feat(mobile): cache latest ios widget entry for fallback (#19824)

* cache the last image an ios widget fetched and use if a fetch fails in a future timeline build

* code review fixes

* downgrade pbx for flutter

* use cache in snapshots

mobile/ios/WidgetExtension/widgets/MemoryWidget.swift

@@ -19,21 +19,23 @@ struct ImmichMemoryProvider: TimelineProvider {
     in context: Context,
     completion: @escaping @Sendable (ImageEntry) -> Void
   ) {
+    let cacheKey = "memory_\(context.family.rawValue)"
+
     Task {
       guard let api = try? await ImmichAPI() else {
-        completion(ImageEntry(date: Date(), image: nil, error: .noLogin))
+        completion(ImageEntry.handleCacheFallback(for: cacheKey, error: .noLogin).entries.first!)
         return
       }
 
       guard let memories = try? await api.fetchMemory(for: Date.now)
       else {
-        completion(ImageEntry(date: Date(), image: nil, error: .fetchFailed))
+        completion(ImageEntry.handleCacheFallback(for: cacheKey).entries.first!)
         return
       }
 
       for memory in memories {
         if let asset = memory.assets.first(where: { $0.type == .image }),
-          var entry = try? await buildEntry(
+          var entry = try? await ImageEntry.build(
             api: api,
             asset: asset,
             dateOffset: 0,
@@ -50,20 +52,14 @@ struct ImmichMemoryProvider: TimelineProvider {
       guard
         let randomImage = try? await api.fetchSearchResults(
           with: SearchFilters(size: 1)
-        ).first
-      else {
-        completion(ImageEntry(date: Date(), image: nil, error: .fetchFailed))
-        return
-      }
-
-      guard
-        var imageEntry = try? await buildEntry(
+        ).first,
+        var imageEntry = try? await ImageEntry.build(
           api: api,
           asset: randomImage,
           dateOffset: 0
         )
       else {
-        completion(ImageEntry(date: Date(), image: nil, error: .fetchFailed))
+        completion(ImageEntry.handleCacheFallback(for: cacheKey).entries.first!)
         return
       }
 
@@ -80,9 +76,12 @@ struct ImmichMemoryProvider: TimelineProvider {
       var entries: [ImageEntry] = []
       let now = Date()
 
+      let cacheKey = "memory_\(context.family.rawValue)"
+
       guard let api = try? await ImmichAPI() else {
-        entries.append(ImageEntry(date: now, image: nil, error: .noLogin))
-        completion(Timeline(entries: entries, policy: .atEnd))
+        completion(
+          ImageEntry.handleCacheFallback(for: cacheKey, error: .noLogin)
+        )
         return
       }
 
@@ -95,7 +94,7 @@ struct ImmichMemoryProvider: TimelineProvider {
           for asset in memory.assets {
             if asset.type == .image && totalAssets < 12 {
               group.addTask {
-                try? await buildEntry(
+                try? await ImageEntry.build(
                   api: api,
                   asset: asset,
                   dateOffset: totalAssets,
@@ -132,7 +131,8 @@ struct ImmichMemoryProvider: TimelineProvider {
       // If we fail to fetch images, we still want to add an entry
       // with a nil image and an error
       if entries.count == 0 {
-        entries.append(ImageEntry(date: now, image: nil, error: .fetchFailed))
+        completion(ImageEntry.handleCacheFallback(for: cacheKey))
+        return
       }
 
       // Resize all images to something that can be stored by iOS
@@ -140,6 +140,9 @@ struct ImmichMemoryProvider: TimelineProvider {
         entries[i].resize()
       }
 
+      // cache the last image
+      try? entries.last!.cache(for: cacheKey)
+
       completion(Timeline(entries: entries, policy: .atEnd))
     }
   }

mobile/ios/WidgetExtension/widgets/RandomWidget.swift

@@ -45,7 +45,7 @@ struct RandomConfigurationAppIntent: WidgetConfigurationIntent {
 
