/**********************************************
    * Copyright (C) 2011 Lukas laag
    * This file is part of lib-gwt-file.
    * 
    * lib-gwt-file is free software: you can redistribute it and/or modify
    * it under the terms of the GNU Lesser General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    * 
   * lib-gwt-file is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU Lesser General Public License for more details.
   * 
   * You should have received a copy of the GNU Lesser General Public License
   * along with lib-gwt-file.  If not, see http://www.gnu.org/licenses/
   **********************************************/
  package org.vectomatic.file;
  
  import org.vectomatic.file.impl.FileListImpl;
  
  import com.google.gwt.dom.client.Document;
  import com.google.gwt.dom.client.Element;
  import com.google.gwt.dom.client.FormElement;
  import com.google.gwt.dom.client.InputElement;
  import com.google.gwt.event.dom.client.ChangeEvent;
  import com.google.gwt.event.dom.client.ChangeHandler;
  import com.google.gwt.event.dom.client.HasChangeHandlers;
  import com.google.gwt.event.shared.HandlerRegistration;
  import com.google.gwt.user.client.Event;
  import com.google.gwt.user.client.ui.HasEnabled;
  import com.google.gwt.user.client.ui.HasName;
  import com.google.gwt.user.client.ui.RootPanel;
  import com.google.gwt.user.client.ui.Widget;
  
  /**
   * FileUpload widget with support for multiple files.
   * @author laaglu
   */
  public class FileUploadExt extends Widget implements HasName, HasChangeHandlers, HasEnabled {
  	/**
  	 * Constructor. This constructors creates instances
  	 * with multiple file support activated by default.
  	 */
  	public FileUploadExt() {
  		this(true);
  	}
  	/**
  	 * Constructor.
  	 * @param multiple true to active multiple file upload support, false otherwise 
  	 */
  	public FileUploadExt(boolean multiple) {
  		this(Document.get().createFileInputElement(), multiple);
  	}
  	
  	protected FileUploadExt(Element element, boolean multiple) {
  	    setElement(element);
  	    setStyleName("gwt-FileUpload");
  		setMultiple(multiple);
  	}
  	
  	/**
  	 * Returns true if support for multiple file upload is activated, false otherwise.
  	 * @return true if support for multiple file upload is activated
  	 */
  	public boolean isMultiple() {
  		return isMultiple(getElement());
  	}
  	private static final native boolean isMultiple(Element element) /*-{
  	  return element.multiple;
  	}-*/;
  	
  	/**
  	 * Sets support for multiple file upload.
  	 * @param value true to activate support for multiple file upload, false otherwise.
  	 */
  	public void setMultiple(boolean value) {
  		setMultiple(getElement(), value);
  	} 
  	private static final native void setMultiple(Element element, boolean value) /*-{
  	  element.multiple = value;
  	}-*/; 
  	/**
  	 * Returns the files selected by the end-user.
  	 * @return the files selected by the end-user.
  	 */
  	public FileList getFiles() {
  		return new FileList(getFiles(getElement()));
  	}
  	private static final native FileListImpl getFiles(Element element) /*-{
  	  return element.files;
  	}-*/;
  	/**
  	 * Shows the file selection box.
  	 */
  	public void click() {
  		click(getElement());
  	}
  	private static final native void click(Element element) /*-{
 	  element.click();
 	}-*/; 
 	
 	@Override
 	public void onBrowserEvent(Event event) {
 		// Fix webkit bug
 		// input file will not fire change event if one chooses the same file twice in a row
 		super.onBrowserEvent(event);
 		Element parent = getElement().getParentElement();
 		Element nextSibling = getElement().getNextSiblingElement();
 		FormElement form = Document.get().createFormElement();
 		form.appendChild(getElement());
 		form.reset();
 		parent.insertBefore(getElement(), nextSibling);
 	}
 	
 	//====================================================
 	//
 	//            Copied from GWT's FileUpload
 	//
 	//====================================================
 	
 	/**
 	 * Creates a FileUploadExt widget that wraps an existing <input
 	 * type='file'> element.
 	 * 
 	 * This element must already be attached to the document. If the element is
 	 * removed from the document, you must call
 	 * {@link RootPanel#detachNow(Widget)}.
 	 * 
 	 * @param element the element to be wrapped
 	 * @param multiple true to active multiple file upload support, false otherwise 
 	 */
 	public static FileUploadExt wrap(Element element, boolean multiple) {
 		// Assert that the element is attached.
 		assert Document.get().getBody().isOrHasChild(element);
 
 		FileUploadExt fileUpload = new FileUploadExt(element, multiple);
 
 		// Mark it attached and remember it for cleanup.
 		fileUpload.onAttach();
 		RootPanel.detachOnWindowClose(fileUpload);
 
 		return fileUpload;
 	}
 	
 	public HandlerRegistration addChangeHandler(ChangeHandler handler) {
 		return addDomHandler(handler, ChangeEvent.getType());
 	}
 
 	/**
 	 * Gets the filename selected by the user. This property has no mutator, as
 	 * browser security restrictions preclude setting it.
 	 * 
 	 * @return the widget's filename
 	 */
 	public String getFilename() {
 		return getInputElement().getValue();
 	}
 
 	public String getName() {
 		return getInputElement().getName();
 	}
 
 	/**
 	 * Gets whether this widget is enabled.
 	 * 
 	 * @return <code>true</code> if the widget is enabled
 	 */
 	public boolean isEnabled() {
 		return !getElement().getPropertyBoolean("disabled");
 	}	
 	/**
 	 * Sets whether this widget is enabled.
 	 * 
 	 * @param enabled
 	 *            <code>true</code> to enable the widget, <code>false</code> to
 	 *            disable it
 	 */
 	public void setEnabled(boolean enabled) {
 		getElement().setPropertyBoolean("disabled", !enabled);
 	}
 
 	public void setName(String name) {
 		getInputElement().setName(name);
 	}
 
 	private InputElement getInputElement() {
 		return getElement().cast();
 	}
 }