package org.gcube.portlets.widgets.ckandatapublisherwidget.client.ui.TwinColumnSelection;

import java.util.Iterator;
import java.util.List;
import java.util.Set;

import com.github.gwtbootstrap.client.ui.Button;
import com.github.gwtbootstrap.client.ui.Popover;
import com.github.gwtbootstrap.client.ui.constants.Placement;
import com.google.gwt.core.client.GWT;
import com.google.gwt.dom.client.Style.BorderStyle;
import com.google.gwt.dom.client.Style.Float;
import com.google.gwt.dom.client.Style.Unit;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.uibinder.client.UiBinder;
import com.google.gwt.uibinder.client.UiField;
import com.google.gwt.user.cellview.client.CellList;
import com.google.gwt.user.cellview.client.HasKeyboardPagingPolicy.KeyboardPagingPolicy;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.user.client.ui.Widget;
import com.google.gwt.view.client.ListDataProvider;
import com.google.gwt.view.client.MultiSelectionModel;
import com.google.gwt.view.client.SelectionChangeEvent;

/**
 * The twin column panels for selection of the files to attach to the catalague product.
 * @author Costantino Perciante at ISTI-CNR (costantino.perciante@isti.cnr.it)
 */
public class TwinColumnSelectionMainPanel extends Composite{

	@UiField 
	VerticalPanel leftContainer;
	@UiField 
	VerticalPanel rightContainer;
	@UiField
	VerticalPanel buttonsPanel;
	@UiField
	Button allToRightButton;
	@UiField
	Button toRightButton;
	@UiField
	Button toLeftButton;
	@UiField
	Button allToLeftButton;
	@UiField
	Button goRootButton;
	@UiField
	Popover popoverResourceSelection;
	@UiField
	Button resourceInfoButton;

	private static final String PANEL_BORDER_COLOR = "#08c";
	private static final String PANEL_HEIGHT = "400px";
	private ShowMorePagerPanel showMorePanelLeft = new ShowMorePagerPanel();
	private ShowMorePagerPanel showMorePanelRight = new ShowMorePagerPanel();
	private CellList<ResourceElementBean> cellListLeft;
	private CellList<ResourceElementBean> cellListRight;
	private ListDataProvider<ResourceElementBean> dataProviderLeft = new ListDataProvider<ResourceElementBean>();
	private ListDataProvider<ResourceElementBean> dataProviderRight = new ListDataProvider<ResourceElementBean>();
	private MultiSelectionModel<ResourceElementBean> selectionModelRight;
	private MultiSelectionModel<ResourceElementBean> selectionModelLeft;
	private final List<ResourceElementBean> initialElements;
	private final static HTML aboutHeader = new HTML("<b>Resource Manager</b>");
	private final static HTML aboutBody = new HTML("Move the files you want to attach to the product on the right panel below."
			+ " Please consider that any complex hierarchy structure you may have will be flatten.");

	private static TwinColumnSelectionMainPanelUiBinder uiBinder = GWT
			.create(TwinColumnSelectionMainPanelUiBinder.class);

	interface TwinColumnSelectionMainPanelUiBinder extends
	UiBinder<Widget, TwinColumnSelectionMainPanel> {
	}

	public TwinColumnSelectionMainPanel(List<ResourceElementBean> elements) {
		initWidget(uiBinder.createAndBindUi(this));

		this.initialElements = elements;
		this.buttonsPanel.getElement().getStyle().setMarginTop(50, Unit.PCT);

		goRootButton.getElement().getStyle().setPaddingLeft(0, Unit.PX);
		allToRightButton.getElement().getStyle().setMarginBottom(4, Unit.PX);
		toRightButton.getElement().getStyle().setMarginBottom(4, Unit.PX);
		toLeftButton.getElement().getStyle().setMarginBottom(4, Unit.PX);
		allToLeftButton.getElement().getStyle().setMarginBottom(4, Unit.PX);
		buttonsPanel.getElement().setAttribute("align", "center");
		popoverResourceSelection.setPlacement(Placement.LEFT);
		popoverResourceSelection.setHeading(aboutHeader.getHTML());
		popoverResourceSelection.setText(aboutBody.getHTML());
		resourceInfoButton.getElement().getStyle().setFloat(Float.RIGHT);
		prepareHandlers();
		initLeftSidePanel(elements);
		initRightSidePanel();

