//
// Copyright (c) 2010-2025 Antmicro
//
// This file is licensed under the MIT License.
// Full license text is available in 'licenses/MIT.txt'.
//

using System.Collections.Generic;
using System.Collections.Immutable;
using System.Linq;

using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Diagnostics;

namespace Antmicro.Renode.CustomAnalyzers
{
    [DiagnosticAnalyzer(LanguageNames.CSharp)]
    public class RenodeClassMembersOrderAnalyzer : DiagnosticAnalyzer
    {
        public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics =>
            ImmutableArray.Create(ClassMembersOrderRule);

        public override void Initialize(AnalysisContext context)
        {
            context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
            context.EnableConcurrentExecution();
            context.RegisterSyntaxTreeAction(CheckClassMembersOrder);
        }

        public const string DiagnosticId = "renode_class_members_order";

        private void CheckClassMembersOrder(SyntaxTreeAnalysisContext context)
        {
            var classes = context
                .Tree
                .GetRoot()
                .DescendantNodes()
                .Where(node => node.IsKind(SyntaxKind.ClassDeclaration));

            foreach(var cls in classes)
            {
                var declarations = cls
                    .ChildNodes()
                    .OfType<MemberDeclarationSyntax>();

                var currentMember = ClassMemberOrder.StaticConstructor;

                foreach(var declaration in declarations)
                {
                    if(TryGetClassMemberOrder(declaration, out var nextMember))
                    {
                        if(nextMember < currentMember)
                        {
                            var diagnostic = Diagnostic.Create(
                                ClassMembersOrderRule,
                                declaration.GetLocation(),
                                new object[] {currentMember, nextMember}
                            );
                            context.ReportDiagnostic(diagnostic);
                        }
                        currentMember = nextMember;
                    }
                }
            }
        }

        public static bool TryGetClassMemberOrder(MemberDeclarationSyntax node, out ClassMemberOrder classMemberOrder)
        {
            var ignoredModifiers = ImmutableHashSet.Create
            (
                "async",
                "extern",
                "internal",
                "override",
                "partial",
                "sealed",
                "unsafe",
                "virtual",
                "volatile"
            );

            var modifiersOrder = new Dictionary<string, int>
            {
                {"public",      0},
                {"protected",   0},
                {"private",     0},
                {"static",      1},
                {"abstract",    2},
                {"readonly",    3},
                {"const",       3},
            }.ToImmutableDictionary();

            var modifiers = node
                .Modifiers
                .OrderBy(mod => modifiersOrder.GetValueOrDefault(mod.ToString(), -1))
                .Aggregate("", (acc, val) => ignoredModifiers.Contains(val.ToString()) ? acc : $"{acc}_{val}");
            var id = $"{modifiers}_{node.Kind()}";

            if(ClassMembersOrderMap.TryGetValue(id, out classMemberOrder))
            {
                return true;
            }
            return false;
        }

#pragma warning disable SA1509
        // SA1509 - No space before opening braces
        public static readonly Dictionary<string, ClassMemberOrder> ClassMembersOrderMap = new Dictionary<string, ClassMemberOrder>
        {
            {"_static_ConstructorDeclaration",                      ClassMemberOrder.StaticConstructor},
            {"_public_static_MethodDeclaration",                    ClassMemberOrder.PublicStaticMethod},
            {"_public_static_PropertyDeclaration",                  ClassMemberOrder.PublicStaticProperty},
            {"_public_static_explicit_OperatorDeclaration",         ClassMemberOrder.PublicStaticExplicitOperator},
            {"_public_static_implicit_OperatorDeclaration",         ClassMemberOrder.PublicStaticImplicitOperator},
            {"_public_static_FieldDeclaration",                     ClassMemberOrder.PublicStaticField},
            {"_public_ConstructorDeclaration",                      ClassMemberOrder.PublicConstructor},
            {"_public_MethodDeclaration",                           ClassMemberOrder.PublicMethod},
            {"_public_abstract_MethodDeclaration",                  ClassMemberOrder.PublicAbstractMethod},
            {"_public_PropertyDeclaration",                         ClassMemberOrder.PublicProperty},
            {"_public_abstract_PropertyDeclaration",                ClassMemberOrder.PublicAbstractProperty},
            {"_public_abstract_readonly_PropertyDeclaration",       ClassMemberOrder.PublicAbstractProperty},
            {"_public_EventFieldDeclaration",                       ClassMemberOrder.PublicEvent},
            {"_public_FieldDeclaration",                            ClassMemberOrder.PublicField},
            {"_public_readonly_FieldDeclaration",                   ClassMemberOrder.PublicReadonlyField},
            {"_public_const_FieldDeclaration",                      ClassMemberOrder.PublicConst},

