using System;

using System.Collections.Generic;

using System.Linq;

namespace Assistance {

	public class Workarea {

		public readonly Document document;

		public Workarea() {

			document = new Document(this);

		}

		public ActivePoint findPoint(Point position) {

			foreach(ActivePoint point in document.points.Reverse<activepoint>())</activepoint>

				if (point.isInside(position))

					return point;

			return null;

		}

		public void getGuidelines(List<guideline> outGuidelines, Point target) {</guideline>

			foreach(Assistant assistant in document.assistants)

				assistant.getGuidelines(outGuidelines, target);

		}

		public void draw(Cairo.Context context, ActivePoint activePoint, Point target, Track track) {

			// canvas

			document.canvas.draw(context);

			// guidelines and track

			List<guideline> guidelines = new List<guideline>();</guideline></guideline>

			if (track != null && track.points.Count > 0) {

				Guideline guideline;

				Track modifiedTrack = modifyTrackByAssistant(track, out guideline);

				getGuidelines(guidelines, modifiedTrack.transform(track.points.Last()).point);

				foreach(Guideline gl in guidelines)

					gl.draw(context);

				track.draw(context, true);

				if (guideline != null) guideline.draw(context, true);

				List<track> modifiedTracks = modifyTrackByModifiers(modifiedTrack);

				rebuildTracks(modifiedTracks);

				foreach(Track t in modifiedTracks)

					t.draw(context);

			} else {

				getGuidelines(guidelines, target);

				foreach(Guideline guideline in guidelines)

					guideline.draw(context);

			}

			// modifiers

			foreach(Modifier modifier in document.modifiers)

				modifier.draw(context);

			// assistants

			foreach(Assistant assistant in document.assistants)

				assistant.draw(context);

			// active points

			foreach(ActivePoint point in document.points)

				point.draw(context, activePoint == point);

		}

		public Track modifyTrackByAssistant(Track track, out Guideline guideline) {

			guideline = null;

			if (track.points.Count < 1)

				return track.createChild(Geometry.noTransform);

			List<guideline> guidelines = new List<guideline>();</guideline></guideline>

			getGuidelines(guidelines, track.points[0].point);

			guideline = Guideline.findBest(guidelines, track);

			if (guideline == null)

				return track.createChild(Geometry.noTransform);

			return track.createChild(guideline.transformPoint);

		}

		public List<track> modifyTrackByModifiers(Track track) {

			List<track> tracks = new List<track>() { track };

			foreach(Modifier modifier in document.modifiers)

				tracks = modifier.modify(tracks);

			return tracks;

		}

		public void rebuildTracks(List<track> tracks) {

			foreach(Track track in tracks)

				track.rebuild();

		}

		public List<track> modifyTrack(Track track) {

			Guideline guideline;

			List<track> tracks = modifyTrackByModifiers(

				modifyTrackByAssistant(track, out guideline) );

			rebuildTracks(tracks);

			return tracks;

		}

		public void paintTrack(Track track) {

			List<track> tracks = modifyTrack(track);

			foreach(Track t in tracks)

				document.canvas.paintTrack(t);

		}

	}

}