/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.g2d.routing.algorithm2;

import gnu.trove.map.hash.TObjectIntHashMap;

import java.awt.geom.AffineTransform;
import java.awt.geom.Path2D;
import java.awt.geom.PathIterator;
import java.awt.geom.Rectangle2D;
import java.util.ArrayList;
import java.util.Collection;

import org.simantics.g2d.routing.Constants;
import org.simantics.g2d.routing.IConnection;
import org.simantics.g2d.routing.IConnection.Connector;
import org.simantics.g2d.routing.IRouter2;

public class Router3 implements IRouter2 {

    LocalRouter localRouter;

    public Router3(boolean roundCorners) {
        this.localRouter = new LocalRouter(roundCorners);
    }

    private Path2D route(double beginX, double beginY, int sDir, Rectangle2D beginObstacle,
            double endX, double endY, int tDir, Rectangle2D endObstacle) {
        localRouter.sx = beginX;
        localRouter.sy = beginY;
        if(beginObstacle == null) {
            localRouter.aMinX = beginX;
            localRouter.aMinY = beginY;
            localRouter.aMaxX = beginX;
            localRouter.aMaxY = beginY;
        }
        else {
            localRouter.aMinX = beginObstacle.getMinX();
            localRouter.aMinY = beginObstacle.getMinY();
            localRouter.aMaxX = beginObstacle.getMaxX();
            localRouter.aMaxY = beginObstacle.getMaxY();
        }
        localRouter.sourceDirection = sDir;

        localRouter.tx = endX;
        localRouter.ty = endY;
        if(endObstacle == null) {
            localRouter.bMinX = endX;
            localRouter.bMinY = endY;
            localRouter.bMaxX = endX;
            localRouter.bMaxY = endY;
        }
        else {
            localRouter.bMinX = endObstacle.getMinX();
            localRouter.bMinY = endObstacle.getMinY();
            localRouter.bMaxX = endObstacle.getMaxX();
            localRouter.bMaxY = endObstacle.getMaxY();
        }
        localRouter.targetDirection = tDir;

        localRouter.route();

        return localRouter.path;
    }

    @Override
    public void route(IConnection connection) {
//        System.out.println("route");

        Collection<?> segments = connection.getSegments();
        if(segments.size() == 1)
            for(Object seg : segments) {
                Connector begin = connection.getBegin(seg);
                Connector end = connection.getEnd(seg);

                double bestLength = Double.POSITIVE_INFINITY;
                Path2D bestPath = null;

                for(int sDir : Constants.POSSIBLE_DIRECTIONS[begin.allowedDirections])
                    for(int tDir : Constants.POSSIBLE_DIRECTIONS[end.allowedDirections]) {
                        Path2D path = route(begin.x, begin.y, sDir, begin.parentObstacle,
                                end.x, end.y, tDir, end.parentObstacle);

                        double length = pathCost(path);
                        if(length < bestLength) {
                            bestLength = length;
                            bestPath = localRouter.path;
                        }
                    }

                if(bestPath != null)
                    connection.setPath(seg, bestPath);
            }
        else {

            SegmentInfo[] sInfos = new SegmentInfo[segments.size()];
            TObjectIntHashMap<Connector> connectorIds = new TObjectIntHashMap<Connector>();
            int sId = 0;
            int cId = 0;
            for(Object seg : segments) {
                Connector begin = connection.getBegin(seg);
                Connector end = connection.getEnd(seg);

                SegmentInfo sInfo = new SegmentInfo();
                sInfo.segment = seg;
                if(connectorIds.contains(begin))
                    sInfo.begin = connectorIds.get(begin);
                else {
                    sInfo.begin = cId;
                    connectorIds.put(begin, cId);
                    cId += 4;
                }
                if(connectorIds.contains(end))
                    sInfo.end = connectorIds.get(end);
                else {
                    sInfo.end = cId;
                    connectorIds.put(end, cId);
                    cId += 4;
                }

                for(int sDir : Constants.POSSIBLE_DIRECTIONS[begin.allowedDirections])
                    for(int tDir : Constants.POSSIBLE_DIRECTIONS[end.allowedDirections]) {
                        Path2D path = route(begin.x, begin.y, sDir, begin.parentObstacle,
                                end.x, end.y, tDir, end.parentObstacle);

