Support Lottie ZIP archive files (#587)

## What does this change?

Resolves #495 🎯

## Type of change

- [x] New feature (non-breaking change which adds functionality)
- [x] This change requires a documentation update

Author: AlexV525

README.md

@@ -400,7 +400,7 @@ Widget build(BuildContext context) {
 | [flutter_svg](https://pub.dev/packages/flutter_svg)     | .svg           | `flutter_svg: true`   | Assets.images.icons.paint.**svg()**       |
 | [flare_flutter](https://pub.dev/packages/flare_flutter) | .flr           | `flare_flutter: true` | Assets.flare.penguin.**flare()**          |
 | [rive](https://pub.dev/packages/rive)                   | .flr           | `rive: true`          | Assets.rive.vehicles.**rive()**           |
-| [lottie](https://pub.dev/packages/lottie)               | .json          | `lottie: true`        | Assets.lottie.hamburgerArrow.**lottie()** |
+| [lottie](https://pub.dev/packages/lottie)               | .json, .zip    | `lottie: true`        | Assets.lottie.hamburgerArrow.**lottie()** |
 
 
 In other cases, the asset is generated as String class.

examples/example/assets/lottie/spinning_carrousel.zip

@@ -88,12 +88,20 @@ class $AssetsLottieGen {
   LottieGenImage get hamburgerArrow =>
       const LottieGenImage('assets/lottie/hamburger_arrow.json');
 
+  /// File path: assets/lottie/spinning_carrousel.zip
+  LottieGenImage get spinningCarrousel =>
+      const LottieGenImage('assets/lottie/spinning_carrousel.zip');
+
   /// Directory path: assets/lottie/wrong
   $AssetsLottieWrongGen get wrong => const $AssetsLottieWrongGen();
 
   /// List of all assets
-  List<LottieGenImage> get values =>
-      [alarmClockLottieV440, geometricalAnimation, hamburgerArrow];
+  List<LottieGenImage> get values => [
+        alarmClockLottieV440,
+        geometricalAnimation,
+        hamburgerArrow,
+        spinningCarrousel
+      ];
 }
 
 class $AssetsMixGen {
@@ -193,11 +201,14 @@ class $AssetsImagesIconsGen {
 class $AssetsLottieWrongGen {
   const $AssetsLottieWrongGen();
 
+  /// File path: assets/lottie/wrong/dummy.zip
+  String get dummy => 'assets/lottie/wrong/dummy.zip';
+
   /// File path: assets/lottie/wrong/rocket-lottie-v439.json
   String get rocketLottieV439 => 'assets/lottie/wrong/rocket-lottie-v439.json';
 
   /// List of all assets
-  List<String> get values => [rocketLottieV439];
+  List<String> get values => [dummy, rocketLottieV439];
 }
 
 class MyAssets {

examples/example/assets/lottie/wrong/dummy.zip

@@ -1,6 +1,8 @@
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:archive/archive_io.dart';
+import 'package:collection/collection.dart';
 import 'package:flutter_gen_core/generators/integrations/integration.dart';
 import 'package:path/path.dart' as p;
 import 'package:pub_semver/pub_semver.dart';
@@ -19,6 +21,11 @@ class LottieIntegration extends Integration {
     'layers', // Must include layers
   ];
 
+  static const _supportedMimeTypes = [
+    'application/json',
+    'application/zip',
+  ];
+
   String get packageExpression => isPackage ? ' = package' : '';
 
   @override
@@ -110,12 +117,33 @@ ${isPackage ? "\n  static const String package = '$packageName';" : ''}
   bool get isConstConstructor => true;
 
   bool isLottieFile(AssetType type) {
-    if (type.mime != 'application/json') {
+    if (!_supportedMimeTypes.contains(type.mime)) {
       return false;
     }
+    if (type.mime == 'application/zip') {
+      final inputStream = InputFileStream(type.fullPath);
+      final archive = ZipDecoder().decodeBuffer(inputStream);
+      final jsonFile = archive.files.firstWhereOrNull(
+        (e) => e.name.endsWith('.json'),
+      );
+      if (jsonFile?.isFile != true) {
+        return false;
+      }
+      final content = utf8.decode(jsonFile!.content);
+      return _isValidJsonFile(type, overrideInput: content);
+    }
+    return _isValidJsonFile(type);
+  }
+
+  bool _isValidJsonFile(AssetType type, {String? overrideInput}) {
     try {
-      final absolutePath = p.join(type.rootPath, type.path);
-      String input = File(absolutePath).readAsStringSync();
+      final String input;
+      if (overrideInput != null) {
+        input = overrideInput;
+      } else {
+        final absolutePath = p.join(type.rootPath, type.path);
+        input = File(absolutePath).readAsStringSync();
+      }
       final fileKeys = jsonDecode(input) as Map<String, dynamic>;
       if (lottieKeys.every(fileKeys.containsKey) && fileKeys['v'] != null) {
         var version = Version.parse(fileKeys['v']);