            {"_protected_static_MethodDeclaration",                 ClassMemberOrder.ProtectedStaticMethod},
            {"_protected_static_PropertyDeclaration",               ClassMemberOrder.ProtectedStaticProperty},
            {"_protected_static_explicit_OperatorDeclaration",      ClassMemberOrder.ProtectedStaticExplicitOperator},
            {"_protected_static_implicit_OperatorDeclaration",      ClassMemberOrder.ProtectedStaticImplicitOperator},
            {"_protected_static_FieldDeclaration",                  ClassMemberOrder.ProtectedStaticField},
            {"_protected_ConstructorDeclaration",                   ClassMemberOrder.ProtectedConstructor},
            {"_protected_MethodDeclaration",                        ClassMemberOrder.ProtectedMethod},
            {"_protected_abstract_MethodDeclaration",               ClassMemberOrder.ProtectedAbstractMethod},
            {"_protected_PropertyDeclaration",                      ClassMemberOrder.ProtectedProperty},
            {"_protected_abstract_PropertyDeclaration",             ClassMemberOrder.ProtectedAbstractProperty},
            {"_protected_abstract_readonly_PropertyDeclaration",    ClassMemberOrder.ProtectedAbstractProperty},
            {"_protected_EventFieldDeclaration",                    ClassMemberOrder.ProtectedEvent},
            {"_protected_FieldDeclaration",                         ClassMemberOrder.ProtectedField},
            {"_protected_readonly_FieldDeclaration",                ClassMemberOrder.ProtectedReadonlyField},
            {"_protected_const_FieldDeclaration",                   ClassMemberOrder.ProtectedConst},

            {"_private_static_MethodDeclaration",                   ClassMemberOrder.PrivateStaticMethod},
            {"_private_static_FieldDeclaration",                    ClassMemberOrder.PrivateStaticField},
            {"_private_ConstructorDeclaration",                     ClassMemberOrder.PrivateConstructor},
            {"_private_MethodDeclaration",                          ClassMemberOrder.PrivateMethod},
            {"_private_abstract_MethodDeclaration",                 ClassMemberOrder.PrivateAbstractMethod},
            {"_private_PropertyDeclaration",                        ClassMemberOrder.PrivateProperty},
            {"_private_abstract_PropertyDeclaration",               ClassMemberOrder.PrivateAbstractProperty},
            {"_private_abstract_readonly_PropertyDeclaration",      ClassMemberOrder.PrivateAbstractProperty},
            {"_private_FieldDeclaration",                           ClassMemberOrder.PrivateField},
            {"_private_readonly_FieldDeclaration",                  ClassMemberOrder.PrivateReadonlyField},
            {"_private_const_FieldDeclaration",                     ClassMemberOrder.PrivateConst},

            {"_public_ClassDeclaration",                            ClassMemberOrder.PublicClass},
            {"_public_abstract_ClassDeclaration",                   ClassMemberOrder.PublicAbstractClass},
            {"_public_StructDeclaration",                           ClassMemberOrder.PublicStruct},
            {"_public_DelegateDeclaration",                         ClassMemberOrder.PublicDelegate},
            {"_public_EnumDeclaration",                             ClassMemberOrder.PublicEnum},

            {"_protected_ClassDeclaration",                         ClassMemberOrder.ProtectedClass},
            {"_protected_abstract_ClassDeclaration",                ClassMemberOrder.ProtectedAbstractClass},
            {"_protected_StructDeclaration",                        ClassMemberOrder.ProtectedStruct},
            {"_protected_DelegateDeclaration",                      ClassMemberOrder.ProtectedDelegate},
            {"_protected_EnumDeclaration",                          ClassMemberOrder.ProtectedEnum},

            {"_private_ClassDeclaration",                           ClassMemberOrder.PrivateClass},
            {"_private_abstract_ClassDeclaration",                  ClassMemberOrder.PrivateAbstractClass},
            {"_private_StructDeclaration",                          ClassMemberOrder.PrivateStruct},
            {"_private_DelegateDeclaration",                        ClassMemberOrder.PrivateDelegate},
            {"_private_EnumDeclaration",                            ClassMemberOrder.PrivateEnum},
        };
#pragma warning restore SA1509

        private static readonly DiagnosticDescriptor ClassMembersOrderRule = new DiagnosticDescriptor(
            DiagnosticId,
            "Class Members Order",
            "Wrong Class Members Order: {1} should be placed before {0}",
            "Design",
            DiagnosticSeverity.Warning,
            isEnabledByDefault: false,
            description: "Checks if class members order is preserved."
        );

        // Order of fields in this Enum is important.
        // It specifies allowed order of class members.
        public enum ClassMemberOrder
        {
            StaticConstructor,
            PublicStaticMethod,
            PublicStaticProperty,
            PublicStaticExplicitOperator,
            PublicStaticImplicitOperator,
            PublicStaticField,
            PublicConstructor,
            PublicMethod,
            PublicAbstractMethod,
            PublicProperty,
            PublicAbstractProperty,
            PublicEvent,
            PublicField,
            PublicReadonlyField,
            PublicConst,
            ProtectedStaticMethod,
            ProtectedStaticProperty,
            ProtectedStaticExplicitOperator,
            ProtectedStaticImplicitOperator,
            ProtectedStaticField,
            ProtectedConstructor,
            ProtectedMethod,
            ProtectedAbstractMethod,
            ProtectedProperty,
            ProtectedAbstractProperty,
            ProtectedEvent,
            ProtectedField,
            ProtectedReadonlyField,
            ProtectedConst,
            PrivateStaticMethod,
            PrivateStaticField,
            PrivateConstructor,
            PrivateMethod,
            PrivateAbstractMethod,
            PrivateProperty,
            PrivateAbstractProperty,
            PrivateField,
            PrivateReadonlyField,
            PrivateConst,
            PublicClass,
            PublicAbstractClass,
            PublicStruct,
            PublicDelegate,
            PublicEnum,
            ProtectedClass,
            ProtectedAbstractClass,
            ProtectedStruct,
            ProtectedDelegate,
            ProtectedEnum,
            PrivateClass,
            PrivateAbstractClass,
            PrivateStruct,
            PrivateDelegate,
            PrivateEnum,
        }
    }
}