package com.example.maptest.model;

import com.mapbox.mapboxsdk.geometry.LatLng;
import java.util.ArrayList;
import java.util.List;

public class Geofence {

    private LatLng center;
    private List<LatLng> polygon;
    private int radius;
    private boolean active = false;

    private Geofence(LatLng center, int radius){
        this.center = center;
        this.radius = radius;
        this.polygon = createGeofence(center,radius);
    }

    public List<LatLng> getPolygon(){
        return polygon;
    }

    public void setActive(boolean active){
        this.active = active;
    }

    public boolean isActive(){
        return active;
    }

    private List<LatLng> createGeofence(LatLng location, double radius) {
        int degreesBetweenPoints = 8; //45 sides
        int numberOfPoints = (int) Math.floor(360 / degreesBetweenPoints);
        double distRadians = radius / 6371000.0; // earth radius in meters
        double centerLatRadians = location.getLatitude() * Math.PI / 180;
        double centerLonRadians = location.getLongitude() * Math.PI / 180;
        List<LatLng> polygons = new ArrayList<>(); //array to hold all the points
        for (int index = 0; index < numberOfPoints; index++) {
            double degrees = index * degreesBetweenPoints;
            double degreeRadians = degrees * Math.PI / 180;
            double pointLatRadians = Math.asin(Math.sin(centerLatRadians) * Math.cos(distRadians) + Math.cos(centerLatRadians) * Math.sin(distRadians) * Math.cos(degreeRadians));
            double pointLonRadians = centerLonRadians + Math.atan2(Math.sin(degreeRadians) * Math.sin(distRadians) * Math.cos(centerLatRadians),
                    Math.cos(distRadians) - Math.sin(centerLatRadians) * Math.sin(pointLatRadians));
            double pointLat = pointLatRadians * 180 / Math.PI;
            double pointLon = pointLonRadians * 180 / Math.PI;
            LatLng point = new LatLng(pointLat, pointLon);
            polygons.add(point);
        }
        return polygons;
    }

    public static class Builder{
        private LatLng center;
        private int radius;

        public Builder(){}

        public Builder addCenter(LatLng center){
            this.center = center;
            return this;
        }

        public Builder addRadius(int radius){
            this.radius = radius;
            return this;
        }

        public Geofence build(){
            return new Geofence(center,radius);
        }
    }
}