using System;

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

using WPFluent.Extensions;


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

        #region PrivateProperty
        private ContentPresenter PART_ContentSite;
        private System.Windows.Controls.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()
        {
            SelectedObjList = [];
            SelectedStrList = [];
        }
        #endregion

        #region Override
        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

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

            PART_ContentSite = GetTemplateChild("PART_ContentSite") as ContentPresenter;
            PART_FilterTextBox = GetTemplateChild("PART_FilterTextBox") as System.Windows.Controls.TextBox;
            PART_Popup = GetTemplateChild("PART_Popup") as Popup;
            if (PART_FilterTextBox != null)
            {
                PART_FilterTextBox.TextChanged += PART_FilterTextBox_TextChanged;
            }
            view = CollectionViewSource.GetDefaultView(ItemsSource);
            if (PART_Popup != null)
            {
                PART_Popup.Opened += PART_Popup_Opened;
            }
            Init();
        }

        protected override void PrepareContainerForItemOverride(DependencyObject element, object item)
        {
            if (item is not CheckComboBoxItem)
            {
                if (element is CheckComboBoxItem checkComboBoxItem && !string.IsNullOrEmpty(DisplayMemberPath))
                {
                    var binding = new Binding(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()
        {
            popupIsFirstOpen = true;

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

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

            if (SelectedStrList == null)
                return;

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

            Value = SelectedStrList.Aggregate(string.Empty, (current, p) => $"{current}{p},")
                .TrimEnd([',']);
        }
        #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 (!popupIsFirstOpen)
                return;

            popupIsFirstOpen = false;

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

            foreach (var obj in SelectedObjList)
            {
                if (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 (PART_FilterTextBox == null || view == null)
                return;

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