                        sInfo.candidates.add(new SegmentCandidate(
                                path, pathCost(path),
                                sDir, tDir
                        ));
                    }

                sInfos[sId++] = sInfo;
            }

            bestCost = Double.POSITIVE_INFINITY;
            bestPaths = new Path2D[sId];
            findBestCandidate(0, sInfos, new Path2D[sId], new int[cId], 0.0);
            //System.out.println("cost: " + bestCost);
            for(int i=0;i<sId;++i) {
                connection.setPath(sInfos[i].segment, bestPaths[i]);
            }
        }
    }

    double bestCost;
    Path2D[] bestPaths;

    void findBestCandidate(int seg, SegmentInfo[] sInfos, Path2D[] chosen, int[] dirCounts, double cost) {
        if(cost >= bestCost)
            return;
        if(seg < sInfos.length) {
            for(SegmentCandidate sCand : sInfos[seg].candidates) {
                chosen[seg] = sCand.path;
                int sId = sInfos[seg].begin + sCand.sDir;
                int tId = sInfos[seg].end + sCand.tDir;
                double nCost = cost + sCand.localCost;
                if(++dirCounts[sId] > 1)
                    nCost += 10.0;
                nCost += 2.0 * (dirCounts[sId ^ 1] + dirCounts[sId ^ 3]);
                if(++dirCounts[tId] > 1)
                    nCost += 10.0;
                nCost += 2.0 * (dirCounts[tId ^ 1] + dirCounts[tId ^ 3]);
                for(int i=0;i<seg;++i)
                    nCost += 10.0*intersections(chosen[i], sCand.path);
                findBestCandidate(seg+1, sInfos, chosen, dirCounts, nCost);
                --dirCounts[sId];
                --dirCounts[tId];
            }
        }
        else {
            bestCost = cost;
            System.arraycopy(chosen, 0, bestPaths, 0, seg);
        }
    }

    static class SegmentInfo {
        Object segment;
        int begin;
        int end;
        ArrayList<SegmentCandidate> candidates = new ArrayList<SegmentCandidate>(4);
    }

    static class SegmentCandidate {
        Path2D path;
        double localCost;
        int sDir;
        int tDir;

        public SegmentCandidate(Path2D path, double localCost, int sDir, int tDir) {
            this.path = path;
            this.localCost = localCost;
            this.sDir = sDir;
            this.tDir = tDir;
        }

    }

    final static AffineTransform identity = new AffineTransform();

    static int intersections(Path2D path1, Path2D path2) {
        int count = 0;
        PathIterator it1 = path1.getPathIterator(identity);
        double begin1X = 0.0, begin1Y = 0.0, end1X = 0.0, end1Y = 0.0;
        double begin2X = 0.0, begin2Y = 0.0, end2X = 0.0, end2Y = 0.0;
        double[] temp = new double[6];
        while(!it1.isDone()) {
            int t1 = it1.currentSegment(temp);
            if(t1 == PathIterator.SEG_MOVETO) {
                end1X = temp[0];
                end1Y = temp[1];
            }
            else if(t1 == PathIterator.SEG_LINETO) {
                begin1X = end1X;
                begin1Y = end1Y;
                end1X = temp[0];
                end1Y = temp[1];

                double min1X, min1Y, max1X, max1Y;
                if(begin1X < end1X) { min1X = begin1X; max1X = end1X; }
                else                { max1X = begin1X; min1X = end1X; }
                if(begin1Y < end1Y) { min1Y = begin1Y; max1Y = end1Y; }
                else                { max1Y = begin1Y; min1Y = end1Y; }

                PathIterator it2 = path2.getPathIterator(identity);
                while(!it2.isDone()) {
                    int t2 = it2.currentSegment(temp);
                    if(t2 == PathIterator.SEG_MOVETO) {
                        end2X = temp[0];
                        end2Y = temp[1];
                    }
                    else if(t2 == PathIterator.SEG_LINETO) {
                        begin2X = end2X;
                        begin2Y = end2Y;
                        end2X = temp[0];
                        end2Y = temp[1];

                        double min2X, min2Y, max2X, max2Y;
                        if(begin2X < end2X) { min2X = begin2X; max2X = end2X; }
                        else                { max2X = begin2X; min2X = end2X; }
                        if(begin2Y < end2Y) { min2Y = begin2Y; max2Y = end2Y; }
                        else                { max2Y = begin2Y; min2Y = end2Y; }

                        if( ((min1X < min2X && max2X < max1X) || (min2X < min1X && max1X < max2X)) &&
                                ((min1Y < min2Y && max2Y < max1Y) || (min2Y < min1Y && max1Y < max2Y)) )
                            ++ count;
                    }
                    it2.next();
                }
            }
            it1.next();
        }
        return count;
    }

    final static AffineTransform IDENTITY = new AffineTransform();

    static double pathCost(Path2D path) {
        double length = 0.0;
        PathIterator it = path.getPathIterator(IDENTITY);
        double[] temp = new double[6];
        double x=0.0, y=0.0;
        double bendCount = 0.0;
        while(!it.isDone()) {
            bendCount += 1.0;
            if(it.currentSegment(temp) != PathIterator.SEG_MOVETO)
                length += Math.abs(x - temp[0] + y - temp[1]);
            x = temp[0];
            y = temp[1];
            it.next();
        }
        //return length * (6.0 + bendCount);
        return bendCount - 1.0 / length;
    }
}