using System;

using System.Drawing;

using System.Windows.Forms;



namespace Nikse.SubtitleEdit.Controls

{

    /// <summary>

    /// TextBox where double click selects current word

    /// </summary>

    public class SETextBox : TextBox

    {

        private string breakChars = "\".!?,)([]<>:;♪{}-/#*| ¿¡" + Environment.NewLine + "\t";

        string _dragText = string.Empty;

        int _dragStartFrom = 0;

        long _dragStartTicks = 0;

        bool _dragRemoveOld = false;

        bool _dragFromThis = false;



        public SETextBox()

        {

            AllowDrop = true;

            DragEnter += new DragEventHandler(SETextBox_DragEnter);

         //   DragOver += new DragEventHandler(SETextBox_DragOver); could draw some gfx where drop position is...

            DragDrop += new DragEventHandler(SETextBox_DragDrop);

            MouseDown += new MouseEventHandler(SETextBox_MouseDown);

            MouseUp += new MouseEventHandler(SETextBox_MouseUp);

            KeyDown += SETextBox_KeyDown;

        }



        void SETextBox_KeyDown(object sender, KeyEventArgs e)

        {

            if (e.Modifiers == Keys.Control && e.KeyCode == Keys.Back)

            {

                int index = SelectionStart;

                if (SelectionLength == 0)

                {

                    string s = Text;

                    int deleteFrom = index-1;



                    if (deleteFrom > 0 && deleteFrom < s.Length)

                    {

                        if (s[deleteFrom] == ' ')

                            deleteFrom--;

                        while (deleteFrom > 0 && !(breakChars).Contains(s.Substring(deleteFrom, 1)))

                        {

                            deleteFrom--;

                        }

                        if (deleteFrom == index - 1)

                        {

                            while (deleteFrom > 0 && (breakChars.Replace(" ", string.Empty)).Contains(s.Substring(deleteFrom - 1, 1)))

                            {

                                deleteFrom--;

                            }

                        }

                        if (s[deleteFrom] == ' ')

                            deleteFrom++;

                        Text = s.Remove(deleteFrom, index - deleteFrom);

                        SelectionStart = deleteFrom;

                    }

                }

                e.SuppressKeyPress = true;

            }

        }



        void SETextBox_MouseUp(object sender, MouseEventArgs e)

        {

            _dragRemoveOld = false;

            _dragFromThis = false;

        }



        void SETextBox_MouseDown(object sender, MouseEventArgs e)

        {

            if (MouseButtons == System.Windows.Forms.MouseButtons.Left && !string.IsNullOrEmpty(_dragText))

            {

                Point pt = new Point(e.X, e.Y);

                int index = GetCharIndexFromPosition(pt);

                if (index >= _dragStartFrom && index <= _dragStartFrom + _dragText.Length)

                {

                    // re-make selection

                    SelectionStart = _dragStartFrom;

                    SelectionLength = _dragText.Length;



                    DataObject dataObject = new DataObject();

                    dataObject.SetText(_dragText, TextDataFormat.UnicodeText);

                    dataObject.SetText(_dragText, TextDataFormat.Text);



                    _dragFromThis = true;

                    if (Control.ModifierKeys == Keys.Control)

                    {

                        _dragRemoveOld = false;

                        DoDragDrop(dataObject, DragDropEffects.Copy);

                    }

                    else if (Control.ModifierKeys == Keys.None)

                    {

                        _dragRemoveOld = true;

                        DoDragDrop(dataObject, DragDropEffects.Move);

                    }

                }

            }

        }



        void SETextBox_DragDrop(object sender, DragEventArgs e)

        {

            Point pt = new Point(e.X, e.Y);

            pt = PointToClient(pt);

            int index = GetCharIndexFromPosition(pt);



            string newText = string.Empty;

            if (e.Data.GetDataPresent(DataFormats.UnicodeText))

                newText = (string)e.Data.GetData(DataFormats.UnicodeText);

            else

                newText = (string)e.Data.GetData(DataFormats.Text);



            if (Text.Trim().Length == 0)

            {

                Text = newText;

            }

            else

            {

                bool justAppend = index == Text.Length - 1 && index > 0;

                if (_dragFromThis)

                {

                    _dragFromThis = false;

                    long milliseconds = (DateTime.Now.Ticks - _dragStartTicks) / 10000;

                    if (milliseconds < 400)

                    {

                        SelectionLength = 0;

