using System;

using System.Collections.Generic;

namespace Assistance {

	public class InputModifierInterpolation: InputManager.Modifier {

		public readonly double precision;

		public readonly double precisionSqr;

		public InputModifierInterpolation(double precision = 1.0) {

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

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

		}

		public void addSegment(Track track, Track.WayPoint p0, Track.WayPoint p1) {

			if ((p1.point.position - p0.point.position).lenSqr() <= precisionSqr)

				{ track.points.Add(p1); return; }

			Track.WayPoint p = track.modifier.calcWayPoint(0.5*(p0.originalIndex + p1.originalIndex));

			addSegment(track, p0, p);

			addSegment(track, p, p1);

		}

		public override List<track> 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];

			Modifier modifier = (Modifier)subTrack.modifier;

			outTracks.Add(subTrack);

			if (!track.isChanged)

				return;

			// remove points

			int start = track.points.Count - track.wayPointsAdded;

			if (start < 0) start = 0;

			int subStart = subTrack.floorIndex(subTrack.indexByOriginalIndex(start));

			if (subTrack.points.Count < subStart) {

				subTrack.points.RemoveRange(subStart, subTrack.points.Count - subStart);

				subTrack.wayPointsRemoved += subTrack.points.Count - subStart;

			}

			// add points

			Track.WayPoint p0 = track.getWayPoint(start - 1);

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

				Track.WayPoint p1 = track.points[i];

				addSegment(subTrack, p0, p1);

				p0 = p1;

			}

			subTrack.wayPointsAdded += subTrack.points.Count - subStart;

		}

	}

}