ui: add PermissionScreen with rationale and denied recovery

app/src/androidTest/java/de/jeanlucmakiola/calendula/ui/permission/PermissionScreenTest.kt

@@ -0,0 +1,31 @@
+package de.jeanlucmakiola.calendula.ui.permission
+
+import androidx.compose.ui.test.assertIsDisplayed
+import androidx.compose.ui.test.junit4.createComposeRule
+import androidx.compose.ui.test.onNodeWithText
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.platform.app.InstrumentationRegistry
+import de.jeanlucmakiola.calendula.R
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+class PermissionScreenTest {
+
+    @get:Rule
+    val composeTestRule = createComposeRule()
+
+    private val res = InstrumentationRegistry.getInstrumentation().targetContext.resources
+
+    @Test
+    fun rationale_renders_title_and_button() {
+        composeTestRule.setContent {
+            PermissionScreen(onGranted = {})
+        }
+        composeTestRule.onNodeWithText(res.getString(R.string.permission_rationale_title))
+            .assertIsDisplayed()
+        composeTestRule.onNodeWithText(res.getString(R.string.permission_request_button))
+            .assertIsDisplayed()
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/permission/PermissionScreen.kt

@@ -0,0 +1,130 @@
+package de.jeanlucmakiola.calendula.ui.permission
+
+import android.Manifest
+import android.content.Intent
+import android.net.Uri
+import android.provider.Settings
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Button
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.calendula.R
+
+@Composable
+fun PermissionScreen(
+    onGranted: () -> Unit,
+    modifier: Modifier = Modifier,
+    viewModel: PermissionViewModel = hiltViewModel(),
+) {
+    val state by viewModel.state.collectAsStateWithLifecycle()
+
+    val launcher = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.RequestPermission(),
+    ) { granted ->
+        if (granted) viewModel.onGranted() else viewModel.onDenied()
+    }
+
+    LaunchedEffect(state) {
+        if (state == PermissionUiState.Granted) onGranted()
+    }
+
+    when (state) {
+        is PermissionUiState.Rationale -> RationaleContent(
+            onRequest = { launcher.launch(Manifest.permission.READ_CALENDAR) },
+            modifier = modifier,
+        )
+        is PermissionUiState.Denied -> DeniedContent(
+            onRetry = {
+                viewModel.onRetry()
+                launcher.launch(Manifest.permission.READ_CALENDAR)
+            },
+            modifier = modifier,
+        )
+        is PermissionUiState.Granted -> {
+            // Transient — LaunchedEffect above fires and parent replaces us.
+        }
+    }
+}
+
+@Composable
+private fun RationaleContent(
+    onRequest: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    Column(
+        modifier = modifier.fillMaxSize().padding(24.dp),
+        verticalArrangement = Arrangement.Center,
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        Text(
+            text = stringResource(R.string.permission_rationale_title),
+            style = MaterialTheme.typography.headlineMedium,
+        )
+        Spacer(Modifier.height(16.dp))
+        Text(
+            text = stringResource(R.string.permission_rationale_body),
+            style = MaterialTheme.typography.bodyLarge,
+        )
+        Spacer(Modifier.height(32.dp))
+        Button(onClick = onRequest) {
+            Text(stringResource(R.string.permission_request_button))
+        }
+    }
+}
+
+@Composable
+private fun DeniedContent(
+    onRetry: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val context = LocalContext.current
+    Column(
+        modifier = modifier.fillMaxSize().padding(24.dp),
+        verticalArrangement = Arrangement.Center,
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        Text(
+            text = stringResource(R.string.permission_denied_title),
+            style = MaterialTheme.typography.headlineMedium,
+        )
+        Spacer(Modifier.height(16.dp))
+        Text(
+            text = stringResource(R.string.permission_denied_body),
+            style = MaterialTheme.typography.bodyLarge,
+        )
+        Spacer(Modifier.height(32.dp))
+        Button(onClick = onRetry) {
+            Text(stringResource(R.string.permission_retry_button))
+        }
+        Spacer(Modifier.height(12.dp))
+        OutlinedButton(
+            onClick = {
+                val intent = Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS).apply {
+                    data = Uri.fromParts("package", context.packageName, null)
+                    addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+                }
+                context.startActivity(intent)
+            },
+        ) {
+            Text(stringResource(R.string.permission_open_settings_button))
+        }
+    }
+}