using CssSyntax;
using CssSyntax.SyntaxTree;
using System;
using System.Collections.Generic;
using System.Linq;

namespace CssDupfinder
{
    public class CssDuplicateSelectorWalker : CssWalker
    {
        private readonly IDictionary<String, List<RangePosition>> selectors = new Dictionary<String, List<RangePosition>>();

        public IDictionary<String, List<RangePosition>> Duplicates
        {
            get { return selectors.Where(s => s.Value.Count > 1).ToDictionary(s => s.Key, s => s.Value); }
        }

        protected override void VisitBeginSelector(string selector, int line, int column)
        {
            List<RangePosition> list;

            if (selectors.ContainsKey(selector))
            {
                list = selectors[selector];
            }
            else
            {
                list = new List<RangePosition>();
                selectors.Add(selector, list);
            }

            list.Add(new RangePosition
            {
                Start = new Position(line, column)
            });
        }

        protected override void VisitEndSelector(string selector, int line, int column)
        {
            selectors[selector].Last().End = new Position(line, column);
        }
    }
}