using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UIElements;
using ZXing;
using ZXing.Common;

namespace BITKit.UX
{
	public class QRVisualElement : VisualElement
	{
		public new class UxmlTraits:VisualElement.UxmlTraits
		{
			private readonly UxmlStringAttributeDescription m_TabsAttribute = new ()
			{
				name = "value"
			};
			public override void Init(VisualElement ve, IUxmlAttributes bag, CreationContext cc)
			{
				base.Init(ve, bag, cc);
				var self = (QRVisualElement)ve;
				self.Value = m_TabsAttribute.GetValueFromBag(bag, cc);
			}
		}
		public new class UxmlFactory : UxmlFactory<QRVisualElement, UxmlTraits> { }
		public QRVisualElement()
		{
			RegisterCallback<GeometryChangedEvent>(x =>
			{
				if (visible)
				{
					Rebuild();
				}
			});
		}
		public string Value
		{
			get => _value;
			set
			{
				_value= value;
				Rebuild();
			}
		}
		private string _value;
		private Texture _texture;
		private void Rebuild()
		{
			if (float.IsNaN(layout.width) || float.IsNaN(layout.height))return;
			if(layout.width <10 || layout.height <10)return;

			var target = _value;
			if (string.IsNullOrEmpty(_value))
			{
				target = nameof(QRVisualElement);
			}
			
			style.backgroundImage = GenerateQRImageWithColor(target, (int)layout.width, (int)layout.height, Color.black, out var bitMatrix);
			
			
			
			Texture2D GenerateQRImageWithColor(string content, int width, int height, Color color, out BitMatrix bitMatrix)
			{
				width=height=Mathf.Max(width,height);
				if (_texture)
				{
					Object.DestroyImmediate(_texture);
				}
				// 编码成color32
				 MultiFormatWriter writer = new MultiFormatWriter();
				Dictionary<EncodeHintType, object> hints = new Dictionary<EncodeHintType, object>();
				//设置字符串转换格式，确保字符串信息保持正确
				hints.Add(EncodeHintType.CHARACTER_SET, "UTF-8");
				// 设置二维码边缘留白宽度（值越大留白宽度大，二维码就减小）
				hints.Add(EncodeHintType.MARGIN, 1);
				hints.Add(EncodeHintType.ERROR_CORRECTION, ZXing.QrCode.Internal.ErrorCorrectionLevel.M);
				//实例化字符串绘制二维码工具
				bitMatrix = writer.encode(content, BarcodeFormat.QR_CODE, width, height, hints);

				// 转成texture2d
				int w = bitMatrix.Width;
				int h = bitMatrix.Height;
				Texture2D texture = new Texture2D(w, h);
				for (int x = 0; x < h; x++)
				{
					for (int y = 0; y < w; y++)
					{
						if (bitMatrix[x, y])
						{
							texture.SetPixel(y, x, color);
						}
						else
						{
							texture.SetPixel(y, x, Color.white);
						}
					}
				}
				texture.Apply();

				//byte[] bytes = texture.EncodeToPNG();
				//string path = System.IO.Path.Combine(Application.dataPath, "qr.png");
				//System.IO.File.WriteAllBytes(path, bytes); 

				_texture = texture;
				return texture;
			}
		}
	}

}