(feat): add cache package

(feat): improve local storage security
(feat): move settings to dedicated settings package

packages/cache/src/helpers.test.ts

@@ -0,0 +1,50 @@
+import { describe, expect, it } from "vitest";
+import {
+  replaceConversation,
+  selectConversationWindows,
+  trimMessages,
+} from "./helpers";
+import type { CachedMessage, ConversationWindow } from "./schemas";
+
+const message = (SendTime: number): CachedMessage => ({
+  SenderId: 1,
+  SendTime,
+  Content: "Y2lwaGVydGV4dA==",
+  MessageState: "received",
+});
+const window = (UserId: number, LastMessageAt: number): ConversationWindow => ({
+  UserId,
+  LastMessageAt,
+  Messages: [],
+});
+
+describe("conversation cache helpers", () => {
+  it("selects the five most recent windows", () => {
+    const selected = selectConversationWindows(
+      [
+        window(1, 1),
+        window(2, 6),
+        window(3, 3),
+        window(4, 4),
+        window(5, 5),
+        window(6, 2),
+      ],
+      5,
+    );
+    expect(selected.map(({ UserId }) => UserId)).toEqual([2, 5, 4, 3, 6]);
+  });
+
+  it("replaces only the matching conversation", () => {
+    expect(
+      replaceConversation([window(1, 1), window(2, 2)], window(1, 9)),
+    ).toEqual([window(1, 9), window(2, 2)]);
+  });
+
+  it("retains the newest messages in chronological order", () => {
+    expect(
+      trimMessages([message(2), message(3), message(1)], 2).map(
+        (item) => item.SendTime,
+      ),
+    ).toEqual([2, 3]);
+  });
+});

packages/cache/src/helpers.ts

@@ -0,0 +1,30 @@
+import type { CachedMessage, ConversationWindow } from "./schemas";
+
+export function trimMessages(
+  messages: readonly CachedMessage[],
+  limit: number,
+): CachedMessage[] {
+  return [...messages]
+    .sort((a, b) => b.SendTime - a.SendTime)
+    .slice(0, limit)
+    .sort((a, b) => a.SendTime - b.SendTime);
+}
+
+export function replaceConversation(
+  windows: readonly ConversationWindow[],
+  replacement: ConversationWindow,
+): ConversationWindow[] {
+  return [
+    replacement,
+    ...windows.filter((item) => item.UserId !== replacement.UserId),
+  ];
+}
+
+export function selectConversationWindows(
+  windows: readonly ConversationWindow[],
+  limit: number,
+): ConversationWindow[] {
+  return [...windows]
+    .sort((a, b) => b.LastMessageAt - a.LastMessageAt || a.UserId - b.UserId)
+    .slice(0, limit);
+}

