feat: offline login persistence

app/src/main/java/com/github/se/travelpouch/model/authentication/NetworkConnectivityHelper.kt

@@ -0,0 +1,49 @@
+package com.github.se.travelpouch.model.authentication
+
+import android.content.Context
+import android.net.ConnectivityManager
+import android.net.Network
+import android.net.NetworkCapabilities
+import android.util.Log
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+
+class NetworkConnectivityHelper(private val context: Context) {
+
+  private val _isConnected: MutableStateFlow<Boolean?> = MutableStateFlow(null)
+  val isConnected: StateFlow<Boolean?> = _isConnected.asStateFlow()
+
+  fun registerNetworkCallback() {
+    val connectivityManager = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
+
+    connectivityManager.registerDefaultNetworkCallback(object : ConnectivityManager.NetworkCallback() {
+      override fun onAvailable(network: Network) {
+        super.onAvailable(network)
+        Log.d("NetworkConnectivityHelper", "Connection available")
+        _isConnected.value = true
+      }
+
+      override fun onUnavailable() {
+        super.onUnavailable()
+        Log.d("NetworkConnectivityHelper", "Connection unavailable")
+        _isConnected.value = false
+      }
+    })
+
+    val activeNetwork = connectivityManager.activeNetwork
+    val initialCapabilities = connectivityManager.getNetworkCapabilities(activeNetwork)
+    if (initialCapabilities != null) {
+      if (initialCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)) {
+        Log.d("NetworkConnectivityHelper", "Connected to the internet")
+        _isConnected.value = true
+      } else {
+        Log.d("NetworkConnectivityHelper", "Not connected to the internet")
+        _isConnected.value = false
+      }
+    } else {
+      Log.d("NetworkConnectivityHelper", "No network capabilities")
+      _isConnected.value = false
+    }
+  }
+}

app/src/main/java/com/github/se/travelpouch/ui/authentication/SignIn.kt

@@ -1,6 +1,7 @@
 // Portions of this code were generated and or inspired by the help of GitHub Copilot or Chatgpt
 package com.github.se.travelpouch.ui.authentication
 
+import com.github.se.travelpouch.model.authentication.NetworkConnectivityHelper
 import android.util.Log
 import android.widget.Toast
 import androidx.compose.animation.AnimatedVisibility
@@ -24,6 +25,7 @@ import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.MutableState
+import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.ui.Alignment
@@ -74,7 +76,14 @@ fun SignInScreen(
   } // this extra state is necessary to prevent token refresh errors
   val waitUntilProfileFetched = rememberSaveable { mutableStateOf(false) }
 
+  val networkHelper = NetworkConnectivityHelper(context)
+  networkHelper.registerNetworkCallback()
+  val isConnectedToNetwork = networkHelper.isConnected.collectAsState()
+
   val currentUser = auth.currentUser
+  if (currentUser != null) {
+    Log.d("SignInScreen", "Current user: ${currentUser.email}")
+  }
 
   // launcher for Firebase authentication
   val launcher =
@@ -196,14 +205,19 @@ fun SignInScreen(
           }
           if (currentUser != null &&
               !signInCompleted
-                  .value) { // extra condition on sign-in completion to avoid unnecessary
+                  .value && isConnectedToNetwork.value != null) { // extra condition on sign-in completion to avoid unnecessary
             // recompositions
             LaunchedEffect(Unit) {
               try {
                 isLoading.value = true
                 methodChosen.value = true
 
-                currentUser.getIdToken(true).await() // We shouldn't continue until this passes
+                if (isConnectedToNetwork.value == true) {
+                  Log.d("SignInScreen", "User connected to network, refresh id token...")
+                  currentUser.getIdToken(true).await() // We shouldn't continue until this passes
+                } else {
+                  Log.d("SignInScreen", "User offline, skipping id token refresh.")
+                }
 
                 Log.d(
                     "SignInScreen",