// Copyright (c) Ivan Bondarev, Stanislav Mikhalkovich (for details please see \doc\copyright.txt)
// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
using System.Collections.Generic;
using PascalABCCompiler.CoreUtils;
using PascalABCCompiler.SyntaxTree;

namespace SyntaxVisitors
{
    public class CapturedLambdaInYieldVisitor : BaseChangeVisitor
    {
        private readonly GeneratedNamesManager generatedNamesManager;

        private CapturedLambdaInYieldVisitor(GeneratedNamesManager generatedNamesManager)
        {
            this.generatedNamesManager = generatedNamesManager;
        }

        public static CapturedLambdaInYieldVisitor Create(GeneratedNamesManager generatedNamesManager) => new CapturedLambdaInYieldVisitor(generatedNamesManager);

        public static void Accept(procedure_definition pd, GeneratedNamesManager generatedNamesManager)
        {
            Create(generatedNamesManager).ProcessNode(pd);
        }

        private string CreateNameForLambdaInYield()
        {
            return generatedNamesManager.GenerateName("@RenLamInYield", "$");
        }

        public override void visit(yield_node yn)
        {
            if (yn.ex is function_lambda_definition)
            {
                syntax_tree_node sn = yn;
                do
                {
                    sn = sn.Parent;
                } while (sn != null && !(sn is procedure_definition));
                procedure_definition pd = sn as procedure_definition;

                if (sn == null)
                {
                    // этого не будет
                }
                var fh = pd.proc_header as function_header;
                if (fh == null)
                {
                    // этого тоже не будет
                }
                var sq = fh.return_type as sequence_type;
                if (sq == null)
                {
                    // и этого не будет
                }

                var lst = new List<statement>();
                var newid = new ident(CreateNameForLambdaInYield(), yn.ex.source_context);
                var vs = new var_statement(newid, sq.elements_type, yn.ex);
                vs.source_context = yn.ex.source_context;
                var newyn = new yield_node(newid, newid.source_context);
                lst.Add(vs);
                lst.Add(newyn);
                ReplaceStatementUsingParent(yn, lst);
            }
        }


    }
}