packages/cache/src/index.ts

@@ -0,0 +1,276 @@
+import type { z } from "zod";
+import { storageDefaults } from "@tensamin/shared/data";
+import {
+  deleteDatabaseEntry,
+  getDatabaseEntry,
+  listDatabaseEntries,
+  setDatabaseEntry,
+} from "@tensamin/shared/indexedDb";
+import {
+  replaceConversation,
+  selectConversationWindows,
+  trimMessages,
+} from "./helpers";
+import {
+  accountIdSchema,
+  contactsSchema,
+  conversationWindowSchema,
+  userProfileSchema,
+  type Contact,
+  type ConversationWindow,
+  type UserProfile,
+} from "./schemas";
+
+export * from "./helpers";
+export * from "./schemas";
+
+type CacheStore = "contacts" | "profiles" | "conversations";
+
+export interface SecureValueCodec {
+  encode(value: unknown): unknown | Promise<unknown>;
+  decode(value: unknown): unknown | Promise<unknown>;
+}
+
+export interface CacheOptions {
+  codec?: SecureValueCodec;
+  contacts?: number;
+  messagesPerChat?: number;
+}
+
+export interface CacheLifecycle {
+  clearAccount(): Promise<void>;
+  close(): Promise<void>;
+}
+
+const identityCodec: SecureValueCodec = {
+  encode: (value) => value,
+  decode: (value) => value,
+};
+
+export function createCache(accountId: string, options: CacheOptions = {}) {
+  const account = accountIdSchema.parse(accountId);
+  const codec = options.codec ?? identityCodec;
+  const getLimits = async () => {
+    const [storedContacts, storedMessagesPerChat] = await Promise.all([
+      getDatabaseEntry("storage", "cache_contacts"),
+      getDatabaseEntry("storage", "cache_messages_per_chat"),
+    ]);
+    return {
+      contacts: Math.max(
+        0,
+        Math.floor(
+          options.contacts ??
+            (typeof storedContacts === "number"
+              ? storedContacts
+              : storageDefaults.cache_contacts),
+        ),
+      ),
+      messagesPerChat: Math.max(
+        0,
+        Math.floor(
+          options.messagesPerChat ??
+            (typeof storedMessagesPerChat === "number"
+              ? storedMessagesPerChat
+              : storageDefaults.cache_messages_per_chat),
+        ),
+      ),
+    };
+  };
+  const prefix = `${account}:`;
+  const storedPrefix = (store: CacheStore) => `${store}:${prefix}`;
+  const storedKey = (store: CacheStore, key: string) =>
+    `${storedPrefix(store)}${key}`;
+  const entries = async (store: CacheStore) => {
+    const storePrefix = storedPrefix(store);
+    return (await listDatabaseEntries("cache", storePrefix)).map(
+      ([key, value]) => [key.slice(storePrefix.length), value] as const,
+    );
+  };
+  let closed = false;
+  const ensureOpen = () => {
+    if (closed) throw new Error("Cache is closed");
+  };
+  const read = async <T>(
+    store: CacheStore,
+    key: string,
+    schema: z.ZodType<T>,
+  ) => {
+    ensureOpen();
+    const value = await getDatabaseEntry("cache", storedKey(store, key));
+    return value === undefined
+      ? undefined
+      : schema.parse(await codec.decode(value));
+  };
+  const write = async <T>(
+    store: CacheStore,
+    key: string,
+    schema: z.ZodType<T>,
+    value: T,
+  ) => {
+    ensureOpen();
+    await setDatabaseEntry(
+      "cache",
+      storedKey(store, key),
+      await codec.encode(schema.parse(value)),
+    );
+  };
+  const remove = async (store: CacheStore, key: string) => {
+    ensureOpen();
+    await deleteDatabaseEntry("cache", storedKey(store, key));
+  };
+  const listConversations = async () => {
+    ensureOpen();
+    const storedEntries = await entries("conversations");
+    const windows = await Promise.all(
+      storedEntries.map(async ([, value]) =>
+        conversationWindowSchema.parse(await codec.decode(value)),
+      ),
+    );
+    const { contacts } = await getLimits();
+    return selectConversationWindows(windows, contacts);
+  };
+
+  return {
+    contacts: {
+      get: () => read("contacts", "authoritative", contactsSchema),
+      replace: (contacts: Contact[]) =>
+        write("contacts", "authoritative", contactsSchema, contacts),
+      clear: () => remove("contacts", "authoritative"),
+    },
+    profiles: {
+      get: (userId: number) =>
+        read("profiles", String(userId), userProfileSchema),
+      put: (profile: UserProfile) =>
+        write("profiles", String(profile.UserId), userProfileSchema, profile),
