using System;

using System.Collections.Generic;

namespace Assistance {

	public class InputModifierSegmentation: InputManager.Modifier {

		public static readonly int maxRecursion = 10;

		public readonly double precision;

		public readonly double precisionSqr;

		public InputModifierSegmentation(double precision = 1.0) {

			this.precision = Math.Max(precision, Geometry.precision);

			this.precisionSqr = this.precision*this.precision;

		}

		public void addSegments(Track track, Track.Point p0, Track.Point p1, int level = 0) {

			if (level >= maxRecursion || (p1.position - p0.position).lenSqr() <= precisionSqr) {

				track.add(p1);

				return;

			}

			Track.Point p = track.modifier.calcPoint(0.5*(p0.originalIndex + p1.originalIndex));

			addSegments(track, p0, p, level + 1);

			addSegments(track, p, p1, level + 1);

		}

		public override void modify(Track track, InputManager.KeyPoint keyPoint, List<Track> outTracks) {

  			if (track.handler == null) {

				track.handler = new Track.Handler(this, track);

				track.handler.tracks.Add(new Track( new Track.Modifier(track.handler) ));

			}

			Track subTrack = track.handler.tracks[0];

			outTracks.Add(subTrack);

			if (!track.wasChanged)

				return;

			// remove points

			int start = track.count - track.pointsAdded;

			if (start < 0) start = 0;

			int subStart = subTrack.floorIndex(subTrack.indexByOriginalIndex(start-1)) + 1;

			subTrack.truncate(subStart);

			// add points

			Track.Point p0 = subTrack.modifier.calcPoint(start - 1);

			for(int i = start; i < track.count; ++i) {

				Track.Point p1 = subTrack.modifier.calcPoint(i);

				addSegments(subTrack, p0, p1);

				p0 = p1;

			}

			track.resetCounters();

		}

	}

}