using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;

namespace Plane.Maps.ChinaOffset
{
    public sealed class ChinaMapOffsetResolver
    {
        private static ChinaMapOffsetResolver _Instance;
        public static ChinaMapOffsetResolver Instance
        {
            get { return _Instance ?? (_Instance = new ChinaMapOffsetResolver()); }
        }

        private ChinaMapOffsetResolver() { }

        private ChinaOffsetMap _CM;
        private ChinaOffsetMap CM { get { return _CM ?? (_CM = new ChinaOffsetMap(LoadResource("chinaoffset"))); } }

        private ChinaOffsetMap _Acm;
        private ChinaOffsetMap Acm { get { return _Acm ?? (_Acm = new ChinaOffsetMap(LoadResource("antichinaoffset"))); } }

        public LatLng StandardToChinaMap(double lat, double lng)
        {
            var dxyRetLngLat = new double[2];
            this.CM.GetLonLatAfterOffset(lng, lat, dxyRetLngLat);
            return new LatLng(dxyRetLngLat[1], dxyRetLngLat[0]);
        }

        public LatLng ChinaMapToStandard(double lat, double lng)
        {
            var dxyRetLngLat = new double[2];
            this.Acm.GetLonLatAfterOffset(lng, lat, dxyRetLngLat);
            return new LatLng(dxyRetLngLat[1], dxyRetLngLat[0]);
        }

        private Stream LoadResource(string simpleName)
        {
            String resourceName = this.GetType().Namespace + ".Resources." + simpleName + ".dat";
            return typeof(ChinaMapOffsetResolver).GetTypeInfo().Assembly.GetManifestResourceStream(resourceName);
        }
    }
}