+      delete: (userId: number) => remove("profiles", String(userId)),
+    },
+    conversations: {
+      list: listConversations,
+      get: (userId: number) =>
+        read("conversations", String(userId), conversationWindowSchema),
+      replace: async (window: ConversationWindow) => {
+        const { contacts, messagesPerChat } = await getLimits();
+        const candidate = conversationWindowSchema.parse({
+          ...window,
+          Messages: trimMessages(window.Messages, messagesPerChat),
+        });
+        const selected = selectConversationWindows(
+          replaceConversation(await listConversations(), candidate),
+          contacts,
+        );
+        await Promise.all(
+          selected.map((item) =>
+            write(
+              "conversations",
+              String(item.UserId),
+              conversationWindowSchema,
+              item,
+            ),
+          ),
+        );
+        const retained = new Set(selected.map((item) => item.UserId));
+        const storedEntries = await entries("conversations");
+        await Promise.all(
+          storedEntries.flatMap(([key]) => {
+            const userId = Number(key);
+            return retained.has(userId)
+              ? []
+              : [
+                  deleteDatabaseEntry(
+                    "cache",
+                    storedKey("conversations", key),
+                  ),
+                ];
+          }),
+        );
+      },
+      replaceSelected: async (windows: ConversationWindow[]) => {
+        const { contacts, messagesPerChat } = await getLimits();
+        const selected = selectConversationWindows(
+          windows.map((window) => ({
+            ...window,
+            Messages: trimMessages(window.Messages, messagesPerChat),
+          })),
+          contacts,
+        );
+        await Promise.all(
+          selected.map((item) =>
+            write(
+              "conversations",
+              String(item.UserId),
+              conversationWindowSchema,
+              item,
+            ),
+          ),
+        );
+        const retained = new Set(selected.map((item) => item.UserId));
+        const storedEntries = await entries("conversations");
+        await Promise.all(
+          storedEntries.flatMap(([key]) => {
+            const userId = Number(key);
+            return retained.has(userId)
+              ? []
+              : [
+                  deleteDatabaseEntry(
+                    "cache",
+                    storedKey("conversations", key),
+                  ),
+                ];
+          }),
+        );
+      },
+      prune: async () => {
+        const { messagesPerChat } = await getLimits();
+        const windows = await listConversations();
+        await Promise.all(
+          windows.map((window) =>
+            write(
+              "conversations",
+              String(window.UserId),
+              conversationWindowSchema,
+              {
+                ...window,
+                Messages: trimMessages(window.Messages, messagesPerChat),
+              },
+            ),
+          ),
+        );
+        const retained = new Set(windows.map((window) => window.UserId));
+        const storedEntries = await entries("conversations");
+        await Promise.all(
+          storedEntries.flatMap(([key]) =>
+            retained.has(Number(key))
+              ? []
+              : [
+                  deleteDatabaseEntry(
+                    "cache",
+                    storedKey("conversations", key),
+                  ),
+                ],
+          ),
+        );
+      },
+      delete: (userId: number) => remove("conversations", String(userId)),
+    },
+    clearAccount: async () => {
+      ensureOpen();
+      await Promise.all(
+        (["contacts", "profiles", "conversations"] as CacheStore[]).map(
+          async (store) => {
+            const storedEntries = await entries(store);
+            await Promise.all(
+              storedEntries.map(([key]) =>
+                deleteDatabaseEntry("cache", storedKey(store, key)),
+              ),
+            );
+          },
+        ),
+      );
+    },
+    close: async () => {
+      closed = true;
+    },
+  };
+}
+
+export type Cache = ReturnType<typeof createCache>;

