// 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 Microsoft.CodeAnalysis.CSharp.Extensions;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Formatting;
using Microsoft.CodeAnalysis.PooledObjects;
using Microsoft.CodeAnalysis.Simplification;

namespace Microsoft.CodeAnalysis.CSharp.Simplification;

internal sealed partial class CSharpNameReducer
{
    private sealed class Rewriter : AbstractReductionRewriter
    {
        public Rewriter(ObjectPool<IReductionRewriter> pool)
            : base(pool)
        {
        }

        public override SyntaxNode VisitPredefinedType(PredefinedTypeSyntax node)
        {
            var oldAlwaysSimplify = this.alwaysSimplify;
            if (!this.alwaysSimplify)
            {
                this.alwaysSimplify = node.HasAnnotation(Simplifier.Annotation);
            }

            var result = SimplifyNode(
                node,
                newNode: base.VisitPredefinedType(node),
                simplifier: s_simplifyName);

            this.alwaysSimplify = oldAlwaysSimplify;

            return result;
        }

        public override SyntaxNode VisitAliasQualifiedName(AliasQualifiedNameSyntax node)
        {
            var oldAlwaysSimplify = this.alwaysSimplify;
            if (!this.alwaysSimplify)
            {
                this.alwaysSimplify = node.HasAnnotation(Simplifier.Annotation);
            }

            var result = SimplifyNode(
                node,
                newNode: base.VisitAliasQualifiedName(node),
                simplifier: s_simplifyName);

            this.alwaysSimplify = oldAlwaysSimplify;

            return result;
        }

        public override SyntaxNode VisitQualifiedName(QualifiedNameSyntax node)
        {
            var oldAlwaysSimplify = this.alwaysSimplify;
            if (!this.alwaysSimplify)
            {
                this.alwaysSimplify = node.HasAnnotation(Simplifier.Annotation);
            }

            var result = SimplifyNode(
                node,
                newNode: base.VisitQualifiedName(node),
                simplifier: s_simplifyName);

            this.alwaysSimplify = oldAlwaysSimplify;

            return result;
        }

        public override SyntaxNode VisitMemberAccessExpression(MemberAccessExpressionSyntax node)
        {
            var oldAlwaysSimplify = this.alwaysSimplify;
            if (!this.alwaysSimplify)
            {
                this.alwaysSimplify = node.HasAnnotation(Simplifier.Annotation);
            }

            var result = SimplifyNode(
                node,
                newNode: base.VisitMemberAccessExpression(node),
                simplifier: s_simplifyName);

            this.alwaysSimplify = oldAlwaysSimplify;

            return result;
        }

        public override SyntaxNode VisitIdentifierName(IdentifierNameSyntax node)
        {
            var oldAlwaysSimplify = this.alwaysSimplify;
            if (!this.alwaysSimplify)
            {
                this.alwaysSimplify = node.HasAnnotation(Simplifier.Annotation);
            }

            var result = SimplifyNode(
                node,
                newNode: base.VisitIdentifierName(node),
                simplifier: s_simplifyName);

            this.alwaysSimplify = oldAlwaysSimplify;

            return result;
        }

        public override SyntaxNode VisitGenericName(GenericNameSyntax node)
        {
            var oldAlwaysSimplify = this.alwaysSimplify;
            if (!this.alwaysSimplify)
            {
                this.alwaysSimplify = node.HasAnnotation(Simplifier.Annotation);
            }

            var result = SimplifyNode(
                node,
                newNode: base.VisitGenericName(node),
                simplifier: s_simplifyName);

            this.alwaysSimplify = oldAlwaysSimplify;

            return result;
        }

        public override SyntaxNode VisitQualifiedCref(QualifiedCrefSyntax node)
        {
            var oldAlwaysSimplify = this.alwaysSimplify;
            if (!this.alwaysSimplify)
            {
                this.alwaysSimplify = node.HasAnnotation(Simplifier.Annotation);
            }

            var result = SimplifyNode(
                node,
                newNode: base.VisitQualifiedCref(node),
                simplifier: s_simplifyName);

            this.alwaysSimplify = oldAlwaysSimplify;

            return result;
        }

        public override SyntaxNode VisitArrayType(ArrayTypeSyntax node)
        {
            var oldAlwaysSimplify = this.alwaysSimplify;
            if (!this.alwaysSimplify)
            {
                this.alwaysSimplify = node.HasAnnotation(Simplifier.Annotation);
            }

            var result = SimplifyNode(
                node,
                newNode: base.VisitArrayType(node),
                simplifier: s_simplifyName);

            this.alwaysSimplify = oldAlwaysSimplify;

            return result;
        }

        public override SyntaxNode VisitNullableType(NullableTypeSyntax node)
        {
            var oldAlwaysSimplify = this.alwaysSimplify;
            if (!this.alwaysSimplify)
            {
                this.alwaysSimplify = node.HasAnnotation(Simplifier.Annotation);
            }

            var result = SimplifyNode(
                node,
                newNode: base.VisitNullableType(node),
                simplifier: s_simplifyName);

            this.alwaysSimplify = oldAlwaysSimplify;

            return result;
        }

        public override SyntaxNode VisitTupleType(TupleTypeSyntax node)
        {
            var oldAlwaysSimplify = this.alwaysSimplify;
            if (!this.alwaysSimplify)
            {
                this.alwaysSimplify = node.HasAnnotation(Simplifier.Annotation);
            }

            var result = SimplifyNode(
                node,
                newNode: base.VisitTupleType(node),
                simplifier: s_simplifyName);

            this.alwaysSimplify = oldAlwaysSimplify;

            return result;
        }

        public override SyntaxNode VisitBinaryExpression(BinaryExpressionSyntax node)
        {
            var isOrAsNode = node.Kind() is SyntaxKind.AsExpression or SyntaxKind.IsExpression;

            var result = (ExpressionSyntax)base.VisitBinaryExpression(node);

            if (result != node && isOrAsNode)
            {
                // In order to handle cases in which simplifying a name would result in code
                // that parses different, we pre-emptively add parentheses that will be
                // simplified away later.
                //
                // For example, this code...
                //
                //     var x = y as Nullable<int> + 1;
                //
                // ...should simplify as...
                //
                //     var x = (y as int?) + 1;
                return result.Parenthesize().WithAdditionalAnnotations(Formatter.Annotation);
            }

            return result;
        }
    }
}