feat(policy): implement core policy management and evaluation interfaces with initial classes

Author: dgarciasquare1

lib/core/interfaces/i_policy_evaluator.dart

@@ -0,0 +1,6 @@
+import 'package:meta/meta.dart';
+
+@immutable
+abstract class IPolicyEvaluator {
+  Future<bool> evaluate(String roleName, String content);
+}

lib/core/interfaces/i_policy_storage.dart

@@ -0,0 +1,8 @@
+import 'package:meta/meta.dart';
+
+@immutable
+abstract class IPolicyStorage {
+  Future<Map<String, dynamic>> loadPolicies();
+  Future<void> savePolicies(Map<String, dynamic> policies);
+  Future<void> clearPolicies();
+}

lib/core/policy_manager.dart

@@ -0,0 +1,21 @@
+import 'package:flutter/foundation.dart';
+import 'package:flutter_policy_engine/core/interfaces/i_policy_storage.dart';
+import 'package:flutter_policy_engine/models/policy.dart';
+
+class PolicyManager extends ChangeNotifier {
+  PolicyManager({
+    required this.storage,
+  });
+
+  final IPolicyStorage storage;
+  Map<String, Policy> _policies = {};
+  bool _isInitialized = false;
+
+  bool get isInitialized => _isInitialized;
+
+  Map<String, Policy> get policies => Map.unmodifiable(_policies);
+
+  Future<void> loadPolicies() async {
+    throw UnimplementedError();
+  }
+}

lib/core/role_evaluator.dart

@@ -0,0 +1,16 @@
+import 'package:flutter_policy_engine/core/interfaces/i_policy_evaluator.dart';
+import 'package:flutter_policy_engine/models/policy.dart';
+import 'package:meta/meta.dart';
+
+@immutable
+class RoleEvaluator implements IPolicyEvaluator {
+  const RoleEvaluator(this._policies);
+
+  final Map<String, Policy> _policies;
+
+  @override
+  Future<bool> evaluate(String roleName, String content) {
+    // TODO: implement evaluate
+    throw UnimplementedError();
+  }
+}

lib/models/policy.dart

@@ -0,0 +1,43 @@
+import 'package:meta/meta.dart';
+
+@immutable
+class Policy {
+  const Policy({
+    required this.roleName,
+    required this.allowedContent,
+    this.metadata = const {},
+  });
+
+  final String roleName;
+  final List<String> allowedContent;
+  final Map<String, dynamic> metadata;
+
+  Policy copyWith({
+    String? roleName,
+    List<String>? allowedContent,
+    Map<String, dynamic>? metadata,
+  }) =>
+      Policy(
+        roleName: roleName ?? this.roleName,
+        allowedContent: allowedContent ?? this.allowedContent,
+        metadata: metadata ?? this.metadata,
+      );
+
+  bool isContentAllowed(String content) => allowedContent.contains(content);
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is Policy &&
+          roleName == other.roleName &&
+          allowedContent.length == other.allowedContent.length &&
+          allowedContent
+              .every((content) => other.allowedContent.contains(content));
+
+  @override
+  int get hashCode => roleName.hashCode ^ allowedContent.hashCode;
+
+  @override
+  String toString() =>
+      'Policy(roleName: $roleName, allowedContent: $allowedContent, metadata: $metadata)';
+}