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/*
 * Copyright (c) 2015-present, Parse, LLC.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */
package com.parse;

import android.location.Criteria;
import android.location.Location;
import android.os.Parcel;
import android.os.Parcelable;

import org.json.JSONArray;
import org.json.JSONException;

import java.util.Locale;
import java.util.List;

import bolts.Continuation;
import bolts.Task;

/**
 * {@code ParsePolygon} represents a set of coordinates that may be associated with a key
 * in a {@link ParseObject} or used as a reference point for geo queries. This allows proximity
 * based queries on the key.
 *
 * Example:
 *  * List points = new ArrayList();
 * points.add(new ParseGeoPoint(0,0));
 * points.add(new ParseGeoPoint(0,1));
 * points.add(new ParseGeoPoint(1,1));
 * points.add(new ParseGeoPoint(1,0));
 * ParsePolygon polygon = new ParsePolygon(points);
 * ParseObject object = new ParseObject("PlaceObject");
 * object.put("area", polygon);
 * object.save();
 * 
 */

public class ParsePolygon implements Parcelable {

  private List coordinates;

  /**
   * Creates a new polygon with the specified {@link ParseGeoPoint}.
   *
   * @param coords
   *          The polygon's coordinates.
   */
  public ParsePolygon(List coords) {
    setCoordinates(coords);
  }

  /**
   * Creates a copy of {@code polygon};
   *
   * @param polygon
   *          The polygon to copy.
   */
  public ParsePolygon(ParsePolygon polygon) {
    this(polygon.getCoordinates());
  }

  /**
   * Creates a new point instance from a {@link Parcel} source. This is used when unparceling a
   * ParsePolygon. Subclasses that need Parcelable behavior should provide their own
   * {@link android.os.Parcelable.Creator} and override this constructor.
   *
   * @param source The recovered parcel.
   */
  protected ParsePolygon(Parcel source) {
    this(source, ParseParcelDecoder.get());
  }

  /**
   * Creates a new point instance from a {@link Parcel} using the given {@link ParseParcelDecoder}.
   * The decoder is currently unused, but it might be in the future, plus this is the pattern we
   * are using in parcelable classes.
   *
   * @param source the parcel
   * @param decoder the decoder
   */
  ParsePolygon(Parcel source, ParseParcelDecoder decoder) {
    setCoordinates(source.readArrayList(null));
  }


  /**
   * Set coordinates. Valid are Array of GeoPoint, ParseGeoPoint or Location
   * at least 3 points
   *
   * @param coords
   *          The polygon's coordinates.
   */
  public void setCoordinates(List coords) {
    this.coordinates = ParsePolygon.validate(coords);
  }

  /**
   * Get coordinates.
   */
  public List getCoordinates() {
    return coordinates;
  }

  /**
   * Get converts coordinate to JSONArray.
   */
  protected JSONArray coordinatesToJSONArray() throws JSONException{
    JSONArray points = new JSONArray();
    for (ParseGeoPoint coordinate : coordinates) {
      JSONArray point = new JSONArray();
      point.put(coordinate.getLatitude());
      point.put(coordinate.getLongitude());
      points.put(point);
    }
    return points;
  }

  /**
   * Checks if this {@code ParsePolygon}; contains {@link ParseGeoPoint}.
   */
  public boolean containsPoint(ParseGeoPoint point) {
    double minX = coordinates.get(0).getLatitude();
    double maxX = coordinates.get(0).getLatitude();
    double minY = coordinates.get(0).getLongitude();
    double maxY = coordinates.get(0).getLongitude();

    for ( int i = 1; i < coordinates.size(); i += 1) {
        ParseGeoPoint geoPoint = coordinates.get(i);
        minX = Math.min(geoPoint.getLatitude(), minX);
        maxX = Math.max(geoPoint.getLatitude(), maxX);
        minY = Math.min(geoPoint.getLongitude(), minY);
        maxY = Math.max(geoPoint.getLongitude(), maxY);
    }

    boolean outside = point.getLatitude() < minX || point.getLatitude() > maxX || point.getLongitude() < minY || point.getLongitude() > maxY;
    if (outside) {
        return false;
    }

    boolean inside = false;
    for (int i = 0, j = coordinates.size() - 1 ; i < coordinates.size(); j = i++) {
      double startX = coordinates.get(i).getLatitude();
      double startY = coordinates.get(i).getLongitude();
      double endX = coordinates.get(j).getLatitude();
      double endY = coordinates.get(j).getLongitude();

      boolean intersect = (( startY > point.getLongitude() ) != ( endY > point.getLongitude() ) &&
          point.getLatitude() < ( endX - startX ) * ( point.getLongitude() - startY ) / ( endY - startY ) + startX);

        if (intersect) {
            inside = !inside;
        }
    }
    return inside;
  }

  /**
   * Throws exception for invalid coordinates.
   */
  static List validate(List coords) {
    if (coords.size() < 3) {
      throw new IllegalArgumentException("Polygon must have at least 3 GeoPoints");
    }
    return coords;
  }

  @Override
  public boolean equals(Object obj) {
    if (obj == null || !(obj instanceof ParsePolygon)) {
      return false;
    }
    if (obj == this) {
      return true;
    }
    ParsePolygon other = (ParsePolygon) obj;

    if (coordinates.size() != other.getCoordinates().size()) {
      return false;
    }

    boolean isEqual = true;
    for (int i = 0; i < coordinates.size(); i += 1) {
      if (coordinates.get(i).getLatitude() != other.getCoordinates().get(i).getLatitude() ||
          coordinates.get(i).getLongitude() != other.getCoordinates().get(i).getLongitude()) {
        isEqual = false;
        break;
      }
    }
    return isEqual;
  }

  @Override
  public String toString() {
    return String.format(Locale.US, "ParsePolygon: %s", coordinates);
  }

  @Override
  public int describeContents() {
    return 0;
  }

  @Override
  public void writeToParcel(Parcel dest, int flags) {
    writeToParcel(dest, ParseParcelEncoder.get());
  }

  void writeToParcel(Parcel dest, ParseParcelEncoder encoder) {
    dest.writeList(coordinates);
  }

  public final static Creator CREATOR = new Creator() {
    @Override
    public ParsePolygon createFromParcel(Parcel source) {
      return new ParsePolygon(source, ParseParcelDecoder.get());
    }

    @Override
    public ParsePolygon[] newArray(int size) {
      return new ParsePolygon[size];
    }
  };
}