using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Markup;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace RazorEngineTest
{
    [ContentProperty("Children")]
    [TemplatePart(Name = "PART_ChildrenContainer", Type = typeof(ItemsControl))]
    public class MyGrid : Control
    {
        [AllowNull]
        private ItemsControl PART_ChildrenContainer;
        [AllowNull]
        private Grid ChildrenContainer;
        static MyGrid()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(MyGrid), new FrameworkPropertyMetadata(typeof(MyGrid)));
        }
        public MyGrid()
        {
            this.Children = new UICollection();
            this.RowDefinitions = new RowDefinitions();
            this.ColDefinitions = new ColDefinitions();
        }
        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();
            this.PART_ChildrenContainer = this.GetTemplateChild("PART_ChildrenContainer") as ItemsControl;
            if (this.PART_ChildrenContainer != null)
                this.PART_ChildrenContainer.Loaded += PART_ChildrenContainer_Loaded;
            else throw new ArgumentNullException($"「{nameof(MyGrid)}」模版必须定义名称为「PART_ChildrenContainer」的「ItemsControl」类型子元素容器...");
        }

        private void PART_ChildrenContainer_Loaded(object sender, RoutedEventArgs e)
        {
            this.ChildrenContainer = this.PART_ChildrenContainer.FindVisualChild<Grid>("ChildrenContainer");
            if (this.ChildrenContainer != null)
            {
                this.ChildrenContainer.ShowGridLines = DesignerProperties.GetIsInDesignMode(this);

                this.ChildrenContainer.RowDefinitions.Clear();
                foreach (var row in this.RowDefinitions) this.ChildrenContainer.RowDefinitions.Add(row);

                this.ChildrenContainer.ColumnDefinitions.Clear();
                foreach (var col in this.ColDefinitions) this.ChildrenContainer.ColumnDefinitions.Add(col);
            }
        }
        /// <summary>
        /// 子元素集合
        /// </summary>
        public UICollection Children
        {
            get { return (UICollection)GetValue(ChildrenProperty); }
            set { SetValue(ChildrenProperty, value); }
        }
        public static readonly DependencyProperty ChildrenProperty =
            DependencyProperty.Register("Children", typeof(UICollection), typeof(MyGrid), new PropertyMetadata(null,
                (d, e) => (d as MyGrid)?.Children_PropertyChangedCallback(e)));
        /// <summary>
        /// 处理「MyGrid.Children」属性变更
        /// </summary>
        protected virtual void Children_PropertyChangedCallback(DependencyPropertyChangedEventArgs e)
        {
            if (e.OldValue is UICollection oldUIColl) oldUIColl.CollectionChanged -= UICollection_CollectionChanged;
            if (e.NewValue is UICollection newUIColl) newUIColl.CollectionChanged += UICollection_CollectionChanged;
        }

        protected virtual void UICollection_CollectionChanged(object? sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
        {
            //TODO：这里可以处理逻辑树的父子级关系
        }
        /// <summary>
        /// 行定义
        /// </summary>
        public RowDefinitions RowDefinitions
        {
            get { return (RowDefinitions)GetValue(RowDefinitionsProperty); }
            protected internal set { SetValue(RowDefinitionsPropertyKey, value); }
        }
        public static readonly DependencyPropertyKey RowDefinitionsPropertyKey =
            DependencyProperty.RegisterReadOnly("RowDefinitions", typeof(RowDefinitions), typeof(MyGrid), new PropertyMetadata(null,
                (d, e) => (d as MyGrid)?.RowDefinitions_PropertyChangedCallback(e)));
        public static readonly DependencyProperty RowDefinitionsProperty = RowDefinitionsPropertyKey.DependencyProperty;
        /// <summary>
        /// 处理「MyGrid.RowDefinitions」属性变更
        /// </summary>
        protected virtual void RowDefinitions_PropertyChangedCallback(DependencyPropertyChangedEventArgs e)
        {
            if (e.OldValue is RowDefinitions oldRows) oldRows.CollectionChanged -= Rows_CollectionChanged;
            if (e.NewValue is RowDefinitions newRows) newRows.CollectionChanged += Rows_CollectionChanged;
        }

        private void Rows_CollectionChanged(object? sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
        {
            if (this.ChildrenContainer != null)
            {
                this.ChildrenContainer.RowDefinitions.Clear();
                foreach (var row in this.RowDefinitions)
                    this.ChildrenContainer.RowDefinitions.Add(row);
            }
        }

        /// <summary>
        /// 列定义
        /// </summary>
        public ColDefinitions ColDefinitions
        {
            get { return (ColDefinitions)GetValue(ColDefinitionsProperty); }
            protected internal set { SetValue(ColDefinitionsPropertyKey, value); }
        }
        public static readonly DependencyPropertyKey ColDefinitionsPropertyKey =
            DependencyProperty.RegisterReadOnly("ColDefinitions", typeof(ColDefinitions), typeof(MyGrid), new PropertyMetadata(null,
                (d, e) => (d as MyGrid)?.ColDefinitions_PropertyChangedCallback(e)));
        public static readonly DependencyProperty ColDefinitionsProperty = ColDefinitionsPropertyKey.DependencyProperty;
        /// <summary>
        /// 处理「MyGrid.ColDefinitions」属性变更
        /// </summary>
        protected virtual void ColDefinitions_PropertyChangedCallback(DependencyPropertyChangedEventArgs e)
        {
            if (e.OldValue is ColDefinitions oldCols) oldCols.CollectionChanged -= Cols_CollectionChanged;
            if (e.NewValue is ColDefinitions newCols) newCols.CollectionChanged += Cols_CollectionChanged;
        }

        private void Cols_CollectionChanged(object? sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
        {
            if (this.ChildrenContainer != null)
            {
                this.ChildrenContainer.ColumnDefinitions.Clear();
                foreach (var col in this.ColDefinitions)
                    this.ChildrenContainer.ColumnDefinitions.Add(col);
            }
        }
    }
    [DefaultMember("Items")]
    public class RowDefinitions : ObservableCollection<RowDefinition> { public RowDefinitions() { } }
    [DefaultMember("Items")]
    public class ColDefinitions : ObservableCollection<ColumnDefinition> { public ColDefinitions() { } }
}