// Copyright (c) 2010 Joe Moorhouse



using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Diagnostics;

using System.Globalization;

using System.IO;

using System.Runtime.InteropServices;

using System.Windows;

using System.Windows.Documents;

using System.Windows.Input;

using System.Reflection;



using ICSharpCode.AvalonEdit;

using ICSharpCode.AvalonEdit.Document;

using ICSharpCode.AvalonEdit.Highlighting;

using ICSharpCode.AvalonEdit.Utils;

using ICSharpCode.AvalonEdit.Editing;



namespace PythonConsoleControl

{

    /// <summary>

    /// Commands that only involve the text editor are outsourced to here.

    /// </summary>

    class PythonEditingCommandHandler

    {

        PythonTextEditor textEditor;

        TextArea textArea;

        

        public PythonEditingCommandHandler(PythonTextEditor textEditor)

        {

            this.textEditor = textEditor;

            this.textArea = textEditor.textArea;

        }



        internal static void CanCutOrCopy(object target, CanExecuteRoutedEventArgs args)

        {

            // HasSomethingSelected for copy and cut commands

            TextArea textArea = GetTextArea(target);

            if (textArea != null && textArea.Document != null)

            {

                args.CanExecute = textArea.Options.CutCopyWholeLine || !textArea.Selection.IsEmpty;

                args.Handled = true;

            }

        }



        internal static TextArea GetTextArea(object target)

        {

            return target as TextArea;

        }



        internal static void OnCopy(object target, ExecutedRoutedEventArgs args)

        {

            TextArea textArea = GetTextArea(target);

            if (textArea != null && textArea.Document != null)

            {

                if (textArea.Selection.IsEmpty && textArea.Options.CutCopyWholeLine)

                {

                    DocumentLine currentLine = textArea.Document.GetLineByNumber(textArea.Caret.Line);

                    CopyWholeLine(textArea, currentLine);

                }

                else

                {

                    CopySelectedText(textArea);

                }

                args.Handled = true;

            }

        }



        internal static void OnCut(object target, ExecutedRoutedEventArgs args)

        {

            TextArea textArea = GetTextArea(target);

            if (textArea != null && textArea.Document != null)

            {

                if (textArea.Selection.IsEmpty && textArea.Options.CutCopyWholeLine)

                {

                    DocumentLine currentLine = textArea.Document.GetLineByNumber(textArea.Caret.Line);

                    CopyWholeLine(textArea, currentLine);

                    textArea.Document.Remove(currentLine.Offset, currentLine.TotalLength);

                }

                else

                {

                    CopySelectedText(textArea);

                    textArea.Selection.ReplaceSelectionWithText(textArea, string.Empty);

                }

                textArea.Caret.BringCaretToView();

                args.Handled = true;

            }

        }



        internal static void CopySelectedText(TextArea textArea)

        {

            var data = textArea.Selection.CreateDataObject(textArea);



            try

            {

                Clipboard.SetDataObject(data, true);

            }

            catch (ExternalException)

            {

                // Apparently this exception sometimes happens randomly.

                // The MS controls just ignore it, so we'll do the same.

                return;

            }



            string text = textArea.Selection.GetText(textArea.Document);

            text = TextUtilities.NormalizeNewLines(text, Environment.NewLine);

            //textArea.OnTextCopied(new TextEventArgs(text));

        }



        internal static void CopyWholeLine(TextArea textArea, DocumentLine line)

        {

            ISegment wholeLine = new VerySimpleSegment(line.Offset, line.TotalLength);

            string text = textArea.Document.GetText(wholeLine);

            // Ensure we use the appropriate newline sequence for the OS

            text = TextUtilities.NormalizeNewLines(text, Environment.NewLine);

            DataObject data = new DataObject(text);



            // Also copy text in HTML format to clipboard - good for pasting text into Word

            // or to the SharpDevelop forums.

            IHighlighter highlighter = textArea.GetService(typeof(IHighlighter)) as IHighlighter;

            HtmlClipboard.SetHtml(data, HtmlClipboard.CreateHtmlFragment(textArea.Document, highlighter, wholeLine, new HtmlOptions(textArea.Options)));



            MemoryStream lineSelected = new MemoryStream(1);

            lineSelected.WriteByte(1);

            data.SetData(LineSelectedType, lineSelected, false);



            try

            {

                Clipboard.SetDataObject(data, true);

            }

            catch (ExternalException)

            {

                // Apparently this exception sometimes happens randomly.

                // The MS controls just ignore it, so we'll do the same.

                return;

            }

            //textArea.OnTextCopied(new TextEventArgs(text));

        }



        internal static ExecutedRoutedEventHandler OnDelete(RoutedUICommand selectingCommand)

        {

            return (target, args) =>

            {

                TextArea textArea = GetTextArea(target);

                if (textArea != null && textArea.Document != null)

                {

                    // call BeginUpdate before running the 'selectingCommand'

                    // so that undoing the delete does not select the deleted character

                    using (textArea.Document.RunUpdate())

                    {

                        Type textAreaType = textArea.GetType();

                        MethodInfo method;

                        if (textArea.Selection.IsEmpty)

                        {

                            TextViewPosition oldCaretPosition = textArea.Caret.Position;

                            selectingCommand.Execute(args.Parameter, textArea);

                            bool hasSomethingDeletable = false;

                            foreach (ISegment s in textArea.Selection.Segments)

                            {

                                method = textAreaType.GetMethod("GetDeletableSegments", BindingFlags.Instance | BindingFlags.NonPublic); 

                                //textArea.GetDeletableSegments(s).Length > 0)

                                if ((int)method.Invoke(textArea, new Object[]{s}) > 0) 

                                {

                                    hasSomethingDeletable = true;

                                    break;

                                }

                            }

                            if (!hasSomethingDeletable)

                            {

                                // If nothing in the selection is deletable; then reset caret+selection

                                // to the previous value. This prevents the caret from moving through read-only sections.

                                textArea.Caret.Position = oldCaretPosition;

                                textArea.Selection = Selection.Empty;

                            }

                        }

                        method = textAreaType.GetMethod("RemoveSelectedText", BindingFlags.Instance | BindingFlags.NonPublic);

                        method.Invoke(textArea, new Object[]{});

                        //textArea.RemoveSelectedText();

                    }

                    textArea.Caret.BringCaretToView();

                    args.Handled = true;

                }

            };

        }



        internal static void CanDelete(object target, CanExecuteRoutedEventArgs args)

        {

            // HasSomethingSelected for delete command

            TextArea textArea = GetTextArea(target);

            if (textArea != null && textArea.Document != null)

            {

                args.CanExecute = !textArea.Selection.IsEmpty;

                args.Handled = true;

            }

        }



        const string LineSelectedType = "MSDEVLineSelect";  // This is the type VS 2003 and 2005 use for flagging a whole line copy



        struct VerySimpleSegment : ISegment

	    {

		    public readonly int Offset, Length;

		

		    int ISegment.Offset {

			    get { return Offset; }

		    }

		

		    int ISegment.Length {

			    get { return Length; }

		    }

		

		    public int EndOffset {

			    get {

				    return Offset + Length;

			    }

		    }



            public VerySimpleSegment(int offset, int length)

		    {

			    this.Offset = offset;

			    this.Length = length;

		    }

        }

    }

}