Fix tests

app/build.gradle.kts

@@ -153,6 +153,7 @@ dependencies {
     androidTestImplementation("androidx.compose.ui:ui-test-junit4")
     val coroutinesVersion = "1.7.1"
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:$coroutinesVersion")
+    testImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:$coroutinesVersion")
     val lifecycleVersion = "2.2.0"
     implementation("androidx.lifecycle:lifecycle-extensions:$lifecycleVersion")
     kapt("androidx.lifecycle:lifecycle-common-java8:$lifecycleVersion")

app/src/androidTest/kotlin/com/wbrawner/simplemarkdown/MarkdownTests.kt

@@ -0,0 +1,269 @@
+package com.wbrawner.simplemarkdown
+
+import android.app.Activity.RESULT_OK
+import android.app.Instrumentation
+import android.content.Context
+import android.content.Intent
+import android.net.Uri
+import android.webkit.WebView
+import androidx.compose.ui.input.key.Key
+import androidx.compose.ui.input.key.KeyEvent
+import androidx.compose.ui.input.key.NativeKeyEvent
+import androidx.compose.ui.semantics.SemanticsProperties
+import androidx.compose.ui.semantics.getOrNull
+import androidx.compose.ui.test.ExperimentalTestApi
+import androidx.compose.ui.test.SemanticsMatcher
+import androidx.compose.ui.test.assert
+import androidx.compose.ui.test.assertIsDisplayed
+import androidx.compose.ui.test.assertIsNotDisplayed
+import androidx.compose.ui.test.hasAnyDescendant
+import androidx.compose.ui.test.hasAnySibling
+import androidx.compose.ui.test.hasContentDescription
+import androidx.compose.ui.test.hasSetTextAction
+import androidx.compose.ui.test.hasText
+import androidx.compose.ui.test.isDialog
+import androidx.compose.ui.test.junit4.ComposeTestRule
+import androidx.compose.ui.test.junit4.createEmptyComposeRule
+import androidx.compose.ui.test.onNodeWithContentDescription
+import androidx.compose.ui.test.onNodeWithText
+import androidx.compose.ui.test.performClick
+import androidx.compose.ui.test.performKeyInput
+import androidx.compose.ui.test.performKeyPress
+import androidx.compose.ui.test.performTextInput
+import androidx.compose.ui.test.performTextInputSelection
+import androidx.compose.ui.test.performTextReplacement
+import androidx.compose.ui.test.printToLog
+import androidx.compose.ui.text.TextRange
+import androidx.core.content.FileProvider
+import androidx.test.core.app.ActivityScenario
+import androidx.test.core.app.ApplicationProvider.getApplicationContext
+import androidx.test.espresso.action.ViewActions.*
+import androidx.test.espresso.intent.Intents.intending
+import androidx.test.espresso.intent.matcher.IntentMatchers.hasAction
+import androidx.test.espresso.intent.rule.IntentsRule
+import androidx.test.espresso.matcher.ViewMatchers.*
+import androidx.test.espresso.web.assertion.WebViewAssertions.webMatches
+import androidx.test.espresso.web.sugar.Web.onWebView
+import androidx.test.espresso.web.webdriver.DriverAtoms.findElement
+import androidx.test.espresso.web.webdriver.DriverAtoms.getText
+import androidx.test.espresso.web.webdriver.Locator
+import androidx.test.platform.app.InstrumentationRegistry.getInstrumentation
+import kotlinx.coroutines.test.runTest
+import org.hamcrest.CoreMatchers.containsString
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import java.io.File
+import java.io.Reader
+
+class MarkdownTests {
+
+    @get:Rule
+    val composeRule = createEmptyComposeRule()
+
+    @get:Rule
+    val intentsRule = IntentsRule()
+
+    private lateinit var file: File
+
+    @Before
+    fun setup() {
+        file = File(getApplicationContext<Context>().filesDir.absolutePath + "/tmp", "temp.md")
+        assertTrue(requireNotNull(file.parentFile).mkdirs())
+        file.delete()
+    }
+
+    @Test
+    @Throws(Exception::class)
+    fun openAppTest() {
+        val context = getInstrumentation().targetContext
+        context.packageManager
+            .getLaunchIntentForPackage(context.packageName)
+            .apply { context.startActivity(this) }
+    }
+
+    @Test
+    fun editAndPreviewMarkdownTest() {
+        ActivityScenario.launch(MainActivity::class.java)
+        composeRule.typeMarkdown("# Header test")
+        composeRule.checkMarkdownEquals("# Header test")
+        composeRule.openPreview()
+        onWebView(isAssignableFrom(WebView::class.java))
+            .forceJavascriptEnabled()
+            .withElement(findElement(Locator.TAG_NAME, "h1"))
+            .check(webMatches(getText(), containsString("Header test")))
+    }
+
+    @Test
+    fun openThenNewMarkdownTest() {
+        val markdownText = "# UI Testing\n\nThe quick brown fox jumped over the lazy dog."
+        file.outputStream().writer().use { it.write(markdownText) }
+        val activityResult = Instrumentation.ActivityResult(RESULT_OK, Intent().apply {
+            data = Uri.fromFile(file)
+            addFlags(Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION)
+        })
+        intending(hasAction(Intent.ACTION_OPEN_DOCUMENT)).respondWith(activityResult)
+        ActivityScenario.launch(MainActivity::class.java)
+        composeRule.openMenu()
+        composeRule.clickOpenMenuItem()
+        composeRule.checkMarkdownEquals(markdownText)
+        composeRule.openMenu()
+        composeRule.clickNewMenuItem()
+        composeRule.verifyDialogIsNotShown()
+        composeRule.checkMarkdownEquals("")
+    }
+
+    @Test
+    fun editThenNewMarkdownTest() {
+        ActivityScenario.launch(MainActivity::class.java)
+        val markdownText = "# UI Testing\n\nThe quick brown fox jumped over the lazy dog."
+        composeRule.typeMarkdown(markdownText)
+        composeRule.openMenu()
+        composeRule.clickNewMenuItem()
+        composeRule.onNode(isDialog()).printToLog("TestDebugging")
+        composeRule.verifyDialogIsShown("Would you like to save your changes?")
+        composeRule.discardChanges()
+        composeRule.checkMarkdownEquals("")
+    }
+
+    @Test
+    fun saveMarkdownWithFileUriTest() = runTest {
+        ActivityScenario.launch(MainActivity::class.java)
+        composeRule.checkTitleEquals("Untitled.md")
+        val markdownText = "# UI Testing\n\nThe quick brown fox jumped over the lazy dog."
+        composeRule.typeMarkdown(markdownText)
+        val activityResult = Instrumentation.ActivityResult(RESULT_OK, Intent().apply {
+            data = Uri.fromFile(file)
+        })
+        intending(hasAction(Intent.ACTION_CREATE_DOCUMENT)).respondWith(activityResult)
+        composeRule.openMenu()
+        composeRule.clickSaveMenuItem()
+        composeRule.awaitIdle()
+        assertEquals(markdownText, file.inputStream().reader().use(Reader::readText))
+        composeRule.checkTitleEquals("temp.md")
+    }
+
+    @Test
+    fun saveMarkdownWithContentUriTest() = runTest {
+        ActivityScenario.launch(MainActivity::class.java)
+        composeRule.checkTitleEquals("Untitled.md")
+        val markdownText = "# UI Testing\n\nThe quick brown fox jumped over the lazy dog."
+        composeRule.typeMarkdown(markdownText)
+        val activityResult = Instrumentation.ActivityResult(RESULT_OK, Intent().apply {
+            data = FileProvider.getUriForFile(
+                getApplicationContext(),
+                "${BuildConfig.APPLICATION_ID}.fileprovider",
+                file
+            )
+        })
+        intending(hasAction(Intent.ACTION_CREATE_DOCUMENT)).respondWith(activityResult)
+        composeRule.openMenu()
+        composeRule.clickSaveMenuItem()
+        composeRule.awaitIdle()
+        assertEquals(markdownText, file.inputStream().reader().use(Reader::readText))
+        composeRule.checkTitleEquals("temp.md")
+    }
+
+    @Test
+    fun loadMarkdownWithFileUriTest() = runTest {
+        ActivityScenario.launch(MainActivity::class.java)
+        composeRule.checkTitleEquals("Untitled.md")
+        val markdownText = "# UI Testing\n\nThe quick brown fox jumped over the lazy dog."
+        file.outputStream().writer().use { it.write(markdownText) }
+        val activityResult = Instrumentation.ActivityResult(RESULT_OK, Intent().apply {
+            data = Uri.fromFile(file)
+        })
+        intending(hasAction(Intent.ACTION_OPEN_DOCUMENT)).respondWith(activityResult)
+        composeRule.openMenu()
+        composeRule.clickOpenMenuItem()
+        composeRule.awaitIdle()
+        composeRule.checkMarkdownEquals(markdownText)
+        composeRule.checkTitleEquals("temp.md")
+    }
+
+    @Test
+    fun loadMarkdownWithContentUriTest() = runTest {
+        ActivityScenario.launch(MainActivity::class.java)
+        composeRule.checkTitleEquals("Untitled.md")
+        val markdownText = "# UI Testing\n\nThe quick brown fox jumped over the lazy dog."
+        file.outputStream().writer().use { it.write(markdownText) }
+        val activityResult = Instrumentation.ActivityResult(RESULT_OK, Intent().apply {
+            data = FileProvider.getUriForFile(
+                getApplicationContext(),
+                "${BuildConfig.APPLICATION_ID}.fileprovider",
+                file
+            )
+        })
+        intending(hasAction(Intent.ACTION_OPEN_DOCUMENT)).respondWith(activityResult)
+        composeRule.openMenu()
+        composeRule.clickOpenMenuItem()
+        composeRule.awaitIdle()
+        composeRule.checkMarkdownEquals(markdownText)
+        composeRule.checkTitleEquals("temp.md")
+    }
+
+
+    @Test
+    fun openEditAndSaveMarkdownTest() = runTest {
+        val markdownText = "# UI Testing\n\nThe quick brown fox jumped over the lazy dog."
+        file.outputStream().writer().use { it.write(markdownText) }
+        val activityResult = Instrumentation.ActivityResult(RESULT_OK, Intent().apply {
+            data = Uri.fromFile(file)
+        })
+        intending(hasAction(Intent.ACTION_OPEN_DOCUMENT)).respondWith(activityResult)
+        ActivityScenario.launch(MainActivity::class.java)
+        composeRule.checkTitleEquals("Untitled.md")
+        composeRule.openMenu()
+        composeRule.clickOpenMenuItem()
+        composeRule.awaitIdle()
+        composeRule.verifyTextIsShown("Successfully loaded temp.md")
+        composeRule.checkMarkdownEquals(markdownText)
+        composeRule.checkTitleEquals("temp.md")
+        val additionalText = "# More info\n\nThis is some additional text"
+        composeRule.typeMarkdown(additionalText)
+        composeRule.openMenu()
+        composeRule.clickSaveMenuItem()
+        composeRule.awaitIdle()
+        composeRule.verifyTextIsShown("Successfully saved temp.md")
+        assertEquals(additionalText, file.inputStream().reader().use(Reader::readText))
+        composeRule.checkTitleEquals("temp.md")
+    }
+
+    private fun ComposeTestRule.checkTitleEquals(title: String) =
+        onNode(hasAnySibling(hasContentDescription("Main Menu")).and(hasText(title)))
+            .assertIsDisplayed()
+
+    private fun ComposeTestRule.typeMarkdown(markdown: String) =
+        onNode(hasSetTextAction()).performTextReplacement(markdown)
+
+
+    private fun ComposeTestRule.checkMarkdownEquals(markdown: String) {
+        val markdownMatcher = SemanticsMatcher("Markdown = [$markdown]") {
+            it.config.getOrNull(SemanticsProperties.EditableText)?.text == markdown
+        }
+        onNode(hasSetTextAction()).assert(markdownMatcher)
+    }
+
+    private fun ComposeTestRule.openPreview() = onNodeWithText("Preview").performClick()
+
+    private fun ComposeTestRule.openMenu() =
+        onNodeWithContentDescription("Editor Actions").performClick()
+
+    private fun ComposeTestRule.clickOpenMenuItem() = onNodeWithText("Open").performClick()
+
+    private fun ComposeTestRule.clickNewMenuItem() = onNodeWithText("New").performClick()
+
+    private fun ComposeTestRule.clickSaveMenuItem() = onNodeWithText("Save").performClick()
+
+    private fun ComposeTestRule.verifyDialogIsShown(text: String) =
+        onNode(isDialog().and(hasAnyDescendant(hasText(text)))).assertIsDisplayed()
+
+    private fun ComposeTestRule.verifyDialogIsNotShown() = onNode(isDialog()).assertIsNotDisplayed()
+
+    private fun ComposeTestRule.discardChanges() = onNodeWithText("No").performClick()
+
+    private fun ComposeTestRule.verifyTextIsShown(text: String) =
+        onNodeWithText(text).assertIsDisplayed()
+}

