Refactor local ad into specific ad subtypes

lib/src/fixtures/fixture_ids.dart

@@ -522,3 +522,11 @@ const kXhosaId = '6643c000a4a4e6e1a8e7b0b2';
 const kYiddishId = '6643c000a4a4e6e1a8e7b0b3';
 const kYorubaId = '6643c000a4a4e6e1a8e7b0b4';
 const kZhuangChuangId = '6643c000a4a4e6e1a8e7b0b5';
+
+// --- LocalAds Fixture IDs ---
+const kLocalAd1Id = '1563c000a4a4e6e1a8e7f0f1';
+const kLocalAd2Id = '2563c000a4a4e6e1a8e7f0f2';
+const kLocalAd3Id = '3563c000a4a4e6e1a8e7f0f3';
+const kLocalAd4Id = '4563c000a4a4e6e1a8e7f0f4';
+const kLocalAd5Id = '5563c000a4a4e6e1a8e7f0f5';
+const kLocalAd6Id = '6563c000a4a4e6e1a8e7f0f6';

lib/src/fixtures/fixtures.dart

@@ -3,6 +3,7 @@ export 'dashboard_summary.dart';
 export 'fixture_ids.dart';
 export 'headlines.dart';
 export 'languages.dart';
+export 'local_ads.dart';
 export 'remote_configs.dart';
 export 'sources.dart';
 export 'topics.dart';

lib/src/fixtures/local_ads.dart

@@ -0,0 +1,39 @@
+import 'package:core/core.dart';
+
+/// A list of predefined local ads for fixture data.
+final localAdsFixturesData = <LocalAd>[
+  const LocalNativeAd(
+    id: kLocalAd1Id,
+    title: 'Discover Our Premium Content',
+    subtitle: 'Unlock exclusive articles and an ad-free experience.',
+    imageUrl: 'https://example.com/ads/premium_native.png',
+    targetUrl: 'https://example.com/premium',
+  ),
+  const LocalBannerAd(
+    id: kLocalAd2Id,
+    imageUrl: 'https://example.com/ads/banner_ad_1.png',
+    targetUrl: 'https://example.com/offer1',
+  ),
+  const LocalInterstitialAd(
+    id: kLocalAd3Id,
+    imageUrl: 'https://example.com/ads/interstitial_ad_1.png',
+    targetUrl: 'https://example.com/special_offer',
+  ),
+  const LocalVideoAd(
+    id: kLocalAd4Id,
+    videoUrl: 'https://example.com/ads/promo_video.mp4',
+    targetUrl: 'https://example.com/watch_more',
+  ),
+  const LocalNativeAd(
+    id: kLocalAd5Id,
+    title: 'Stay Informed with Daily Briefings',
+    subtitle: 'Get the top news delivered straight to your inbox.',
+    imageUrl: 'https://example.com/ads/briefing_native.png',
+    targetUrl: 'https://example.com/subscribe',
+  ),
+  const LocalBannerAd(
+    id: kLocalAd6Id,
+    imageUrl: 'https://example.com/ads/banner_ad_2.png',
+    targetUrl: 'https://example.com/offer2',
+  ),
+];

lib/src/models/feed_decorators/local_ad.dart

@@ -1,83 +1,47 @@
 import 'package:core/core.dart';
-import 'package:json_annotation/json_annotation.dart';
 import 'package:meta/meta.dart';
 
-part 'local_ad.g.dart';
-
 /// {@template local_ad}
-/// Defines a single custom ad that can be served locally.
-/// Includes title and subtitle to mimic native ads.
+/// An abstract base class for all local ad types.
+///
+/// This class acts as a router for deserializing specific local ad types
+/// (e.g., native, banner, interstitial, video) based on their `adType` field.
+/// Concrete implementations must provide their own `toJson` method.
 /// {@endtemplate}
 @immutable
-@JsonSerializable(explicitToJson: true, includeIfNull: true, checked: true)
-class LocalAd extends FeedItem {
+abstract class LocalAd extends FeedItem {
   /// {@macro local_ad}
-  const LocalAd({
-    required this.id,
-    required this.title,
-    required this.subtitle,
-    required this.imageUrl,
-    required this.targetUrl,
-    required this.adType,
-  }) : super(type: 'localAd');
-
-  /// Creates a [LocalAd] from JSON data.
-  factory LocalAd.fromJson(Map<String, dynamic> json) =>
-      _$LocalAdFromJson(json);
-
-  /// Converts this [LocalAd] instance to JSON data.
-  Map<String, dynamic> toJson() {
-    final json = _$LocalAdToJson(this);
-    json['type'] = type;
-    return json;
+  const LocalAd({required this.adType}) : super(type: 'localAd');
+
+  /// Factory method to create a [LocalAd] instance from a JSON map.
+  ///
+  /// This factory uses the `adType` field in the JSON map to dispatch to the
+  /// correct concrete `fromJson` constructor for each local ad type.
+  ///
+  /// Throws [FormatException] if the `adType` field is missing or unknown.
+  factory LocalAd.fromJson(Map<String, dynamic> json) {
+    final adType = json['adType'] as String?;
+    if (adType == null) {
+      throw const FormatException('Missing "adType" field in LocalAd JSON.');
+    }
+
+    switch (adType) {
+      case 'native':
+        return LocalNativeAd.fromJson(json);
+      case 'banner':
+        return LocalBannerAd.fromJson(json);
+      case 'interstitial':
+        return LocalInterstitialAd.fromJson(json);
+      case 'video':
+        return LocalVideoAd.fromJson(json);
+      default:
+        throw FormatException('Unknown LocalAd type: $adType');
+    }
   }
 