packages/cache/src/schemas.ts

@@ -0,0 +1,27 @@
+import { mtp } from "@tensamin/shared/data";
+import { z } from "zod";
+
+export const accountIdSchema = z.string().min(1);
+export const contactSchema = z.object({
+  LastMessageAt: z.number(),
+  UserId: z.number(),
+  LastMessage: z
+    .object({ Content: z.base64(), SenderId: z.number() })
+    .optional(),
+  Messages: z.array(mtp.MessageGet.response),
+});
+export const contactsSchema = z.array(contactSchema);
+export const userProfileSchema = mtp.GetUserData.response;
+
+// Content remains the protocol base64 ciphertext. This package never decrypts messages.
+export const cachedMessageSchema = mtp.MessageGet.response;
+export const conversationWindowSchema = z.object({
+  UserId: z.number(),
+  LastMessageAt: z.number(),
+  Messages: z.array(cachedMessageSchema),
+});
+
+export type Contact = z.infer<typeof contactSchema>;
+export type UserProfile = z.infer<typeof userProfileSchema>;
+export type CachedMessage = z.infer<typeof cachedMessageSchema>;
+export type ConversationWindow = z.infer<typeof conversationWindowSchema>;

packages/cache/src/sync.tsx

@@ -0,0 +1,271 @@
+import { useCallback, useEffect, useRef, useState } from "react";
+import {
+  createCache,
+  type CachedMessage,
+  type UserProfile,
+} from "@tensamin/cache";
+import { useMTP, type MTPExchange, type ProtocolMessage } from "@tensamin/mtp";
+import { useStorage } from "@tensamin/storage/context";
+import { secureValueCodec } from "@tensamin/storage/secure";
+
+function isError(message: ProtocolMessage) {
+  return message.type.startsWith("Error");
+}
+
+export default function CacheSync() {
+  const { addInterceptor, contextReady, freshContacts, subscribePush } =
+    useMTP();
+  const { load } = useStorage();
+  const [accountId, setAccountId] = useState(0);
+  const queueRef = useRef(Promise.resolve());
+  const reactionPartnersRef = useRef(new Map<number, number>());
+
+  useEffect(() => {
+    void load("user_id").then(setAccountId);
+  }, [load]);
+
+  const enqueue = useCallback((operation: () => Promise<void>) => {
+    const next = queueRef.current.then(operation);
+    queueRef.current = next.catch(() => undefined);
+    return next;
+  }, []);
+
+  const secureCache = useCallback(
+    () =>
+      createCache(String(accountId), {
+        codec: secureValueCodec,
+      }),
+    [accountId],
+  );
+
+  const replaceMessage = useCallback(
+    async (
+      partnerId: number,
+      sendTime: number,
+      edit: Partial<CachedMessage>,
+    ) => {
+      const cache = secureCache();
+      const window = await cache.conversations.get(partnerId);
+      if (!window) return;
+      await cache.conversations.replace({
+        ...window,
+        Messages: window.Messages.map((message) =>
+          message.SendTime === sendTime ? { ...message, ...edit } : message,
+        ),
+      });
+    },
+    [secureCache],
+  );
+
+  const insertMessage = useCallback(
+    async (partnerId: number, message: CachedMessage) => {
+      const cache = secureCache();
+      const window = await cache.conversations.get(partnerId);
+      await cache.conversations.replace({
+        UserId: partnerId,
+        LastMessageAt: Math.max(window?.LastMessageAt ?? 0, message.SendTime),
+        Messages: [
+          ...(window?.Messages ?? []).filter(
+            (cached) => cached.SendTime !== message.SendTime,
+          ),
+          message,
+        ],
+      });
+    },
+    [secureCache],
+  );
+
+  const removeMessage = useCallback(
+    async (partnerId: number, sendTime: number) => {
+      const cache = secureCache();
+      const window = await cache.conversations.get(partnerId);
+      if (!window) return;
+      await cache.conversations.replace({
+        ...window,
+        Messages: window.Messages.filter(
+          (message) => message.SendTime !== sendTime,
+        ),
+      });
+    },
+    [secureCache],
+  );
+
+  useEffect(() => {
+    if (!accountId || !contextReady) return;
+    void enqueue(async () => {
+      const cache = secureCache();
+      await cache.contacts.replace(freshContacts);
+      await cache.conversations.replaceSelected(
+        freshContacts.map((contact) => ({
+          UserId: contact.UserId,
+          LastMessageAt: contact.LastMessageAt,
+          Messages: contact.Messages,
+        })),
+      );
+    });
+  }, [accountId, contextReady, enqueue, freshContacts, secureCache]);
+
+  const synchronizeExchange = useCallback(
+    async ({ type, data, response }: MTPExchange) => {
+      if (!accountId || isError(response)) return;
+      const request = (data ?? {}) as Record<string, unknown>;
+      const result = response.data as Record<string, unknown>;
+
+      if (type === "GetUserData") {
+        await createCache(String(accountId)).profiles.put(
+          result as unknown as UserProfile,
+        );
+        return;
+      }
+
+      if (type === "MessagesGet" && Number(request.Offset) === 0) {
+        const partnerId = Number(request.UserId);