   @Parameter(title: "Album")
   var album: Album?
-  
+
   @Parameter(title: "Show Album Name", default: false)
   var showAlbumName: Bool
 }
@@ -54,7 +54,7 @@ struct RandomConfigurationAppIntent: WidgetConfigurationIntent {
 
 struct ImmichRandomProvider: AppIntentTimelineProvider {
   func placeholder(in context: Context) -> ImageEntry {
-    ImageEntry(date: Date(), image: nil)
+    ImageEntry(date: Date())
   }
 
   func snapshot(
@@ -63,26 +63,23 @@ struct ImmichRandomProvider: AppIntentTimelineProvider {
   ) async
     -> ImageEntry
   {
+    let cacheKey = "random_none_\(context.family.rawValue)"
+    
     guard let api = try? await ImmichAPI() else {
-      return ImageEntry(date: Date(), image: nil, error: .noLogin)
+      return ImageEntry.handleCacheFallback(for: cacheKey, error: .noLogin).entries.first!
     }
 
     guard
       let randomImage = try? await api.fetchSearchResults(
         with: SearchFilters(size: 1)
-      ).first
-    else {
-      return ImageEntry(date: Date(), image: nil, error: .fetchFailed)
-    }
-
-    guard
-      var entry = try? await buildEntry(
+      ).first,
+      var entry = try? await ImageEntry.build(
         api: api,
         asset: randomImage,
         dateOffset: 0
       )
     else {
-      return ImageEntry(date: Date(), image: nil, error: .fetchFailed)
+      return ImageEntry.handleCacheFallback(for: cacheKey).entries.first!
     }
 
     entry.resize()
@@ -99,30 +96,34 @@ struct ImmichRandomProvider: AppIntentTimelineProvider {
     var entries: [ImageEntry] = []
     let now = Date()
 
-    // If we don't have a server config, return an entry with an error
-    guard let api = try? await ImmichAPI() else {
-      entries.append(ImageEntry(date: now, image: nil, error: .noLogin))
-      return Timeline(entries: entries, policy: .atEnd)
-    }
-
     // nil if album is NONE or nil
     let albumId =
       configuration.album?.id != "NONE" ? configuration.album?.id : nil
-    var albumName: String? = albumId != nil ? configuration.album?.albumName : nil
-    
+    let albumName: String? =
+      albumId != nil ? configuration.album?.albumName : nil
+
+    let cacheKey = "random_\(albumId ?? "none")_\(context.family.rawValue)"
+
+    // If we don't have a server config, return an entry with an error
+    guard let api = try? await ImmichAPI() else {
+      return ImageEntry.handleCacheFallback(for: cacheKey, error: .noLogin)
+    }
+
     if albumId != nil {
       // make sure the album exists on server, otherwise show error
       guard let albums = try? await api.fetchAlbums() else {
-        entries.append(ImageEntry(date: now, image: nil, error: .fetchFailed))
-        return Timeline(entries: entries, policy: .atEnd)
+        return ImageEntry.handleCacheFallback(for: cacheKey)
       }
 
       if !albums.contains(where: { $0.id == albumId }) {
-        entries.append(ImageEntry(date: now, image: nil, error: .albumNotFound))
-        return Timeline(entries: entries, policy: .atEnd)
+        return ImageEntry.handleCacheFallback(
+          for: cacheKey,
+          error: .albumNotFound
+        )
       }
     }
 
+    // build entries
     entries.append(
       contentsOf: (try? await generateRandomEntries(
         api: api,
@@ -134,9 +135,9 @@ struct ImmichRandomProvider: AppIntentTimelineProvider {
         ?? []
     )
 
-    // If we fail to fetch images, we still want to add an entry with a nil image and an error
+    // Load or save a cached asset for when network conditions are bad
     if entries.count == 0 {
-      entries.append(ImageEntry(date: now, image: nil, error: .fetchFailed))
+      return ImageEntry.handleCacheFallback(for: cacheKey)
     }
 
     // Resize all images to something that can be stored by iOS
@@ -144,6 +145,9 @@ struct ImmichRandomProvider: AppIntentTimelineProvider {
       entries[i].resize()
     }
 
+    // cache the last image
+    try? entries.last!.cache(for: cacheKey)
+
     return Timeline(entries: entries, policy: .atEnd)
   }
 }