Keep the formatting of a caption that is being edited

Editing the caption of a media message dropped all of its formatting: bold,
links and the rest came back as plain text, and saving wrote that plain text
over the formatted caption.

The composer was being opened on the plain caption. Editing a message body
already starts from its HTML when rich text editing is on, and the caption
path was the only one that did not - it read `captionOrNull()` and never had
the caption's HTML to read, because the timeline content only kept the
already-parsed `formattedCaption`.

Media contents now carry the caption's HTML alongside the parsed one, the
same way text contents carry `htmlBody`, and editing a caption starts from it
when rich text editing is on. The save path already sent the composer's HTML,
so nothing changes there.

Part of #6730

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/MessagesPresenter.kt

@@ -51,6 +51,7 @@ import io.element.android.features.messages.impl.timeline.model.event.TimelineIt
 import io.element.android.features.messages.impl.timeline.model.event.TimelineItemStateContent
 import io.element.android.features.messages.impl.timeline.model.event.TimelineItemTextBasedContent
 import io.element.android.features.messages.impl.timeline.model.event.captionOrNull
+import io.element.android.features.messages.impl.timeline.model.event.htmlCaptionOrNull
 import io.element.android.features.messages.impl.timeline.protection.TimelineProtectionState
 import io.element.android.features.messages.impl.voicemessages.composer.DefaultVoiceMessageComposerPresenter
 import io.element.android.features.roomcall.api.RoomCallState
@@ -377,7 +378,7 @@ class MessagesPresenter(
             TimelineItemAction.Edit,
             TimelineItemAction.EditPoll -> handleActionEdit(targetEvent, composerState, enableTextFormatting)
             TimelineItemAction.AddCaption -> handleActionAddCaption(targetEvent, composerState)
-            TimelineItemAction.EditCaption -> handleActionEditCaption(targetEvent, composerState)
+            TimelineItemAction.EditCaption -> handleActionEditCaption(targetEvent, composerState, enableTextFormatting)
             TimelineItemAction.RemoveCaption -> handleRemoveCaption(targetEvent)
             TimelineItemAction.Reply -> handleActionReply(targetEvent, composerState, timelineProtectionState)
             TimelineItemAction.ReplyInThread -> {
@@ -546,10 +547,15 @@ class MessagesPresenter(
     private suspend fun handleActionEditCaption(
         targetEvent: TimelineItem.Event,
         composerState: MessageComposerState,
+        enableTextFormatting: Boolean,
     ) {
         val composerMode = MessageComposerMode.EditCaption(
             eventOrTransactionId = targetEvent.eventOrTransactionId,
-            content = targetEvent.content.captionOrNull().orEmpty(),
+            content = if (enableTextFormatting) {
+                targetEvent.content.htmlCaptionOrNull() ?: targetEvent.content.captionOrNull()
+            } else {
+                targetEvent.content.captionOrNull()
+            }.orEmpty(),
         )
         composerState.eventSink(
             MessageComposerEvent.SetMode(composerMode)

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/factories/event/TimelineItemContentMessageFactory.kt

