Open relevant post when notification is clicked

Closes #7

lib/api/api.dart

@@ -141,6 +141,11 @@ class APIRequestBuilder {
     return this;
   }
 
+  APIRequestBuilder withIds(List<int> ids) {
+    _addArg('with_ids=${ids.join(',')}');
+    return this;
+  }
+
   /// Executes the API request and returns the JSON data
   Future<Map<String, dynamic>> fetch() async {
     if (api.apiKey == null || api.apiUrl == null) {

lib/main.dart

@@ -16,13 +16,16 @@ import 'api/api.dart';
 // fetching a large list
 const FETCH_MAX_POSTS = 1000;
 
+// Store these globally so our notification handler can access them
+BuildContext? globalContext;
+final api = FeverAPI();
+
 void main() {
   setupBackgroundTasks();
   runApp(MyApp());
 }
 
 class MyApp extends StatelessWidget {
-  final api = FeverAPI();
   SharedPreferences? prefs;
 
   MyApp({super.key});
@@ -60,6 +63,7 @@ class MyApp extends StatelessWidget {
             themeMode: ThemeMode.system,
             home: FutureBuilder<bool>(
               builder: (context, snapshot) {
+                globalContext = context;
                 if (snapshot.hasData && prefs != null) {
                   return MyHomePage(title: 'Feet', api: api, prefs: prefs!);
                 }

lib/notifications/tasks.dart

@@ -1,6 +1,8 @@
 import 'dart:math';
 
 import 'package:feet/api/api.dart';
+import 'package:feet/main.dart';
+import 'package:feet/pages/article.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_local_notifications/flutter_local_notifications.dart';
@@ -79,9 +81,11 @@ void callbackDispatcher() {
           }
 
           await FlutterLocalNotificationsPlugin().show(
-            Random().nextInt(10000000), // Can't use the post ID here because FreshRSS's IDs are too large
+            Random().nextInt(
+                10000000), // Can't use the post ID here because FreshRSS's IDs are too large
             feed != null ? 'New post - ${feed.title}' : 'New post',
             item.title,
+            payload: 'item/${item.id}',
             NotificationDetails(
               android: AndroidNotificationDetails(
                 'new_posts',
@@ -117,6 +121,35 @@ void setupBackgroundTasks() async {
 
   await Permission.notification.request();
 
+  await FlutterLocalNotificationsPlugin().initialize(
+    const InitializationSettings(
+      android: AndroidInitializationSettings('@mipmap/ic_launcher'),
+    ),
+    onSelectNotification: handleNotificationClick,
+  );
+
+  var launchDetails =
+      await FlutterLocalNotificationsPlugin().getNotificationAppLaunchDetails();
+
+  if (launchDetails?.payload != null && launchDetails!.payload!.isNotEmpty) {
+    handleNotificationClick(launchDetails.payload);
+  }
+
+  // Test notification
+  //if (kDebugMode) {
+  //  await FlutterLocalNotificationsPlugin().show(
+  //      Random().nextInt(1000000),
+  //      "Test Notification",
+  //      "Test Notification Body",
+  //      const NotificationDetails(
+  //        android: AndroidNotificationDetails(
+  //          'new_posts',
+  //          'New posts',
+  //        ),
+  //      ),
+  //      payload: "item/1675609277381551");
+  //}
+
   // Runs every 15 minutes
   await Workmanager().registerPeriodicTask(
     'fetch_notifications',
@@ -125,3 +158,47 @@ void setupBackgroundTasks() async {
     initialDelay: const Duration(seconds: 60),
   );
 }
+
+Future<void> handleNotificationClick(String? payload) async {
+  print("Notification click: $payload");
+  if (globalContext == null) {
+    print("Global context not available.");
+    return;
+  }
+  if (payload == null) {
+    print("Didn't receive a payload");
+    return;
+  }
+
+  try {
+    if (payload.startsWith('item/')) {
+      if (!api.loggedIn()) {
+        print("API client is not logged in");
+        return;
+      }
+
+      var id = toInt(payload.split('/')[1]);
+      var item = api.cache.items.get(id);
+      if (item == null) {
+        var res = await api.request().withItems().withIds([id]).execute();
+        item = api.cache.items.get(id);
+        if (item == null) throw 'Didn\'t receive item $id from API: $res';
+      }
+
+      Navigator.of(globalContext!).push(
+        MaterialPageRoute(
+          builder: (context) => ArticlePage(article: item!),
+        ),
+      );
+
+      if (!item.isRead) {
+        await api
+          .request()
+          .markItem(item, ItemMarkType.read)
+          .execute();
+      }
+    }
+  } catch (e) {
+    print("Error while handling notification click: $e");
+  }
+}