// SHA-1 hex (uppercase, 40 chars) — required as the `cs` (checksum) field
// on SHIP requests and on the inbound photo `extra` JSON. Verified by inbound
// capture of a real KakaoTalk client photo (2026-05).
export async function sha1Hex(data: Uint8Array): Promise<string> {
  const hashBuf = await crypto.subtle.digest('SHA-1', data)
  return Array.from(new Uint8Array(hashBuf))
    .map((b) => b.toString(16).padStart(2, '0').toUpperCase())
    .join('')
}

const MIME_BY_EXT: Record<string, string> = {
  jpg: 'image/jpeg',
  jpeg: 'image/jpeg',
  png: 'image/png',
  gif: 'image/gif',
  webp: 'image/webp',
  mp4: 'video/mp4',
  mov: 'video/quicktime',
  webm: 'video/webm',
  mkv: 'video/x-matroska',
  m4v: 'video/x-m4v',
  m4a: 'audio/m4a',
  mp3: 'audio/mpeg',
  wav: 'audio/wav',
  ogg: 'audio/ogg',
  pdf: 'application/pdf',
  csv: 'text/csv',
  txt: 'text/plain',
  json: 'application/json',
  zip: 'application/zip',
  doc: 'application/msword',
  docx: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
  xls: 'application/vnd.ms-excel',
  xlsx: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
  ppt: 'application/vnd.ms-powerpoint',
  pptx: 'application/vnd.openxmlformats-officedocument.presentationml.presentation',
}

export function guessMimeFromFilename(filename: string): string {
  const dot = filename.lastIndexOf('.')
  if (dot < 0 || dot === filename.length - 1) return 'application/octet-stream'
  const ext = filename.slice(dot + 1).toLowerCase()
  return MIME_BY_EXT[ext] ?? 'application/octet-stream'
}