From 0e7cdfa2b5e7707a814e302228a82f4ae8587c5b Mon Sep 17 00:00:00 2001
From: William Brawner <me@wbrawner.com>
Date: Mon, 5 Oct 2020 20:43:56 -0700
Subject: [PATCH] Fix an issue with deleting changes upon device rotation

---
 .../simplemarkdown/utility/ErrorHandler.kt     |  1 +
 .../view/fragment/EditFragment.kt              |  9 ++++++---
 .../view/fragment/MainFragment.kt              |  2 +-
 .../viewmodel/MarkdownViewModel.kt             | 18 +++++++++++++++---
 4 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/app/src/free/java/com/wbrawner/simplemarkdown/utility/ErrorHandler.kt b/app/src/free/java/com/wbrawner/simplemarkdown/utility/ErrorHandler.kt
index 7bc5eda..3894dec 100644
--- a/app/src/free/java/com/wbrawner/simplemarkdown/utility/ErrorHandler.kt
+++ b/app/src/free/java/com/wbrawner/simplemarkdown/utility/ErrorHandler.kt
@@ -1,5 +1,6 @@
 package com.wbrawner.simplemarkdown.utility
 
+import android.util.Log
 import kotlin.reflect.KProperty
 
 class errorHandlerImpl {
diff --git a/app/src/main/java/com/wbrawner/simplemarkdown/view/fragment/EditFragment.kt b/app/src/main/java/com/wbrawner/simplemarkdown/view/fragment/EditFragment.kt
index b0ce8f3..c5ac0b4 100644
--- a/app/src/main/java/com/wbrawner/simplemarkdown/view/fragment/EditFragment.kt
+++ b/app/src/main/java/com/wbrawner/simplemarkdown/view/fragment/EditFragment.kt
@@ -95,15 +95,18 @@ class EditFragment : Fragment(), ViewPagerPage, CoroutineScope {
             false
         }
         markdownEditor?.setText(viewModel.markdownUpdates.value)
-        viewModel.originalMarkdown.observe(viewLifecycleOwner, Observer {
-            markdownEditor?.setText(it)
+        viewModel.editorActions.observe(viewLifecycleOwner, Observer {
+            if (it.consumed.getAndSet(true)) return@Observer
+            if (it is MarkdownViewModel.EditorAction.Load) {
+                markdownEditor?.setText(it.markdown)
+            }
         })
         launch {
             val enableReadability = withContext(Dispatchers.IO) {
                 context?.let {
                     PreferenceManager.getDefaultSharedPreferences(it)
                             .getBoolean(getString(R.string.readability_enabled), false)
-                }?: false
+                } ?: false
             }
             if (enableReadability) {
                 if (readabilityWatcher == null) {
diff --git a/app/src/main/java/com/wbrawner/simplemarkdown/view/fragment/MainFragment.kt b/app/src/main/java/com/wbrawner/simplemarkdown/view/fragment/MainFragment.kt
index 6665b61..ed21617 100644
--- a/app/src/main/java/com/wbrawner/simplemarkdown/view/fragment/MainFragment.kt
+++ b/app/src/main/java/com/wbrawner/simplemarkdown/view/fragment/MainFragment.kt
@@ -252,7 +252,7 @@ class MainFragment : Fragment(), ActivityCompat.OnRequestPermissionsResultCallba
     }
 
     private fun promptSaveOrDiscardChanges() {
-        if (viewModel.originalMarkdown.value == viewModel.markdownUpdates.value) {
+        if (viewModel.shouldPromptSave()) {
             viewModel.reset("Untitled.md")
             PreferenceManager.getDefaultSharedPreferences(requireContext()).edit {
                 remove(getString(R.string.pref_key_autosave_uri))
diff --git a/app/src/main/java/com/wbrawner/simplemarkdown/viewmodel/MarkdownViewModel.kt b/app/src/main/java/com/wbrawner/simplemarkdown/viewmodel/MarkdownViewModel.kt
index f1a2d6c..f90aad0 100644
--- a/app/src/main/java/com/wbrawner/simplemarkdown/viewmodel/MarkdownViewModel.kt
+++ b/app/src/main/java/com/wbrawner/simplemarkdown/viewmodel/MarkdownViewModel.kt
@@ -9,15 +9,18 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 import java.io.FileInputStream
 import java.io.Reader
+import java.util.concurrent.atomic.AtomicBoolean
 
 class MarkdownViewModel : ViewModel() {
     val fileName = MutableLiveData<String>("Untitled.md")
     val markdownUpdates = MutableLiveData<String>()
-    val originalMarkdown = MutableLiveData<String>()
+    val editorActions = MutableLiveData<EditorAction>()
     val uri = MutableLiveData<Uri>()
+    private val isDirty = AtomicBoolean(false)
 
     fun updateMarkdown(markdown: String?) {
         this.markdownUpdates.postValue(markdown ?: "")
+        isDirty.set(true)
     }
 
     suspend fun load(context: Context, uri: Uri?): Boolean {
@@ -32,7 +35,8 @@ class MarkdownViewModel : ViewModel() {
                         // If we don't get anything back, then we can assume that reading the file failed
                         return@withContext false
                     }
-                    originalMarkdown.postValue(content)
+                    isDirty.set(false)
+                    editorActions.postValue(EditorAction.Load(content))
                     markdownUpdates.postValue(content)
                     this@MarkdownViewModel.fileName.postValue(fileName)
                     this@MarkdownViewModel.uri.postValue(uri)
@@ -66,7 +70,15 @@ class MarkdownViewModel : ViewModel() {
 
     fun reset(untitledFileName: String) {
         fileName.postValue(untitledFileName)
-        originalMarkdown.postValue("")
         markdownUpdates.postValue("")
+        isDirty.set(false)
+    }
+
+    fun shouldPromptSave() = isDirty.get()
+
+    sealed class EditorAction {
+        val consumed = AtomicBoolean(false)
+
+        data class Load(val markdown: String) : EditorAction()
     }
 }