app/src/main/java/com/wbrawner/simplemarkdown/MainActivity.kt

@@ -14,9 +14,9 @@ import androidx.compose.animation.core.tween
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.Help
 import androidx.compose.material.icons.filled.Edit
 import androidx.compose.material.icons.filled.Favorite
-import androidx.compose.material.icons.filled.Help
 import androidx.compose.material.icons.filled.Info
 import androidx.compose.material.icons.filled.PrivacyTip
 import androidx.compose.material.icons.filled.Settings
@@ -128,8 +128,7 @@ class MainActivity : AppCompatActivity(), ActivityCompat.OnRequestPermissionsRes
                             viewModel = viewModel,
                             enableWideLayout = windowSizeClass.widthSizeClass == WindowWidthSizeClass.Expanded,
                             enableAutosave = autosaveEnabled,
-                            enableReadability = readabilityEnabled,
-                            darkMode = darkModePreference
+                            enableReadability = readabilityEnabled
                         )
                     }
                     composable(Route.SETTINGS.path) {
@@ -173,7 +172,7 @@ enum class Route(
     EDITOR("/", "Editor", Icons.Default.Edit),
     SETTINGS("/settings", "Settings", Icons.Default.Settings),
     SUPPORT("/support", "Support SimpleMarkdown", Icons.Default.Favorite),
-    HELP("/help", "Help", Icons.Default.Help),
+    HELP("/help", "Help", Icons.AutoMirrored.Filled.Help),
     ABOUT("/about", "About", Icons.Default.Info),
     PRIVACY("/privacy", "Privacy", Icons.Default.PrivacyTip),
 }

app/src/main/java/com/wbrawner/simplemarkdown/MarkdownViewModel.kt

@@ -7,30 +7,34 @@ import androidx.lifecycle.viewmodel.CreationExtras
 import com.wbrawner.simplemarkdown.utility.FileHelper
 import com.wbrawner.simplemarkdown.utility.Preference
 import com.wbrawner.simplemarkdown.utility.PreferenceHelper
-import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.coroutineScope
 import kotlinx.coroutines.flow.MutableStateFlow
-import kotlinx.coroutines.flow.asSharedFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
+import kotlinx.coroutines.withContext
 import timber.log.Timber
 import java.io.File
 import java.net.URI
-import java.util.concurrent.atomic.AtomicBoolean
+
+data class EditorState(
+    val fileName: String = "Untitled.md",
+    val markdown: String = "",
+    val path: URI? = null,
+    val dirty: Boolean = false,
+    val toast: String? = null,
+    val alert: AlertDialogModel? = null,
+    val saveCallback: (() -> Unit)? = null
+)
 
 class MarkdownViewModel(
     private val fileHelper: FileHelper,
     private val preferenceHelper: PreferenceHelper
 ) : ViewModel() {
-    private val _fileName = MutableStateFlow("Untitled.md")
-    val fileName = _fileName.asStateFlow()
-    private val _markdown = MutableStateFlow("")
-    val markdown = _markdown.asStateFlow()
-    private val path = MutableStateFlow<URI?>(null)
-    private val isDirty = AtomicBoolean(false)
-    private val _effects = MutableSharedFlow<Effect>()
-    val effects = _effects.asSharedFlow()
+    private val _state = MutableStateFlow(EditorState())
+    val state = _state.asStateFlow()
     private val saveMutex = Mutex()
 
