feat: DATA-12840 Implement lazy loading for DB

Author: bc-rmalyavc

src/lib/db.ts

@@ -1,11 +1,12 @@
-import { initializeApp } from 'firebase/app';
+import { FirebaseApp, initializeApp } from 'firebase/app';
 import {
   deleteDoc,
   doc,
   getDoc,
   getFirestore,
   setDoc,
   Timestamp,
+  Firestore
 } from 'firebase/firestore';
 import { env } from '~/env.mjs';
 
@@ -26,21 +27,29 @@ export interface AuthProps {
   user: User;
 }
 
-const { FIRE_API_KEY, FIRE_DOMAIN, FIRE_PROJECT_ID } = env;
-
-const firebaseConfig = {
-  apiKey: FIRE_API_KEY,
-  authDomain: FIRE_DOMAIN,
-  projectId: FIRE_PROJECT_ID,
-};
-
 export interface ClientTokenData {
   token: string;
   expiresAt: Timestamp;
 }
 
-const app = initializeApp(firebaseConfig);
-const db = getFirestore(app);
+let app: FirebaseApp;
+let db: Firestore;
+
+function getDb() {
+  if (!db) {
+    const { FIRE_API_KEY, FIRE_DOMAIN, FIRE_PROJECT_ID } = env;
+
+    const firebaseConfig = {
+      apiKey: FIRE_API_KEY,
+      authDomain: FIRE_DOMAIN,
+      projectId: FIRE_PROJECT_ID,
+    };
+
+    app = initializeApp(firebaseConfig);
+    db = getFirestore(app);
+  }
+  return db;
+}
 
 // Firestore data management functions
 
@@ -49,7 +58,7 @@ export async function setUser(user: User) {
   if (!user) return Promise.resolve();
 
   const { email, id, username } = user;
-  const ref = doc(db, 'users', String(id));
+  const ref = doc(getDb(), 'users', String(id));
   const data: UserData = { email };
 
   if (username) {
@@ -70,7 +79,7 @@ export async function setStore(props: AuthProps) {
   if (!accessToken || !scope) return null;
 
   const storeHash = context?.split('/')[1] || '';
-  const ref = doc(db, 'store', storeHash);
+  const ref = doc(getDb(), 'store', storeHash);
   const data = { accessToken, adminId: id, scope };
 
   await setDoc(ref, data);
@@ -88,27 +97,27 @@ export async function setStoreUser(session: AuthProps) {
 
   const storeHash = context.split('/')[1];
   const documentId = `${userId}_${storeHash}`;
-  const ref = doc(db, 'storeUsers', documentId);
+  const ref = doc(getDb(), 'storeUsers', documentId);
 
   await setDoc(ref, { storeHash });
 }
 
 export async function deleteUser(storeHash: string, user: User) {
   const docId = `${user.id}_${storeHash}`;
-  const ref = doc(db, 'storeUsers', docId);
+  const ref = doc(getDb(), 'storeUsers', docId);
 
   await deleteDoc(ref);
 }
 
 export async function getStoreToken(storeHash: string): Promise<string | null> {
   if (!storeHash) return null;
-  const storeDoc = await getDoc(doc(db, 'store', storeHash));
+  const storeDoc = await getDoc(doc(getDb(), 'store', storeHash));
 
   return storeDoc.data()?.accessToken;
 }
 
 export async function deleteStore(storeHash: string) {
-  const ref = doc(db, 'store', storeHash);
+  const ref = doc(getDb(), 'store', storeHash);
   await deleteDoc(ref);
 }
 
@@ -120,7 +129,7 @@ export async function saveClientToken(clientToken: string): Promise<string> {
   const exchangeToken = crypto.randomUUID();
   const expiresAt = Timestamp.fromMillis(Date.now() + 120 * 1000); // 2 minutes from now
 
-  const ref = doc(db, 'exchangeTokens', exchangeToken);
+  const ref = doc(getDb(), 'exchangeTokens', exchangeToken);
   const data: Omit<ClientTokenData, 'expiresAt'> & { expiresAt: Timestamp } = {
     token: clientToken,
     expiresAt
@@ -132,7 +141,7 @@ export async function saveClientToken(clientToken: string): Promise<string> {
 }
 
 export async function getClientTokenMaybeAndDelete(exchangeToken: string): Promise<string | false> {
-  const ref = doc(db, 'exchangeTokens', exchangeToken);
+  const ref = doc(getDb(), 'exchangeTokens', exchangeToken);
   const docSnap = await getDoc(ref);
 
   await deleteDoc(ref);