add notifications with snackbar

composeApp/src/commonMain/kotlin/in/procyk/shin/App.kt

@@ -1,30 +1,58 @@
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.SnackbarDuration
+import androidx.compose.material3.SnackbarHost
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.runtime.*
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.input.key.*
 import `in`.procyk.shin.createHttpClient
 import `in`.procyk.shin.ui.ShortenRequest
 import `in`.procyk.shin.ui.ShortenResponse
 import `in`.procyk.shin.ui.theme.ShinTheme
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.launch
 
 @Composable
 fun ShinApp() {
     val client = remember { createHttpClient() }
     ShinTheme {
-        var shortenedUrl by remember<MutableState<String?>> { mutableStateOf(null) }
-        Column(
-            modifier = Modifier
-                .fillMaxSize()
-                .onKeyEvent { event -> event.isEscDown.also { if (it) shortenedUrl = null } },
-            verticalArrangement = Arrangement.Center,
+        val snackbarHostState = remember { SnackbarHostState() }
+        val snackbarHostStateScope = rememberCoroutineScope()
+        Scaffold(
+            snackbarHost = { SnackbarHost(hostState = snackbarHostState) }
         ) {
-            ShortenRequest(client, onResponse = { shortenedUrl = it })
-            ShortenResponse(shortenedUrl)
+            var shortenedUrl by remember<MutableState<String?>> { mutableStateOf(null) }
+            Column(
+                modifier = Modifier
+                    .fillMaxSize()
+                    .onKeyEvent { event -> event.isEscDown.also { if (it) shortenedUrl = null } },
+                verticalArrangement = Arrangement.Center,
+            ) {
+                ShortenRequest(
+                    client = client,
+                    onResponse = { shortenedUrl = it },
+                    onError = { snackbarHostStateScope.showErrorSnackbarNotification(snackbarHostState, it) })
+                ShortenResponse(shortenedUrl)
+            }
         }
     }
 }
 
+private fun CoroutineScope.showErrorSnackbarNotification(
+    snackbarHostState: SnackbarHostState,
+    message: String,
+) {
+    launch {
+        snackbarHostState.showSnackbar(
+            message = message,
+            withDismissAction = true,
+            duration = SnackbarDuration.Short,
+        )
+    }
+}
+
 private val KeyEvent.isEscDown: Boolean
     get() = key == Key.Escape && type == KeyEventType.KeyDown

composeApp/src/commonMain/kotlin/in/procyk/shin/ui/ShortenRequest.kt

@@ -29,6 +29,7 @@ import kotlinx.coroutines.launch
 internal fun ShortenRequest(
     client: HttpClient,
     onResponse: (String) -> Unit,
+    onError: (String) -> Unit,
     space: Dp = 8.dp,
 ) {
     BoxWithConstraints {
@@ -42,7 +43,13 @@ internal fun ShortenRequest(
                 ),
                 horizontalAlignment = Alignment.CenterHorizontally,
             ) {
-                ShortenRequestElements(client, onResponse, fillMaxWidth = true, maxTextFieldWidth = maxWidth / 2)
+                ShortenRequestElements(
+                    client = client,
+                    onResponse = onResponse,
+                    onError = onError,
+                    fillMaxWidth = true,
+                    maxTextFieldWidth = maxWidth / 2
+                )
             }
         } else {
             Row(
@@ -53,7 +60,13 @@ internal fun ShortenRequest(
                 ),
                 verticalAlignment = Alignment.Bottom,
             ) {
-                ShortenRequestElements(client, onResponse, fillMaxWidth = false, maxTextFieldWidth = maxWidth / 2)
+                ShortenRequestElements(
+                    client = client,
+                    onResponse = onResponse,
+                    onError = onError,
+                    fillMaxWidth = false,
+                    maxTextFieldWidth = maxWidth / 2
+                )
             }
         }
     }
@@ -63,6 +76,7 @@ internal fun ShortenRequest(
 private fun ShortenRequestElements(
     client: HttpClient,
     onResponse: (String) -> Unit,
+    onError: (String) -> Unit,
     fillMaxWidth: Boolean,
     maxTextFieldWidth: Dp,
 ) {
@@ -91,7 +105,7 @@ private fun ShortenRequestElements(
             .applyIf(!fillMaxWidth) { widthIn(max = maxTextFieldWidth) },
         keyboardOptions = KeyboardOptions(imeAction = ImeAction.Done),
         keyboardActions = KeyboardActions(
-            onDone = { client.askForShortenedUrl(scope, url, shortenedProtocol, onResponse) }
+            onDone = { client.askForShortenedUrl(scope, url, shortenedProtocol, onResponse, onError) }
         ),
         singleLine = true,
         shape = RoundedCornerShape(12.dp),
@@ -101,7 +115,7 @@ private fun ShortenRequestElements(
             .height(56.dp)
             .applyIf(fillMaxWidth) { fillMaxWidth() },
         shape = RoundedCornerShape(12.dp),
-        onClick = { client.askForShortenedUrl(scope, url, shortenedProtocol, onResponse) }
+        onClick = { client.askForShortenedUrl(scope, url, shortenedProtocol, onResponse, onError) }
     ) {
         Text(
             text = "Shorten",
@@ -164,12 +178,14 @@ private fun HttpClient.askForShortenedUrl(
     url: String,
     shortenedProtocol: ShortenedProtocol,
     onResponse: (String) -> Unit,
+    onError: (String) -> Unit,
 ): Job = scope.launch {
     try {
         post<Shorten>(Shorten(shortenedProtocol.buildUrl(url)))
             .takeIf { it.status == HttpStatusCode.OK }
             ?.bodyAsText()
             ?.let(onResponse)
     } catch (_: Exception) {
+        onError("Cannot connect to Shin. Try again later…")
     }
 }