feat(media): implement caching for chat media and update components to use cached media

src/data/storage/chat/index.ts

@@ -5,4 +5,5 @@
 export * from "./chat_storage";
 export * from "./local_chat_db";
 export * from "./local_chat_storage";
+export * from "./local_chat_media_storage";
 export * from "./local_message";

src/data/storage/chat/local_chat_db.ts

@@ -32,13 +32,34 @@ export interface LocalMessageRow {
   sessionId: string;
 }
 
+export type LocalChatMediaKind = "image" | "audio";
+
+export interface LocalChatMediaRow {
+  cacheKey: string;
+  ownerKey: string;
+  messageId: string;
+  kind: LocalChatMediaKind;
+  remoteUrl: string;
+  blob: Blob;
+  mimeType: string;
+  byteSize: number;
+  createdAt: number;
+  updatedAt: number;
+  lastAccessedAt: number;
+}
+
 export class LocalChatDB extends Dexie {
   messages!: Table<LocalMessageRow, number>;
+  media!: Table<LocalChatMediaRow, string>;
 
   constructor(dbName: string = "cozsweet-chat") {
     super(dbName);
     this.version(1).stores({
       messages: "++dbId",
     });
+    this.version(2).stores({
+      messages: "++dbId",
+      media: "cacheKey, ownerKey, messageId, kind, remoteUrl, updatedAt, lastAccessedAt",
+    });
   }
 }

src/data/storage/chat/local_chat_media_storage.ts

@@ -0,0 +1,88 @@
+"use client";
+
+import { Result, type Result as ResultT } from "@/utils";
+
+import {
+  LocalChatDB,
+  type LocalChatMediaKind,
+  type LocalChatMediaRow,
+} from "./local_chat_db";
+
+export type { LocalChatMediaKind, LocalChatMediaRow };
+
+export interface SaveLocalChatMediaInput {
+  cacheKey: string;
+  ownerKey: string;
+  messageId: string;
+  kind: LocalChatMediaKind;
+  remoteUrl: string;
+  blob: Blob;
+  mimeType: string;
+}
+
+export class LocalChatMediaStorage {
+  private readonly db: LocalChatDB;
+  private static _instance: LocalChatMediaStorage | null = null;
+
+  constructor(db?: LocalChatDB) {
+    this.db = db ?? new LocalChatDB();
+  }
+
+  static getInstance(): LocalChatMediaStorage {
+    if (!LocalChatMediaStorage._instance) {
+      LocalChatMediaStorage._instance = new LocalChatMediaStorage();
+    }
+    return LocalChatMediaStorage._instance;
+  }
+
+  /** @internal */
+  static _resetForTests(): void {
+    LocalChatMediaStorage._instance = null;
+  }
+
+  async getMedia(cacheKey: string): Promise<ResultT<LocalChatMediaRow | null>> {
+    try {
+      const row = (await this.db.media.get(cacheKey)) ?? null;
+      if (row) {
+        await this.db.media.update(cacheKey, {
+          lastAccessedAt: Date.now(),
+        });
+      }
+      return Result.ok(row);
+    } catch (e) {
+      return Result.err(e);
+    }
+  }
+
+  async saveMedia(input: SaveLocalChatMediaInput): Promise<ResultT<void>> {
+    try {
+      const now = Date.now();
+      const existing = await this.db.media.get(input.cacheKey);
+      await this.db.media.put({
+        cacheKey: input.cacheKey,
+        ownerKey: input.ownerKey,
+        messageId: input.messageId,
+        kind: input.kind,
+        remoteUrl: input.remoteUrl,
+        blob: input.blob,
+        mimeType: input.mimeType,
+        byteSize: input.blob.size,
+        createdAt: existing?.createdAt ?? now,
+        updatedAt: now,
+        lastAccessedAt: now,
+      });
+      return Result.ok(undefined);
+    } catch (e) {
+      return Result.err(e);
+    }
+  }
+
+  async clearAll(): Promise<ResultT<void>> {
+    try {
+      await this.db.media.clear();
+      return Result.ok(undefined);
+    } catch (e) {
+      return Result.err(e);
+    }
+  }
+}