+        const messages = result.Messages as CachedMessage[];
+        const cache = secureCache();
+        const previous = await cache.conversations.get(partnerId);
+        await cache.conversations.replace({
+          UserId: partnerId,
+          LastMessageAt: Math.max(
+            previous?.LastMessageAt ?? 0,
+            ...messages.map((message) => message.SendTime),
+          ),
+          // This replacement is authoritative: absent server messages are deleted.
+          Messages: messages,
+        });
+        return;
+      }
+
+      if (type === "MessageSend") {
+        const partnerId = Number(request.ReceiverId);
+        await insertMessage(partnerId, {
+          Content: String(request.Content),
+          Files: request.Files as CachedMessage["Files"],
+          MessageState: "sent",
+          SenderId: accountId,
+          SendTime: Number(request.SendTime),
+        });
+        return;
+      }
+
+      if (type === "MessageEdit") {
+        await replaceMessage(
+          Number(request.ChatPartnerId),
+          Number(request.SendTime),
+          { Content: String(request.Content), Edited: true },
+        );
+        return;
+      }
+
+      if (type === "MessageDelete") {
+        await removeMessage(
+          Number(request.ChatPartnerId),
+          Number(request.SendTime),
+        );
+        return;
+      }
+
+      if (type === "MessageReactionAdd" || type === "MessageReactionRemove") {
+        const partnerId = Number(request.ChatPartnerId);
+        const sendTime = Number(request.SendTime);
+        const reaction = String(request.Reaction);
+        const cache = secureCache();
+        const window = await cache.conversations.get(partnerId);
+        const message = window?.Messages.find(
+          (candidate) => candidate.SendTime === sendTime,
+        );
+        if (!message) return;
+        const reactions = (message.Reactions ?? []).filter(
+          (candidate) =>
+            candidate.SenderId !== accountId || candidate.Reaction !== reaction,
+        );
+        if (type === "MessageReactionAdd") {
+          reactions.push({ SenderId: accountId, Reaction: reaction });
+        }
+        await replaceMessage(partnerId, sendTime, { Reactions: reactions });
+        return;
+      }
+
+      if (type === "MessageState") {
+        await replaceMessage(
+          Number(result.ChatPartnerId),
+          Number(result.SendTime),
+          {
+            MessageState: result.MessageState as CachedMessage["MessageState"],
+          },
+        );
+        return;
+      }
+
+      if (type === "MessageGet") {
+        const message = result as unknown as CachedMessage;
+        const mappedPartner = reactionPartnersRef.current.get(message.SendTime);
+        reactionPartnersRef.current.delete(message.SendTime);
+        if (mappedPartner) {
+          await insertMessage(mappedPartner, message);
+          return;
+        }
+        const windows = await secureCache().conversations.list();
+        const window = windows.find((candidate) =>
+          candidate.Messages.some(
+            (cached) => cached.SendTime === message.SendTime,
+          ),
+        );
+        if (window) await insertMessage(window.UserId, message);
+      }
+    },
+    [accountId, insertMessage, removeMessage, replaceMessage, secureCache],
+  );
+
+  useEffect(() => {
+    if (!accountId) return;
+    return addInterceptor((exchange) =>
+      enqueue(() => synchronizeExchange(exchange)),
+    );
+  }, [accountId, addInterceptor, enqueue, synchronizeExchange]);
+
+  const synchronizePush = useCallback(
+    async (message: ProtocolMessage) => {
+      if (!accountId || isError(message)) return;
+      const data = message.data as Record<string, unknown>;
+      if (message.type === "MessageLive") {
+        await insertMessage(
+          Number(data.SenderId),
+          data.Message as CachedMessage,
+        );
+        return;
+      }
+      if (message.type === "MessageEditLive") {
+        await replaceMessage(
+          Number(data.ChatPartnerId),
+          Number(data.SendTime),
+          { Content: String(data.Content), Edited: true },
+        );
+        return;
+      }
+      if (message.type === "MessageState") {
+        await replaceMessage(
+          Number(data.ChatPartnerId),
+          Number(data.SendTime),
+          { MessageState: data.MessageState as CachedMessage["MessageState"] },
+        );
+        return;
+      }
+      if (message.type === "MessageReactionLive") {
+        reactionPartnersRef.current.set(
+          Number(data.SendTime),
+          Number(data.ChatPartnerId),
+        );
+      }
+    },
+    [accountId, insertMessage, replaceMessage],
+  );
+
+  useEffect(() => {
+    if (!accountId || !contextReady) return;
+    return subscribePush((message) => {
+      void enqueue(() => synchronizePush(message));
+    });
+  }, [accountId, contextReady, enqueue, subscribePush, synchronizePush]);
+
+  return null;
+}