using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using UnityEditor;
using UnityEditor.UIElements;
using UnityEngine;
using UnityEngine.UIElements;
using Object = UnityEngine.Object;

namespace BITKit
{
	public class MaterialPaletteWindow : EditorWindow
	{
		[MenuItem("Tools/Scenes/Material Palette")]
		public static void Open()
		{
			GetWindow<MaterialPaletteWindow>().Show();
		}

		private Button buildButton;
		private Label _titleLabel;
		private VisualElement _container;

		private MeshRenderer[] _renderers=Array.Empty<MeshRenderer>();
		
		private void OnEnable()
		{
			UnityEditor.Selection.selectionChanged += OnSelectionChanged;
			
			rootVisualElement.Clear();
			_titleLabel = rootVisualElement.Create<Label>();
			_container = rootVisualElement.Create<VisualElement>();
			
			_titleLabel.text = "选择一个物体";
		}

		private void OnDisable()
		{
			UnityEditor.Selection.selectionChanged -= OnSelectionChanged;
		}

		private void OnSelectionChanged()
		{
			var actives = UnityEditor.Selection.gameObjects;
			
			_container.Clear();
			
			_renderers = actives.SelectMany(x => x.GetComponentsInChildren<MeshRenderer>()).ToArray();
			
			var materials = _renderers.SelectMany(x => x.sharedMaterials).Distinct().ToArray();
			
			_titleLabel.text = actives is not {Length:0} ?$"选择了{actives.Length }个物体,{materials.Length}个材质" : "未选择物体";
			
			foreach (var material in materials)
			{
				var filed = _container.Create<ObjectField>();
				filed.label = material.name;
				filed.objectType = typeof(Material);
				filed.allowSceneObjects = false;
				filed.value = material;
				filed.RegisterValueChangedCallback(OnChanged);
			}
		}

		private void OnChanged(ChangeEvent<Object> evt)
		{
			if(evt.newValue is not Material value) return;
			var list = new List<Object>();
			foreach (var renderer in _renderers)
			{
				var sharedMaterials = renderer.sharedMaterials;
				var isDirty = false;
				for (var i = 0; i < sharedMaterials.Length; i++)
				{
					var current = sharedMaterials[i];
					if(current != evt.previousValue) continue;
					sharedMaterials[i] = value;
					isDirty = true;
				}

				if (!isDirty) continue;
				renderer.sharedMaterials = sharedMaterials;
				list.Add(renderer);
				EditorUtility.SetDirty(renderer);
			}

			if (list.Count > 0)
			{
				OnSelectionChanged();
			}
		}
	}

}