initial commit

lib/course-thumbnail-utils.ts

@@ -0,0 +1,87 @@
+import { readdir, stat } from 'fs/promises'
+import { join, extname, basename } from 'path'
+import { writeFile, mkdir } from 'fs/promises'
+import { existsSync } from 'fs'
+
+const LOCAL_THUMBNAIL_NAMES = ['cover', 'thumbnail']
+const LOCAL_THUMBNAIL_EXTS = ['.jpg', '.jpeg', '.png', '.webp']
+
+const COVER_GRADIENTS = [
+  'bg-gradient-to-br from-indigo-500 via-purple-500 to-pink-500',
+  'bg-gradient-to-br from-blue-500 via-cyan-500 to-teal-500',
+  'bg-gradient-to-br from-emerald-500 via-green-500 to-lime-500',
+  'bg-gradient-to-br from-orange-500 via-red-500 to-rose-500',
+  'bg-gradient-to-br from-violet-500 via-fuchsia-500 to-pink-500',
+  'bg-gradient-to-br from-sky-500 via-blue-500 to-indigo-500',
+  'bg-gradient-to-br from-amber-500 via-orange-500 to-red-500',
+  'bg-gradient-to-br from-teal-500 via-emerald-500 to-green-500',
+]
+
+export function getDeterministicGradient(title: string): string {
+  let hash = 0
+  for (let i = 0; i < title.length; i++) {
+    hash = ((hash << 5) - hash + title.charCodeAt(i)) | 0
+  }
+  const index = Math.abs(hash) % COVER_GRADIENTS.length
+  return COVER_GRADIENTS[index]
+}
+
+export async function getLocalCourseThumbnailPath(coursePath: string): Promise<string | null> {
+  try {
+    const entries = await readdir(coursePath, { withFileTypes: true })
+    const files = entries.filter(e => e.isFile())
+
+    for (const baseName of LOCAL_THUMBNAIL_NAMES) {
+      for (const ext of LOCAL_THUMBNAIL_EXTS) {
+        const match = files.find(f => f.name.toLowerCase() === `${baseName}${ext}`)
+        if (match) {
+          return join(coursePath, match.name)
+        }
+      }
+    }
+  } catch {
+    // coursePath may not exist yet or be unreadable
+  }
+  return null
+}
+
+export async function ensurePublicThumbnail(
+  courseSlug: string,
+  sourcePath: string,
+): Promise<string | null> {
+  const ext = extname(sourcePath).toLowerCase()
+  if (!['.jpg', '.jpeg', '.png', '.webp'].includes(ext)) return null
+
+  const thumbDir = join(process.cwd(), 'public', 'thumbnails', 'courses')
+  if (!existsSync(thumbDir)) {
+    await mkdir(thumbDir, { recursive: true })
+  }
+
+  const targetName = `${courseSlug}-thumb${ext}`
+  const targetPath = join(thumbDir, targetName)
+
+  try {
+    const sourceStat = await stat(sourcePath)
+    const targetStat = await stat(targetPath).catch(() => null)
+    if (!targetStat || sourceStat.mtimeMs !== targetStat.mtimeMs || sourceStat.size !== targetStat.size) {
+      const { copyFile } = await import('fs/promises')
+      await copyFile(sourcePath, targetPath)
+      const targetStat2 = await stat(targetPath)
+      await stat(targetPath) // ensure exists
+      try {
+        // touch target mtime to match source so next run can diff by mtime
+        const { utimes } = await import('fs/promises')
+        await utimes(targetPath, new Date(sourceStat.mtimeMs), new Date(sourceStat.mtimeMs))
+      } catch {
+        // ignore utimes failure; content copy is what matters
+      }
+    }
+    return `/thumbnails/courses/${targetName}`
+  } catch {
+    return null
+  }
+}
+
+export function getThumbnailPriority(coursePath: string): 'local' | 'downloaded' | 'gradient' {
+  return 'local'
+}