Open a full-screen preview when tapping a gallery item

Tapping a gallery tile/row opens the existing media preview scoped to that gallery's attachments, paging between them. Introduces a typed MediaPreviewItemID (replacing the stringly-typed preview identifier) and a gallery-scoped TimelineMediaPreviewDataSource; the tap routes through TimelineInteractionHandler/TimelineViewModel. Non-previewable (.other) items are skipped without shifting the tapped index.

Co-authored-by: svetoslav.mitov <svetoslav.mitov@sportinno.com>

just use id instead of previewID

removed horrible multiline ternary

pr suggestions

remove redundant code

remove empty caption display + gallery uses the appropriate media timeline actions

ElementX/Sources/Services/Room/JoinedRoomProxy.swift

@@ -227,6 +227,7 @@ class JoinedRoomProxy: JoinedRoomProxyProtocol {
                 case .file: .file
                 case .image: .image
                 case .video: .video
+                case .gallery: .gallery
                 }
             }
             

ElementX/Sources/Services/Timeline/TimelineController/TimelineControllerProtocol.swift

@@ -26,6 +26,7 @@ enum TimelineControllerAction {
     }
     
     case displayMediaPreview(item: EventBasedMessageTimelineItemProtocol, timelineViewModel: TimelineViewModelKind)
+    case displayGalleryPreview(galleryItem: GalleryRoomTimelineItem, initialIndex: Int)
     case displayLocation(StaticLocationData)
     case displayLiveLocation(sender: TimelineItemSender, initialLiveLocationShare: LiveLocationShare)
     case none

ElementX/Sources/Services/Timeline/TimelineItems/EventBasedMessageTimelineItemProtocol.swift

@@ -36,7 +36,7 @@ nonisolated extension EventBasedMessageTimelineItemProtocol {
     }
     
     var hasMediaCaption: Bool {
-        mediaCaption != nil
+        mediaCaption?.isBlank == false
     }
     
     var mediaCaption: String? {

ElementX/Sources/Services/Timeline/TimelineItems/Items/Messages/GalleryRoomTimelineItemContent.swift

@@ -111,6 +111,16 @@ nonisolated enum GalleryItem: Hashable, Identifiable {
         }
     }
     
+    var fileSize: UInt? {
+        switch self {
+        case .image(_, let content): content.imageInfo.fileSize
+        case .video(_, let content): content.videoInfo.fileSize
+        case .audio(_, let content): content.fileSize
+        case .file(_, let content): content.fileSize
+        case .other: nil
+        }
+    }
+    
     var blurhash: String? {
         switch self {
         case .image(_, let content): content.blurhash

ElementX/Sources/Services/Timeline/TimelineProxyProtocol.swift

@@ -41,7 +41,7 @@ enum TimelineFocus {
 }
 
 enum TimelineAllowedMessageType {
-    case audio, file, image, video
+    case audio, file, image, video, gallery
 }
 
 enum TimelineProxyError: Error {