using System.Collections;
using System.ComponentModel;

namespace System.Windows.Forms
{
    public partial class ListControl : Control
    {
        protected new System.Windows.Controls.Primitives.Selector control { get; private set; }

        public ObjectCollection Items { get; private set; }
        
        public int SelectedIndex
        {
            get => control.SelectedIndex;
            set => control.SelectedIndex = value;
        }

        public object SelectedItem
        {
            get => control.SelectedItem;
            set => control.SelectedItem = value;
        }

        public bool FormattingEnabled { get; set; }

        public bool IntegralHeight { get; set; } // TODO?

        private bool sorted;
        public bool Sorted
        {
            get => sorted;
            set
            {
                if (value != sorted)
                {
                    sorted = value;
                    if (value)
                        control.Items.SortDescriptions.Add(new SortDescription("", ListSortDirection.Ascending));
                    else
                        control.Items.SortDescriptions.Clear();
                }
            }
        }

        public object DataSource
        {
            get => control.ItemsSource;
            set
            {
                control.Items.Clear();
                control.ItemsSource = value as IEnumerable;
            }
        }

        public event EventHandler SelectedIndexChanged;
        public event EventHandler SelectedValueChanged;

        protected virtual void OnSelectionChanged(EventArgs e)
        {
            OnSelectedIndexChanged(e);
            OnSelectedValueChanged(e);
        }

        // mimic winforms behavior: do not raise events if the list is empty (for example, when we clear it)
        protected virtual void OnSelectedIndexChanged(EventArgs e)
        {
            if (Items.Count > 0) 
                SelectedIndexChanged?.Invoke(this, e);
        }

        protected virtual void OnSelectedValueChanged(EventArgs e)
        {
            if (Items.Count > 0) 
                SelectedValueChanged?.Invoke(this, e);
        }

        protected void SetControl(System.Windows.Controls.Primitives.Selector control)
        {
            base.SetControl(control);
            this.control = control;
            control.SelectionChanged += (sender, e) => OnSelectionChanged(e);
            Items = new ObjectCollection(control.Items);
        }

        protected internal virtual object GetItem(int index) => Items[index];

        public int FindStringExact(string text)
        {
            for (int i = 0; i < Items.Count; i++)
                if (GetItem(i).ToString() == text)
                    return i;
            return -1;
        }

        public int FindString(string text)
        {
            for (int i = 0; i < Items.Count; i++)
                if (GetItem(i).ToString().StartsWith(text, StringComparison.OrdinalIgnoreCase))
                    return i;
            return -1;
        }

        public string GetItemText(object item)
        {
            return item?.ToString() ?? "";
        }

        public void BeginUpdate() { }

        public void EndUpdate() { }
    }
}