                        if (index == Text.Length - 1 && index > 0)

                            index++;

                        SelectionStart = index;

                        return; // too fast - nobody can drag'n'drop this fast

                    }



                    if (index >= _dragStartFrom && index <= _dragStartFrom + _dragText.Length)

                        return; // don't drop same text at same position



                    if (_dragRemoveOld)

                    {

                        _dragRemoveOld = false;

                        Text = Text.Remove(_dragStartFrom, _dragText.Length);



                        // fix spaces

                        if (_dragStartFrom == 0 && Text.Length > 0 && Text[0] == ' ')

                        {

                            Text = Text.Remove(0, 1);

                            index--;

                        }

                        else if (_dragStartFrom > 1 && Text.Length > _dragStartFrom + 1 && Text[_dragStartFrom] == ' ' && Text[_dragStartFrom - 1] == ' ')

                        {

                            Text = Text.Remove(_dragStartFrom, 1);

                            if (_dragStartFrom < index)

                                index--;

                        }

                        else if (_dragStartFrom > 0 && Text.Length > _dragStartFrom + 1 && Text[_dragStartFrom] == ' ' && ";:]<.!?".Contains(Text[_dragStartFrom + 1].ToString()))

                        {

                            Text = Text.Remove(_dragStartFrom, 1);

                            if (_dragStartFrom < index)

                                index--;

                        }



                        // fix index

                        if (index > _dragStartFrom)

                            index -= _dragText.Length;

                        if (index < 0)

                            index = 0;

                    }

                }

                if (justAppend)

                {

                    index = Text.Length;

                    Text += newText;

                }

                else

                {

                    Text = Text.Insert(index, newText);

                }



                // fix start spaces

                int endIndex = index + newText.Length;

                if (index > 0 && !newText.StartsWith(" ") && Text[index - 1] != ' ')

                {

                    Text = Text.Insert(index, " ");

                    endIndex++;

                }

                else if (index > 0 && newText.StartsWith(" ") && Text[index - 1] == ' ')

                {

                    Text = Text.Remove(index, 1);

                    endIndex--;

                }



                // fix end spaces

                if (endIndex < Text.Length && !newText.EndsWith(" ") && Text[endIndex] != ' ')

                {

                    bool lastWord = ";:]<.!?".Contains(Text[endIndex].ToString());

                    if (!lastWord)

                        Text = Text.Insert(endIndex, " ");

                }

                else if (endIndex < Text.Length && newText.EndsWith(" ") && Text[endIndex] == ' ')

                {

                    Text = Text.Remove(endIndex, 1);

                }



                SelectionStart = index+1;

                SelectCurrentWord(this);

            }



            _dragRemoveOld = false;

            _dragFromThis = false;

        }



        void SETextBox_DragEnter(object sender, DragEventArgs e)

        {

            if (e.Data.GetDataPresent(DataFormats.Text) || e.Data.GetDataPresent(DataFormats.UnicodeText))

            {

                if (Control.ModifierKeys == Keys.Control)

                    e.Effect = DragDropEffects.Copy;

                else

                    e.Effect = DragDropEffects.Move;

            }

            else

            {

                e.Effect = DragDropEffects.None;

            }

        }



        protected override void WndProc(ref Message m)

        {

            const int WM_DBLCLICK = 0xA3;

            const int WM_LBUTTONDBLCLK = 0x203;

            const int WM_LBUTTONDOWN = 0x0201;



            if (m.Msg == WM_DBLCLICK || m.Msg == WM_LBUTTONDBLCLK)

            {

                SelectCurrentWord(this);

                return;

            }

            if (m.Msg == WM_LBUTTONDOWN)

            {

                _dragText = SelectedText;

                _dragStartFrom = SelectionStart;

                _dragStartTicks = DateTime.Now.Ticks;

            }

            base.WndProc(ref m);

        }



        private void SelectCurrentWord(TextBox tb)

        {

            int selectionLength = 0;

            int i = tb.SelectionStart;

            while (i > 0 && breakChars.Contains(tb.Text.Substring(i - 1, 1)) == false)

                i--;

            tb.SelectionStart = i;

            for (; i < tb.Text.Length; i++)

            {

                if (breakChars.Contains(tb.Text.Substring(i, 1)))

                    break;

                selectionLength++;

            }

            tb.SelectionLength = selectionLength;

            if (selectionLength > 0)

                this.OnMouseMove(null);

        }



    }

}