using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Threading;


namespace wenku8
{
    class ContentView: ListBox
    {
        private String[] ps;
        // Number of paragraph to display
        private int displayLimit = 64;
        // Number of section splitted
        private int section;
        // Current section
        private int currentSection = 0;
        // Total Numbers of paragraphs
        private int l;

        public ContentView(String[] paragraphs)
        {
            ps = paragraphs;
            l = ps.Length;
            section = Convert.ToInt32(Math.Ceiling(Convert.ToDouble(ps.Length / displayLimit)));

            initObjects();
        }

        public void NewContent(String[] paragraphs)
        {
            this.Items.Clear();
            ps = paragraphs;
            l = ps.Length;
            section = Convert.ToInt32(Math.Ceiling(Convert.ToDouble(ps.Length / displayLimit)));
            currentSection = 0;

            initObjects();
        }

        private void initObjects()
        {
            addSection();
        }

        private void addSection()
        {
            int lineIndex = currentSection*displayLimit;
            ListBoxItem wrapper = null;
            for (int i = 0; i < displayLimit; i++)
            {
                if (lineIndex + i < l)
                {
                    wrapper = new ListBoxItem();
                    TextBlock p = new TextBlock();
                    p.Text = ps[currentSection * displayLimit + i];
                    p.TextWrapping = TextWrapping.Wrap;
                    wrapper.Content = p;
                    this.Items.Add(wrapper);
                }
                else
                {
                    break;
                }
            }
            wrapper.Loaded += wrapper_Loaded;
        }

        void wrapper_Loaded(object sender, RoutedEventArgs e)
        {
            // This detects if the last item is loaded
            // so trigger the listbox to show more items
            if (currentSection < section)
            {
                currentSection++;
                addSection();
            }
        }
    }
}