Fix saving changes to statuses when editing (#3103)

* Fix saving changes to statuses when editing

With the previous code backing out of a status editing operation where changes
had been made  (whether it was editing an existing status, a scheduled status,
or a draft) would prompt the user to save the changes as a new draft.

See https://github.com/tuskyapp/Tusky/issues/2704 and
https://github.com/tuskyapp/Tusky/issues/2705 for more detail.

The fix:

- Create an enum to represent the four different kinds of edits that can
  happen
  - Editing a new status (i.e., composing it for the first time)
  - Editing a posted status
  - Editing a draft
  - Editing a scheduled status

- Store this in ComposeOptions, and set it appropriately everywhere
  ComposeOptions is created.

- Check the edit kind when backing out of ComposeActivity, and use this to
  show one of three different dialogs as appropriate so the user can:
  - Save as new draft or discard changes
  - Continue editing or discard changes
  - Update existing draft or discard changes

Also fix ComposeViewModel.didChange(), which erroneously reported false if the
old text started with the new text (e.g., if the old text was "hello, world"
and it was edited to "hello", didChange() would not consider that to be a
change).

Fixes https://github.com/tuskyapp/Tusky/issues/2704,
https://github.com/tuskyapp/Tusky/issues/2705

* Use orEmpty extension function

app/src/main/java/com/keylesspalace/tusky/components/account/AccountActivity.kt

@@ -811,9 +811,12 @@ class AccountActivity : BottomSheetActivity(), ActionButtonActivity, HasAndroidI
     private fun mention() {
         loadedAccount?.let {
             val options = if (viewModel.isSelf) {
-                ComposeActivity.ComposeOptions()
+                ComposeActivity.ComposeOptions(kind = ComposeActivity.ComposeKind.NEW)
             } else {
-                ComposeActivity.ComposeOptions(mentionedUsernames = setOf(it.username))
+                ComposeActivity.ComposeOptions(
+                    mentionedUsernames = setOf(it.username),
+                    kind = ComposeActivity.ComposeKind.NEW
+                )
             }
             val intent = ComposeActivity.startIntent(this, options)
             startActivity(intent)

app/src/main/java/com/keylesspalace/tusky/components/compose/ComposeActivity.kt

@@ -1115,30 +1115,79 @@ class ComposeActivity :
         val contentText = binding.composeEditField.text.toString()
         val contentWarning = binding.composeContentWarningField.text.toString()
         if (viewModel.didChange(contentText, contentWarning)) {
-
-            val warning = if (!viewModel.media.value.isEmpty()) {
-                R.string.compose_save_draft_loses_media
-            } else {
-                R.string.compose_save_draft
-            }
-
-            AlertDialog.Builder(this)
-                .setMessage(warning)
-                .setPositiveButton(R.string.action_save) { _, _ ->
-                    viewModel.stopUploads()
-                    saveDraftAndFinish(contentText, contentWarning)
-                }
-                .setNegativeButton(R.string.action_delete) { _, _ ->
-                    viewModel.stopUploads()
-                    deleteDraftAndFinish()
-                }
-                .show()
+            when (viewModel.composeKind) {
+                ComposeKind.NEW -> getSaveAsDraftOrDiscardDialog(contentText, contentWarning)
+                ComposeKind.EDIT_DRAFT -> getUpdateDraftOrDiscardDialog(contentText, contentWarning)
+                ComposeKind.EDIT_POSTED -> getContinueEditingOrDiscardDialog()
+                ComposeKind.EDIT_SCHEDULED -> getContinueEditingOrDiscardDialog()
+            }.show()
         } else {
             viewModel.stopUploads()
             finishWithoutSlideOutAnimation()
         }
     }
 
+    /**
+     * User is editing a new post, and can either save the changes as a draft or discard them.
+     */
+    private fun getSaveAsDraftOrDiscardDialog(contentText: String, contentWarning: String): AlertDialog.Builder {
+        val warning = if (viewModel.media.value.isNotEmpty()) {
+            R.string.compose_save_draft_loses_media
+        } else {
+            R.string.compose_save_draft
+        }
+
+        return AlertDialog.Builder(this)
+            .setMessage(warning)
+            .setPositiveButton(R.string.action_save) { _, _ ->
+                viewModel.stopUploads()
+                saveDraftAndFinish(contentText, contentWarning)
+            }
+            .setNegativeButton(R.string.action_delete) { _, _ ->
+                viewModel.stopUploads()
+                deleteDraftAndFinish()
+            }
+    }
+
+    /**
+     * User is editing an existing draft, and can either update the draft with the new changes or
+     * discard them.
+     */
+    private fun getUpdateDraftOrDiscardDialog(contentText: String, contentWarning: String): AlertDialog.Builder {
+        val warning = if (viewModel.media.value.isNotEmpty()) {
+            R.string.compose_save_draft_loses_media
+        } else {
+            R.string.compose_save_draft
+        }
+
+        return AlertDialog.Builder(this)
+            .setMessage(warning)
+            .setPositiveButton(R.string.action_save) { _, _ ->
+                viewModel.stopUploads()
+                saveDraftAndFinish(contentText, contentWarning)
+            }
+            .setNegativeButton(R.string.action_discard) { _, _ ->
+                viewModel.stopUploads()
+                finishWithoutSlideOutAnimation()
+            }
+    }
+
+    /**
+     * User is editing a post (scheduled, or posted), and can either go back to editing, or
+     * discard the changes.
+     */
+    private fun getContinueEditingOrDiscardDialog(): AlertDialog.Builder {
+        return AlertDialog.Builder(this)
+            .setMessage(R.string.compose_unsaved_changes)
+            .setPositiveButton(R.string.action_continue_edit) { _, _ ->
+                // Do nothing, dialog will dismiss, user can continue editing
+            }
+            .setNegativeButton(R.string.action_discard) { _, _ ->
+                viewModel.stopUploads()
+                finishWithoutSlideOutAnimation()
+            }
+    }
+
     private fun deleteDraftAndFinish() {
         viewModel.deleteDraft()
         finishWithoutSlideOutAnimation()
@@ -1217,6 +1266,24 @@ class ComposeActivity :
         }
     }
 
