add settings for image packs

Closes #131

lib/models/account_data.dart

@@ -29,6 +29,9 @@ class const AccountData({
   static const imagePackRoomsKey = "m.image_pack.rooms";
   static const legacyImagePackRoomsKey = "im.ponies.emote_rooms";
 
+  ImagePackRooms get enabledImagePacks =>
+      imagePackRooms ?? legacyImagePackRooms ?? const .new();
+
   Map<String, Object?> toJson() => _$AccountDataToJson(this);
 
   factory AccountData.fromJson(Map<String, Object?> json) =>
@@ -53,6 +56,29 @@ class const ImagePackRooms({
   /// empty) object
   final IMap<String, IMap<String, Map<String, dynamic>>> rooms = const .empty(),
 }) with _$ImagePackRooms {
+  bool contains(String roomId, String stateKey) =>
+      rooms[roomId]?.containsKey(stateKey) ?? false;
+
+  ImagePackRooms withPack(
+    String roomId,
+    String stateKey, {
+    required bool enabled,
+  }) {
+    final packs =
+        rooms[roomId] ?? const IMap<String, Map<String, dynamic>>.empty();
+    final updated = switch ((enabled, packs.containsKey(stateKey))) {
+      (true, false) => packs.add(stateKey, const {}),
+      (false, true) => packs.remove(stateKey),
+      _ => packs,
+    };
+
+    return copyWith(
+      rooms: updated.isEmpty
+          ? rooms.remove(roomId)
+          : rooms.add(roomId, updated),
+    );
+  }
+
   Map<String, Object?> toJson() => _$ImagePackRoomsToJson(this);
 
   factory ImagePackRooms.fromJson(Map<String, Object?> json) =>

lib/models/content/image_pack.dart

@@ -7,11 +7,14 @@ part "image_pack.g.dart";
 
 /// An image pack (MSC2545), from a room's state.
 @Freezed(toJson: false, fromJson: false)
-@JsonSerializable()
+@JsonSerializable(includeIfNull: false)
 class const ImagePackContent({
   final IMap<String, PackImage> images = const .empty(),
   final PackInfo? pack,
 }) extends Content with _$ImagePackContent {
+  /// Whether the pack has images or a name, as deleted packs are left empty.
+  bool get hasContent => images.isNotEmpty || pack?.displayName != null;
+
   IMap<String, PackImage> imagesFor(ImageUsage usage) => images.where(
     (_, image) => switch ((image.usage, pack?.usage ?? const .empty())) {
       (final usages, _) when usages.isNotEmpty => usages.contains(usage),
@@ -30,12 +33,12 @@ class const ImagePackContent({
 }
 
 @Freezed(toJson: false, fromJson: false)
-@JsonSerializable()
+@JsonSerializable(includeIfNull: false)
 class const PackImage({
   required final Uri url,
   final String? body,
   final ImageInfo? info,
-  @JsonKey(fromJson: ImageUsage.setFromJson)
+  @JsonKey(fromJson: ImageUsage.setFromJson, toJson: ImageUsage.setToJson)
   final ISet<ImageUsage> usage = const .empty(),
 }) with _$PackImage {
   Map<String, Object?> toJson() => _$PackImageToJson(this);
@@ -45,12 +48,12 @@ class const PackImage({
 }
 
 @Freezed(toJson: false, fromJson: false)
-@JsonSerializable()
+@JsonSerializable(includeIfNull: false)
 class const PackInfo({
   final String? displayName,
   final Uri? avatarUrl,
   final String? attribution,
-  @JsonKey(fromJson: ImageUsage.setFromJson)
+  @JsonKey(fromJson: ImageUsage.setFromJson, toJson: ImageUsage.setToJson)
   final ISet<ImageUsage> usage = const .empty(),
 }) with _$PackInfo {
   Map<String, Object?> toJson() => _$PackInfoToJson(this);
@@ -66,4 +69,8 @@ enum ImageUsage {
   /// Ignores usages we don't know about.
   static ISet<ImageUsage> setFromJson(List<dynamic>? json) =>
       ISet(values.where((value) => json?.contains(value.name) ?? false));
+
+  /// Omits an empty set, which means every usage.
+  static List<String>? setToJson(ISet<ImageUsage> usages) =>
+      usages.isEmpty ? null : usages.map((usage) => usage.name).toList();
 }

lib/models/image_pack.dart

@@ -13,21 +13,42 @@ class const ImagePack({
   /// Map of shortcode to images
   required final IMap<String, PackImage> emoticons,
   required final IMap<String, PackImage> stickers,
+
+  /// The state event the pack is from, for editing it.
+  required final ImagePackContent content,
 }) with _$ImagePack {
-  static String emojiMarkdown(String shortcode, String url) {
-    final title = ":$shortcode:".replaceAll(r"\", r"\\").replaceAll('"', r'\"');
-    return '![:$shortcode:]($url "Emoji: $title")';
-  }
+  /// The pack's avatar, or its first image if it has none.
+  Uri? get icon => avatar ?? content.images.values.firstOrNull?.url;
+
+  String get imageCountLabel => content.images.length == 1
+      ? "1 image"
+      : "${content.images.length} images";
+
+  /// The name of a pack without one, from its room's name and state key.
+  static String fallbackName(String roomName, String stateKey) =>
+      stateKey.isEmpty ? roomName : "$roomName - $stateKey";
+
+  static String emojiMarkdown(
+    String shortcode,
+    String url, {
+    String? description,
+  }) =>
+      '![:$shortcode:]($url "Emoji: ${switch (description) {
+        final description? when description.isNotEmpty => description,
+        _ => ":$shortcode:",
+      }.replaceAll(r"\", r"\\").replaceAll('"', r'\"')}")';
 
   factory ImagePack.fromContent(
     ImagePackContent content, {
-    required String id,
-    required String fallbackName,
+    required String roomId,
+    required String roomName,
+    required String stateKey,
   }) => .new(
-    id: id,
-    name: content.pack?.displayName ?? fallbackName,
+    id: "$roomId/$stateKey",
+    name: content.pack?.displayName ?? fallbackName(roomName, stateKey),
     avatar: content.pack?.avatarUrl,
     emoticons: content.imagesFor(.emoticon),
     stickers: content.imagesFor(.sticker),
+    content: content,
   );
 }