From 069bc1b14abab8aef1c29de62f4f65747587edd6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noe=CC=81=20Malzieu?= <noe.malzieu@gmail.com>
Date: Mon, 24 Jun 2024 17:56:39 +0200
Subject: [PATCH 1/2] Start working on killing db connection when backgrounded

---
 utils/xmtpRN/client.ts | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/utils/xmtpRN/client.ts b/utils/xmtpRN/client.ts
index 27f8703d4..d00bd910d 100644
--- a/utils/xmtpRN/client.ts
+++ b/utils/xmtpRN/client.ts
@@ -62,3 +62,27 @@ export const isOnXmtp = async (address: string) =>
 export const xmtpClientByAccount: {
   [account: string]: ConverseXmtpClientType;
 } = {};
+
+// On iOS, it's important to stop writing to SQLite database
+// when the app is going from BACKGROUNDED to SUSPENDED
+// (see https://github.com/xmtp/xmtp-ios/issues/336)
+
+// There are currently 2 SQLite databases:
+// 1st one managed by Converse, created to store v2 XMTP data
+// 2nd one managed by LibXMTP, created to store v3 XMTP data
+
+// Let's just stop writing to both of them as soon as the app is BACKGROUNDED
+
+export const dropXmtpClientsDbConnections = async () => {
+  await Promise.all(
+    Object.values(xmtpClientByAccount).map((c) =>
+      c.dropLocalDatabaseConnection()
+    )
+  );
+};
+
+export const reconnectXmtpClientsDbConnections = async () => {
+  await Promise.all(
+    Object.values(xmtpClientByAccount).map((c) => c.reconnectLocalDatabase())
+  );
+};

From 667428fe09f2710ad0f4791da96de5575f3b5d35 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noe=CC=81=20Malzieu?= <noe.malzieu@gmail.com>
Date: Tue, 25 Jun 2024 12:09:54 +0200
Subject: [PATCH 2/2] Postpone writing to Converse SQLite when app is
 backgrounded

---
 components/XmtpEngine.tsx  | 15 ++++++++++++++-
 data/db/index.ts           | 10 ++++++++--
 utils/xmtpRN/client.web.ts |  4 ++++
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/components/XmtpEngine.tsx b/components/XmtpEngine.tsx
index 3f5f0480e..cf9fed309 100644
--- a/components/XmtpEngine.tsx
+++ b/components/XmtpEngine.tsx
@@ -11,6 +11,10 @@ import { useAppStore } from "../data/store/appStore";
 import { useSelect } from "../data/store/storeHelpers";
 import { getTopicsData } from "../utils/api";
 import { loadSavedNotificationMessagesToContext } from "../utils/notifications";
+import {
+  dropXmtpClientsDbConnections,
+  reconnectXmtpClientsDbConnections,
+} from "../utils/xmtpRN/client";
 import { createPendingConversations } from "../utils/xmtpRN/conversations";
 import { sendPendingMessages } from "../utils/xmtpRN/send";
 import { syncXmtpClient } from "../utils/xmtpRN/sync";
@@ -72,10 +76,16 @@ export default function XmtpEngine() {
           appState.current.match(/inactive|background/) &&
           hydrationDone
         ) {
+          await reconnectXmtpClientsDbConnections();
           loadSavedNotificationMessagesToContext();
           if (isInternetReachableRef.current) {
             syncAccounts(accounts);
           }
+        } else if (
+          nextAppState.match(/inactive|background/) &&
+          appState.current === "active"
+        ) {
+          await dropXmtpClientsDbConnections();
         }
         appState.current = nextAppState;
       }
@@ -105,7 +115,10 @@ export default function XmtpEngine() {
   const runningCron = useRef(false);
 
   const xmtpCron = useCallback(async () => {
-    if (!useAppStore.getState().splashScreenHidden) {
+    if (
+      !useAppStore.getState().splashScreenHidden ||
+      AppState.currentState.match(/inactive|background/)
+    ) {
       return;
     }
     runningCron.current = true;
diff --git a/data/db/index.ts b/data/db/index.ts
index 0d6246874..41737f757 100644
--- a/data/db/index.ts
+++ b/data/db/index.ts
@@ -1,4 +1,4 @@
-import { Platform } from "react-native";
+import { AppState, Platform } from "react-native";
 import RNFS from "react-native-fs";
 import { Repository } from "typeorm/browser";
 
@@ -38,7 +38,13 @@ export const getRepository = async <T extends keyof RepositoriesForAccount>(
   // init. This means methods that try to interact with the database too
   // early will not fail but just take longer to execute!
 
-  while (!repositories[account]?.[entity]) {
+  // We also use the same mechanism to postpone writing to
+  // database if the app is in background
+
+  while (
+    !repositories[account]?.[entity] ||
+    AppState.currentState.match(/inactive|background/)
+  ) {
     console.log(`Database for ${account} not yet initialized`);
     await new Promise((r) => setTimeout(r, 100));
   }
diff --git a/utils/xmtpRN/client.web.ts b/utils/xmtpRN/client.web.ts
index ec45f8150..0e8d69102 100644
--- a/utils/xmtpRN/client.web.ts
+++ b/utils/xmtpRN/client.web.ts
@@ -37,3 +37,7 @@ export const isOnXmtp = async (address: string) =>
   Client.canMessage(getCleanAddress(address), {
     env,
   });
+
+export const dropXmtpClientsDbConnections = async () => {};
+
+export const reconnectXmtpClientsDbConnections = async () => {};