import QRCode from 'qrcode'

function loadImage(src) {
  return new Promise((resolve, reject) => {
    const img = new Image()
    img.crossOrigin = 'anonymous'
    img.onload = () => resolve(img)
    img.onerror = reject
    img.src = src
  })
}

/** 在 canvas 上绘制喜庆二维码，中心为配置图或圆圈大囍 */
export async function renderFestiveQr(canvas, url, options = {}) {
  const size = options.size || 148
  const centerImg = String(options.centerImg || '').trim()

  await QRCode.toCanvas(canvas, url, {
    width: size,
    margin: 1,
    color: {
      dark: '#8b0000',
      light: '#fff8e7',
    },
    errorCorrectionLevel: 'H',
  })

  const ctx = canvas.getContext('2d')
  if (!ctx) return

  const w = canvas.width
  const h = canvas.height
  const cx = w / 2
  const cy = h / 2
  const diameter = Math.round(Math.min(w, h) * 0.3)
  const r = diameter / 2
  const ring = Math.max(2, Math.round(w * 0.012))

  ctx.save()
  // 外圈底
  ctx.beginPath()
  ctx.arc(cx, cy, r + ring, 0, Math.PI * 2)
  ctx.fillStyle = '#fff8e7'
  ctx.fill()
  ctx.strokeStyle = '#c41e3a'
  ctx.lineWidth = ring
  ctx.stroke()

  let drewImg = false
  if (centerImg) {
    try {
      const img = await loadImage(centerImg)
      ctx.beginPath()
      ctx.arc(cx, cy, r - 0.5, 0, Math.PI * 2)
      ctx.clip()
      const side = (r - 0.5) * 2
      const scale = Math.max(side / img.width, side / img.height)
      const dw = img.width * scale
      const dh = img.height * scale
      ctx.drawImage(img, cx - dw / 2, cy - dh / 2, dw, dh)
      drewImg = true
    } catch {
      drewImg = false
    }
  }

  if (!drewImg) {
    ctx.beginPath()
    ctx.arc(cx, cy, r - 0.5, 0, Math.PI * 2)
    ctx.fillStyle = 'rgba(255, 248, 231, 0.96)'
    ctx.fill()
    ctx.strokeStyle = '#c41e3a'
    ctx.lineWidth = Math.max(1.5, ring * 0.7)
    ctx.stroke()
    ctx.fillStyle = '#c41e3a'
    ctx.font = `700 ${Math.round(r * 1.45)}px "Noto Serif SC","Source Han Serif SC","Songti SC",serif`
    ctx.textAlign = 'center'
    ctx.textBaseline = 'middle'
    ctx.fillText('囍', cx, cy + r * 0.04)
  }

  ctx.restore()
}