package org.activityinfo.server.report.generator.map.cluster;

/*
 * #%L
 * ActivityInfo Server
 * %%
 * Copyright (C) 2009 - 2013 UNICEF
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the 
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public 
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/gpl-3.0.html>.
 * #L%
 */

import com.google.common.collect.Lists;
import org.activityinfo.model.type.geo.AiLatLng;
import org.activityinfo.legacy.shared.model.AdminEntityDTO;
import org.activityinfo.legacy.shared.model.SiteDTO;
import org.activityinfo.legacy.shared.reports.content.Point;
import org.activityinfo.legacy.shared.reports.model.PointValue;
import org.activityinfo.legacy.shared.reports.model.clustering.AdministrativeLevelClustering;
import org.activityinfo.server.report.generator.map.RadiiCalculator;
import org.activityinfo.server.report.generator.map.TiledMap;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Clusters a set of points by the administrative level the points reside in,
 * calculated per country
 */
public class AdminLevelClusterer implements Clusterer {
    private AdministrativeLevelClustering model;
    private RadiiCalculator radiiCalculator;

    public AdminLevelClusterer(AdministrativeLevelClustering adminLevelClustering, RadiiCalculator radiiCalculator) {
        super();
        this.model = adminLevelClustering;
        this.radiiCalculator = radiiCalculator;
    }

    @Override
    public List<Cluster> cluster(TiledMap map, List<PointValue> points) {

        // admin entity id -> cluster
        Map<Integer, Cluster> adminClusters = new HashMap<Integer, Cluster>();

        for (PointValue pv : points) {
            AdminEntityDTO entity = getAdminEntityId(pv);
            if (entity != null) {
                Cluster cluster = adminClusters.get(entity.getId());
                if (cluster == null) {
                    cluster = new Cluster(pv);
                    cluster.setPoint(adminCenter(map, entity));
                    cluster.setTitle(entity.getName());
                    adminClusters.put(entity.getId(), cluster);
                } else {
                    cluster.addPointValue(pv);
                }
            }
        }

        ArrayList<Cluster> clusters = Lists.newArrayList();

        // update centers of clusters based on points, if any
        for (Cluster cluster : adminClusters.values()) {
            updateCenter(cluster);
            if (cluster.hasPoint()) {
                clusters.add(cluster);
            }
        }
        radiiCalculator.calculate(clusters);

        return clusters;
    }

    private void updateCenter(Cluster cluster) {
        double count = 0;
        double sumX = 0;
        double sumY = 0;

        for (PointValue pv : cluster.getPointValues()) {
            if (pv.hasPoint()) {
                count++;
                sumX += pv.getPoint().getDoubleX();
                sumY += pv.getPoint().getDoubleY();
            }
        }

        if (count > 0) {
            cluster.setPoint(new Point(sumX / count, sumY / count));
        }
    }

    private Point adminCenter(TiledMap map, AdminEntityDTO entity) {
        if (entity.getBounds() == null) {
            return null;
        } else {
            AiLatLng center = new AiLatLng((entity.getBounds().getMinLat() + entity.getBounds().getMaxLat()) / 2d,
                    (entity.getBounds().getMinLon() + entity.getBounds().getMaxLon()) / 2d);

            return map.fromLatLngToPixel(center);
        }
    }

    private AdminEntityDTO getAdminEntityId(PointValue pv) {
        return getAdminEntity(pv.getSite());
    }

    private AdminEntityDTO getAdminEntity(SiteDTO site) {
        Map<Integer, AdminEntityDTO> membership = site.getAdminEntities();
        for (Integer levelId : model.getAdminLevels()) {
            if (membership.containsKey(levelId)) {
                return membership.get(levelId);
            }
        }
        return null;
    }

    @Override
    public boolean isMapped(SiteDTO site) {
        return getAdminEntity(site) != null;
    }
}