	}

	/**
	 * Initialize the left side panel
	 */
	private void initLeftSidePanel(List<ResourceElementBean> elements) {

		// initialize the left side list
		ResourceCellLeft cell = new ResourceCellLeft();

		// Set a key provider that provides a unique key for each object. 
		cellListLeft = new CellList<ResourceElementBean>(cell, ResourceElementBean.KEY_PROVIDER);
		cellListLeft.setPageSize(elements.size());
		cellListLeft.setKeyboardPagingPolicy(KeyboardPagingPolicy.INCREASE_RANGE); 

		// Add a selection model so we can select cells.
		selectionModelLeft = new MultiSelectionModel<ResourceElementBean>(ResourceElementBean.KEY_PROVIDER);
		cellListLeft.setSelectionModel(selectionModelLeft);

		// perform an action on selection
		selectionModelLeft.addSelectionChangeHandler(new SelectionChangeEvent.Handler() {
			public void onSelectionChange(SelectionChangeEvent event) {
				Iterator<ResourceElementBean> selectedObjectsIterator = selectionModelLeft.getSelectedSet().iterator();
				while (selectedObjectsIterator.hasNext()) {
					ResourceElementBean selectedBean = (ResourceElementBean) selectedObjectsIterator.next();
					if(selectedBean.isFolder()){
						if(selectionModelLeft.getSelectedSet().size() == 1){
							dataProviderLeft.setList(selectedBean.getChildren());
							dataProviderLeft.refresh();
							dataProviderLeft.flush();
						}
						selectionModelLeft.setSelected(selectedBean, false);
					}
				}
				// enable the buttons that allows to move the objects to the right
				enableMoveToRightButtons(selectionModelLeft.getSelectedSet());
			}
		});

		// set the list into the provider
		dataProviderLeft.setList(elements);

		// set the cell list into the provider
		dataProviderLeft.addDataDisplay(cellListLeft);

		// manage showMorePanelLeft
		showMorePanelLeft.setDisplay(cellListLeft);
		showMorePanelLeft.setHeight(PANEL_HEIGHT);
		showMorePanelLeft.getElement().getStyle().setBorderStyle(BorderStyle.SOLID);
		showMorePanelLeft.getElement().getStyle().setBorderColor(PANEL_BORDER_COLOR);

		// add the list to the leftContainerPanel
		leftContainer.add(showMorePanelLeft);
	}

	/**
	 * Initialize the left side panel
	 */
	private void initRightSidePanel() {

		// initialize the left side list
		ResourceCellRight cell = new ResourceCellRight();

		// Set a key provider that provides a unique key for each object. 
		cellListRight = new CellList<ResourceElementBean>(cell, ResourceElementBean.KEY_PROVIDER);
		cellListRight.setKeyboardPagingPolicy(KeyboardPagingPolicy.INCREASE_RANGE); 

		// Add a selection model so we can select cells.
		selectionModelRight = new MultiSelectionModel<ResourceElementBean>(ResourceElementBean.KEY_PROVIDER);
		cellListRight.setSelectionModel(selectionModelRight);

		// perform an action on selection
		selectionModelRight.addSelectionChangeHandler(new SelectionChangeEvent.Handler() {
			public void onSelectionChange(SelectionChangeEvent event) {
				enableMoveToLeftButtons(selectionModelRight.getSelectedSet());
			}
		});

		// set the cell list into the provider
		dataProviderRight.addDataDisplay(cellListRight);

		// manage showMorePanelRight
		showMorePanelRight.setDisplay(cellListRight);
		showMorePanelRight.setHeight(PANEL_HEIGHT);
		showMorePanelRight.getElement().getStyle().setBorderStyle(BorderStyle.SOLID);
		showMorePanelRight.getElement().getStyle().setBorderColor(PANEL_BORDER_COLOR);

		// add the list to the leftContainerPanel
		rightContainer.add(showMorePanelRight);