examples/example/lib/gen/assets.gen.dart

@@ -3,7 +3,6 @@ import 'package:flutter_gen_core/utils/identifer.dart';
 import 'package:flutter_gen_core/utils/string.dart';
 import 'package:mime/mime.dart' show lookupMimeType;
 import 'package:path/path.dart' as p;
-import 'package:path/path.dart';
 
 /// https://github.com/dart-lang/mime/blob/master/lib/src/default_extension_map.dart
 class AssetType {
@@ -40,12 +39,15 @@ class AssetType {
 
   bool get isUnKnownMime => mime == null;
 
-  String get extension => p.extension(path);
+  /// Returns a name for this asset.
+  String get name => p.withoutExtension(path);
 
   String get baseName => p.basenameWithoutExtension(path);
 
+  String get extension => p.extension(path);
+
   /// Returns the full absolute path for reading the asset file.
-  String get fullPath => join(rootPath, path);
+  String get fullPath => p.join(rootPath, path);
 
   // Replace to Posix style for Windows separator.
   String get posixStylePath => path.replaceAll(r'\', r'/');
@@ -56,10 +58,12 @@ class AssetType {
     _children.add(type);
   }
 
-  /// Returns a name for this asset.
-  String get name {
-    return withoutExtension(path);
-  }
+  @override
+  String toString() => 'AssetType('
+      'rootPath: $rootPath, '
+      'path: $path, '
+      'flavors: $flavors'
+      ')';
 }
 
 /// Represents a AssetType with modifiers on it to mutate the [name] to ensure
@@ -99,15 +103,14 @@ class UniqueAssetType extends AssetType {
   String get name {
     // Omit root directory from the name if it is either asset or assets.
     // TODO(bramp): Maybe move this into the _flatStyleDefinition
-    String p = path.replaceFirst(RegExp(r'^asset(s)?[/\\]'), '');
+    String result = path.replaceFirst(RegExp(r'^asset(s)?[/\\]'), '');
     if (basenameOnly) {
-      p = basename(p);
+      result = p.basename(result);
     }
     if (!needExtension) {
-      p = withoutExtension(p);
+      result = p.withoutExtension(result);
     }
-
-    return style(convertToIdentifier(p)) + suffix;
+    return style(convertToIdentifier(result)) + suffix;
   }
 
   @override

packages/core/lib/generators/integrations/lottie_integration.dart

@@ -25,6 +25,7 @@ dependencies:
   glob: ^2.0.0
 
   dart_style: ^2.2.4
+  archive: ^3.4.0
   args: ^2.0.0
   pub_semver: ^2.0.0
   vector_graphics_compiler: ^1.1.9

packages/core/lib/settings/asset_type.dart

@@ -1,8 +1,34 @@
 import 'package:collection/collection.dart';
+import 'package:flutter_gen_core/settings/asset_type.dart';
 import 'package:flutter_gen_core/settings/flavored_asset.dart';
 import 'package:test/test.dart';
 
 void main() {
+  group(AssetType, () {
+    test('constructor', () {
+      final assetType = AssetType(
+        rootPath: 'root',
+        path: 'assets/single.jpg',
+        flavors: {'flavor'},
+      );
+      expect(assetType, isA<AssetType>());
+      expect(assetType.name, 'assets/single');
+      expect(assetType.baseName, 'single');
+      expect(assetType.extension, '.jpg');
+      expect(assetType.isUnKnownMime, false);
+      expect(
+        assetType,
+        predicate<AssetType>(
+          (e) => SetEquality().equals(e.flavors, {'flavor'}),
+        ),
+      );
+      expect(
+        assetType.toString(),
+        'AssetType(rootPath: root, path: assets/single.jpg, flavors: {flavor})',
+      );
+    });
+  });
+
   group(FlavoredAsset, () {
     test('constructor', () {
       expect(