test(ci): add exporter heading levels and a11y typography smoke; update MAIN_PLAN

lib/assets/assetManager.ts

@@ -0,0 +1,98 @@
+export type AssetInput = {
+  name: string
+  type: string
+  bytes: Uint8Array
+}
+
+export type AssetRef = {
+  originalName: string
+  mimeType: string
+  bytes: Uint8Array
+  hash8: string
+  ext: string
+  path: string // assets/<hash8>.<ext>
+}
+
+export type AssetManagerOptions = {
+  maxBytes: number
+  allowedExts: string[] // e.g., ['png','jpg','jpeg','webp','svg']
+}
+
+function extOf(name: string): string {
+  const i = name.lastIndexOf('.')
+  return i >= 0 ? name.slice(i + 1).toLowerCase() : ''
+}
+
+// Simple FNV-1a 32-bit hash -> 8-hex chars
+function hash8(bytes: Uint8Array): string {
+  let h = 0x811c9dc5 >>> 0
+  for (let i = 0; i < bytes.length; i++) {
+    h ^= bytes[i]
+    h = Math.imul(h, 0x01000193) >>> 0
+  }
+  return ('00000000' + h.toString(16)).slice(-8)
+}
+
+export class AssetManager {
+  private readonly maxBytes: number
+  private readonly allowed: Set<string>
+  private byHash = new Map<string, AssetRef>()
+  private byOriginal = new Map<string, string>() // originalName -> path
+
+  constructor(opts: AssetManagerOptions) {
+    this.maxBytes = opts.maxBytes
+    this.allowed = new Set(opts.allowedExts.map((e) => e.toLowerCase()))
+  }
+
+  async add(file: AssetInput): Promise<AssetRef> {
+    const ext = extOf(file.name)
+    if (!this.allowed.has(ext)) {
+      throw new Error('Invalid extension')
+    }
+    if (file.bytes.length > this.maxBytes) {
+      throw new Error('File size exceeded')
+    }
+    const h = hash8(file.bytes)
+    const existing = this.byHash.get(h)
+    if (existing) {
+      // map original name for rewrite convenience
+      if (!this.byOriginal.has(file.name)) this.byOriginal.set(file.name, existing.path)
+      return existing
+    }
+
+    const path = `assets/${h}.${ext}`
+    const ref: AssetRef = {
+      originalName: file.name,
+      mimeType: file.type,
+      bytes: file.bytes,
+      hash8: h,
+      ext,
+      path,
+    }
+    this.byHash.set(h, ref)
+    if (!this.byOriginal.has(file.name)) this.byOriginal.set(file.name, path)
+    return ref
+  }
+
+  list(): AssetRef[] {
+    return Array.from(this.byHash.values())
+  }
+
+  toZipStructure(): Record<string, Uint8Array> {
+    const out: Record<string, Uint8Array> = {}
+    for (const ref of this.byHash.values()) {
+      out[ref.path] = ref.bytes
+    }
+    return out
+  }
+
+  rewriteUrl(urlOrLocalRef: string): string {
+    if (/^https?:\/\//i.test(urlOrLocalRef)) return urlOrLocalRef
+    if (urlOrLocalRef.startsWith('local:')) {
+      const key = urlOrLocalRef.slice('local:'.length)
+      const p = this.byOriginal.get(key)
+      return p ?? urlOrLocalRef
+    }
+    return urlOrLocalRef
+  }
+}