BITFALL/Assets/Plugins/FastScriptReload/Scripts/Editor/Compilation/CodeRewriting/ManualUserDefinedScriptOverridesRewriter.cs

using System;
using System.Linq;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp.Syntax;

namespace FastScriptReload.Editor.Compilation.CodeRewriting
{
    public class ManualUserDefinedScriptOverridesRewriter : FastScriptReloadCodeRewriterBase
    {
        private readonly SyntaxNode _userDefinedOverridesRoot;

        public ManualUserDefinedScriptOverridesRewriter(SyntaxNode userDefinedOverridesRoot, bool writeRewriteReasonAsComment, bool visitIntoStructuredTrivia = false)
            : base(writeRewriteReasonAsComment, visitIntoStructuredTrivia)
        {
            _userDefinedOverridesRoot = userDefinedOverridesRoot;
        }
        
        //TODO: refactor to use OverrideDeclarationWithMatchingUserDefinedIfExists
        public override SyntaxNode VisitConversionOperatorDeclaration(ConversionOperatorDeclarationSyntax node)
        {
            var methodFQDN = RoslynUtils.GetMemberFQDN(node, "operator");
            var matchingInOverride = _userDefinedOverridesRoot.DescendantNodes()
                //implicit conversion operators do not have name, just parameter list
                .OfType<BaseMethodDeclarationSyntax>()
                .FirstOrDefault(m => m.ParameterList.ToString() == node.ParameterList.ToString() //parameter lists is type / order / names, all good for targetting if there's a proper match
                                      && methodFQDN == RoslynUtils.GetMemberFQDN(m, "operator") //make sure same FQDN, even though there's no name there could be more implicit operators in file
                );

            if (matchingInOverride != null)
            {
                return AddRewriteCommentIfNeeded(matchingInOverride.WithTriviaFrom(node), $"User defined custom conversion override", true);
            }
            else {
                return base.VisitConversionOperatorDeclaration(node);
            }
        }

        //TODO: refactor to use OverrideDeclarationWithMatchingUserDefinedIfExists
        public override SyntaxNode VisitMethodDeclaration(MethodDeclarationSyntax node)
        {
            var methodName = node.Identifier.ValueText;
            var methodFQDN = RoslynUtils.GetMemberFQDN(node, node.Identifier.ToString());
            var matchingInOverride = _userDefinedOverridesRoot.DescendantNodes()
                .OfType<MethodDeclarationSyntax>()
                .FirstOrDefault(m => m.Identifier.ValueText == methodName
                                     && m.ParameterList.Parameters.Count == node.ParameterList.Parameters.Count
                                     && m.ParameterList.ToString() == node.ParameterList.ToString() //parameter lists is type / order / names, all good for targetting if there's a proper match
                                     && m.TypeParameterList?.ToString() == node.TypeParameterList?.ToString() //typed paratemets are for generics, also check
                                     && methodFQDN == RoslynUtils.GetMemberFQDN(m, m.Identifier.ToString()) //last check for mathod FQDN (potentially slower than others)
                );

            if (matchingInOverride != null)
            {
                return AddRewriteCommentIfNeeded(matchingInOverride.WithTriviaFrom(node), $"User defined custom method override", true);
            }
            else {
                return base.VisitMethodDeclaration(node);
            }
        }
        
        
        public override SyntaxNode VisitConstructorDeclaration(ConstructorDeclarationSyntax node)
        {
            return OverrideDeclarationWithMatchingUserDefinedIfExists(
                node, 
                (d) => d.Identifier.ValueText, 
                (d) => HasSameParametersPredicate(node.ParameterList)(d.ParameterList), 
                (d) => base.VisitConstructorDeclaration(d)
            );
        }
        
        public override SyntaxNode VisitDestructorDeclaration(DestructorDeclarationSyntax node)
        {
            return OverrideDeclarationWithMatchingUserDefinedIfExists(
                node, 
                (d) => d.Identifier.ValueText, 
                (d) => HasSameParametersPredicate(node.ParameterList)(d.ParameterList), 
                (d) => base.VisitDestructorDeclaration(d)
            );
        }
        
        public override SyntaxNode VisitPropertyDeclaration(PropertyDeclarationSyntax node)
        {
            return OverrideDeclarationWithMatchingUserDefinedIfExists(
                node, 
                (d) => d.Identifier.ValueText, 
                (d) => true, 
                (d) => base.VisitPropertyDeclaration(d)
            );
        }

        private SyntaxNode OverrideDeclarationWithMatchingUserDefinedIfExists<T>(T node, Func<T, string> getName, 
            Func<T, bool> customFindMatchInOverridePredicate, Func<T, SyntaxNode> visitDefault)
            where T: MemberDeclarationSyntax
        {
            var name = getName(node);
            var fqdn = RoslynUtils.GetMemberFQDN(node, name);
            var matchingInOverride = _userDefinedOverridesRoot.DescendantNodes()
                .OfType<T>()
                .FirstOrDefault(d =>
                    {
                        var declarationName = getName(d);
                        return declarationName == name
                               && customFindMatchInOverridePredicate(d)
                               && fqdn == RoslynUtils.GetMemberFQDN(d, declarationName);                     //last check for mathod FQDN (potentially slower than others)
                    }

                );

            if (matchingInOverride != null)
            {
                return AddRewriteCommentIfNeeded(matchingInOverride.WithTriviaFrom(node),
                    $"User defined custom {typeof(T)} override", true);
            }
            else
            {
                return visitDefault(node);
            }
        }
        
        private Func<ParameterListSyntax, bool> HasSameParametersPredicate(ParameterListSyntax parameters)
        {
            return (resolvedParams) => resolvedParams.Parameters.Count == parameters.Parameters.Count
                                       && resolvedParams.ToString() == parameters.ToString();
        }
    }
}