feat: simplify materials library and use real metadata

services/db.ts

@@ -8,6 +8,8 @@ type ApiAsset = {
   name: string;
   kind: 'document' | 'spreadsheet' | 'archive' | 'image' | 'link';
   url: string;
+  sizeBytes: number | null;
+  createdAt: string;
   description: string;
 };
 
@@ -88,9 +90,19 @@ const toAttachment = (asset: ApiAsset): Attachment => ({
   name: asset.name,
   type: toAttachmentType(asset.kind),
   url: asset.url,
+  size: asset.sizeBytes === null ? undefined : formatBytes(asset.sizeBytes),
+  sizeBytes: asset.sizeBytes ?? undefined,
+  createdAt: asset.createdAt,
   description: asset.description,
 });
 
+const formatBytes = (bytes: number) => {
+  if (bytes < 1024) return `${bytes} B`;
+  const units = ['KB', 'MB', 'GB'];
+  const index = Math.min(Math.floor(Math.log(bytes) / Math.log(1024)) - 1, units.length - 1);
+  return `${new Intl.NumberFormat('pt-BR', { maximumFractionDigits: 1 }).format(bytes / 1024 ** (index + 1))} ${units[index]}`;
+};
+
 const toDuration = (seconds: number | null) => {
   if (!seconds || seconds < 1) return '—';
   const totalSeconds = Math.round(seconds);
@@ -166,10 +178,19 @@ const toAssetPayload = (attachment: Attachment) => ({
   name: attachment.name,
   kind: toAssetKind(attachment.type),
   url: attachment.url,
+  sizeBytes: attachment.sizeBytes ?? parseSizeBytes(attachment.size),
   description: attachment.description || '',
   accessLevel: 'enrolled' as const,
 });
 
+const parseSizeBytes = (value?: string) => {
+  if (!value) return null;
+  const match = value.trim().replace(',', '.').match(/^(\d+(?:\.\d+)?)\s*(B|KB|MB|GB)$/i);
+  if (!match) return null;
+  const units: Record<string, number> = { B: 1, KB: 1024, MB: 1024 ** 2, GB: 1024 ** 3 };
+  return Math.round(Number(match[1]) * units[match[2].toUpperCase()]);
+};
+
 const toCoursePayload = (course: Course) => ({
   title: course.title,
   description: course.description,