     init {
@@ -39,71 +43,114 @@ class MarkdownViewModel(
         }
     }
 
-    suspend fun updateMarkdown(markdown: String?) {
-        this@MarkdownViewModel._markdown.emit(markdown ?: "")
-        isDirty.set(true)
+    fun updateMarkdown(markdown: String?) {
+        _state.value = _state.value.copy(
+            markdown = markdown ?: "",
+            dirty = true
+        )
+    }
+
+    fun dismissToast() {
+        _state.value = _state.value.copy(toast = null)
+    }
+
+    fun dismissAlert() {
+        _state.value = _state.value.copy(alert = null)
+    }
+
+    private fun unsetSaveCallback() {
+        _state.value = _state.value.copy(saveCallback = null)
     }
 
     suspend fun load(loadPath: String?) {
-        if (loadPath.isNullOrBlank()) {
-            Timber.i("No URI provided to load, attempting to load last autosaved file")
-            preferenceHelper[Preference.AUTOSAVE_URI]
-                ?.let {
-                    val autosaveUri = it as? String
-                    if (autosaveUri.isNullOrBlank()) {
-                        preferenceHelper[Preference.AUTOSAVE_URI] = null
-                    } else {
-                        Timber.d("Using uri from shared preferences: $it")
-                        load(autosaveUri)
-                    }
-                }
-            return
-        }
-        try {
-            val uri = URI.create(loadPath)
-            fileHelper.open(uri)
-                ?.let { (name, content) ->
-                    path.emit(uri)
-                    _effects.emit(Effect.ClearText)
-                    _fileName.emit(name)
-                    _markdown.emit(content)
-                    isDirty.set(false)
-                    preferenceHelper[Preference.AUTOSAVE_URI] = loadPath
-                } ?: _effects.emit(Effect.Error("Failed to open file at path: $loadPath"))
-        } catch (e: Exception) {
-            Timber.e(e, "Failed to open file at path: $loadPath")
+        saveMutex.withLock {
+            val actualLoadPath = loadPath
+                ?.ifBlank { null }
+                ?: preferenceHelper[Preference.AUTOSAVE_URI]
+                    ?.let {
+                        val autosaveUri = it as? String
+                        if (autosaveUri.isNullOrBlank()) {
+                            preferenceHelper[Preference.AUTOSAVE_URI] = null
+                            null
+                        } else {
+                            Timber.d("Using uri from shared preferences: $it")
+                            autosaveUri
+                        }
+                    } ?: return
+            Timber.d("Loading file at $actualLoadPath")
+            try {
+                val uri = URI.create(actualLoadPath)
+                fileHelper.open(uri)
+                    ?.let { (name, content) ->
+                        _state.value = _state.value.copy(
+                            path = uri,
+                            fileName = name,
+                            markdown = content,
+                            dirty = false,
+                            toast = "Successfully loaded $name"
+                        )
+                        preferenceHelper[Preference.AUTOSAVE_URI] = actualLoadPath
+                    } ?: throw IllegalStateException("Opened file was null")
+            } catch (e: Exception) {
+                Timber.e(e, "Failed to open file at path: $actualLoadPath")
+                _state.value = _state.value.copy(
+                    alert = AlertDialogModel(
+                        text = "Failed to open file at path: $actualLoadPath",
+                        confirmButton = AlertDialogModel.ButtonModel("OK", onClick = ::dismissAlert)
+                    )
+                )
+            }
         }
     }
 
-    suspend fun save(savePath: URI? = path.value, promptSavePath: Boolean = true): Boolean {
-        return saveMutex.withLock {
-            if (savePath == null) {
-                Timber.w("Attempted to save file with empty path")
-                if (promptSavePath) {
-                    _effects.emit(Effect.OpenSaveDialog {})
+    suspend fun save(savePath: URI? = null, interactive: Boolean = true): Boolean =
+        saveMutex.withLock {
+            val actualSavePath = savePath
+                ?: _state.value.path
+                ?: run {
+                    Timber.w("Attempted to save file with empty path")
+                    if (interactive) {
+                        _state.value = _state.value.copy(saveCallback = ::unsetSaveCallback)
+                    }
+                    return@withLock false
                 }
-                return false
-            }
             try {
-                val name = fileHelper.save(savePath, markdown.value)
-                _fileName.emit(name)
-                path.emit(savePath)
-                isDirty.set(false)
-                Timber.i("Saved file ${fileName.value} to uri $savePath")
-                Timber.i("Persisting autosave uri in shared prefs: $savePath")
-                preferenceHelper[Preference.AUTOSAVE_URI] = savePath
+                Timber.i("Saving file to $actualSavePath...")
+                val currentState = _state.value
+                val name = fileHelper.save(actualSavePath, currentState.markdown)
+                _state.value = currentState.copy(
+                    fileName = name,
+                    path = actualSavePath,
+                    dirty = false,
+                    toast = if (interactive) "Successfully saved $name" else null
+                )
+                Timber.i("Saved file $name to uri $actualSavePath")
+                Timber.i("Persisting autosave uri in shared prefs: $actualSavePath")
+                preferenceHelper[Preference.AUTOSAVE_URI] = actualSavePath
                 true
             } catch (e: Exception) {
-                val message = "Failed to save file to $savePath"
+                val message = "Failed to save file to $actualSavePath"
                 Timber.e(e, message)
-                _effects.emit(Effect.Error(message))
+                _state.value = _state.value.copy(
+                    alert = AlertDialogModel(
+                        text = message,
+                        confirmButton = AlertDialogModel.ButtonModel(
+                            text = "OK",
+                            onClick = ::dismissAlert
+                        )
+                    )
+                )
                 false
             }
         }
-    }
 
     suspend fun autosave() {
-        if (!isDirty.get()) {
+        val isAutoSaveEnabled = preferenceHelper[Preference.AUTOSAVE_ENABLED] as Boolean
+        if (!isAutoSaveEnabled) {
+            Timber.i("Ignoring autosave as autosave not enabled")
+            return
+        }
+        if (!_state.value.dirty) {
             Timber.d("Ignoring autosave as contents haven't changed")
             return
         }
@@ -111,52 +158,59 @@ class MarkdownViewModel(
             Timber.i("Ignoring autosave since manual save is already in progress")
             return
         }
-        val isAutoSaveEnabled = preferenceHelper[Preference.AUTOSAVE_ENABLED] as Boolean
-        if (!isAutoSaveEnabled) {
-            Timber.i("Ignoring autosave as autosave not enabled")
-            return
-        }
-        if (!save(promptSavePath = false)) {
-            // The user has left the app, with autosave enabled, and we don't already have a
-            // Uri for them or for some reason we were unable to save to the original Uri. In
-            // this case, we need to just save to internal file storage so that we can recover
-            val file = File(fileHelper.defaultDirectory, fileName.value).toURI()
-            Timber.i("No cached uri for autosave, saving to $file instead")
-            save(file)
+        Timber.d("Performing autosave")
+        if (!save(interactive = false)) {
+            withContext(Dispatchers.IO) {
+                // The user has left the app, with autosave enabled, and we don't already have a
+                // Uri for them or for some reason we were unable to save to the original Uri. In
+                // this case, we need to just save to internal file storage so that we can recover
+                val file = File(fileHelper.defaultDirectory, _state.value.fileName).toURI()
+                Timber.i("No cached uri for autosave, saving to $file instead")
+                // Here we call the fileHelper directly so that the file is still registered as dirty.
+                // This prevents the user from ending up in a scenario where they've autosaved the file
+                // to an internal storage location, thus marking it as not dirty, but no longer able to
+                // access the file if the accidentally go to create a new file without properly saving
+                // the current one
+                fileHelper.save(file, _state.value.markdown)
+                preferenceHelper[Preference.AUTOSAVE_URI] = file
+            }
         }
     }
 
