export type DocumentAttachmentMeta = {
  fileName?: string;
  contentType?: string;
};

export const DOCUMENT_FILE_ACCEPT =
  'image/*,.pdf,.doc,.docx,.xls,.xlsx,.ppt,.pptx,.txt,.rtf,.odt,application/pdf,application/msword,application/vnd.openxmlformats-officedocument.wordprocessingml.document';

const EXTENSION_TO_MIME: Record<string, string> = {
  jpg: 'image/jpeg',
  jpeg: 'image/jpeg',
  png: 'image/png',
  webp: 'image/webp',
  gif: 'image/gif',
  pdf: 'application/pdf',
  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',
  txt: 'text/plain',
  rtf: 'application/rtf',
  odt: 'application/vnd.oasis.opendocument.text'
};

export function resolveDocumentFileContentType(file: File) {
  const fromType = file.type?.trim();
  if (fromType && fromType !== 'application/octet-stream') {
    return fromType;
  }
  const extension = file.name.split('.').pop()?.toLowerCase() ?? '';
  return EXTENSION_TO_MIME[extension] ?? 'application/octet-stream';
}

export function inferAttachmentContentType(storageKey: string, meta?: DocumentAttachmentMeta) {
  if (meta?.contentType) return meta.contentType;
  const extension = storageKey.split('.').pop()?.toLowerCase() ?? '';
  return EXTENSION_TO_MIME[extension] ?? 'application/octet-stream';
}

export function isImageAttachment(contentType: string) {
  return contentType.startsWith('image/');
}

export function isPdfAttachment(contentType: string) {
  return contentType === 'application/pdf';
}

export function attachmentKindLabel(contentType: string) {
  if (isImageAttachment(contentType)) return 'Изображение';
  if (isPdfAttachment(contentType)) return 'PDF';
  if (contentType.includes('word') || contentType === 'application/msword') return 'Word';
  if (contentType.includes('excel') || contentType === 'application/vnd.ms-excel') return 'Excel';
  if (contentType.includes('powerpoint') || contentType === 'application/vnd.ms-powerpoint') return 'PowerPoint';
  if (contentType === 'text/plain') return 'Текст';
  return 'Файл';
}

export function attachmentDisplayName(storageKey: string, meta?: DocumentAttachmentMeta) {
  if (meta?.fileName?.trim()) return meta.fileName.trim();
  const parts = storageKey.split('/');
  return parts[parts.length - 1] ?? 'Файл';
}

export function attachmentFileExtension(contentType: string, fileName?: string) {
  const fromName = fileName?.split('.').pop()?.toUpperCase();
  if (fromName && fromName.length <= 5) return fromName;
  if (isPdfAttachment(contentType)) return 'PDF';
  if (contentType.includes('word')) return 'DOC';
  if (contentType.includes('excel')) return 'XLS';
  if (contentType.includes('powerpoint')) return 'PPT';
  if (contentType === 'text/plain') return 'TXT';
  if (isImageAttachment(contentType)) return 'IMG';
  return 'FILE';
}