import QRCode from 'qrcode'

self.onmessage = async (e) => {
  const { id, text, ecc, isBgTransparent, bgType, bgColor1, bgColor2, bgGradPos, fgType, fgColor1, fgColor2, fgGradPos } = e.data

  if (!text) {
    self.postMessage({ id, svgContent: '' })
    return
  }

  try {
    let svgContent = await QRCode.toString(text, {
      type: 'svg',
      errorCorrectionLevel: ecc,
      margin: 1,
      color: {
        dark: fgType === 'solid' ? fgColor1 : '#000000',
        light: isBgTransparent ? '#00000000' : (bgType === 'solid' ? bgColor1 : '#00000000')
      }
    })

    let defsHtml = ''

    if (fgType !== 'solid') {
      const isLinear = fgType === 'linear'
      const pos = fgGradPos || { x1: 0, y1: 0, x2: 100, y2: 100 }
      const r = Math.sqrt(Math.pow(pos.x2 - pos.x1, 2) + Math.pow(pos.y2 - pos.y1, 2))
      defsHtml += isLinear
        ? `<linearGradient id="qr-fg-grad" x1="${pos.x1}%" y1="${pos.y1}%" x2="${pos.x2}%" y2="${pos.y2}%"><stop offset="0%" stop-color="${fgColor1}" /><stop offset="100%" stop-color="${fgColor2}" /></linearGradient>`
        : `<radialGradient id="qr-fg-grad" cx="${pos.x1}%" cy="${pos.y1}%" r="${r}%"><stop offset="0%" stop-color="${fgColor1}" /><stop offset="100%" stop-color="${fgColor2}" /></radialGradient>`
    }

    if (!isBgTransparent && bgType !== 'solid') {
      const isLinear = bgType === 'linear'
      const pos = bgGradPos || { x1: 0, y1: 0, x2: 100, y2: 100 }
      const r = Math.sqrt(Math.pow(pos.x2 - pos.x1, 2) + Math.pow(pos.y2 - pos.y1, 2))
      defsHtml += isLinear
        ? `<linearGradient id="qr-bg-grad" x1="${pos.x1}%" y1="${pos.y1}%" x2="${pos.x2}%" y2="${pos.y2}%"><stop offset="0%" stop-color="${bgColor1}" /><stop offset="100%" stop-color="${bgColor2}" /></linearGradient>`
        : `<radialGradient id="qr-bg-grad" cx="${pos.x1}%" cy="${pos.y1}%" r="${r}%"><stop offset="0%" stop-color="${bgColor1}" /><stop offset="100%" stop-color="${bgColor2}" /></radialGradient>`
    }

    if (defsHtml) {
      svgContent = svgContent.replace('shape-rendering="crispEdges">', `shape-rendering="crispEdges"><defs>${defsHtml}</defs>`)
    }

    if (fgType !== 'solid') {
      // qrcode outputs <path stroke="#000000"...> so it's safe to replace
      svgContent = svgContent.replace(/stroke="#000000"/g, 'stroke="url(#qr-fg-grad)"')
    }

    if (!isBgTransparent && bgType !== 'solid') {
      // Find viewBox to inject background rect
      const viewBoxMatch = svgContent.match(/viewBox="0 0 (\d+) (\d+)"/)
      if (viewBoxMatch) {
        const w = viewBoxMatch[1]
        const h = viewBoxMatch[2]
        // Inject a rect immediately inside the svg
        svgContent = svgContent.replace('</defs>', `</defs><rect width="${w}" height="${h}" fill="url(#qr-bg-grad)" />`)
      }
    }

    self.postMessage({ id, svgContent })
  } catch (err) {
    self.postMessage({ id, error: err.message })
  }
}