Refactor LocalizableError to be immutable

app/src/main/java/eu/steffo/twom/composables/errorhandling/LocalizableError.kt

@@ -4,53 +4,24 @@ import androidx.annotation.StringRes
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.res.stringResource
 
-class LocalizableError {
+data class LocalizableError(
-    @StringRes
+    @StringRes val stringResourceId: Int,
-    var stringResourceId: Int? = null
+    val throwable: Throwable? = null,
-        private set
+)
 
-    var throwable: Throwable? = null
+@Composable
-        private set
+fun LocalizableError?.render(): String? {
-
+    return if (this == null) {
-    fun set(stringResourceId: Int) {
+        null
-        this.stringResourceId = stringResourceId
+    } else if (this.throwable == null) {
-        this.throwable = null
+        stringResource(stringResourceId)
-    }
+    } else {
-
+        stringResource(stringResourceId, throwable.toString())
-    fun set(stringResourceId: Int, throwable: Throwable) {
-        this.stringResourceId = stringResourceId
-        this.throwable = throwable
-    }
-
-    fun clear() {
-        this.stringResourceId = null
-        this.throwable = null
-    }
-
-    fun occurred(): Boolean {
-        return stringResourceId != null
-    }
-
-    @Composable
-    fun renderString(): String? {
-        val stringResourceId = this.stringResourceId
-        val throwable = this.throwable
-
-        return if (stringResourceId == null) {
-            null
-        } else if (throwable == null) {
-            stringResource(stringResourceId)
-        } else {
-            stringResource(stringResourceId, throwable.toString())
-        }
-    }
-
-    @Composable
-    fun Show(contents: @Composable (rendered: String) -> Unit) {
-        val rendered = renderString()
-
-        if (rendered != null) {
-            contents(rendered)
-        }
     }
 }
+
+@Composable
+fun LocalizableError?.Display(contents: @Composable (rendered: String) -> Unit) {
+    val rendered = this.render() ?: return
+    contents(rendered)
+}

app/src/main/java/eu/steffo/twom/composables/login/LoginForm.kt

@@ -21,6 +21,7 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.tooling.preview.Preview
 import eu.steffo.twom.R
+import eu.steffo.twom.composables.errorhandling.Display
 import eu.steffo.twom.composables.errorhandling.ErrorText
 import eu.steffo.twom.composables.errorhandling.LocalizableError
 import eu.steffo.twom.composables.fields.PasswordField
@@ -58,10 +59,10 @@ fun LoginForm(
     var password by rememberSaveable { mutableStateOf("") }
 
     var loginStep by rememberSaveable { mutableStateOf(LoginStep.NONE) }
-    val error by remember { mutableStateOf(LocalizableError()) }
+    var error by remember { mutableStateOf<LocalizableError?>(null) }
 
     suspend fun doLogin() {
-        error.clear()
+        error = null
 
         Log.d("Login", "Getting authentication service...")
         loginStep = LoginStep.SERVICE
@@ -81,7 +82,7 @@ fun LoginForm(
                 "User seems to have input an invalid Matrix ID: $username",
                 e
             )
-            error.set(R.string.login_error_username_invalid)
+            error = LocalizableError(R.string.login_error_username_invalid)
             return
         } catch (e: Throwable) {
             Log.e(
@@ -89,7 +90,7 @@ fun LoginForm(
                 "Something went wrong while retrieving .well-known data for: $username",
                 e
             )
-            error.set(R.string.login_error_wellknown_generic, e)
+            error = LocalizableError(R.string.login_error_wellknown_generic, e)
             return
         }
         if (wellKnown !is WellknownResult.Prompt) {
@@ -97,7 +98,7 @@ fun LoginForm(
                 "Login",
                 "Data is not .well-known for: $username"
             )
-            error.set(R.string.login_error_wellknown_missing)
+            error = LocalizableError(R.string.login_error_wellknown_missing)
             return
         }
 
@@ -119,7 +120,7 @@ fun LoginForm(
                 "Something went wrong while retrieving login flows for: ${wellKnown.homeServerUrl}",
                 e
             )
-            error.set(R.string.login_error_flows_generic, e)
+            error = LocalizableError(R.string.login_error_flows_generic, e)
             return
         }
 
@@ -134,7 +135,7 @@ fun LoginForm(
                 "Something went wrong while setting up the login wizard.",
                 e
             )
-            error.set(R.string.login_error_wizard_generic, e)
+            error = LocalizableError(R.string.login_error_wizard_generic, e)
             return
         }
 
@@ -153,7 +154,7 @@ fun LoginForm(
                 "Something went wrong while logging in as: $username",
                 e
             )
-            error.set(R.string.login_error_login_generic, e)
+            error = LocalizableError(R.string.login_error_login_generic, e)
             return
         }
 
