import { IconString } from '../components/display/icon'

export type AttachmentPreviewKind = 'image' | 'video' | 'file'

// Document picker providers sometimes hand back assets without a usable
// MIME type (Android `MediaStore` content URIs, some cloud-storage
// providers). The asset's `type` then arrives as `application/octet-stream`
// or undefined even though the file is genuinely an image or video. Fall
// back to extension-based classification in that case so the preview
// matches the actual content.
const IMAGE_EXTENSIONS = new Set(['bmp', 'gif', 'heic', 'heif', 'jpeg', 'jpg', 'png', 'webp'])

const VIDEO_EXTENSIONS = new Set([
  '3gp',
  'avi',
  'h263',
  'h264',
  'm4v',
  'mkv',
  'mov',
  'mp4',
  'mpeg',
  'mpeg4',
  'mpg',
  'webm',
  'wmv',
])

export function pickAttachmentPreviewKind(
  type: string | undefined,
  name?: string
): AttachmentPreviewKind {
  if (type?.startsWith('image/')) return 'image'
  if (type?.startsWith('video/')) return 'video'
  const ext = name?.split('.').pop()?.toLowerCase()
  if (ext && IMAGE_EXTENSIONS.has(ext)) return 'image'
  if (ext && VIDEO_EXTENSIONS.has(ext)) return 'video'
  return 'file'
}

export function getAttachmentIconName(type: string | undefined): IconString {
  if (type?.startsWith('image/')) return 'general.outlinedImageFile'
  if (type?.startsWith('video/')) return 'general.outlinedVideoFile'
  if (type?.startsWith('audio/')) return 'general.outlinedMusicFile'
  if (type === 'application/pdf') return 'general.outlinedPdfFile'
  return 'general.outlinedGenericFile'
}