-    suspend fun reset(untitledFileName: String, force: Boolean = false) {
+    fun reset(untitledFileName: String, force: Boolean = false) {
         Timber.i("Resetting view model to default state")
-        if (!force && isDirty.get()) {
-            _effects.emit(Effect.Prompt(
-                "Would you like to save your changes?",
-                confirm = {
-                    viewModelScope.launch {
-                        _effects.emit(Effect.OpenSaveDialog {
-                            reset(untitledFileName, false)
-                        })
+        if (!force && _state.value.dirty) {
+            _state.value = _state.value.copy(alert = AlertDialogModel(
+                text = "Would you like to save your changes?",
+                confirmButton = AlertDialogModel.ButtonModel(
+                    text = "Yes",
+                    onClick = {
+                        _state.value = _state.value.copy(
+                            saveCallback = {
+                                reset(untitledFileName, false)
+                            }
+                        )
                     }
-                },
-                cancel = {
-                    viewModelScope.launch {
+                ),
+                dismissButton = AlertDialogModel.ButtonModel(
+                    text = "No",
+                    onClick = {
                         reset(untitledFileName, true)
                     }
-                }
+                )
             ))
             return
         }
-        _fileName.emit(untitledFileName)
-        _markdown.emit("")
-        path.emit(null)
-        _effects.emit(Effect.ClearText)
-        isDirty.set(false)
+        _state.value = EditorState(fileName = untitledFileName)
         Timber.i("Removing autosave uri from shared prefs")
         preferenceHelper[Preference.AUTOSAVE_URI] = null
     }
 
     companion object {
-        fun factory(fileHelper: FileHelper, preferenceHelper: PreferenceHelper): ViewModelProvider.Factory = object : ViewModelProvider.Factory {
+        fun factory(
+            fileHelper: FileHelper,
+            preferenceHelper: PreferenceHelper
+        ): ViewModelProvider.Factory = object : ViewModelProvider.Factory {
             @Suppress("UNCHECKED_CAST")
             override fun <T : ViewModel> create(
                 modelClass: Class<T>,
@@ -166,13 +220,12 @@ class MarkdownViewModel(
             }
         }
     }
-
-    sealed interface Effect {
-        data class OpenSaveDialog(val postSaveBlock: suspend () -> Unit) : Effect
-        data class Prompt(val text: String, val confirm: () -> Unit, val cancel: () -> Unit) :
-            Effect
-
-        data object ClearText : Effect
-        data class Error(val text: String) : Effect
-    }
+}
+
+data class AlertDialogModel(
+    val text: String,
+    val confirmButton: ButtonModel,
+    val dismissButton: ButtonModel? = null
+) {
+    data class ButtonModel(val text: String, val onClick: () -> Unit)
 }

app/src/main/java/com/wbrawner/simplemarkdown/ui/MainScreen.kt

@@ -1,6 +1,7 @@
 package com.wbrawner.simplemarkdown.ui
 
 import android.content.Intent
+import android.net.Uri
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.foundation.ExperimentalFoundationApi
@@ -21,7 +22,7 @@ import androidx.compose.foundation.pager.HorizontalPager
 import androidx.compose.foundation.pager.rememberPagerState
 import androidx.compose.foundation.text.KeyboardOptions
 import androidx.compose.material.icons.Icons
-import androidx.compose.material.icons.filled.ArrowBack
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
 import androidx.compose.material.icons.filled.Menu
 import androidx.compose.material.icons.filled.MoreVert
 import androidx.compose.material.icons.filled.Share
@@ -39,6 +40,9 @@ import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.NavigationDrawerItem
 import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Snackbar
+import androidx.compose.material3.SnackbarHost
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.material3.Tab
 import androidx.compose.material3.TabRow
 import androidx.compose.material3.Text
@@ -47,11 +51,9 @@ import androidx.compose.material3.TextField
 import androidx.compose.material3.TextFieldDefaults
 import androidx.compose.material3.TopAppBar
 import androidx.compose.material3.rememberDrawerState
-import androidx.compose.material3.windowsizeclass.WindowSizeClass
-import androidx.compose.material3.windowsizeclass.WindowWidthSizeClass
-import androidx.compose.material3.windowsizeclass.calculateWindowSizeClass
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.State
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
@@ -59,7 +61,6 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
-import androidx.compose.ui.ExperimentalComposeUiApi
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.platform.LocalContext
@@ -67,6 +68,7 @@ import androidx.compose.ui.platform.LocalSoftwareKeyboardController
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.text.AnnotatedString
 import androidx.compose.ui.text.SpanStyle
+import androidx.compose.ui.text.TextRange
 import androidx.compose.ui.text.TextStyle
 import androidx.compose.ui.text.font.FontFamily
 import androidx.compose.ui.text.input.KeyboardCapitalization
@@ -75,15 +77,18 @@ import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.core.content.ContextCompat.startActivity
 import androidx.navigation.NavController
+import com.wbrawner.simplemarkdown.AlertDialogModel
+import com.wbrawner.simplemarkdown.EditorState
 import com.wbrawner.simplemarkdown.MarkdownViewModel
 import com.wbrawner.simplemarkdown.R
 import com.wbrawner.simplemarkdown.Route
 import com.wbrawner.simplemarkdown.model.Readability
-import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
 import java.net.URI
+import kotlin.reflect.KProperty1
 
