using System.Collections.Generic;
using Aspose.Words;
using Aspose.Words.Replacing;

namespace Kreta.BusinessLogic.Utils
{
    public class WordTextReplacer : IReplacingCallback
    {
        public List<Run> _nodes = new List<Run>();

        ReplaceAction IReplacingCallback.Replacing(ReplacingArgs e)
        {
            // This is a Run node that contains either the beginning or the complete match.
            var currentNode = e.MatchNode;

            // The first (and may be the only) run can contain text before the match, 
            // in this case it is necessary to split the run.
            if (e.MatchOffset > 0)
            {
                currentNode = SplitRun((Run)currentNode, e.MatchOffset);
            }

            var runs = new System.Collections.ArrayList();

            // Find all runs that contain parts of the match string.
            var remainingLength = e.Match.Value.Length;
            while (

            (remainingLength > 0) &&

            (currentNode != null) &&

            (currentNode.GetText().Length <= remainingLength))
            {

                runs.Add(currentNode);

                remainingLength -= currentNode.GetText().Length;

                // Select the next Run node. 
                // Have to loop because there could be other nodes such as BookmarkStart etc.
                do
                {
                    currentNode = currentNode.NextSibling;
                }
                while ((currentNode != null) && (currentNode.NodeType != NodeType.Run));
            }

            // Split the last run that contains the match if there is any text left.
            if ((currentNode != null) && (remainingLength > 0))
            {
                SplitRun((Run)currentNode, remainingLength);
                runs.Add(currentNode);
            }

            var runText = "";
            foreach (Run run in runs)
            {
                runText += run.Text;
            }

            ((Run)runs[0]).Text = runText;

            for (var i = 1; i < runs.Count; i++)
            {
                ((Run)runs[i]).Remove();
            }

            _nodes.Add((Run)runs[0]);

            return ReplaceAction.Replace;
        }

        private static Run SplitRun(Run run, int position)
        {
            var afterRun = (Run)run.Clone(true);
            afterRun.Text = run.Text.Substring(position);
            run.Text = run.Text.Substring(0, position);
            run.ParentNode.InsertAfter(afterRun, run);
            return afterRun;
        }
    }
}