	}

	/**
	 * Enable/disable the buttons to move objects from left to right properly.
	 * @param setselectedItemsLeft
	 */
	private void enableMoveToRightButtons(Set<ResourceElementBean> setselectedItemsLeft){

		if(setselectedItemsLeft == null || setselectedItemsLeft.isEmpty()){
			allToRightButton.setEnabled(false);
			toRightButton.setEnabled(false);
		}
		else if(setselectedItemsLeft.size() > 1){
			allToRightButton.setEnabled(true);
			toRightButton.setEnabled(false);
		}
		else{
			allToRightButton.setEnabled(false);
			toRightButton.setEnabled(true);
		}
	}

	/**
	 * Enable/disable the buttons to move objects from right to left properly.
	 * @param setselectedItemsRight
	 */
	private void enableMoveToLeftButtons(Set<ResourceElementBean> setselectedItemsRight){

		if(setselectedItemsRight == null || setselectedItemsRight.isEmpty()){
			allToLeftButton.setEnabled(false);
			allToLeftButton.setEnabled(false);
		}
		else if(setselectedItemsRight.size() > 1){
			allToLeftButton.setEnabled(true);
			toLeftButton.setEnabled(false);
		}
		else{
			allToLeftButton.setEnabled(false);
			toLeftButton.setEnabled(true);
		}
	}

	/**
	 * Prepare the buttons' handlers
	 */
	private void prepareHandlers() {

		goRootButton.addClickHandler(new ClickHandler() {

			@Override
			public void onClick(ClickEvent event) {

				dataProviderLeft.setList(initialElements);
				dataProviderLeft.flush();

			}
		});

		allToRightButton.addClickHandler(new ClickHandler() {

			@Override
			public void onClick(ClickEvent event) {

				moveToRight(selectionModelLeft.getSelectedSet());

			}
		});

		toRightButton.addClickHandler(new ClickHandler() {

			@Override
			public void onClick(ClickEvent event) {

				moveToRight(selectionModelLeft.getSelectedSet());

			}
		});

		allToLeftButton.addClickHandler(new ClickHandler() {

			@Override
			public void onClick(ClickEvent event) {

				moveToLeft(selectionModelRight.getSelectedSet());

			}
		});

		toLeftButton.addClickHandler(new ClickHandler() {

			@Override
			public void onClick(ClickEvent event) {

				moveToLeft(selectionModelRight.getSelectedSet());

			}
		});
	}

	/**
	 * Move to right elements
	 * @param set the elements to move
	 */
	private void moveToRight(Set<ResourceElementBean> setSelected){

		if(setSelected == null || setSelected.isEmpty())
			return;

		Iterator<ResourceElementBean> iterator = setSelected.iterator();
		while (iterator.hasNext()) {
			ResourceElementBean resourceElementBean = (ResourceElementBean) iterator
					.next();
			resourceElementBean.setMovedToRight(true);	

			int indexRight = dataProviderRight.getList().indexOf(resourceElementBean);
			if(indexRight >= 0)
				dataProviderRight.getList().set(indexRight, resourceElementBean);
			else
				dataProviderRight.getList().add(resourceElementBean);

			int indexLeft = dataProviderLeft.getList().indexOf(resourceElementBean);
			if(indexLeft >= 0)
				dataProviderLeft.getList().set(indexLeft, resourceElementBean);
		}
	}

	/**
	 * Move to left elements
	 * @param setSelected the elements to move
	 */
	private void moveToLeft(Set<ResourceElementBean> setSelected){

		if(setSelected == null || setSelected.isEmpty())
			return;

		Iterator<ResourceElementBean> iterator = setSelected.iterator();
		while (iterator.hasNext()) {
			ResourceElementBean resourceElementBean = (ResourceElementBean) iterator.next();
			resourceElementBean.setMovedToRight(false);

			int indexLeft = dataProviderLeft.getList().indexOf(resourceElementBean);
			if(indexLeft != -1)
				dataProviderLeft.getList().set(indexLeft, resourceElementBean); // replace
			else
				dataProviderLeft.getList().add(resourceElementBean);
			int indexRight = dataProviderRight.getList().indexOf(resourceElementBean);
			if(indexRight >= 0)
				dataProviderLeft.getList().set(indexLeft, resourceElementBean);
		}
	}

}