 @Composable
 fun MainScreen(
@@ -91,164 +96,216 @@ fun MainScreen(
     viewModel: MarkdownViewModel,
     enableWideLayout: Boolean,
     enableAutosave: Boolean,
-    enableReadability: Boolean,
-    darkMode: String,
+    enableReadability: Boolean
 ) {
-    var lockSwiping by remember { mutableStateOf(false) }
     val coroutineScope = rememberCoroutineScope()
-    val fileName by viewModel.fileName.collectAsState()
-    val openFileLauncher =
-        rememberLauncherForActivityResult(ActivityResultContracts.OpenDocument()) {
-            coroutineScope.launch {
-                viewModel.load(it.toString())
-            }
-        }
-    val saveFileLauncher =
-        rememberLauncherForActivityResult(ActivityResultContracts.CreateDocument("text/*")) {
-            it?.let {
-                coroutineScope.launch {
-                    viewModel.save(URI.create(it.toString()))
-                }
-            }
-        }
-    var errorMessage by remember { mutableStateOf<String?>(null) }
-    var promptEffect by remember { mutableStateOf<MarkdownViewModel.Effect.Prompt?>(null) }
-    var clearText by remember { mutableStateOf(0) }
-    LaunchedEffect(viewModel) {
-        viewModel.effects.collect { effect ->
-            when (effect) {
-                is MarkdownViewModel.Effect.OpenSaveDialog -> saveFileLauncher.launch(fileName)
-                is MarkdownViewModel.Effect.Error -> errorMessage = effect.text
-                is MarkdownViewModel.Effect.Prompt -> promptEffect = effect
-                is MarkdownViewModel.Effect.ClearText -> clearText++
-            }
-        }
-    }
+    val fileName by viewModel.collectAsState(EditorState::fileName, "")
+    val markdown by viewModel.collectAsState(EditorState::markdown, "")
+    val alert by viewModel.collectAsState(EditorState::alert, null)
+    val saveCallback by viewModel.collectAsState(EditorState::saveCallback, null)
     LaunchedEffect(enableAutosave) {
         if (!enableAutosave) return@LaunchedEffect
         while (isActive) {
-            delay(30_000)
+            delay(500)
             viewModel.autosave()
         }
     }
-    errorMessage?.let { message ->
-        AlertDialog(
-            onDismissRequest = { errorMessage = null },
-            confirmButton = {
-                TextButton(onClick = { errorMessage = null }) {
-                    Text("OK")
-                }
-            },
-            text = { Text(message) }
-        )
+    val toast by viewModel.collectAsState(EditorState::toast, null)
+    MainScreen(
+        fileName = fileName,
+        markdown = markdown,
+        setMarkdown = viewModel::updateMarkdown,
+        message = toast,
+        dismissMessage = viewModel::dismissToast,
+        alert = alert,
+        dismissAlert = viewModel::dismissAlert,
+        navigate = {
+            navController.navigate(it.path)
+        },
+        navigateBack = { navController.popBackStack() },
+        loadFile = {
+            coroutineScope.launch {
+                viewModel.load(it.toString())
+            }
+        },
+        saveFile = {
+            coroutineScope.launch {
+                viewModel.save(it)
+            }
+        },
+        saveCallback = saveCallback,
+        reset = {
+            viewModel.reset("Untitled.md")
+        },
+        enableWideLayout = enableWideLayout,
+        enableReadability = enableReadability,
+    )
+}
+
+@Composable
+private fun MainScreen(
+    fileName: String = "Untitled.md",
+    markdown: String = "",
+    setMarkdown: (String) -> Unit = {},
+    message: String? = null,
+    dismissMessage: () -> Unit = {},
+    alert: AlertDialogModel? = null,
+    dismissAlert: () -> Unit = {},
+    navigate: (Route) -> Unit = {},
+    navigateBack: () -> Unit = {},
+    loadFile: (Uri?) -> Unit = {},
+    saveFile: (URI?) -> Unit = {},
+    saveCallback: (() -> Unit)? = null,
+    reset: () -> Unit = {},
+    enableWideLayout: Boolean = false,
+    enableReadability: Boolean = false
+) {
+    var lockSwiping by remember { mutableStateOf(false) }
+    val openFileLauncher =
+        rememberLauncherForActivityResult(ActivityResultContracts.OpenDocument()) {
+            loadFile(it)
+        }
+    val saveFileLauncher =
+        rememberLauncherForActivityResult(ActivityResultContracts.CreateDocument("text/*")) {
+            it?.let { uri -> saveFile(URI.create(uri.toString())) }
+        }
+    saveCallback?.let { callback ->
+        val launcher =
+            rememberLauncherForActivityResult(ActivityResultContracts.CreateDocument("text/*")) {
+                it?.let { uri -> saveFile(URI.create(uri.toString())) }
+                callback()
+            }
+        LaunchedEffect(callback) {
+            launcher.launch(fileName)
+        }
     }
-    promptEffect?.let { prompt ->
+
+    val snackBarState = remember { SnackbarHostState() }
+
+    LaunchedEffect(message) {
+        message?.let {
+            snackBarState.showSnackbar(it)
+            dismissMessage()
+        }
+    }
+
+    alert?.let {
         AlertDialog(
-            onDismissRequest = { errorMessage = null },
+            onDismissRequest = dismissAlert,
             confirmButton = {
-                TextButton(onClick = {
-                    prompt.confirm()
-                    promptEffect = null
-                }) {
-                    Text("Yes")
+                TextButton(onClick = it.confirmButton.onClick) {
+                    Text(it.confirmButton.text)
                 }
             },
             dismissButton = {
-                TextButton(onClick = {
-                    prompt.cancel()
-                    promptEffect = null
-                }) {
-                    Text("No")
+                it.dismissButton?.let { dismissButton ->
+                    TextButton(onClick = dismissButton.onClick) {
+                        Text(dismissButton.text)
+                    }
                 }
             },
-            text = { Text(prompt.text) }
+            text = { Text(it.text) }
         )
     }
-    MarkdownNavigationDrawer(navigate = { navController.navigate(it.path) }) { drawerState ->
-        Scaffold(topBar = {
-            val context = LocalContext.current
-            MarkdownTopAppBar(title = fileName,
-                backAsUp = false,
-                navController = navController,
-                drawerState = drawerState,
-                actions = {
-                    IconButton(onClick = {
-                        val shareIntent = Intent(Intent.ACTION_SEND)
-                        shareIntent.putExtra(Intent.EXTRA_TEXT, viewModel.markdown.value)
-                        shareIntent.type = "text/plain"
-                        startActivity(
-                            context, Intent.createChooser(
-                                shareIntent, context.getString(R.string.share_file)
-                            ), null
-                        )
-                    }) {
-                        Icon(imageVector = Icons.Default.Share, contentDescription = "Share")
-                    }
-                    Box {
-                        var menuExpanded by remember { mutableStateOf(false) }
-                        IconButton(onClick = { menuExpanded = true }) {
-                            Icon(imageVector = Icons.Default.MoreVert, "Editor Actions")
+
+    MarkdownNavigationDrawer(navigate) { drawerState ->
+        Scaffold(
+            topBar = {
+                val context = LocalContext.current
+                MarkdownTopAppBar(title = fileName,
+                    backAsUp = false,
+                    goBack = navigateBack,
+                    drawerState = drawerState,
+                    actions = {
+                        IconButton(onClick = {
+                            val shareIntent = Intent(Intent.ACTION_SEND)
+                            shareIntent.putExtra(Intent.EXTRA_TEXT, markdown)
+                            shareIntent.type = "text/plain"
+                            startActivity(
+                                context, Intent.createChooser(
+                                    shareIntent, context.getString(R.string.share_file)
+                                ), null
+                            )
+                        }) {
+                            Icon(imageVector = Icons.Default.Share, contentDescription = "Share")
                         }
-                        DropdownMenu(expanded = menuExpanded,
-                            onDismissRequest = { menuExpanded = false }) {
-                            DropdownMenuItem(text = { Text("New") }, onClick = {
-                                menuExpanded = false
-                                coroutineScope.launch {
-                                    viewModel.reset("Untitled.md")
-                                }
-                            })
-                            DropdownMenuItem(text = { Text("Open") }, onClick = {
-                                menuExpanded = false
-                                openFileLauncher.launch(arrayOf("text/*"))
-                            })
-                            DropdownMenuItem(text = { Text("Save") }, onClick = {
-                                menuExpanded = false
-                                coroutineScope.launch {
-                                    viewModel.save()
-                                }
-                            })
-                            DropdownMenuItem(text = { Text("Save as…") },
-                                onClick = {
+                        Box {
+                            var menuExpanded by remember { mutableStateOf(false) }
+                            IconButton(onClick = { menuExpanded = true }) {
+                                Icon(imageVector = Icons.Default.MoreVert, "Editor Actions")
+                            }
+                            DropdownMenu(expanded = menuExpanded,
+                                onDismissRequest = { menuExpanded = false }) {
+                                DropdownMenuItem(text = { Text("New") }, onClick = {
                                     menuExpanded = false
-                                    saveFileLauncher.launch(fileName)
+                                    reset()
                                 })
-                            if (!enableWideLayout) {
-                                DropdownMenuItem(text = {
-                                    Row(verticalAlignment = Alignment.CenterVertically) {
-                                        Text("Lock Swiping")
-                                        Checkbox(
-                                            checked = lockSwiping,
-                                            onCheckedChange = { lockSwiping = !lockSwiping })
-                                    }
-                                }, onClick = {
-                                    lockSwiping = !lockSwiping
+                                DropdownMenuItem(text = { Text("Open") }, onClick = {
                                     menuExpanded = false
+                                    openFileLauncher.launch(arrayOf("text/*"))
                                 })
+                                DropdownMenuItem(text = { Text("Save") }, onClick = {
+                                    menuExpanded = false
+                                    saveFile(null)
+                                })
+                                DropdownMenuItem(text = { Text("Save as…") },
+                                    onClick = {
+                                        menuExpanded = false
+                                        saveFileLauncher.launch(fileName)
+                                    })
+                                if (!enableWideLayout) {
+                                    DropdownMenuItem(text = {
+                                        Row(verticalAlignment = Alignment.CenterVertically) {
+                                            Text("Lock Swiping")
+                                            Checkbox(
+                                                checked = lockSwiping,
+                                                onCheckedChange = { lockSwiping = !lockSwiping })
+                                        }
+                                    }, onClick = {
+                                        lockSwiping = !lockSwiping
+                                        menuExpanded = false
+                                    })
+                                }
                             }
                         }
                     }
-                })
-        }) { paddingValues ->
-            val markdown by viewModel.markdown.collectAsState()
-            val (textFieldValue, setTextFieldValue) = remember(clearText) {
-                val annotatedMarkdown = if (enableReadability) {
-                    markdown.annotateReadability()
-                } else {
-                    AnnotatedString(markdown)
-                }
-                mutableStateOf(TextFieldValue(annotatedMarkdown))
-            }
-            val setTextFieldAndViewModelValues: (TextFieldValue) -> Unit = {
-                setTextFieldValue(it)
-                coroutineScope.launch {
-                    viewModel.updateMarkdown(it.text)
+                )
+            },
+            snackbarHost = {
+                SnackbarHost(
+                    modifier = Modifier.imePadding(),
+                    hostState = snackBarState
+                ) {
+                    Snackbar(it)
                 }
             }
+        ) { paddingValues ->
             if (enableWideLayout) {
-                Row(modifier = Modifier.fillMaxSize().padding(paddingValues)) {
-                    MarkdownTextField(modifier = Modifier.fillMaxHeight().weight(1f), textFieldValue, setTextFieldAndViewModelValues)
-                    Spacer(modifier = Modifier.fillMaxHeight().width(1.dp).background(color = MaterialTheme.colorScheme.primary))
-                    MarkdownPreview(modifier = Modifier.fillMaxHeight().weight(1f), markdown, darkMode)
+                Row(
+                    modifier = Modifier
+                        .fillMaxSize()
+                        .padding(paddingValues)
+                ) {
+                    MarkdownTextField(
+                        modifier = Modifier
+                            .fillMaxHeight()
+                            .weight(1f),
+                        markdown = markdown,
+                        setMarkdown = setMarkdown,
+                        enableReadability = enableReadability
+                    )
+                    Spacer(
+                        modifier = Modifier
+                            .fillMaxHeight()
+                            .width(1.dp)
+                            .background(color = MaterialTheme.colorScheme.primary)
+                    )
+                    MarkdownPreview(
+                        modifier = Modifier
+                            .fillMaxHeight()
+                            .weight(1f),
+                        markdown = markdown
+                    )
                 }
             } else {
                 Column(
@@ -257,12 +314,10 @@ fun MainScreen(
                         .padding(paddingValues)
                 ) {
                     TabbedMarkdownEditor(
-                        coroutineScope,
-                        lockSwiping,
-                        textFieldValue,
-                        setTextFieldAndViewModelValues,
-                        markdown,
-                        darkMode
+                        markdown = markdown,
+                        setMarkdown = setMarkdown,
+                        lockSwiping = lockSwiping,
+                        enableReadability = enableReadability
                     )
                 }
             }
@@ -273,13 +328,12 @@ fun MainScreen(
 @Composable
 @OptIn(ExperimentalFoundationApi::class)
 private fun TabbedMarkdownEditor(
-    coroutineScope: CoroutineScope,
-    lockSwiping: Boolean,
-    textFieldValue: TextFieldValue,
-    setTextFieldAndViewModelValues: (TextFieldValue) -> Unit,
     markdown: String,
-    darkMode: String
+    setMarkdown: (String) -> Unit,
+    lockSwiping: Boolean,
+    enableReadability: Boolean
 ) {
+    val coroutineScope = rememberCoroutineScope()
     val pagerState = rememberPagerState { 2 }
     TabRow(selectedTabIndex = pagerState.currentPage) {
         Tab(text = { Text("Edit") },
@@ -301,9 +355,14 @@ private fun TabbedMarkdownEditor(
             }
         }
         if (page == 0) {
-            MarkdownTextField(modifier = Modifier.fillMaxSize(), textFieldValue, setTextFieldAndViewModelValues)
+            MarkdownTextField(
+                modifier = Modifier.fillMaxSize(),
+                markdown = markdown,
+                setMarkdown = setMarkdown,
+                enableReadability = enableReadability
+            )
         } else {
-            MarkdownPreview(modifier = Modifier.fillMaxSize(), markdown, darkMode)
+            MarkdownPreview(modifier = Modifier.fillMaxSize(), markdown)
         }
     }
 }
@@ -371,7 +430,7 @@ fun MarkdownNavigationDrawer(
 @Composable
 fun MarkdownTopAppBar(
     title: String,
-    navController: NavController,
+    goBack: () -> Unit,
     backAsUp: Boolean = true,
     drawerState: DrawerState? = null,
     actions: (@Composable RowScope.() -> Unit)? = null
@@ -382,7 +441,7 @@ fun MarkdownTopAppBar(
     }, navigationIcon = {
         val (icon, contentDescription, onClick) = remember {
             if (backAsUp) {
-                Triple(Icons.Default.ArrowBack, "Go Back") { navController.popBackStack() }
+                Triple(Icons.AutoMirrored.Filled.ArrowBack, "Go Back", goBack)
             } else {
                 Triple(
                     Icons.Default.Menu, "Main Menu"
@@ -406,10 +465,26 @@ fun MarkdownTopAppBar(
 @Composable
 fun MarkdownTextField(
     modifier: Modifier,
-    textFieldValue: TextFieldValue,
-    setTextFieldValue: (TextFieldValue) -> Unit,
+    markdown: String,
+    setMarkdown: (String) -> Unit,
     enableReadability: Boolean = false
 ) {
+    val (selection, setSelection) = remember { mutableStateOf(TextRange.Zero) }
+    val (composition, setComposition) = remember { mutableStateOf<TextRange?>(null) }
+    val textFieldValue = remember(markdown) {
+        val annotatedMarkdown = if (enableReadability) {
+            markdown.annotateReadability()
+        } else {
+            AnnotatedString(markdown)
+        }
+        TextFieldValue(annotatedMarkdown, selection, composition)
+    }
+    val setTextFieldAndViewModelValues: (TextFieldValue) -> Unit = {
+        setSelection(it.selection)
+        setComposition(it.composition)
+        setMarkdown(it.text)
+    }
+
     TextField(
         modifier = modifier.imePadding(),
         colors = TextFieldDefaults.colors(
@@ -421,15 +496,7 @@ fun MarkdownTextField(
             unfocusedIndicatorColor = Color.Transparent
         ),
         value = textFieldValue,
-        onValueChange = {
-            setTextFieldValue(
-                if (enableReadability) {
-                    it.copy(annotatedString = it.text.annotateReadability())
-                } else {
-                    it
-                }
-            )
-        },
+        onValueChange = setTextFieldAndViewModelValues,
         placeholder = {
             Text("Markdown here…")
         },
@@ -440,3 +507,8 @@ fun MarkdownTextField(
         keyboardOptions = KeyboardOptions(capitalization = KeyboardCapitalization.Sentences)
     )
 }
+
+@Composable
+fun <P> MarkdownViewModel.collectAsState(prop: KProperty1<EditorState, P>, initial: P): State<P> =
+    state.map { prop.get(it) }
+        .collectAsState(initial)

