// Copyright (c) 2022 - schick Informatik
// bsmd.AIS2Service [MonitorZone.cs]: %UserDisplayName%
// Description: Represents a geographical area that should be checked against
// ship positions

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace bsmd.AIS2Service
{
    internal class MonitorZone
    {
        private List<GeoPoint> _vertices;

        public MonitorZone(List<GeoPoint> vertices)
        {
            _vertices = vertices;
        }

        public bool IsPointInPolygon4(GeoPoint testPoint)
        {
            bool result = false;
            int j = _vertices.Count() - 1;
            for (int i = 0; i < _vertices.Count(); i++)
            {
                if (_vertices[i].Lat < testPoint.Lat && _vertices[j].Lat >= testPoint.Lat || _vertices[j].Lat < testPoint.Lat && _vertices[i].Lat >= testPoint.Lat)
                {
                    if (_vertices[i].Lon + (testPoint.Lat - _vertices[i].Lat) / (_vertices[j].Lat - _vertices[i].Lat) * (_vertices[j].Lon - _vertices[i].Lon) < testPoint.Lon)
                    {
                        result = !result;
                    }
                }
                j = i;
            }
            return result;
        }
    }

    internal class GeoPoint
    {
        public GeoPoint(double lat, double lon)
        {
            Lat = lat; Lon = lon;
        }

        public double Lat { get; private set; }
        public double Lon { get; private set; }
    }

}