@@ -108,6 +108,7 @@ class TimelineItemContentMessageFactory(
                     fileSize = messageType.info?.size ?: 0,
                     caption = messageType.caption?.trimEnd(),
                     formattedCaption = formattedCaption,
+                    htmlCaption = messageType.formattedCaption?.body,
                     isEdited = content.isEdited,
                     mediaSource = messageType.source,
                     thumbnailSource = messageType.info?.thumbnailSource,
@@ -132,6 +133,7 @@ class TimelineItemContentMessageFactory(
                     fileSize = messageType.info?.size ?: 0,
                     caption = messageType.caption?.trimEnd(),
                     formattedCaption = formattedCaption,
+                    htmlCaption = messageType.formattedCaption?.body,
                     isEdited = content.isEdited,
                     mediaSource = messageType.source,
                     thumbnailSource = messageType.info?.thumbnailSource,
@@ -174,6 +176,7 @@ class TimelineItemContentMessageFactory(
                     fileSize = messageType.info?.size ?: 0,
                     caption = messageType.caption?.trimEnd(),
                     formattedCaption = formattedCaption,
+                    htmlCaption = messageType.formattedCaption?.body,
                     isEdited = content.isEdited,
                     thumbnailSource = messageType.info?.thumbnailSource,
                     mediaSource = messageType.source,
@@ -198,6 +201,7 @@ class TimelineItemContentMessageFactory(
                     fileSize = messageType.info?.size ?: 0,
                     caption = messageType.caption?.trimEnd(),
                     formattedCaption = formattedCaption,
+                    htmlCaption = messageType.formattedCaption?.body,
                     isEdited = content.isEdited,
                     mediaSource = messageType.source,
                     duration = messageType.info?.duration ?: Duration.ZERO,
@@ -216,6 +220,7 @@ class TimelineItemContentMessageFactory(
                     fileSize = messageType.info?.size ?: 0,
                     caption = messageType.caption?.trimEnd(),
                     formattedCaption = formattedCaption,
+                    htmlCaption = messageType.formattedCaption?.body,
                     isEdited = content.isEdited,
                     mediaSource = messageType.source,
                     duration = messageType.info?.duration ?: Duration.ZERO,
@@ -235,6 +240,7 @@ class TimelineItemContentMessageFactory(
                     fileSize = messageType.info?.size ?: 0,
                     caption = messageType.caption?.trimEnd(),
                     formattedCaption = formattedCaption,
+                    htmlCaption = messageType.formattedCaption?.body,
                     isEdited = content.isEdited,
                     thumbnailSource = messageType.info?.thumbnailSource,
                     mediaSource = messageType.source,
@@ -345,6 +351,7 @@ class TimelineItemContentMessageFactory(
                         body = messageType.body,
                         caption = messageType.body.trimEnd().takeIf { it.isNotEmpty() },
                         formattedCaption = formattedCaption,
+                        htmlCaption = messageType.formatted?.body,
                         isEdited = content.isEdited,
                         items = galleryItems.toImmutableList(),
                     )
@@ -402,6 +409,7 @@ class TimelineItemContentMessageFactory(
                         body = messageType.body,
                         caption = messageType.body.trimEnd().takeIf { it.isNotEmpty() },
                         formattedCaption = formattedCaption,
+                        htmlCaption = messageType.formatted?.body,
                         isEdited = content.isEdited,
                         attachments = attachments.toImmutableList(),
                     )

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/model/event/TimelineItemAttachmentsContent.kt

@@ -14,6 +14,7 @@ data class TimelineItemAttachmentsContent(
     val body: String,
     val caption: String?,
     val formattedCaption: CharSequence?,
+    val htmlCaption: String? = null,
     override val isEdited: Boolean,
     val attachments: ImmutableList<AttachmentItem>,
 ) : TimelineItemEventContent, TimelineItemEventMutableContent {

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/model/event/TimelineItemAudioContent.kt

@@ -17,6 +17,7 @@ data class TimelineItemAudioContent(
     override val fileSize: Long?,
     override val caption: String?,
     override val formattedCaption: CharSequence?,
+    override val htmlCaption: String? = null,
     override val isEdited: Boolean,
     val duration: Duration,
     override val mediaSource: MediaSource,

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/model/event/TimelineItemEventContent.kt

@@ -33,6 +33,9 @@ sealed interface TimelineItemEventContentWithAttachment :
     val fileSize: Long?
     val caption: String?
     val formattedCaption: CharSequence?
+
+    /** The caption as it was written, in HTML, so that editing it can start from the formatted text. */
+    val htmlCaption: String?
     val mediaSource: MediaSource
     val mimeType: String
     val formattedFileSize: String
@@ -127,6 +130,13 @@ fun TimelineItemEventContent.formattedCaptionOrNull(): CharSequence? = when (thi
     else -> null
 }
 
+fun TimelineItemEventContent.htmlCaptionOrNull(): String? = when (this) {
+    is TimelineItemEventContentWithAttachment -> htmlCaption
+    is TimelineItemGalleryContent -> htmlCaption
+    is TimelineItemAttachmentsContent -> htmlCaption
+    else -> null
+}
+
 fun TimelineItemEventContentWithAttachment.duration(): Duration? {
     return when (this) {
         is TimelineItemAudioContent -> duration

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/model/event/TimelineItemFileContent.kt

@@ -16,6 +16,7 @@ data class TimelineItemFileContent(
     override val fileSize: Long?,
     override val caption: String?,
     override val formattedCaption: CharSequence?,
+    override val htmlCaption: String? = null,
     override val isEdited: Boolean,
     override val mediaSource: MediaSource,
     val thumbnailSource: MediaSource?,

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/model/event/TimelineItemGalleryContent.kt

@@ -16,6 +16,7 @@ data class TimelineItemGalleryContent(
     val body: String,
     val caption: String?,
     val formattedCaption: CharSequence?,
+    val htmlCaption: String? = null,
     override val isEdited: Boolean,
     val items: ImmutableList<GalleryItem>,
 ) : TimelineItemEventContent, TimelineItemEventMutableContent {

