using System;
using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Forms;
using System.Windows.Media;

namespace CustomControls
{
    [DesignTimeVisible(false)]
    public class OwnerDrawComboBox : System.Windows.Controls.ComboBox
    {
        private bool isOwnerDraw;
        private bool isDropDownList;
        private System.Drawing.Graphics measureGraphics;
        private System.Drawing.Graphics MeasureGraphics => measureGraphics ??= System.Drawing.Graphics.FromHwnd(IntPtr.Zero);

        public string ComboText
        {
            get { return (string)GetValue(ComboTextProperty); }
            set { SetValue(ComboTextProperty, value); }
        }

        public static readonly DependencyProperty ComboTextProperty =
            DependencyProperty.Register("ComboText", typeof(string), typeof(OwnerDrawComboBox), new PropertyMetadata(""));

        public double DropDownWidth
        {
            get { return (double)GetValue(DropDownWidthProperty); }
            set { SetValue(DropDownWidthProperty, value); }
        }

        public static readonly DependencyProperty DropDownWidthProperty =
            DependencyProperty.Register("DropDownWidth", typeof(double), typeof(OwnerDrawComboBox), new PropertyMetadata(0.0));

        public double ItemHeight
        {
            get { return (double)GetValue(ItemHeightProperty); }
            set { SetValue(ItemHeightProperty, value); }
        }
        public readonly static DependencyProperty ItemHeightProperty = DependencyProperty.Register(
            "ItemHeight", typeof(double), typeof(OwnerDrawComboBox), new UIPropertyMetadata(15.0));


        public event EventHandler TextChanged;
        public event DrawItemEventHandler DrawItem;
        public event MeasureItemEventHandler MeasureItem;

        internal void TextBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            OnTextChanged(e);
        }

        internal void TextBox_PreviewMouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)
        {
            var tb = (sender as System.Windows.Controls.TextBox);
            if (!tb.IsKeyboardFocusWithin)
            {
                e.Handled = true;
                tb.Focus();
            }
        }

        internal void TextBox_GotKeyboardFocus(object sender, System.Windows.Input.KeyboardFocusChangedEventArgs e)
        {
            (sender as System.Windows.Controls.TextBox).SelectAll();
        }

        internal void OnTextChanged(EventArgs e) => TextChanged?.Invoke(this, e);

        internal void OnDrawItem(object sender, DrawItemEventArgs args) => DrawItem?.Invoke(this, args);
        
        internal Size OnMeasureItem(int index, Size size)
        {
            var scale = Helper.GetDpiScale(this);
            var args = new MeasureItemEventArgs(MeasureGraphics, index, (int)(ItemHeight * scale));
            MeasureItem?.Invoke(this, args);
            size.Height = index >= 0 ? (args.ItemHeight / scale) : ItemHeight;
            return size;
        }

        public void SetOwnerDraw()
        {
            isOwnerDraw = true;
            if (isDropDownList)
                Template = (ControlTemplate)Resources["ComboBoxTemplate"];
            else
                Template = (ControlTemplate)Resources["ComboBoxEditableTemplate"];
            ItemContainerStyle = (Style)Resources["ItemContainerStyle1"];
            ItemTemplate = (DataTemplate)Resources["ItemTemplate1"];
        }

        public void SetDropDownList()
        {
            isDropDownList = true;
            Template = (ControlTemplate)Resources["ComboBoxTemplate"];
            if (isOwnerDraw)
                ItemTemplate = (DataTemplate)Resources["ItemTemplate1"];
            else
                ItemTemplate = (DataTemplate)Resources["ItemTemplate"];
        }
    }

    [DesignTimeVisible(false)]
    public class OwnerDrawComboBoxItem : OwnerDrawItem
    {
        protected override void OnRender(DrawingContext drawingContext)
        {
            OwnerDrawComboBox comboBox = null;
            int index = 0;
            bool isSelected = false;
            bool isMouseOver = false;
            bool comboboxEdit = false;

            var listItem = WpfHelper.FindAncestor<System.Windows.Controls.ComboBoxItem>(this);
            if (listItem != null)
            {
                comboBox = ItemsControl.ItemsControlFromItemContainer(listItem) as OwnerDrawComboBox;
                index = comboBox.ItemContainerGenerator.IndexFromContainer(listItem);
                isSelected = listItem.IsSelected;
                isMouseOver = listItem.IsMouseOver;
            }
            else
            {
                comboBox = WpfHelper.FindAncestor<OwnerDrawComboBox>(this);
                index = comboBox.SelectedIndex;
                comboboxEdit = true;
            }
            OnDrawItem(drawingContext, index, isSelected, comboBox.IsEnabled, isMouseOver, comboboxEdit, comboBox.OnDrawItem);
        }
        
        protected override Size MeasureOverride(Size constraint)
        {
            OwnerDrawComboBox comboBox = null;
            int index = 0;

            var listItem = WpfHelper.FindAncestor<System.Windows.Controls.ComboBoxItem>(this);
            if (listItem != null)
            {
                comboBox = ItemsControl.ItemsControlFromItemContainer(listItem) as OwnerDrawComboBox;
                index = comboBox.ItemContainerGenerator.IndexFromContainer(listItem);
            }
            else
            {
                comboBox = WpfHelper.FindAncestor<OwnerDrawComboBox>(this);
                index = -1;
            }

            return comboBox.OnMeasureItem(index, base.MeasureOverride(constraint));
        }
    }
}