app/src/main/java/com/wbrawner/simplemarkdown/ui/MarkdownInfoScreen.kt

@@ -22,7 +22,7 @@ fun MarkdownInfoScreen(
         topBar = {
             MarkdownTopAppBar(
                 title = title,
-                navController = navController,
+                goBack = { navController.popBackStack() },
             )
         }
     ) { paddingValues ->
@@ -35,8 +35,7 @@ fun MarkdownInfoScreen(
             modifier = Modifier
                 .fillMaxSize()
                 .padding(paddingValues),
-            markdown = markdown,
-            "Auto"
+            markdown = markdown
         )
     }
 }

app/src/main/java/com/wbrawner/simplemarkdown/ui/MarkdownPreview.kt

@@ -3,6 +3,7 @@ package com.wbrawner.simplemarkdown.ui
 import android.content.Context
 import android.view.ViewGroup
 import android.webkit.WebView
+import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
@@ -24,9 +25,9 @@ private const val container = "<main id=\"content\"></main>"
 
 @OptIn(ExperimentalStdlibApi::class)
 @Composable
-fun MarkdownPreview(modifier: Modifier = Modifier, markdown: String, darkMode: String) {
+fun MarkdownPreview(modifier: Modifier = Modifier, markdown: String) {
     val materialColors = MaterialTheme.colorScheme
-    val style = remember(darkMode) {
+    val style = remember(isSystemInDarkTheme()) {
         """body {
             |   background: #${materialColors.surface.toArgb().toHexString().substring(2)};
             |   color: #${materialColors.onSurface.toArgb().toHexString().substring(2)};

app/src/main/java/com/wbrawner/simplemarkdown/ui/SettingsScreen.kt

@@ -35,7 +35,7 @@ import com.wbrawner.simplemarkdown.utility.PreferenceHelper
 @Composable
 fun SettingsScreen(navController: NavController, preferenceHelper: PreferenceHelper) {
     Scaffold(topBar = {
-        MarkdownTopAppBar(title = "Settings", navController = navController)
+        MarkdownTopAppBar(title = "Settings", goBack = { navController.popBackStack() })
     }) { paddingValues ->
         Column(
             modifier = Modifier

