using System.IO;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Semmle.Extraction.Kinds;

namespace Semmle.Extraction.CSharp.Entities.Expressions
{
    internal class Unary : Expression<PrefixUnaryExpressionSyntax>
    {
        private Unary(ExpressionNodeInfo info, ExprKind kind)
            : base(info.SetKind(UnaryOperatorKind(info.Context, info.Kind, info.Node)))
        {
            operatorKind = kind;
        }

        private readonly ExprKind operatorKind;

        public static Unary Create(ExpressionNodeInfo info)
        {
            var ret = new Unary(info, info.Kind);
            ret.TryPopulate();
            return ret;
        }

        protected override void PopulateExpression(TextWriter trapFile)
        {
            Create(Context, Syntax.Operand, this, 0);
            OperatorCall(trapFile, Syntax);

            if ((operatorKind == ExprKind.PRE_INCR || operatorKind == ExprKind.PRE_DECR) &&
                Kind == ExprKind.OPERATOR_INVOCATION)
            {
                trapFile.mutator_invocation_mode(this, 1);
            }
        }
    }
}