// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
#nullable disable
 
using System.Collections.Immutable;
using System.Diagnostics;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.CSharp.Symbols
{
    internal sealed class SourceDestructorSymbol : SourceMemberMethodSymbol
    {
        private TypeWithAnnotations _lazyReturnType;
 
        internal SourceDestructorSymbol(
            SourceMemberContainerTypeSymbol containingType,
            DestructorDeclarationSyntax syntax,
            bool isNullableAnalysisEnabled,
            BindingDiagnosticBag diagnostics) :
            base(containingType, syntax.GetReference(), GetSymbolLocation(syntax, out Location location), isIterator: SyntaxFacts.HasYieldOperations(syntax.Body),
                 MakeModifiersAndFlags(containingType, syntax, isNullableAnalysisEnabled, location, diagnostics, out bool modifierErrors))
        {
            this.CheckUnsafeModifier(DeclarationModifiers, diagnostics);
 
            bool hasBlockBody = syntax.Body != null;
            bool isExpressionBodied = IsExpressionBodied;
 
            if (syntax.Identifier.ValueText != containingType.Name)
            {
                diagnostics.Add(ErrorCode.ERR_BadDestructorName, syntax.Identifier.GetLocation());
            }
 
            if (hasBlockBody || isExpressionBodied)
            {
                if (IsExtern)
                {
                    diagnostics.Add(ErrorCode.ERR_ExternHasBody, location, this);
                }
            }
 
            if (!modifierErrors && !hasBlockBody && !isExpressionBodied && !IsExtern)
            {
                diagnostics.Add(ErrorCode.ERR_ConcreteMissingBody, location, this);
            }
 
            Debug.Assert(syntax.ParameterList.Parameters.Count == 0);
 
            if (containingType.IsStatic)
            {
                diagnostics.Add(ErrorCode.ERR_DestructorInStaticClass, location);
            }
            else if (!containingType.IsReferenceType)
            {
                diagnostics.Add(ErrorCode.ERR_OnlyClassesCanContainDestructors, location);
            }
 
            CheckForBlockAndExpressionBody(
                syntax.Body, syntax.ExpressionBody, syntax, diagnostics);
        }
 
        private static (DeclarationModifiers, Flags) MakeModifiersAndFlags(NamedTypeSymbol containingType, DestructorDeclarationSyntax syntax, bool isNullableAnalysisEnabled, Location location, BindingDiagnosticBag diagnostics, out bool modifierErrors)
        {
            DeclarationModifiers declarationModifiers = MakeModifiers(containingType, syntax.Modifiers, location, diagnostics, out modifierErrors);
            Flags flags = MakeFlags(
                                    MethodKind.Destructor, RefKind.None, declarationModifiers, returnsVoid: true, returnsVoidIsSet: true,
                                    isExpressionBodied: syntax.IsExpressionBodied(), isExtensionMethod: false,
                                    isVarArg: false, isNullableAnalysisEnabled: isNullableAnalysisEnabled, isExplicitInterfaceImplementation: false, hasThisInitializer: false);
 
            return (declarationModifiers, flags);
        }
 
        private static Location GetSymbolLocation(DestructorDeclarationSyntax syntax, out Location location)
        {
            location = syntax.Identifier.GetLocation();
            return location;
        }
 
        protected override void MethodChecks(BindingDiagnosticBag diagnostics)
        {
            var syntax = GetSyntax();
            var bodyBinder = this.DeclaringCompilation.GetBinderFactory(syntaxReferenceOpt.SyntaxTree).GetBinder(syntax, syntax, this);
            _lazyReturnType = TypeWithAnnotations.Create(bodyBinder.GetSpecialType(SpecialType.System_Void, diagnostics, syntax));
        }
 
        internal DestructorDeclarationSyntax GetSyntax()
        {
            Debug.Assert(syntaxReferenceOpt != null);
            return (DestructorDeclarationSyntax)syntaxReferenceOpt.GetSyntax();
        }
 
        internal override ExecutableCodeBinder TryGetBodyBinder(BinderFactory binderFactoryOpt = null, bool ignoreAccessibility = false)
        {
            return TryGetBodyBinderFromSyntax(binderFactoryOpt, ignoreAccessibility);
        }
 
        internal override int ParameterCount
        {
            get { return 0; }
        }
 
        public override ImmutableArray<ParameterSymbol> Parameters
        {
            get { return ImmutableArray<ParameterSymbol>.Empty; }
        }
 
        public override ImmutableArray<TypeParameterSymbol> TypeParameters
        {
            get { return ImmutableArray<TypeParameterSymbol>.Empty; }
        }
 
        public override ImmutableArray<ImmutableArray<TypeWithAnnotations>> GetTypeParameterConstraintTypes()
            => ImmutableArray<ImmutableArray<TypeWithAnnotations>>.Empty;
 
        public override ImmutableArray<TypeParameterConstraintKind> GetTypeParameterConstraintKinds()
            => ImmutableArray<TypeParameterConstraintKind>.Empty;
 
        public override TypeWithAnnotations ReturnTypeWithAnnotations
        {
            get
            {
                LazyMethodChecks();
                return _lazyReturnType;
            }
        }
 
        private static DeclarationModifiers MakeModifiers(NamedTypeSymbol containingType, SyntaxTokenList modifiers, Location location, BindingDiagnosticBag diagnostics, out bool modifierErrors)
        {
            // Check that the set of modifiers is allowed
            const DeclarationModifiers allowedModifiers = DeclarationModifiers.Extern | DeclarationModifiers.Unsafe;
            var mods = ModifierUtils.MakeAndCheckNonTypeMemberModifiers(isOrdinaryMethod: false, isForInterfaceMember: containingType.IsInterface, modifiers, DeclarationModifiers.None, allowedModifiers, location, diagnostics, out modifierErrors);
 
            mods = (mods & ~DeclarationModifiers.AccessibilityMask) | DeclarationModifiers.Protected; // we mark destructors protected in the symbol table
 
            return mods;
        }
 
        public override string Name
        {
            get { return WellKnownMemberNames.DestructorName; }
        }
 
        internal override OneOrMany<SyntaxList<AttributeListSyntax>> GetAttributeDeclarations()
        {
            // destructors can't have return type attributes
            return OneOrMany.Create(this.GetSyntax().AttributeLists);
        }
 
        internal override OneOrMany<SyntaxList<AttributeListSyntax>> GetReturnTypeAttributeDeclarations()
        {
            // destructors can't have return type attributes
            return OneOrMany.Create(default(SyntaxList<AttributeListSyntax>));
        }
 
        internal sealed override bool IsMetadataVirtual(IsMetadataVirtualOption option = IsMetadataVirtualOption.None)
        {
            return true;
        }
 
        internal override bool IsMetadataFinal
        {
            get
            {
                return false;
            }
        }
 
        internal sealed override bool IsMetadataNewSlot(bool ignoreInterfaceImplementationChanges = false)
        {
            return (object)this.ContainingType.BaseTypeNoUseSiteDiagnostics == null;
        }
 
        internal override bool GenerateDebugInfo
        {
            get { return true; }
        }
 
        internal sealed override int? TryGetOverloadResolutionPriority()
        {
            return null;
        }
    }
}