Forbid adding friends twice

app/src/main/java/be/ugent/sel/studeez/domain/implementation/FirebaseFriendshipDAO.kt

@@ -1,11 +1,10 @@
 package be.ugent.sel.studeez.domain.implementation
 
-import androidx.compose.runtime.collectAsState
 import be.ugent.sel.studeez.common.snackbar.SnackbarManager
 import be.ugent.sel.studeez.data.local.models.Friendship
 import be.ugent.sel.studeez.data.remote.FirebaseFriendship.ACCEPTED
-import be.ugent.sel.studeez.data.remote.FirebaseFriendship.FRIENDSSINCE
 import be.ugent.sel.studeez.data.remote.FirebaseFriendship.FRIENDID
+import be.ugent.sel.studeez.data.remote.FirebaseFriendship.FRIENDSSINCE
 import be.ugent.sel.studeez.domain.AccountDAO
 import be.ugent.sel.studeez.domain.FriendshipDAO
 import be.ugent.sel.studeez.domain.implementation.FirebaseCollections.FRIENDS_COLLECTION
@@ -18,6 +17,7 @@ import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.tasks.await
 import javax.inject.Inject
 import kotlin.coroutines.resume
 import kotlin.coroutines.resumeWithException
@@ -75,24 +75,40 @@ class FirebaseFriendshipDAO @Inject constructor(
         val currentUserId: String = auth.currentUserId
         val otherUserId: String = id
 
-        // Add entry to current user
-        currentUserDocument()
-            .collection(FRIENDS_COLLECTION)
-            .add(mapOf(
-                FRIENDID to otherUserId,
-                ACCEPTED to true, // TODO Make it not automatically accepted.
-                FRIENDSSINCE to Timestamp.now()
-            ))
-
-        // Add entry to other user
+        // Check if the friendship already exists for the logged in user
+        var allowed = false
         firestore.collection(USER_COLLECTION)
-            .document(otherUserId)
+            .document(currentUserId)
             .collection(FRIENDS_COLLECTION)
-            .add(mapOf(
-                FRIENDID to currentUserId,
-                ACCEPTED to true, // TODO Make it not automatically accepted.
-                FRIENDSSINCE to Timestamp.now()
-            ))
+            .whereEqualTo(FRIENDID, otherUserId)
+            .get()
+            .addOnSuccessListener {
+                allowed = it.documents.isEmpty()
+
+                if (allowed) {
+                    // Add entry to current user
+                    currentUserDocument()
+                        .collection(FRIENDS_COLLECTION)
+                        .add(mapOf(
+                            FRIENDID to otherUserId,
+                            ACCEPTED to true, // TODO Make it not automatically accepted.
+                            FRIENDSSINCE to Timestamp.now()
+                        ))
+
+                    // Add entry to other user
+                    firestore.collection(USER_COLLECTION)
+                        .document(otherUserId)
+                        .collection(FRIENDS_COLLECTION)
+                        .add(mapOf(
+                            FRIENDID to currentUserId,
+                            ACCEPTED to true, // TODO Make it not automatically accepted.
+                            FRIENDSSINCE to Timestamp.now()
+                        ))
+                }
+            }.addOnSuccessListener {
+                val message = if (allowed) AppText.success else AppText.already_friend
+                SnackbarManager.showMessage(message)
+            }
 
         return true
     }

app/src/main/java/be/ugent/sel/studeez/screens/profile/public_profile/PublicProfileScreen.kt

@@ -18,6 +18,7 @@ import be.ugent.sel.studeez.R
 import be.ugent.sel.studeez.common.composable.Headline
 import be.ugent.sel.studeez.common.composable.SecondaryScreenTemplate
 import be.ugent.sel.studeez.common.composable.drawer.DrawerEntry
+import be.ugent.sel.studeez.common.snackbar.SnackbarManager
 import be.ugent.sel.studeez.data.local.models.User
 import be.ugent.sel.studeez.resources
 import be.ugent.sel.studeez.screens.profile.AmountOfFriendsButton
@@ -30,7 +31,7 @@ data class PublicProfileActions(
     val getUserDetails: () -> Flow<User>,
     val getAmountOfFriends: () -> Flow<Int>,
     val onViewFriendsClick: () -> Unit,
-    val sendFriendRequest: () -> Boolean
+    val sendFriendRequest: () -> Unit
 )
 
 fun getPublicProfileActions(
@@ -43,9 +44,11 @@ fun getPublicProfileActions(
             userId = viewModel.uiState.value.userId
         ) },
         onViewFriendsClick = { viewModel.onViewFriendsClick(open) },
-        sendFriendRequest = { viewModel.sendFriendRequest(
-            userId = viewModel.uiState.value.userId
-        ) }
+        sendFriendRequest = {
+            viewModel.sendFriendRequest(
+                userId = viewModel.uiState.value.userId
+            )
+        }
     )
 }
 
@@ -129,7 +132,7 @@ fun PublicProfilePreview() {
                 },
                 getAmountOfFriends = { flowOf(113) },
                 onViewFriendsClick = {},
-                sendFriendRequest = { true }
+                sendFriendRequest = {}
             ),
             popUp = {}
         )
@@ -138,7 +141,7 @@ fun PublicProfilePreview() {
 
 @Composable
 fun PublicProfileEllipsis(
-    sendFriendRequest: () -> Boolean
+    sendFriendRequest: () -> Unit
 ) {
     var expanded by remember { mutableStateOf(false) }
 
@@ -172,7 +175,7 @@ fun PublicProfileEllipsis(
 fun PublicProfileEllipsisPreview() {
     StudeezTheme {
         PublicProfileEllipsis(
-            sendFriendRequest = { true }
+            sendFriendRequest = {}
         )
     }
 }

app/src/main/java/be/ugent/sel/studeez/screens/profile/public_profile/PublicProfileViewModel.kt

@@ -1,6 +1,7 @@
 package be.ugent.sel.studeez.screens.profile.public_profile
 
 import androidx.compose.runtime.mutableStateOf
+import be.ugent.sel.studeez.common.snackbar.SnackbarManager
 import be.ugent.sel.studeez.data.SelectedUserId
 import be.ugent.sel.studeez.data.local.models.User
 import be.ugent.sel.studeez.domain.FriendshipDAO
@@ -11,6 +12,7 @@ import be.ugent.sel.studeez.screens.StudeezViewModel
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.Flow
 import javax.inject.Inject
+import be.ugent.sel.studeez.R.string as AppText
 
 @HiltViewModel
 class PublicProfileViewModel @Inject constructor(
@@ -53,8 +55,8 @@ class PublicProfileViewModel @Inject constructor(
 
     fun sendFriendRequest(
         userId: String
-    ): Boolean {
-        return friendshipDAO.sendFriendshipRequest(userId)
+    ) {
+        friendshipDAO.sendFriendshipRequest(userId)
     }
 
 }

app/src/main/res/values/strings.xml

@@ -136,6 +136,7 @@
     <string name="show_profile">Show profile</string>
     <string name="click_search_friends">Click to search friends</string>
     <string name="searching_friends">Searching friends</string>
+    <string name="already_friend">You are already befriended with that person.</string>
 
     <!-- ========== Create & edit screens ========== -->