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/model/event/TimelineItemImageContent.kt

@@ -19,6 +19,7 @@ data class TimelineItemImageContent(
     override val fileSize: Long?,
     override val caption: String?,
     override val formattedCaption: CharSequence?,
+    override val htmlCaption: String? = null,
     override val isEdited: Boolean,
     override val mediaSource: MediaSource,
     val thumbnailSource: MediaSource?,

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/model/event/TimelineItemImageContentPreviewParam.kt

@@ -28,6 +28,7 @@ fun aTimelineItemImageContent(
     blurhash: String? = A_BLUR_HASH,
     filename: String = "A picture.jpg",
     caption: String? = null,
+    htmlCaption: String? = null,
     width: Int? = null,
     height: Int? = 300,
 ) = TimelineItemImageContent(
@@ -35,6 +36,7 @@ fun aTimelineItemImageContent(
     fileSize = 4 * 1024 * 1024L,
     caption = caption,
     formattedCaption = null,
+    htmlCaption = htmlCaption,
     isEdited = false,
     mediaSource = MediaSource(""),
     thumbnailSource = null,

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/model/event/TimelineItemStickerContent.kt

@@ -15,6 +15,7 @@ data class TimelineItemStickerContent(
     override val fileSize: Long?,
     override val caption: String?,
     override val formattedCaption: CharSequence?,
+    override val htmlCaption: String? = null,
     override val isEdited: Boolean,
     override val mediaSource: MediaSource,
     val thumbnailSource: MediaSource?,

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/model/event/TimelineItemVideoContent.kt

@@ -16,6 +16,7 @@ data class TimelineItemVideoContent(
     override val fileSize: Long?,
     override val caption: String?,
     override val formattedCaption: CharSequence?,
+    override val htmlCaption: String? = null,
     override val isEdited: Boolean,
     val duration: Duration,
     override val mediaSource: MediaSource,

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/model/event/TimelineItemVoiceContent.kt

@@ -19,6 +19,7 @@ data class TimelineItemVoiceContent(
     override val fileSize: Long?,
     override val caption: String?,
     override val formattedCaption: CharSequence?,
+    override val htmlCaption: String? = null,
     override val isEdited: Boolean,
     val duration: Duration,
     override val mediaSource: MediaSource,

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/MessagesPresenterTest.kt

@@ -989,6 +989,33 @@ class MessagesPresenterTest {
         }
     }
 
+    @Test
+    fun `present - handle action edit caption starts from the formatted caption`() = runTest {
+        val messageEvent = aMessageEvent(
+            content = aTimelineItemImageContent(
+                caption = "Hello world",
+                htmlCaption = "<b>Hello</b> world",
+            )
+        )
+        val composerRecorder = EventsRecorder<MessageComposerEvent>()
+        val presenter = createMessagesPresenter(
+            messageComposerPresenter = { aMessageComposerState(eventSink = composerRecorder, showTextFormatting = true) },
+        )
+        presenter.testWithLifecycleOwner {
+            val initialState = awaitItem()
+            initialState.eventSink(MessagesEvent.HandleAction(TimelineItemAction.EditCaption, messageEvent))
+            awaitItem()
+            composerRecorder.assertSingle(
+                MessageComposerEvent.SetMode(
+                    composerMode = MessageComposerMode.EditCaption(
+                        eventOrTransactionId = AN_EVENT_ID.toEventOrTransactionId(),
+                        content = "<b>Hello</b> world",
+                    )
+                )
+            )
+        }
+    }
+
     @Test
     fun `present - handle action add caption`() = runTest {
         val composerRecorder = EventsRecorder<MessageComposerEvent>()

features/messages/impl/src/test/kotlin/io/element/android/features/messages/impl/timeline/factories/event/TimelineItemContentMessageFactoryTest.kt

@@ -297,6 +297,7 @@ class TimelineItemContentMessageFactoryTest : RobolectricTest() {
             fileSize = 555L,
             caption = "body.mp4 caption",
             formattedCaption = SpannedString("formatted"),
+            htmlCaption = "formatted",
             isEdited = true,
             duration = 1.minutes,
             mediaSource = MediaSource(url = "url", json = null),
@@ -539,6 +540,7 @@ class TimelineItemContentMessageFactoryTest : RobolectricTest() {
             fileSize = 888L,
             caption = "body.jpg caption",
             formattedCaption = SpannedString("formatted"),
+            htmlCaption = "formatted",
             isEdited = true,
             mediaSource = MediaSource(url = "url", json = null),
             thumbnailSource = MediaSource("url_thumbnail"),