)
    entry.writeUInt8(0, 3)
    entry.writeUInt16LE(1, 4)
    entry.writeUInt16LE(32, 6)
    entry.writeUInt32LE(png.length, 8)
    entry.writeUInt32LE(offset, 12)
    offset += png.length
    dirEntries.push(entry)
  }

  return Buffer.concat([header, ...dirEntries, ...entries.map((e) => e.png)])
}

mkdirSync(resourcesDir, { recursive: true })

const icoEntries = ICO_SIZES.map((size) => ({ size, png: render(pick(), size) }))
writeFileSync(join(buildDir, 'icon.ico'), buildIco(icoEntries))

writeFileSync(join(buildDir, 'icon.png'), render(masterSvg, 1024))
writeFileSync(join(resourcesDir, 'icon.png'), render(masterSvg, 512))
// 托盘：Windows 通知区域按 16/20/24/32 取用，给 32px 让系统自行缩放
writeFileSync(join(resourcesDir, 'tray.png'), render(masterSvg, 32))

// 备用图：常用尺寸各出一张 PNG，供托盘、商店页、文档等场景直接取用
const PNG_SIZES = [16, 20, 24, 32, 40, 48, 64, 96, 128, 180, 256, 512, 1024]
const sizesDir = join(buildDir, 'sizes')
mkdirSync(sizesDir, { recursive: true })
for (const size of PNG_SIZES) {
  writeFileSync(join(sizesDir, `icon-${size}.png`), render(pick(), size))
}

// 对照表：浅色与深色背景下，各尺寸的真实观感
const sampleSizes = [128, 64, 48, 32, 16]
function tile(size) {
  return render(pick(), size).toString('base64')
}
const rows = [
  { label: '浅色任务栏', bg: '#FFFFFF', fg: '#475467' },
  { label: '深色任务栏', bg: '#202124', fg: '#D0D5DD' }
]
let y = 78
const rowSvg = rows
  .map((row) => {
    let x = 150
    const imgs = sampleSizes
      .map((size) => {
        const markup = `<image x="${x}" y="${y + (128 - size) / 2}" width="${size}" height="${size}" href="data:image/png;base64,${tile(size)}"/>`
        x += size + 28
        return markup
      })
      .join('')
    const label = `<text x="40" y="${y + 68}" font-size="13" fill="${row.fg}" font-family="system-ui, 'Microsoft YaHei', sans-serif">${row.label}</text>`
    const block = `<rect x="20" y="${y}" width="640" height="128" rx="10" fill="${row.bg}"/>${label}${imgs}`
    y += 152
    return block
  })
  .join('')

const previewSvg = `<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 680 ${y + 10}" width="680" height="${y + 10}">
  <rect width="680" height="${y + 10}" fill="#F7F8FA"/>
  <text x="20" y="34" font-size="15" font-weight="500" fill="#1F2328" font-family="system-ui, 'Microsoft YaHei', sans-serif">YCode 图标：128 / 64 / 48 / 32 / 16 px 实际尺寸对照</text>
  <text x="20" y="56" font-size="12" fill="#667085" font-family="system-ui, 'Microsoft YaHei', sans-serif">五颗星按国旗制式：一大四小（3:1），四颗小星各有一角尖对准大星中心；旗面为深红渐变＋柔和光泽</text>
  ${rowSvg}
</svg>`

writeFileSync(join(buildDir, 'icon-preview.png'), new Resvg(previewSvg, { fitTo: { mode: 'width', value: 1360 } }).render().asPng())

console.log('icon.ico', icoEntries.length, 'sizes')
console.log('icon.png / resources/icon.png / icon-preview.png done')
console.log('build/sizes/icon-{', PNG_SIZES.join(','), '}.png done')