app/src/main/java/com/wbrawner/simplemarkdown/ui/SupportScreen.kt

@@ -37,7 +37,7 @@ import com.wbrawner.simplemarkdown.utility.SupportLinks
 @Composable
 fun SupportScreen(navController: NavController) {
     Scaffold(topBar = {
-        MarkdownTopAppBar(title = "Support SimpleMarkdown", navController = navController)
+        MarkdownTopAppBar(title = "Support SimpleMarkdown", goBack = { navController.popBackStack() })
     }) { paddingValues ->
         val context = LocalContext.current
         Column(

app/src/main/java/com/wbrawner/simplemarkdown/utility/FileHelper.kt

@@ -2,6 +2,8 @@ package com.wbrawner.simplemarkdown.utility
 
 import android.content.Context
 import android.content.Intent
+import android.os.Environment
+import android.provider.MediaStore
 import androidx.core.net.toUri
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
@@ -32,14 +34,21 @@ interface FileHelper {
 }
 
 class AndroidFileHelper(private val context: Context) : FileHelper {
-    override val defaultDirectory: File = context.filesDir
+    override val defaultDirectory: File = context.getExternalFilesDir(Environment.DIRECTORY_DOCUMENTS)
+        ?: context.filesDir
 
     override suspend fun open(source: URI): Pair<String, String>? = withContext(Dispatchers.IO) {
         val uri = source.toString().toUri()
-        context.contentResolver.takePersistableUriPermission(
-            uri,
-            Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_GRANT_WRITE_URI_PERMISSION
-        )
+        try {
+            context.contentResolver.takePersistableUriPermission(
+                uri,
+                Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_GRANT_WRITE_URI_PERMISSION
+            )
+        } catch (e: SecurityException) {
+            // We weren't granted the persistent read/write permission for this file.
+            // TODO: Return whether or not we got the persistent permission in order to determine
+            //      whether or not we should show this file in the recent files section
+        }
         context.contentResolver.openFileDescriptor(uri, "r")
             ?.use {
                 uri.getName(context) to FileInputStream(it.fileDescriptor).reader()

app/src/test/java/com/wbrawner/simplemarkdown/FakeFileHelper.kt

@@ -1,29 +1,39 @@
 package com.wbrawner.simplemarkdown
 
 import com.wbrawner.simplemarkdown.utility.FileHelper
+import kotlinx.coroutines.delay
 import java.io.File
 import java.net.URI
 
 class FakeFileHelper : FileHelper {
-    override val defaultDirectory: File
-        get() = File.createTempFile("sm", null)
+    override val defaultDirectory: File by lazy {
+        File.createTempFile("simplemarkdown", null)
             .apply {
                 delete()
                 mkdir()
             }
+    }
 
     var file: Pair<String, String> = "Untitled.md" to "This is a test file"
     var openedUris = ArrayDeque<URI>()
     var savedData = ArrayDeque<SavedData>()
+    @Volatile
+    var errorOnOpen: Boolean = false
+    @Volatile
+    var errorOnSave: Boolean = false
 
     override suspend fun open(source: URI): Pair<String, String> {
+        delay(1000)
+        if (errorOnOpen) error("errorOnOpen set to true")
         openedUris.addLast(source)
         return file
     }
 
     override suspend fun save(destination: URI, content: String): String {
+        delay(1000)
+        if (errorOnSave) error("errorOnSave set to true")
         savedData.addLast(SavedData(destination, content))
-        return file.first
+        return destination.path.substringAfterLast("/")
     }
 }
 

app/src/test/java/com/wbrawner/simplemarkdown/FakePreferenceHelper.kt

@@ -6,7 +6,7 @@ import kotlinx.coroutines.flow.StateFlow
 
 class FakePreferenceHelper: PreferenceHelper {
     val preferences = mutableMapOf<Preference, Any?>()
-    override fun get(preference: Preference): Any? = preferences[preference]
+    override fun get(preference: Preference): Any? = preferences[preference]?: preference.default
 
     override fun set(preference: Preference, value: Any?) {
         preferences[preference] = value

app/src/test/java/com/wbrawner/simplemarkdown/MarkdownViewModelTest.kt

@@ -1,56 +1,296 @@
 package com.wbrawner.simplemarkdown
 
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewmodel.CreationExtras
 import com.wbrawner.simplemarkdown.utility.Preference
-import kotlinx.coroutines.runBlocking
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.test.StandardTestDispatcher
+import kotlinx.coroutines.test.TestResult
+import kotlinx.coroutines.test.TestScope
+import kotlinx.coroutines.test.advanceTimeBy
+import kotlinx.coroutines.test.advanceUntilIdle
+import kotlinx.coroutines.test.runCurrent
+import kotlinx.coroutines.test.runTest
+import kotlinx.coroutines.test.setMain
 import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertNull
 import org.junit.Assert.assertTrue
 import org.junit.Before
 import org.junit.Test
+import timber.log.Timber
+import java.io.File
 import java.net.URI
+import java.util.Deque
+import java.util.concurrent.ConcurrentLinkedDeque
 
 class MarkdownViewModelTest {
     private lateinit var fileHelper: FakeFileHelper
     private lateinit var preferenceHelper: FakePreferenceHelper
+    private lateinit var viewModelFactory: ViewModelProvider.Factory
     private lateinit var viewModel: MarkdownViewModel
+    private lateinit var viewModelScope: TestScope
 
+    @OptIn(ExperimentalCoroutinesApi::class)
     @Before
     fun setup() {
+        Timber.plant(object: Timber.Tree() {
+            override fun log(priority: Int, tag: String?, message: String, t: Throwable?) {
+                println("$tag/$priority: $message")
+                t?.printStackTrace()
+            }
+        })
+        val scheduler = StandardTestDispatcher()
+        Dispatchers.setMain(scheduler)
+        viewModelScope = TestScope(scheduler)
         fileHelper = FakeFileHelper()
         preferenceHelper = FakePreferenceHelper()
-        viewModel = MarkdownViewModel(fileHelper, preferenceHelper)
+        viewModelFactory = MarkdownViewModel.factory(fileHelper, preferenceHelper)
+        viewModel = viewModelFactory.create(MarkdownViewModel::class.java, CreationExtras.Empty)
+        viewModelScope.advanceUntilIdle()
     }
 
     @Test
-    fun testMarkdownUpdate() = runBlocking {
-        assertEquals("", viewModel.markdown.value)
+    fun testMarkdownUpdate() = runTest {
+        assertEquals("", viewModel.state.value.markdown)
         viewModel.updateMarkdown("Updated content")
-        assertEquals("Updated content", viewModel.markdown.value)
+        assertEquals("Updated content", viewModel.state.value.markdown)
     }
 
     @Test
-    fun testLoadWithNoPathAndNoAutosaveUri() = runBlocking {
+    fun testLoadWithNoPathAndNoAutosaveUri() = runTest {
         viewModel.load(null)
         assertTrue(fileHelper.openedUris.isEmpty())
     }
 
     @Test
-    fun testLoadWithNoPathAndAutosaveUri() = runBlocking {
+    fun testAutoLoad() = runTest {
         val uri = URI.create("file:///home/user/Untitled.md")
         preferenceHelper[Preference.AUTOSAVE_URI] = uri.toString()
-        viewModel.load(null)
+        viewModel = viewModelFactory.create(MarkdownViewModel::class.java, CreationExtras.Empty)
+        viewModelScope.advanceUntilIdle()
         assertEquals(uri, fileHelper.openedUris.firstOrNull())
         val (fileName, contents) = fileHelper.file
-        assertEquals(fileName, viewModel.fileName.value)
-        assertEquals(contents, viewModel.markdown.value)
+        assertEquals(fileName, viewModel.state.value.fileName)
+        assertEquals(contents, viewModel.state.value.markdown)
     }
 
