using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.Linq;
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.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Xml.Linq;

namespace compdfkit_tools.PDFControlUI
{
    public partial class CPDFThumbnailUI : UserControl
    {
        /// <summary>
        /// 缩略图列表点击选中事件
        /// </summary>
        public event EventHandler<int> SelectionChanged;

        /// <summary>
        /// 滚动状态改变事件
        /// </summary>
        public event EventHandler<ScrollChangedEventArgs> ViewChanged;

        /// <summary>
        /// 缩略图结果列表
        /// </summary>
        private List<ThumbnailItem> thumbResultList=new List<ThumbnailItem>();
        public CPDFThumbnailUI()
        {
            InitializeComponent();
        }

        /// <summary>
        /// 选中结果改变事件
        /// </summary>
        private void ThumbListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            SelectionChanged?.Invoke(this, ThumbListBox.SelectedIndex);
        }

        /// <summary>
        /// 设置缩略图列表
        /// </summary>
        /// <param name="thumbList"></param>
        public void SetThumbResult(List<ThumbnailItem> thumbList)
        {
            thumbResultList?.Clear();
            ThumbListBox.ItemsSource = null;
            if (thumbList == null || thumbList.Count == 0)
            {
                return;
            }
            thumbResultList.AddRange(thumbList);
            ThumbListBox.ItemsSource = thumbResultList;
        }

        /// <summary>
        /// 内容滚动事件
        /// </summary>
        private void ThumbListBox_ScrollChanged(object sender, ScrollChangedEventArgs e)
        {
            ViewChanged?.Invoke(this, e);
        }

        /// <summary>
        /// 判断指定对象是否可见
        /// </summary>
        public bool IsItemVisible(ThumbnailItem checkItem)
        {
            if (ThumbListBox == null || thumbResultList == null || thumbResultList.Count == 0)
            {
                return false;
            }
            try
            {
                int index = thumbResultList.IndexOf(checkItem);
                if (index != -1)
                {
                    ListBoxItem itemContainer = (ListBoxItem)ThumbListBox.ItemContainerGenerator.ContainerFromIndex(index);
                    if (itemContainer==null || itemContainer.IsVisible == false || itemContainer.Visibility != Visibility.Visible)
                    {
                        return false;
                    }

                    GeneralTransform transform = itemContainer.TransformToAncestor(ThumbListBox);
                    Rect visualRect= transform.TransformBounds(new Rect(
                        0,
                        0,
                        itemContainer.ActualWidth,
                        itemContainer.ActualHeight
                        ));
                    Rect containerRect=new Rect(
                        0,
                        0,
                        ThumbListBox.ActualWidth,
                        ThumbListBox.ActualHeight);

                    if (containerRect.IntersectsWith(visualRect))
                    {
                        return true;
                    }
                }
            }
            catch(Exception ex)
            {

            }
           
            return false;
        }
    }

    /// <summary>
    /// 缩略图对象
    /// </summary>
    public class ThumbnailItem
    {
        /// <summary>
        /// 图像宽度
        /// </summary>
        public int ImageWidth { get; set; }

        /// <summary>
        /// 图像高度
        /// </summary>
        public int ImageHeight { get; set; }

        /// <summary>
        ///缩略图宽度
        /// </summary>
        public int ThumbnailWidth { get; set; }

        /// <summary>
        /// 缩略图高度
        /// </summary>
        public int ThumbnailHeight { get; set; }

        /// <summary>
        /// 展示页码
        /// </summary>
        public string ShowPageText
        {
            get
            {
                if (PageIndex >= 0)
                {
                    return (PageIndex + 1).ToString();
                }

                return string.Empty;
            }
        }

        /// <summary>
        /// 页面索引(以0开始)
        /// </summary>
        public int PageIndex { get; set; } = -1;

        /// <summary>
        /// 缩略图像内容
        /// </summary>
        public Image ImageData { get; set; } = new Image();
    }
}