+    /**
+     * Status' kind. This particularly affects how the status is handled if the user
+     * backs out of the edit.
+     */
+    enum class ComposeKind {
+        /** Status is new */
+        NEW,
+
+        /** Editing a posted status */
+        EDIT_POSTED,
+
+        /** Editing a status started as an existing draft */
+        EDIT_DRAFT,
+
+        /** Editing an an existing scheduled status */
+        EDIT_SCHEDULED
+    }
+
     @Parcelize
     data class ComposeOptions(
         // Let's keep fields var until all consumers are Kotlin
@@ -1240,6 +1307,7 @@ class ComposeActivity :
         var modifiedInitialState: Boolean? = null,
         var language: String? = null,
         var statusId: String? = null,
+        var kind: ComposeKind? = null
     ) : Parcelable
 
     companion object {

app/src/main/java/com/keylesspalace/tusky/components/compose/ComposeViewModel.kt

@@ -95,6 +95,8 @@ class ComposeViewModel @Inject constructor(
     val media: MutableStateFlow<List<QueuedMedia>> = MutableStateFlow(emptyList())
     val uploadError = MutableSharedFlow<Throwable>(replay = 0, extraBufferCapacity = 1, onBufferOverflow = BufferOverflow.DROP_OLDEST)
 
+    lateinit var composeKind: ComposeActivity.ComposeKind
+
     // Used in ComposeActivity to pass state to result function when cropImage contract inflight
     var cropImageItemOld: QueuedMedia? = null
 
@@ -213,15 +215,8 @@ class ComposeViewModel @Inject constructor(
     }
 
     fun didChange(content: String?, contentWarning: String?): Boolean {
-
-        val textChanged = !(
-            content.isNullOrEmpty() ||
-                startingText?.startsWith(content.toString()) ?: false
-            )
-
-        val contentWarningChanged = showContentWarning.value &&
-            !contentWarning.isNullOrEmpty() &&
-            !startingContentWarning.startsWith(contentWarning.toString())
+        val textChanged = content.orEmpty() != startingText.orEmpty()
+        val contentWarningChanged = contentWarning.orEmpty() != startingContentWarning
         val mediaChanged = media.value.isNotEmpty()
         val pollChanged = poll.value != null
         val didScheduledTimeChange = hasScheduledTimeChanged
@@ -411,6 +406,8 @@ class ComposeViewModel @Inject constructor(
             return
         }
 
+        composeKind = composeOptions?.kind ?: ComposeActivity.ComposeKind.NEW
+
         val preferredVisibility = accountManager.activeAccount!!.defaultPostPrivacy
 
         val replyVisibility = composeOptions?.replyVisibility ?: Status.Visibility.UNKNOWN

app/src/main/java/com/keylesspalace/tusky/components/drafts/DraftsActivity.kt

@@ -112,6 +112,7 @@ class DraftsActivity : BaseActivity(), DraftActionListener {
                             scheduledAt = draft.scheduledAt,
                             language = draft.language,
                             statusId = draft.statusId,
+                            kind = ComposeActivity.ComposeKind.EDIT_DRAFT
                         )
 
                         bottomSheet.state = BottomSheetBehavior.STATE_HIDDEN
@@ -149,6 +150,7 @@ class DraftsActivity : BaseActivity(), DraftActionListener {
             scheduledAt = draft.scheduledAt,
             language = draft.language,
             statusId = draft.statusId,
+            kind = ComposeActivity.ComposeKind.EDIT_DRAFT
         )
 
         startActivity(ComposeActivity.startIntent(this, composeOptions))

app/src/main/java/com/keylesspalace/tusky/components/notifications/NotificationHelper.java

@@ -371,6 +371,7 @@ public class NotificationHelper {
         composeOptions.setMentionedUsernames(mentionedUsernames);
         composeOptions.setModifiedInitialState(true);
         composeOptions.setLanguage(actionableStatus.getLanguage());
+        composeOptions.setKind(ComposeActivity.ComposeKind.NEW);
 
