#region License
/* 
 * Copyright (C) 1999-2022 John Källén.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#endregion

using Reko.Core;
using Reko.Core.Expressions;
using Reko.Core.Operators;
using Reko.Core.Types;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Reko.Evaluation
{
    public class DistributedSliceRule
    {
        private DataType? dt;
        private Expression? eLeft;
        private Expression? eRight;
        private Operator? op;
        private int offset;

        public DistributedSliceRule()
        {
        }

        public bool Match(BinaryExpression binExp)
        {
            if (binExp.Operator.Type.IsAddOrSub())
            {
                if (binExp.Left is Slice slLeft && binExp.Right is Slice slRight)
                {
                    if (slLeft.DataType == slRight.DataType && 
                        slLeft.Offset == slRight.Offset)
                    {
                        this.dt = slLeft.DataType;
                        this.eLeft = slLeft.Expression;
                        this.eRight = slRight.Expression;
                        this.op = binExp.Operator;
                        this.offset = slLeft.Offset;
                        return true;
                    }
                }
            }
            return false;
        }

        public Expression Transform(EvaluationContext ctx)
        {
            return new Slice(
                dt!, 
                new BinaryExpression(
                    this.op!, 
                    this.eLeft!.DataType, 
                    this.eLeft!, 
                    this.eRight!),
                this.offset);
        }
    }
}
