/**
 * pdfmake accepts ONLY PNG and JPEG images ("Unknown image format" otherwise).
 * Customer logos come from AD_Image uploads (any format — the lead page sniffs
 * JPEG vs "PNG" only, so a WebP/GIF/SVG/AVIF logo used to reach pdfmake as a
 * mislabelled PNG and killed the whole quote preview). Website screenshots
 * can be WebP too. This normalises any data URL to a PNG/JPEG data URL:
 * real PNG/JPEG pass through (with the mime corrected), everything else is
 * converted with sharp; anything unusable returns null so the caller simply
 * leaves the image out instead of failing the PDF.
 */
const sniff = (buf: Buffer): 'png' | 'jpeg' | 'other' | 'empty' => {
  if (!buf || buf.length < 12) return 'empty'
  if (buf[0] === 0x89 && buf[1] === 0x50 && buf[2] === 0x4e && buf[3] === 0x47) return 'png'
  if (buf[0] === 0xff && buf[1] === 0xd8 && buf[2] === 0xff) return 'jpeg'
  return 'other'
}

export const parseDataUrl = (dataUrl: any): { mime: string; buffer: Buffer } | null => {
  const s = String(dataUrl || '')
  const m = s.match(/^data:([^;,]*)(;[^,]*)?,(.*)$/s)
  if (!m) return null
  const isB64 = /;base64/i.test(m[2] || '')
  try {
    const buffer = isB64 ? Buffer.from(m[3], 'base64') : Buffer.from(decodeURIComponent(m[3]), 'utf8')
    return { mime: (m[1] || '').toLowerCase(), buffer }
  } catch { return null }
}

/** PNG/JPEG data URL for pdfmake, or null when the input cannot be used. */
export const normalizePdfImage = async (dataUrl: any): Promise<string | null> => {
  const parsed = parseDataUrl(dataUrl)
  if (!parsed) return null
  const kind = sniff(parsed.buffer)
  if (kind === 'empty') return null
  if (kind === 'png') return `data:image/png;base64,${parsed.buffer.toString('base64')}`
  if (kind === 'jpeg') return `data:image/jpeg;base64,${parsed.buffer.toString('base64')}`
  try {
    const sharp = (await import('sharp')).default
    const png = await sharp(parsed.buffer, { animated: false }).png().toBuffer()
    return `data:image/png;base64,${png.toString('base64')}`
  } catch (err: any) {
    console.warn('[pdfImages] image dropped — cannot convert to PNG:', err?.message || err)
    return null
  }
}