using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Data;

using Wpf.Ui.Extend.Extensions;

namespace Wpf.Ui.Extend.Controls
{
    /// <summary>
    /// 通过该类，对绑定的集合->重新创建为CheckComboBoxItem->应用默认样式
    /// </summary>
    public class CheckComboBox : ComboBoxEx
    {
        #region PrivateProperty
        private ContentPresenter PART_ContentSite;
        private TextBox PART_FilterTextBox;
        private ICollectionView view;
        private Popup PART_Popup;

        private bool popupIsFirstOpen;
        #endregion

        #region DependencyProperty
        public static readonly DependencyProperty ContentProperty =
            DependencyProperty.Register(nameof(Content), typeof(string), typeof(CheckComboBox), new PropertyMetadata(string.Empty));
        /// <summary>
        /// 内容
        /// </summary>
        public string Content
        {
            get { return (string)GetValue(ContentProperty); }
            set { SetValue(ContentProperty, value); }
        }

        public static readonly DependencyProperty ValueProperty =
            DependencyProperty.Register(nameof(Value), typeof(string), typeof(CheckComboBox), new PropertyMetadata(string.Empty));
        /// <summary>
        /// 值
        /// </summary>
        public string Value
        {
            get { return (string)GetValue(ValueProperty); }
            set { SetValue(ValueProperty, value); }
        }

        #region SelectedObjList
        [Bindable(true), Description("获取或者设置当前勾选项列表")]
        public ObservableCollection<object> SelectedObjList
        {
            get { return (ObservableCollection<object>)GetValue(SelectedObjListProperty); }
            set { SetValue(SelectedObjListProperty, value); }
        }

        public static readonly DependencyProperty SelectedObjListProperty =
            DependencyProperty.Register(nameof(SelectedObjList), typeof(ObservableCollection<object>), typeof(CheckComboBox), new PropertyMetadata(null, OnSelectedObjListChanged));

        private static void OnSelectedObjListChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var checkComboBox = d as CheckComboBox;
            if (checkComboBox.ItemsSource != null)
                checkComboBox.SetCheckComboBoxValueAndContent();
        }
        #endregion

        #region SelectedStrList

        public ObservableCollection<string> SelectedStrList
        {
            get { return (ObservableCollection<string>)GetValue(SelectedStrListProperty); }
            set { SetValue(SelectedStrListProperty, value); }
        }

        public static readonly DependencyProperty SelectedStrListProperty =
            DependencyProperty.Register(nameof(SelectedStrList), typeof(ObservableCollection<string>), typeof(CheckComboBox));

        #endregion

        /// <summary>
        /// 获取或者设置最多显示的选中个数
        /// </summary>
        public int MaxShowNumber
        {
            get { return (int)GetValue(MaxShowNumberProperty); }
            set { SetValue(MaxShowNumberProperty, value); }
        }

        public static readonly DependencyProperty MaxShowNumberProperty =
            DependencyProperty.Register(nameof(MaxShowNumber), typeof(int), typeof(CheckComboBox), new PropertyMetadata(3));


        #endregion

        #region Constructors
        static CheckComboBox()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(CheckComboBox), new FrameworkPropertyMetadata(typeof(CheckComboBox)));
        }
        public CheckComboBox()
        {
            this.SelectedObjList = [];
            this.SelectedStrList = [];
        }
        #endregion

        #region Override

        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            if (this.PART_FilterTextBox != null)
            {
                this.PART_FilterTextBox.TextChanged -= PART_FilterTextBox_TextChanged;
            }
            if (PART_Popup != null)
            {
                this.PART_Popup.Opened -= PART_Popup_Opened;
            }

            this.PART_ContentSite = this.GetTemplateChild("PART_ContentSite") as ContentPresenter;
            this.PART_FilterTextBox = this.GetTemplateChild("PART_FilterTextBox") as TextBox;
            this.PART_Popup = this.GetTemplateChild("PART_Popup") as Popup;
            if (this.PART_FilterTextBox != null)
            {
                this.PART_FilterTextBox.TextChanged += PART_FilterTextBox_TextChanged;
            }
            view = CollectionViewSource.GetDefaultView(this.ItemsSource);
            if (PART_Popup != null)
            {
                this.PART_Popup.Opened += PART_Popup_Opened;
            }
            this.Init();
        }
        protected override void PrepareContainerForItemOverride(DependencyObject element, object item)
        {
            if (item is not CheckComboBoxItem)
            {
                if (element is CheckComboBoxItem checkComboBoxItem && !string.IsNullOrEmpty(this.DisplayMemberPath))
                {
                    var binding = new Binding(this.DisplayMemberPath);
                    checkComboBoxItem.SetBinding(CheckComboBoxItem.ContentProperty, binding);
                }
            }

