feat(05-01): create in-memory image store with explicit cleanup

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/lib/images/store.ts

@@ -0,0 +1,113 @@
+/**
+ * In-Memory Image Store
+ *
+ * Temporary storage for images that need to be served via URL to external providers.
+ * Images are stored in memory and served via /api/images/[id] endpoint.
+ *
+ * Features:
+ * - Store base64 data URLs as binary buffers
+ * - Retrieve images by unique ID
+ * - Explicit cleanup (no TTL - callers handle lifecycle)
+ *
+ * Note: Store is cleared on server restart (no persistence).
+ */
+
+import { randomUUID } from "crypto";
+
+/**
+ * Stored image data with parsed content
+ */
+interface StoredImage {
+  data: Buffer;
+  mimeType: string;
+}
+
+/**
+ * In-memory image storage
+ */
+const imageStore: Map<string, StoredImage> = new Map();
+
+/**
+ * Parse a base64 data URL into its components
+ *
+ * @param base64DataUrl - Data URL in format: data:{mimeType};base64,{data}
+ * @returns Parsed mimeType and Buffer, or null if invalid format
+ */
+function parseBase64DataUrl(
+  base64DataUrl: string
+): { mimeType: string; data: Buffer } | null {
+  const match = base64DataUrl.match(/^data:([^;]+);base64,(.+)$/);
+  if (!match) {
+    return null;
+  }
+
+  const [, mimeType, base64Data] = match;
+  const data = Buffer.from(base64Data, "base64");
+
+  return { mimeType, data };
+}
+
+/**
+ * Store an image and return its unique ID
+ *
+ * @param base64DataUrl - Image as base64 data URL (data:{mimeType};base64,{data})
+ * @returns Unique ID for retrieving the image
+ * @throws Error if data URL format is invalid
+ */
+export function storeImage(base64DataUrl: string): string {
+  const parsed = parseBase64DataUrl(base64DataUrl);
+  if (!parsed) {
+    throw new Error(
+      "Invalid base64 data URL format. Expected: data:{mimeType};base64,{data}"
+    );
+  }
+
+  const id = randomUUID();
+  imageStore.set(id, {
+    data: parsed.data,
+    mimeType: parsed.mimeType,
+  });
+
+  return id;
+}
+
+/**
+ * Retrieve a stored image by ID
+ *
+ * @param id - Image ID returned from storeImage
+ * @returns Image data and mimeType, or null if not found
+ */
+export function getImage(id: string): StoredImage | null {
+  return imageStore.get(id) ?? null;
+}
+
+/**
+ * Delete a stored image
+ *
+ * @param id - Image ID to delete
+ * @returns true if image existed and was deleted, false if not found
+ */
+export function deleteImage(id: string): boolean {
+  return imageStore.delete(id);
+}
+
+/**
+ * Delete multiple stored images (for batch cleanup)
+ *
+ * @param ids - Array of image IDs to delete
+ */
+export function deleteImages(ids: string[]): void {
+  for (const id of ids) {
+    imageStore.delete(id);
+  }
+}
+
+/**
+ * Get store statistics (for debugging)
+ */
+export function getStoreStats(): { size: number; ids: string[] } {
+  return {
+    size: imageStore.size,
+    ids: Array.from(imageStore.keys()),
+  };
+}