/*
Copyright (c) 2003-2009, CKSource - Frederico Knabben. All rights reserved.
For licensing, see LICENSE.html or http://ckeditor.com/license
*/

/**
 * @file Clipboard support
 */

(function()
{
	// Tries to execute any of the paste, cut or copy commands in IE. Returns a
	// boolean indicating that the operation succeeded.
	var execIECommand = function( editor, command )
	{
		var doc = editor.document,
			body = doc.getBody();

		var	enabled = false;
		var onExec = function()
		{
			enabled = true;
		};

		// The following seems to be the only reliable way to detect that
		// clipboard commands are enabled in IE. It will fire the
		// onpaste/oncut/oncopy events only if the security settings allowed
		// the command to execute.
		body.on( command, onExec );

		doc.$.execCommand( command );

		body.removeListener( command, onExec );

		return enabled;
	};

	// Attempts to execute the Cut and Copy operations.
	var tryToCutCopy =
		CKEDITOR.env.ie ?
			function( editor, type )
			{
				return execIECommand( editor, type );
			}
		:		// !IE.
			function( editor, type )
			{
				try
				{
					// Other browsers throw an error if the command is disabled.
					return editor.document.$.execCommand( type );
				}
				catch( e )
				{
					return false;
				}
			};

	// A class that represents one of the cut or copy commands.
	var cutCopyCmd = function( type )
	{
		this.type = type;
		this.canUndo = ( this.type == 'cut' );		// We can't undo copy to clipboard.
	};

	cutCopyCmd.prototype =
	{
		exec : function( editor, data )
		{
			var success = tryToCutCopy( editor, this.type );

			if ( !success )
				alert( editor.lang.clipboard[ this.type + 'Error' ] );		// Show cutError or copyError.

			return success;
		}
	};

	// Paste command.
	var pasteCmd =
		CKEDITOR.env.ie ?
			{
				exec : function( editor, data )
				{
					// Prevent IE from pasting at the begining of the document.
					editor.focus();

					if ( !editor.fire( 'beforePaste' )
						&& !execIECommand( editor, 'paste' ) )
					{
							editor.openDialog( 'paste' );
					}
				}
			}
		:
			{
				exec : function( editor )
				{
					try
					{
						if ( !editor.fire( 'beforePaste' )
							&& !editor.document.$.execCommand( 'Paste', false, null ) )
						{
							throw 0;
						}
					}
					catch ( e )
					{
						// Open the paste dialog.
						editor.openDialog( 'paste' );
					}
				}
			};

	// Listens for some clipboard related keystrokes, so they get customized.
	var onKey = function( event )
	{
		switch ( event.data.keyCode )
		{
			// Paste
			case CKEDITOR.CTRL + 86 :		// CTRL+V
			case CKEDITOR.SHIFT + 45 :		// SHIFT+INS

				var editor = this;
				editor.fire( 'saveSnapshot' );		// Save before paste

				if ( editor.fire( 'beforePaste' ) )
					event.cancel();

				setTimeout( function()
					{
						editor.fire( 'saveSnapshot' );		// Save after paste
					}, 0 );
				return;

			// Cut
			case CKEDITOR.CTRL + 88 :		// CTRL+X
			case CKEDITOR.SHIFT + 46 :		// SHIFT+DEL

				// Save Undo snapshot.
				editor = this;
				editor.fire( 'saveSnapshot' );		// Save before paste
				setTimeout( function()
					{
						editor.fire( 'saveSnapshot' );		// Save after paste
					}, 0 );
		}
	};

	// Register the plugin.
	CKEDITOR.plugins.add( 'clipboard',
		{
			init : function( editor )
			{
				function addButtonCommand( buttonName, commandName, command, ctxMenuOrder )
				{
					var lang = editor.lang[ commandName ];

					editor.addCommand( commandName, command );
					editor.ui.addButton( buttonName,
						{
							label : lang,
							command : commandName
						});

					// If the "menu" plugin is loaded, register the menu item.
					if ( editor.addMenuItems )
					{
						editor.addMenuItem( commandName,
							{
								label : lang,
								command : commandName,
								group : 'clipboard',
								order : ctxMenuOrder
							});
					}
				}

				addButtonCommand( 'Cut', 'cut', new cutCopyCmd( 'cut' ), 1 );
				addButtonCommand( 'Copy', 'copy', new cutCopyCmd( 'copy' ), 4 );
				addButtonCommand( 'Paste', 'paste', pasteCmd, 8 );

				CKEDITOR.dialog.add( 'paste', CKEDITOR.getUrl( this.path + 'dialogs/paste.js' ) );

				editor.on( 'key', onKey, editor );

				// If the "contextmenu" plugin is loaded, register the listeners.
				if ( editor.contextMenu )
				{
					function stateFromNamedCommand( command )
					{
						return editor.document.$.queryCommandEnabled( command ) ? CKEDITOR.TRISTATE_OFF : CKEDITOR.TRISTATE_DISABLED;
					}

					editor.contextMenu.addListener( function()
						{
							return {
								cut : stateFromNamedCommand( 'Cut' ),

								// Browser bug: 'Cut' has the correct states for both Copy and Cut.
								copy : stateFromNamedCommand( 'Cut' ),
								paste : CKEDITOR.env.webkit ? CKEDITOR.TRISTATE_OFF : stateFromNamedCommand( 'Paste' )
							};
						});
				}
			}
		});
})();