            base.PrepareContainerForItemOverride(element, item);
        }

        protected override DependencyObject GetContainerForItemOverride()
        {
            return new CheckComboBoxItem();
        }

        protected override bool IsItemItsOwnContainerOverride(object item)
        {
            return (item is CheckComboBoxItem);
        }

        #endregion

        #region PrivateFunction
        private void Init()
        {
            this.popupIsFirstOpen = true;

            if (this.SelectedObjList != null)
            {
                foreach (var obj in this.SelectedObjList)
                {
                    if (string.IsNullOrWhiteSpace(this.DisplayMemberPath))
                    {
                        this.SelectedStrList.Add(obj.ToString());
                    }
                    else
                    {
                        this.SelectedStrList.Add(obj.GetPropertyValue(this.DisplayMemberPath).ToString());
                    }
                }
            }
            this.SetCheckComboBoxValueAndContent();
        }

        private void SetCheckComboBoxValueAndContent()
        {
            if (SelectedObjList == null || SelectedObjList.Count <= 0)
                SelectedStrList = [];

            if (this.SelectedStrList == null) return;

            this.Content = this.SelectedStrList.Count > this.MaxShowNumber
                ? $"选中{this.SelectedStrList.Count}个"
                : this.SelectedStrList.Aggregate("", (current, p) => current + (p + ", ")).TrimEnd(new char[] { ' ' }).TrimEnd(new char[] { ',' });

            this.Value = this.SelectedStrList.Aggregate("", (current, p) => current + (p + ",")).TrimEnd(new char[] { ',' });
        }
        #endregion

        #region Internal
        /// <summary>
        /// 行选中
        /// </summary>
        /// <param name="item"></param>
        internal void NotifyCheckComboBoxItemClicked(CheckComboBoxItem item)
        {
            var itemContent = Convert.ToString(item.Content);
            this.SelectedStrList ??= [];
            this.SelectedObjList ??= [];
            if (item.IsSelected)
            {
                if (!this.SelectedStrList.Contains(item.Content))
                {
                    this.SelectedStrList.Add(itemContent);
                }
                if (!this.SelectedObjList.Contains(item.DataContext))
                {
                    this.SelectedObjList.Add(item.DataContext);
                }
            }
            else
            {
                if (this.SelectedStrList.Contains(itemContent))
                {
                    this.SelectedStrList.Remove(itemContent);
                }
                if (this.SelectedObjList.Contains(item.DataContext))
                {
                    this.SelectedObjList.Remove(item.DataContext);
                }
            }
            this.SetCheckComboBoxValueAndContent();
        }
        #endregion

        #region Event Implement Function
        /// <summary>
        /// 每次Open回显数据不太好，先这么处理
        /// </summary>
        private void PART_Popup_Opened(object sender, EventArgs e)
        {
            if (!this.popupIsFirstOpen) return;

            this.popupIsFirstOpen = false;

            if (this.ItemsSource == null || this.SelectedObjList == null) return;

            foreach (var obj in this.SelectedObjList)
            {
                if (this.ItemContainerGenerator.ContainerFromItem(obj) is CheckComboBoxItem checkComboBoxItem)
                    checkComboBoxItem.IsSelected = true;
            }
        }
        /// <summary>
        /// 搜索关键字
        /// </summary>
        private void PART_FilterTextBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            if (this.PART_FilterTextBox == null || view == null) return;

            view.Filter += (o) =>
            {
                var value = Convert.ToString(o.GetPropertyValue(this.DisplayMemberPath)).ToLower();
                return value.Contains(this.PART_FilterTextBox.Text);
            };
            foreach (var obj in this.SelectedObjList)
            {
                if (this.ItemContainerGenerator.ContainerFromItem(obj) is CheckComboBoxItem checkComboBoxItem)
                    checkComboBoxItem.IsSelected = true;
            }
        }
        #endregion
    }
}