using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.ComponentModel;
using ElmSharp;
using Tizen.Location;
using Tizen.Maps;
using Xamarin.Forms.Platform.Tizen;

namespace Xamarin.Forms.Maps.Tizen
{
	public class MapRenderer : ViewRenderer<Map, MapView>
	{
		const string MoveMessageName = "MapMoveToRegion";

		bool _disposed;
		Overlay _marker;
		bool _isLocatorStarted = false;
		Lazy<Locator> _locator = new Lazy<Locator>(InitializeLocator);
		Dictionary<Pin, MapObject> _pins = new Dictionary<Pin, MapObject>();

		static Locator InitializeLocator()
		{
			var locator = new Locator(LocationType.Hybrid)
			{
				// Set the default interval to 15s same as UWP
				Interval = 15
			};
			return locator;
		}

		public MapRenderer()
		{
		}

		protected override void OnElementChanged(ElementChangedEventArgs<Map> e)
		{
			if (Control == null)
			{
				var mapControl = new MapView(Platform.Tizen.Forms.Context.MainWindow, FormsMaps.MapService);
				SetNativeControl(mapControl);
			}

			if (e.OldElement != null)
			{
				((ObservableCollection<Pin>)e.OldElement.Pins).CollectionChanged -= OnCollectionChanged;

				MessagingCenter.Unsubscribe<Map, MapSpan>(this, MoveMessageName);
			}
			if (e.NewElement != null)
			{
				((ObservableCollection<Pin>)e.NewElement.Pins).CollectionChanged += OnCollectionChanged;
				if (e.NewElement.Pins.Count > 0)
				{
					AddPins(e.NewElement.Pins);
				}

				MessagingCenter.Subscribe<Map, MapSpan>(this, MoveMessageName, OnMoveToRegion, e.NewElement);

				UpdateMapType();
				UpdateHasScrollEnabled();
				UpdateHasZoomEnabled();
				UpdateIsShowingUser();
			}
			base.OnElementChanged(e);
		}

		protected override void Dispose(bool disposing)
		{
			if (_disposed)
			{
				return;
			}

			_disposed = true;

			if (disposing)
			{
				MessagingCenter.Unsubscribe<Map, MapSpan>(this, "MapMoveToRegion");
				if (Element != null)
				{
					((ObservableCollection<Pin>)Element.Pins).CollectionChanged -= OnCollectionChanged;
				}
				Control.Unrealize();
			}
			base.Dispose(disposing);
		}

		protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
		{
			base.OnElementPropertyChanged(sender, e);

			if (e.PropertyName == Map.MapTypeProperty.PropertyName)
				UpdateMapType();
			else if (e.PropertyName == Map.IsShowingUserProperty.PropertyName)
				UpdateIsShowingUser();
			else if (e.PropertyName == Map.HasScrollEnabledProperty.PropertyName)
				UpdateHasScrollEnabled();
			else if (e.PropertyName == Map.HasZoomEnabledProperty.PropertyName)
				UpdateHasZoomEnabled();
		}

		void OnMoveToRegion(Map map, MapSpan span)
		{
			var newCenter = new Geocoordinates(span.Center.Latitude, span.Center.Longitude);
			Control.Center = newCenter;
		}


		void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
		{
			if (e.NewItems != null)
			{
				AddPins(e.NewItems);
			}
			if (e.OldItems != null)
			{
				RemovePins(e.OldItems);
			}
			if (e.Action == NotifyCollectionChangedAction.Reset)
			{
				ClearPins();
			}
		}

		void AddPins(IEnumerable pins)
		{
			foreach (Pin pin in pins)
			{
				var coordinates = new Geocoordinates(pin.Position.Latitude, pin.Position.Longitude);
				var rectangle = new Background(Platform.Tizen.Forms.Context.MainWindow);
				// TODO: Need to change BubbleOverlay to default Marker
				// TODO: Need to handle Pin.Clicked event
				var nativePin = new BubbleOverlay(coordinates, rectangle);
				Control.Add(nativePin);
				_pins.Add(pin, nativePin);
			}
		}

		void RemovePins(IEnumerable pins)
		{
			foreach (Pin pin in pins)
			{
				if (_pins.ContainsKey(pin))
				{
					Control.Remove(_pins[pin]);
					_pins.Remove(pin);
				}
			}
		}

		void ClearPins()
		{
			foreach (var pin in _pins)
			{
				Control.Remove(pin.Value);
			}
			_pins.Clear();
		}

		void UpdateHasZoomEnabled()
		{
			if (Element.HasZoomEnabled == true)
				Control.ZoomChanged += Dummy;
			else
				Control.ZoomChanged -= Dummy;
		}

		void UpdateHasScrollEnabled()
		{
			if (Element.HasScrollEnabled == true)
				Control.Scrolled += Dummy;
			else
				Control.Scrolled -= Dummy;
		}

		void Dummy(object sender, MapGestureEventArgs e)
		{
			//TODO: The implementation of Tizen.Maps needs to be changed to remove this method
		}

		void ApplyIsShowingUser(Geocoordinates coordinates)
		{
			if (_marker == null)
			{
				var rectangle = new Background(Platform.Tizen.Forms.Context.MainWindow);
				// TODO: Need to change BubbleOverlay to Default Overlay
				_marker = new BubbleOverlay(coordinates, rectangle);
				_marker.IsVisible = false;
				Control.Add(_marker);
			}
			_marker.Coordinates = coordinates;

			if (!_marker.IsVisible)
			{
				_marker.IsVisible = true;
				Control.Center = coordinates;
				Control.ZoomLevel = 13;
			}
		}
		void UpdateIsShowingUser()
		{
			if (Element.IsShowingUser)
			{
				_locator.Value.LocationChanged += OnLocationChanged;
				if (!_isLocatorStarted)
				{
					_locator.Value.Start();
					_isLocatorStarted = true;
				}
			}
			else
			{
				if (_locator.IsValueCreated)
				{
					_locator.Value.LocationChanged -= OnLocationChanged;
					_locator.Value.Stop();
					_isLocatorStarted = false;
				}
				if (_marker != null)
					_marker.IsVisible = false;
			}
		}

		void OnLocationChanged(object sender, LocationChangedEventArgs e)
		{
			ApplyIsShowingUser(new Geocoordinates(e.Location.Latitude, e.Location.Longitude));
		}

		void UpdateMapType()
		{
			switch (Element.MapType)
			{
				case MapType.Street:
					Control.MapType = MapTypes.Normal;
					break;
				case MapType.Satellite:
					Control.MapType = MapTypes.Satellite;
					break;
				case MapType.Hybrid:
					Control.MapType = MapTypes.Hybrid;
					break;
				default:
					throw new ArgumentOutOfRangeException();
			}
		}
	}
}