@@ -170,7 +171,7 @@ fun LoginForm(
         LinearProgressIndicator(
             modifier = Modifier.fillMaxWidth(),
             progress = loginStep.step.toFloat() / LoginStep.DONE.step.toFloat(),
-            color = if (error.occurred()) MaterialTheme.colorScheme.error else ProgressIndicatorDefaults.linearColor
+            color = if (error != null) MaterialTheme.colorScheme.error else ProgressIndicatorDefaults.linearColor
         )
         Row(Modifier.basePadding()) {
             Text(LocalContext.current.getString(R.string.login_text))
@@ -211,7 +212,7 @@ fun LoginForm(
         Row(Modifier.basePadding()) {
             Button(
                 modifier = Modifier.fillMaxWidth(),
-                enabled = (username != "" && (loginStep == LoginStep.NONE || error.occurred())),
+                enabled = (username != "" && (loginStep == LoginStep.NONE || error != null)),
                 onClick = {
                     scope.launch { doLogin() }
                 },
@@ -219,7 +220,7 @@ fun LoginForm(
                 Text(LocalContext.current.getString(R.string.login_complete_text))
             }
         }
-        error.Show {
+        error.Display {
             Row(Modifier.basePadding()) {
                 ErrorText(
                     text = it

app/src/main/java/eu/steffo/twom/composables/main/RoomListItem.kt

@@ -52,7 +52,7 @@ fun RoomListItem(
     }
 
     var expanded by rememberSaveable { mutableStateOf(false) }
-    val error by remember { mutableStateOf(LocalizableError()) }
+    var error by remember { mutableStateOf<LocalizableError?>(null) }
 
     // TODO: Display a running indicator
 
@@ -65,7 +65,7 @@ fun RoomListItem(
                 session.roomService().joinRoom(roomId, "Opened the invite")
             } catch (e: Throwable) {
                 Log.e("Main", "Failed to open invite to room `$roomId`: $error")
-                error.set(R.string.main_error_join_generic, e)
+                error = LocalizableError(R.string.main_error_join_generic, e)
                 return
             }
             Log.d("Main", "Successfully opened invite to room `$roomId`!")
@@ -81,7 +81,7 @@ fun RoomListItem(
             session.roomService().leaveRoom(roomId, "Decided to leave the room")
         } catch (e: Throwable) {
             Log.e("Main", "Failed to leave room `$roomId`: $error")
-            error.set(R.string.main_error_leave_generic, e)
+            error = LocalizableError(R.string.main_error_leave_generic, e)
             return
         }
         Log.d("Main", "Successfully left room `$roomId`!")

app/src/main/java/eu/steffo/twom/composables/viewroom/InviteUserForm.kt

@@ -15,6 +15,7 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.stringResource
 import eu.steffo.twom.R
+import eu.steffo.twom.composables.errorhandling.Display
 import eu.steffo.twom.composables.errorhandling.ErrorText
 import eu.steffo.twom.composables.errorhandling.LoadingText
 import eu.steffo.twom.composables.errorhandling.LocalizableError
@@ -67,7 +68,7 @@ fun InviteUserForm(
     )
 
     var busy by rememberSaveable { mutableStateOf(false) }
-    val error by remember { mutableStateOf(LocalizableError()) }
+    var error by remember { mutableStateOf<LocalizableError?>(null) }
 
     Button(
         modifier = Modifier
@@ -78,7 +79,7 @@ fun InviteUserForm(
         onClick = {
             scope.launch SendInvite@{
                 busy = true
-                error.clear()
+                error = null
 
                 Log.d("Room", "Sending invite to `$userId`...")
 
@@ -86,7 +87,7 @@ fun InviteUserForm(
                     room.membershipService().invite(userId)
                 } catch (e: Throwable) {
                     Log.e("Room", "Failed to send invite to `$userId`: $error")
-                    error.set(R.string.room_error_invite_generic, e)
+                    error = LocalizableError(R.string.room_error_invite_generic, e)
                     busy = false
                     return@SendInvite
                 }
@@ -103,7 +104,7 @@ fun InviteUserForm(
         )
     }
 
-    error.Show {
+    error.Display {
         ErrorText(
             modifier = Modifier
                 .basePadding()

app/src/main/java/eu/steffo/twom/composables/viewroom/ViewRoomForm.kt

@@ -14,6 +14,7 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.stringResource
 import eu.steffo.twom.R
+import eu.steffo.twom.composables.errorhandling.Display
 import eu.steffo.twom.composables.errorhandling.ErrorText
 import eu.steffo.twom.composables.errorhandling.LoadingText
 import eu.steffo.twom.composables.errorhandling.LocalizableError
@@ -76,13 +77,13 @@ fun ViewRoomForm() {
     val published = observeRSVP(room = room, member = member)!!
 
     var isPublishRunning by rememberSaveable { mutableStateOf(false) }
-    val publishError by remember { mutableStateOf(LocalizableError()) }
+    var publishError by remember { mutableStateOf<LocalizableError?>(null) }
 
     RSVPForm(
         published = published,
         onRequestPublish = { answer, comment ->
             isPublishRunning = true
-            publishError.clear()
+            publishError = null
 
             scope.launch Publish@{
                 Log.d(
@@ -100,7 +101,7 @@ fun ViewRoomForm() {
                     )
                 } catch (e: Throwable) {
                     Log.e("Room", "Failed to update eu.steffo.twom.rsvp: $publishError")
-                    publishError.set(R.string.room_error_publish_generic, e)
+                    publishError = LocalizableError(R.string.room_error_publish_generic, e)
                     isPublishRunning = false
                     return@Publish
                 }
@@ -122,7 +123,7 @@ fun ViewRoomForm() {
                             "Room",
                             "Failed to redact old RSVP: $publishError"
                         )
-                        publishError.set(R.string.room_error_redact_generic, e)
+                        publishError = LocalizableError(R.string.room_error_redact_generic, e)
                         isPublishRunning = false
                         return@Publish
                     }
@@ -139,7 +140,7 @@ fun ViewRoomForm() {
         isPublishRunning = isPublishRunning,
     )
 
-    publishError.Show {
+    publishError.Display {
         Row(Modifier.basePadding()) {
             ErrorText(
                 text = it