         Intent composeIntent = ComposeActivity.startIntent(
                 context,

app/src/main/java/com/keylesspalace/tusky/components/scheduled/ScheduledStatusActivity.kt

@@ -128,7 +128,8 @@ class ScheduledStatusActivity : BaseActivity(), ScheduledStatusActionListener, I
                 inReplyToId = item.params.inReplyToId,
                 visibility = item.params.visibility,
                 scheduledAt = item.scheduledAt,
-                sensitive = item.params.sensitive
+                sensitive = item.params.sensitive,
+                kind = ComposeActivity.ComposeKind.EDIT_SCHEDULED
             )
         )
         startActivity(intent)

app/src/main/java/com/keylesspalace/tusky/components/search/fragments/SearchStatusesFragment.kt

@@ -223,6 +223,7 @@ class SearchStatusesFragment : SearchFragment<StatusViewData.Concrete>(), Status
                 replyingStatusAuthor = actionableStatus.account.localUsername,
                 replyingStatusContent = status.content.toString(),
                 language = actionableStatus.language,
+                kind = ComposeActivity.ComposeKind.NEW
             )
         )
         bottomSheetActivity?.startActivityWithSlideInAnimation(intent)
@@ -481,6 +482,7 @@ class SearchStatusesFragment : SearchFragment<StatusViewData.Concrete>(), Status
                                         sensitive = redraftStatus.sensitive,
                                         poll = redraftStatus.poll?.toNewPoll(status.createdAt),
                                         language = redraftStatus.language,
+                                        kind = ComposeActivity.ComposeKind.NEW
                                     )
                                 )
                                 startActivity(intent)
@@ -510,6 +512,7 @@ class SearchStatusesFragment : SearchFragment<StatusViewData.Concrete>(), Status
                         language = status.language,
                         statusId = source.id,
                         poll = status.poll?.toNewPoll(status.createdAt),
+                        kind = ComposeActivity.ComposeKind.EDIT_POSTED,
                     )
                     startActivity(ComposeActivity.startIntent(requireContext(), composeOptions))
                 },

app/src/main/java/com/keylesspalace/tusky/fragment/SFragment.kt

@@ -45,6 +45,7 @@ import com.keylesspalace.tusky.PostLookupFallbackBehavior
 import com.keylesspalace.tusky.R
 import com.keylesspalace.tusky.StatusListActivity.Companion.newHashtagIntent
 import com.keylesspalace.tusky.ViewMediaActivity.Companion.newIntent
+import com.keylesspalace.tusky.components.compose.ComposeActivity
 import com.keylesspalace.tusky.components.compose.ComposeActivity.Companion.startIntent
 import com.keylesspalace.tusky.components.compose.ComposeActivity.ComposeOptions
 import com.keylesspalace.tusky.components.report.ReportActivity.Companion.getIntent
@@ -135,6 +136,7 @@ abstract class SFragment : Fragment(), Injectable {
             replyingStatusAuthor = account.localUsername,
             replyingStatusContent = actionableStatus.content.parseAsMastodonHtml().toString(),
             language = actionableStatus.language,
+            kind = ComposeActivity.ComposeKind.NEW
         )
 
         val intent = startIntent(requireContext(), composeOptions)
@@ -411,6 +413,7 @@ abstract class SFragment : Fragment(), Injectable {
                                 modifiedInitialState = true,
                                 language = sourceStatus.language,
                                 poll = sourceStatus.poll?.toNewPoll(sourceStatus.createdAt),
+                                kind = ComposeActivity.ComposeKind.NEW
                             )
                             startActivity(startIntent(requireContext(), composeOptions))
                         }
@@ -437,6 +440,7 @@ abstract class SFragment : Fragment(), Injectable {
                         language = status.language,
                         statusId = source.id,
                         poll = status.poll?.toNewPoll(status.createdAt),
+                        kind = ComposeActivity.ComposeKind.EDIT_POSTED
                     )
                     startActivity(startIntent(requireContext(), composeOptions))
                 },

app/src/main/res/values/strings.xml

@@ -109,6 +109,8 @@
     <string name="action_delete">Delete</string>
     <string name="action_delete_conversation">Delete conversation</string>
     <string name="action_delete_and_redraft">Delete and re-draft</string>
+    <string name="action_discard">Discard changes</string>
+    <string name="action_continue_edit">Continue editing</string>
     <string name="action_send">TOOT</string>
     <string name="action_send_public">TOOT!</string>
     <string name="action_retry">Retry</string>
@@ -443,6 +445,7 @@
     <string name="lock_account_label_description">Requires you to manually approve followers</string>
     <string name="compose_save_draft">Save draft?</string>
     <string name="compose_save_draft_loses_media">Save draft? (Attachments will be uploaded again when you restore the draft.)</string>
+    <string name="compose_unsaved_changes">You have unsaved changes.</string>
     <string name="send_post_notification_title">Sending post…</string>
     <string name="send_post_notification_error_title">Error sending post</string>
     <string name="send_post_notification_channel_name">Sending Posts</string>