using System;
using System.Collections;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using SkiaSharp;
using UnityEngine;
using UnityEngine.UIElements;


namespace BITKit.UX
{
	public class SkiaChart : VisualElement
	{
		public new class UxmlTraits : VisualElement.UxmlTraits
		{
			private readonly UxmlStringAttributeDescription m_JsonAttribute = new()
			{
				name = "Json"
			};

			private readonly UxmlBoolAttributeDescription m_allowWarningsAttribute = new()
			{
				name = "allowWarnings",
				defaultValue = false
			};

			public override void Init(VisualElement ve, IUxmlAttributes bag, CreationContext cc)
			{
				base.Init(ve, bag, cc);
				var x = (SkiaChart)ve;
				x.Json = m_JsonAttribute.GetValueFromBag(bag, cc);
				x.AllowWarning = m_allowWarningsAttribute.GetValueFromBag(bag, cc);

			}
		}

		public new class UxmlFactory : UxmlFactory<SkiaChart, UxmlTraits>
		{
		}

		public SkiaChart()
		{
			RegisterCallback<GeometryChangedEvent>(x =>
			{
				if (visible)
				{
					Rebuild();
				}
			});
			RegisterCallback<CustomStyleResolvedEvent>(OnCustomStyleResolved);

			style.flexDirection = FlexDirection.Row;
			_dataContainer = this.Create<VisualElement>();
			_chartContainer = this.Create<VisualElement>();
			_chartContainer.style.flexGrow = 1;

			_dataContainer.style.justifyContent = Justify.SpaceBetween;

			_dataContainer.name = "Data";
			_chartContainer.name = "Chart";
		}

		private void OnCustomStyleResolved(CustomStyleResolvedEvent evt)
		{
			if (evt.customStyle.TryGetValue(new CustomStyleProperty<Color>("--chart-secondary-color"),
				    out var helpLineColor))
			{
				_secondaryColor = helpLineColor;
			}

			Rebuild();
		}

		public string Json
		{
			get => _json;
			set
			{
				_json = value;
				Rebuild();
			}
		}

		private string _json;
		public bool AllowWarning { get; set; }

		public Color SecondaryColor
		{
			get => _secondaryColor;
			set
			{
				_secondaryColor = value;
				Rebuild();
			}
		}

		private Color _secondaryColor;

		private readonly VisualElement _dataContainer;
		private readonly VisualElement _chartContainer;

		private void Rebuild()
		{
			if (float.IsNaN(layout.width) || float.IsNaN(layout.height))
			{
				if (AllowWarning)
					BIT4Log.Log<SkiaChart>("Width or height is NaN");
				return;
			}

			JArray[] array;
			float[] data;
			try
			{
				array = JsonConvert.DeserializeObject<JArray[]>(Json);
				data = array.SelectMany(x => x.ToObject<float[]>()).ToArray();
			}
			catch (Exception e)
			{
				if (AllowWarning)
					Debug.LogException(e);
				return;
			}

			if (data is null or { Length: 0 })
			{
				if (AllowWarning)
					BIT4Log.Log<SkiaChart>("Data is null or empty");
				return;
			}

			_dataContainer.Clear();
			_chartContainer.Clear();
			// _chartContainer.style.marginBottom = 8;
			// _chartContainer.style.marginLeft = 8;
			// _chartContainer.style.marginRight = 8;
			// _chartContainer.style.marginTop = 8;
			_dataContainer.style.flexDirection = FlexDirection.ColumnReverse;

			//假如min是x,max是y,将中间的差用data.Length划分
			var max = data.Max();
			var min = data.Min();

			var difference = max - min;
			
			var maxLength = array.Select(x => x.Count).Max();

			max = max + difference / maxLength;
			min = min - difference / maxLength;
			difference = max - min;

	

			//Debug.Log($"min:{min} max:{max} difference:{difference} max:{max}");

			for (var i = 0; i <= maxLength; i++)
			{
				var label = _dataContainer.Create<Label>();

				//var value = (max - min) / (data.Length - 1) * i + min;

				var t = (float)i / maxLength;
				var value = Mathf.Lerp(min,max,t);
				label.text = Math.Round(value, 2).ToString();
			}

			if (_chartContainer.layout.width is float.NaN or < 10 || _chartContainer.layout.height is float.NaN or < 10)
			{
				if (AllowWarning)
					BIT4Log.Log<SkiaChart>("Width or height is NaN or less than 10");
				return;
			}

			var info = new SKImageInfo(
				width: (int)_chartContainer.layout.width,
				height: (int)_chartContainer.layout.height,
				colorType: SKColorType.Rgba8888,
				alphaType: SKAlphaType.Premul
			);

			using var surface = SKSurface.Create(info);

			using var canvas = surface.Canvas;

			using var linePaint = new SKPaint();

			linePaint.StrokeWidth = resolvedStyle.unityTextOutlineWidth;
			linePaint.IsAntialias = true;
			linePaint.Style = SKPaintStyle.Stroke;

			using var helpLinePaint = new SKPaint();
			helpLinePaint.Color = resolvedStyle.unityTextOutlineColor.ToSKColor();
			helpLinePaint.StrokeWidth = 1;
			helpLinePaint.Style = SKPaintStyle.Stroke;

			using var fillPaint = new SKPaint();
			fillPaint.Color = new SKColor(200, 200, 200, 200);
			fillPaint.Style = SKPaintStyle.Fill;


			for (var index = 0; index < array.Length; index++)
			{
				var _array = array[index];
				DoubleBuffer<SKPoint> buffer = new();

				data = _array.ToObject<float[]>();

				var path = new SKPath { FillType = SKPathFillType.EvenOdd };

				path.MoveTo(0, 0);
				path.LineTo(0, 0);

				if (_array.Count is not 1 && customStyle.TryGetValue(new CustomStyleProperty<Color>($"--color-{index}"),
					    out var _myStyle))
				{
					linePaint.Color = _myStyle.ToSKColor();
				}
				else
				{
					linePaint.Color = resolvedStyle.color.ToSKColor();
				}

				for (var i = 1; i <= data.Length; i++)
				{
					var value = data[i-1];
					var posX = (float)info.Width / data.Length * (i);
					var p = (value - min) / difference;
					var poxY = info.Height * p;

					var currentPoint = new SKPoint(posX, poxY);
					if (buffer.TryGetRelease(out var previousPoint))
					{
						canvas.DrawLine(previousPoint, currentPoint, linePaint);
					}

					if (i == data.Length)
					{
						var label = _chartContainer.Create<Label>();
					label.text = Math.Round(value, 2).ToString(CultureInfo.InvariantCulture);
					label.style.position = Position.Absolute;
					label.style.left = posX; //-label.layout.width/2;
					label.style.bottom = poxY; //- label.layout.height/2; 
					//label.transform.position = new Vector3(-label.layout.width/2, poxY, 0);
					}
					

					canvas.DrawLine(posX, 0, posX, poxY, helpLinePaint);

					path.LineTo(posX, poxY);

					buffer.Release(currentPoint);
				}

				path.LineTo(info.Width, 0);
				path.Close();
			}

			var texture = info.ToTexture2D(surface);

			_chartContainer.style.backgroundImage = texture;
		}
	}
}