     @Test
-    fun testLoadWithPath() = runBlocking {
+    fun testLoadWithPath() = runTest {
         val uri = URI.create("file:///home/user/Untitled.md")
         viewModel.load(uri.toString())
         assertEquals(uri, fileHelper.openedUris.firstOrNull())
         val (fileName, contents) = fileHelper.file
-        assertEquals(fileName, viewModel.fileName.value)
-        assertEquals(contents, viewModel.markdown.value)
+        assertEquals(fileName, viewModel.state.value.fileName)
+        assertEquals(contents, viewModel.state.value.markdown)
+    }
+
+    @Test
+    fun testLoadWithEmptyPath() = runTest {
+        preferenceHelper[Preference.AUTOSAVE_URI] = ""
+        viewModel.load("")
+        assertEquals(null, preferenceHelper[Preference.AUTOSAVE_URI])
+        assertTrue(fileHelper.openedUris.isEmpty())
+    }
+
+    @Test
+    fun testLoadWithInvalidUri() = runTest {
+        viewModel.load(":/:/")
+    }
+
+    @Test
+    fun testLoadWithError() = runTest {
+        fileHelper.errorOnOpen = true
+        val uri = URI.create("file:///home/user/Untitled.md")
+        viewModel.load(uri.toString())
+        assertNotNull(viewModel.state.value.alert)
+    }
+
+    @Test
+    fun testSaveWithNullPath() = runTest {
+        assertFalse(viewModel.save(null, false))
+        assertNull(viewModel.state.value.alert)
+        assertNull(viewModel.state.value.saveCallback)
+    }
+
+    @Test
+    fun testSaveWithNullPathAndPrompt() = runTest {
+        assertFalse(viewModel.save(null, true))
+        assertNotNull(viewModel.state.value.saveCallback)
+        viewModel.state.value.saveCallback!!.invoke()
+        assertNull(viewModel.state.value.saveCallback)
+    }
+
+    @Test
+    fun testSaveWithValidPath() = runTest {
+        val uri = URI.create("file:///home/user/Saved.md")
+        val testMarkdown = "# Test"
+        viewModel.updateMarkdown(testMarkdown)
+        assertEquals(testMarkdown, viewModel.state.value.markdown)
+        assertTrue(viewModel.save(uri))
+        assertEquals("Saved.md", viewModel.state.value.fileName)
+        assertEquals(uri, fileHelper.savedData.last().uri)
+        assertEquals(testMarkdown, fileHelper.savedData.last().content)
+        assertEquals(uri, preferenceHelper[Preference.AUTOSAVE_URI])
+    }
+
+    @Test
+    fun testSaveWithException() = runTest {
+        val uri = URI.create("file:///home/user/Untitled.md")
+        val testMarkdown = "# Test"
+        viewModel.updateMarkdown(testMarkdown)
+        assertEquals(testMarkdown, viewModel.state.value.markdown)
+        fileHelper.errorOnSave = true
+        assertNull(viewModel.state.value.alert)
+        assertFalse(viewModel.save(uri))
+        assertNotNull(viewModel.state.value.alert)
+        requireNotNull(viewModel.state.value.alert?.confirmButton?.onClick).invoke()
+        assertNull(viewModel.state.value.alert)
+    }
+
+    @Test
+    fun testResetWithSavedChanges() = runTest {
+        viewModel.updateMarkdown("# Test")
+        val uri = URI.create("file:///home/user/Saved.md")
+        assertTrue(viewModel.save(uri))
+        assertFalse(viewModel.state.value.dirty)
+        assertNull(viewModel.state.value.alert)
+        viewModel.reset("New.md")
+        assertNull(viewModel.state.value.alert)
+        with(viewModel.state.value) {
+            assertEquals("New.md", fileName)
+            assertEquals("", markdown)
+            assertNull(path)
+            assertNull(saveCallback)
+            assertNull(alert)
+            assertFalse(dirty)
+        }
+    }
+
+    @Test
+    fun testResetWithUnsavedChanges() = runTest {
+        viewModel.updateMarkdown("# Test")
+        assertTrue(viewModel.state.value.dirty)
+        assertNull(viewModel.state.value.alert)
+        viewModel.reset("Untitled.md")
+        with(viewModel.state.value.alert) {
+            assertNotNull(this)
+            requireNotNull(this)
+            val onClick = dismissButton?.onClick
+            assertNotNull(onClick)
+            requireNotNull(onClick)
+            onClick.invoke()
+        }
+        assertEquals(viewModel.state.value, EditorState())
+    }
+
+    @Test
+    fun testResetWithUnsavedChangesAndPrompt() = runTest {
+        viewModel.updateMarkdown("# Test")
+        assertTrue(viewModel.state.value.dirty)
+        assertNull(viewModel.state.value.alert)
+        viewModel.reset("Untitled.md")
+        assertNull(viewModel.state.value.saveCallback)
+        with(viewModel.state.value.alert) {
+            assertNotNull(this)
+            requireNotNull(this)
+            confirmButton.onClick.invoke()
+        }
+        val uri = URI.create("file:///home/user/Saved.md")
+        viewModel.save(uri)
+        assertNotNull(viewModel.state.value.saveCallback)
+        requireNotNull(viewModel.state.value.saveCallback).invoke()
+        assertEquals(viewModel.state.value, EditorState())
+    }
+
+    @Test
+    fun testForceResetWithUnsavedChanges() = runTest {
+        viewModel.updateMarkdown("# Test")
+        assertTrue(viewModel.state.value.dirty)
+        val uri = URI.create("file:///home/user/Saved.md")
+        assertTrue(viewModel.save(uri))
+        assertFalse(viewModel.state.value.dirty)
+        viewModel.updateMarkdown("# Test\n\nDirty changes")
+        assertTrue(viewModel.state.value.dirty)
+        assertNull(viewModel.state.value.alert)
+        viewModel.reset("Unsaved.md", true)
+        assertNull(viewModel.state.value.alert)
+        with(viewModel.state.value) {
+            assertEquals("Unsaved.md", fileName)
+            assertEquals("", markdown)
+            assertNull(path)
+            assertNull(saveCallback)
+            assertNull(alert)
+            assertFalse(dirty)
+        }
+        assertNull(preferenceHelper[Preference.AUTOSAVE_URI])
+    }
+
+    @Test
+    fun testAutosaveWithPreferenceDisabled() = runTest {
+        preferenceHelper[Preference.AUTOSAVE_ENABLED] = false
+        viewModel.updateMarkdown("# Test")
+        assertTrue(viewModel.state.value.dirty)
+        viewModel.autosave()
+        assertEquals(0, fileHelper.savedData.count())
+    }
+
+    @Test
+    fun testAutosaveWithNoNewData() = runTest {
+        viewModel.updateMarkdown("# Test")
+        val uri = URI.create("file:///home/user/Saved.md")
+        assertTrue(viewModel.save(uri))
+        assertEquals(1, fileHelper.savedData.count())
+        assertFalse(viewModel.state.value.dirty)
+        viewModel.autosave()
+        assertEquals(1, fileHelper.savedData.count())
+    }
+
+    @Test
+    fun testAutosaveWithSaveInProgress() = runTest {
+        viewModel.updateMarkdown("# Test")
+        val uri = URI.create("file:///home/user/Saved.md")
+        val coroutineScope = TestScope(StandardTestDispatcher())
+        coroutineScope.launch {
+            assertTrue(viewModel.save(uri))
+        }
+        coroutineScope.advanceTimeBy(500)
+        assertEquals(0, fileHelper.savedData.count())
+        assertTrue(viewModel.state.value.dirty)
+        viewModel.autosave()
+        assertEquals(0, fileHelper.savedData.count())
+        coroutineScope.advanceTimeBy(1000)
+        assertEquals(1, fileHelper.savedData.count())
+    }
+
+    @Test
+    fun testAutosaveWithUnknownUri() = runTest {
+        viewModel.updateMarkdown("# Test")
+        assertTrue(viewModel.state.value.dirty)
+        viewModel.autosave()
+        assertTrue(viewModel.state.value.dirty)
+        assertEquals(1, fileHelper.savedData.count())
+        assertEquals(
+            File(fileHelper.defaultDirectory, "Untitled.md").toURI(),
+            fileHelper.savedData.first().uri
+        )
+    }
+
+    @Test
+    fun testAutosaveWithKnownUri() = runTest {
+        viewModel.updateMarkdown("# Test")
+        assertTrue(viewModel.state.value.dirty)
+        val uri = URI.create("file:///home/user/Saved.md")
+        assertTrue(viewModel.save(uri))
+        assertEquals(1, fileHelper.savedData.count())
+        assertFalse(viewModel.state.value.dirty)
+        viewModel.updateMarkdown("# Test\n\nDirty changes")
+        assertTrue(viewModel.state.value.dirty)
+        viewModel.autosave()
+        assertEquals(2, fileHelper.savedData.count())
     }
 }