import { fileExtension, isImageMimeType } from '@dorfteich/shared';

/** Human-readable byte size (binary units) for the file listings (#61). */
export function formatBytes(bytes: number): string {
  if (bytes < 1024) return `${bytes} B`;
  const units = ['KiB', 'MiB', 'GiB', 'TiB'];
  let value = bytes / 1024;
  let unit = 0;
  while (value >= 1024 && unit < units.length - 1) {
    value /= 1024;
    unit += 1;
  }
  return `${value.toFixed(value < 10 ? 1 : 0)} ${units[unit]}`;
}

/**
 * A tiny emoji glyph standing in for a file-type icon (no icon asset pipeline
 * yet) — enough to tell an image, a document, a spreadsheet, and an archive
 * apart at a glance in the attachment lists.
 */
export function fileGlyph(fileName: string, mimeType: string): string {
  if (isImageMimeType(mimeType) || mimeType === 'image/svg+xml') return '🖼️';
  const ext = fileExtension(fileName);
  if (ext === 'pdf') return '📕';
  if (['doc', 'docx', 'odt', 'rtf', 'txt', 'md'].includes(ext)) return '📄';
  if (['xls', 'xlsx', 'ods', 'csv'].includes(ext)) return '📊';
  if (['ppt', 'pptx', 'odp'].includes(ext)) return '📽️';
  if (['zip'].includes(ext)) return '🗜️';
  return '📎';
}

/** The permission-checked download URL for an attachment (ADR 0011). */
export const mediaUrl = (fileId: string): string => `/api/v1/media/${fileId}`;