-  /// Unique identifier for the local ad.
-  final String id;
-
-  /// The title of the local ad.
-  final String title;
-
-  /// The subtitle or description of the local ad.
-  final String subtitle;
-
-  /// The URL of the image for the local ad.
-  final String imageUrl;
-
-  /// The URL to navigate to when the local ad is clicked.
-  final String targetUrl;
-
-  /// The type of the ad (e.g., banner, native, interstitial).
-  final AdType adType;
+  /// The type of the ad (e.g., banner, native, interstitial, video).
+  final String adType;
 
   @override
-  List<Object?> get props => [
-    id,
-    title,
-    subtitle,
-    imageUrl,
-    targetUrl,
-    adType,
-    type,
-  ];
-
-  /// Creates a copy of this [LocalAd] but with the given fields replaced with
-  /// the new values.
-  LocalAd copyWith({
-    String? id,
-    String? title,
-    String? subtitle,
-    String? imageUrl,
-    String? targetUrl,
-    AdType? adType,
-  }) {
-    return LocalAd(
-      id: id ?? this.id,
-      title: title ?? this.title,
-      subtitle: subtitle ?? this.subtitle,
-      imageUrl: imageUrl ?? this.imageUrl,
-      targetUrl: targetUrl ?? this.targetUrl,
-      adType: adType ?? this.adType,
-    );
-  }
+  List<Object?> get props => [adType, type];
 }

lib/src/models/local_ads/local_ads.dart

@@ -0,0 +1,4 @@
+export 'local_banner_ad.dart';
+export 'local_interstitial_ad.dart';
+export 'local_native_ad.dart';
+export 'local_video_ad.dart';

lib/src/models/local_ads/local_banner_ad.dart

@@ -0,0 +1,54 @@
+import 'package:core/core.dart';
+import 'package:json_annotation/json_annotation.dart';
+import 'package:meta/meta.dart';
+
+part 'local_banner_ad.g.dart';
+
+/// {@template local_banner_ad}
+/// Defines a custom banner ad that can be served locally.
+///
+/// Banner ads are typically rectangular images with a target URL.
+/// {@endtemplate}
+@immutable
+@JsonSerializable(explicitToJson: true, includeIfNull: true, checked: true)
+class LocalBannerAd extends LocalAd {
+  /// {@macro local_banner_ad}
+  const LocalBannerAd({
+    required this.id,
+    required this.imageUrl,
+    required this.targetUrl,
+  }) : super(adType: 'banner');
+
+  /// Creates a [LocalBannerAd] from JSON data.
+  factory LocalBannerAd.fromJson(Map<String, dynamic> json) =>
+      _$LocalBannerAdFromJson(json);
+
+  /// Unique identifier for the local banner ad.
+  final String id;
+
+  /// The URL of the image for the local banner ad.
+  final String imageUrl;
+
+  /// The URL to navigate to when the local banner ad is clicked.
+  final String targetUrl;
+
+  Map<String, dynamic> toJson() {
+    final json = _$LocalBannerAdToJson(this);
+    json['adType'] = adType;
+    json['type'] = type;
+    return json;
+  }
+
+  @override
+  List<Object?> get props => [id, imageUrl, targetUrl, adType, type];
+
+  /// Creates a copy of this [LocalBannerAd] but with the given fields replaced with
+  /// the new values.
+  LocalBannerAd copyWith({String? id, String? imageUrl, String? targetUrl}) {
+    return LocalBannerAd(
+      id: id ?? this.id,
+      imageUrl: imageUrl ?? this.imageUrl,
+      targetUrl: targetUrl ?? this.targetUrl,
+    );
+  }
+}

lib/src/models/local_ads/local_interstitial_ad.dart

@@ -0,0 +1,59 @@
+import 'package:core/core.dart';
+import 'package:json_annotation/json_annotation.dart';
+import 'package:meta/meta.dart';
+
+part 'local_interstitial_ad.g.dart';
+
+/// {@template local_interstitial_ad}
+/// Defines a custom interstitial ad that can be served locally.
+///
+/// Interstitial ads are full-screen advertisements, typically with an image
+/// and a target URL, that appear between content transitions.
+/// {@endtemplate}
+@immutable
+@JsonSerializable(explicitToJson: true, includeIfNull: true, checked: true)
+class LocalInterstitialAd extends LocalAd {
+  /// {@macro local_interstitial_ad}
+  const LocalInterstitialAd({
+    required this.id,
+    required this.imageUrl,
+    required this.targetUrl,
+  }) : super(adType: 'interstitial');
+
+  /// Creates a [LocalInterstitialAd] from JSON data.
+  factory LocalInterstitialAd.fromJson(Map<String, dynamic> json) =>
+      _$LocalInterstitialAdFromJson(json);
+
+  /// Unique identifier for the local interstitial ad.
+  final String id;
+
+  /// The URL of the image for the local interstitial ad.
+  final String imageUrl;
+
+  /// The URL to navigate to when the local interstitial ad is clicked.
+  final String targetUrl;
+
+  Map<String, dynamic> toJson() {
+    final json = _$LocalInterstitialAdToJson(this);
+    json['adType'] = adType;
+    json['type'] = type;
+    return json;
+  }
+
+  @override
+  List<Object?> get props => [id, imageUrl, targetUrl, adType, type];
+
+  /// Creates a copy of this [LocalInterstitialAd] but with the given fields
+  /// replaced with the new values.
+  LocalInterstitialAd copyWith({
+    String? id,
+    String? imageUrl,
+    String? targetUrl,
+  }) {
+    return LocalInterstitialAd(
+      id: id ?? this.id,
+      imageUrl: imageUrl ?? this.imageUrl,
+      targetUrl: targetUrl ?? this.targetUrl,
+    );
+  }
+}