/**
 * 
 */
package org.richfaces.renderkit.html;

import java.io.IOException;
import java.util.Map;

import javax.faces.FacesException;
import javax.faces.application.Application;
import javax.faces.component.UIComponent;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;
import javax.faces.convert.Converter;
import javax.faces.el.ValueBinding;

import org.ajax4jsf.context.AjaxContext;
import org.ajax4jsf.model.DataVisitor;
import org.ajax4jsf.renderkit.RendererUtils.HTML;
import org.richfaces.component.UIScrollableDataTable;
import org.richfaces.model.selection.ClientSelection;
import org.richfaces.model.selection.Selection;
import org.richfaces.model.selection.SimpleSelection;
import org.richfaces.renderkit.CompositeRenderer;
import org.richfaces.renderkit.RendererContributor;
import org.richfaces.renderkit.ScriptOptions;

/**
 * @author Maksim Kaszynski
 * 
 */
public class SelectionRendererContributor implements RendererContributor, HTMLEncodingContributor {


	public static final String CLIENT_SELECTION = "clientSelection";
	
	public static final String getSelectionInputName(FacesContext context,
			UIScrollableDataTable grid) {
		String id = grid.getBaseClientId(context) + ":s";
		
		return id;
	}

	public void decode(FacesContext context, UIComponent component,
			CompositeRenderer compositeRenderer) {
		
		UIScrollableDataTable grid = (UIScrollableDataTable) component;
		
		ExternalContext externalContext = context.getExternalContext();
		Map requestParamMap = externalContext.getRequestParameterMap();
		Application application = context.getApplication();
		
		String id = getSelectionInputName(context, grid);
		
		String value = (String) requestParamMap.get(id);
		
		Converter converter = application.createConverter(ClientSelection.class);
		
		ClientSelection _oldClientSelection = 
			(ClientSelection) grid.getAttributes().get(CLIENT_SELECTION);
		
		final ClientSelection oldClientSelection = 
			_oldClientSelection == null ? 
					new ClientSelection() :
						_oldClientSelection;
		
		final ClientSelection clientSelection = 
			(ClientSelection) converter.getAsObject(context, grid, value);

		
		
		
		final ScrollableDataTableRendererState state = 
			ScrollableDataTableRendererState.createState(context, grid);
		
		state.setRowIndex(ScrollableDataTableUtils.getClientRowIndex(grid));
		
		final SimpleSelection simpleSelection = grid.getSelection() == null ? new SimpleSelection()
				: (SimpleSelection) grid.getSelection();

		
		
		if (clientSelection.isReset() || clientSelection.isSelectAll()) {
			simpleSelection.clear();
		}
		
		try {
			grid.walk(context, 
					new DataVisitor() {
						public void process(FacesContext context, Object rowKey,
								Object argument) throws IOException {
						
							int i = state.getRowIndex();
							
							if (shouldAddToSelection(i, oldClientSelection, clientSelection)) {
								
								simpleSelection.addKey(rowKey);
							
							} else if (shouldRemoveFromSelection(i, oldClientSelection, clientSelection)){
								
								simpleSelection.removeKey(rowKey);
							
							}
							
							state.nextRow();
							
						}
					}, 
				state);
		} catch(IOException e) {
			throw new FacesException(e);
		}
		
		grid.setSelection(simpleSelection);
		
		ValueBinding selectionBinding = grid.getValueBinding("selection");
		if (selectionBinding != null) {
			selectionBinding.setValue(context, simpleSelection);
		}
		
		ScrollableDataTableRendererState.restoreState(context);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.richfaces.renderkit.RendererContributor#getAcceptableClass()
	 */
	public Class getAcceptableClass() {
		return UIScrollableDataTable.class;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.richfaces.renderkit.RendererContributor#getScriptContribution(javax.faces.context.FacesContext,
	 *      javax.faces.component.UIComponent)
	 */
	public String getScriptContribution(FacesContext context,
			UIComponent component) {
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.richfaces.renderkit.RendererContributor#getScriptDependencies()
	 */
	public String[] getScriptDependencies() {
		return null;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.richfaces.renderkit.RendererContributor#getStyleDependencies()
	 */
	public String[] getStyleDependencies() {
		return null;
	}

	public ScriptOptions buildOptions(FacesContext context,
			UIComponent component) {
		ScriptOptions scriptOptions = new ScriptOptions(component);
		scriptOptions.addOption("selectionInput", getSelectionInputName(
				context, (UIScrollableDataTable) component));
		scriptOptions.addOption("selectedClass");
		scriptOptions.addOption("activeClass");
		return scriptOptions;
	}
	
	
	public void encode(FacesContext context, UIComponent component)
			throws IOException {
		
		UIScrollableDataTable grid = (UIScrollableDataTable) component;
		
		encodeSelection(context, grid);
		writeSelection(context, grid);
	}
	
	
	//Decide whether to add new row to selection based on comparison with old one
	public boolean shouldAddToSelection(int i, ClientSelection oldSelection, ClientSelection newSelection) {
		
		return newSelection.isSelectAll() || 
			(newSelection.isSelected(i) && (!oldSelection.isSelected(i) || newSelection.isReset())) ;
	}

	//Decide whether to remove new row to selection based on comparison with old one
	public boolean shouldRemoveFromSelection(int i, ClientSelection oldSelection, ClientSelection newSelection) {
		return !newSelection.isReset() && (!newSelection.isSelectAll() && (!newSelection.isSelected(i) && oldSelection.isSelected(i)));
	}
	

	private void encodeSelection(FacesContext context, UIScrollableDataTable grid) throws IOException {
		final ScrollableDataTableRendererState state = ScrollableDataTableRendererState.createState(context, grid);
		
		state.setRowIndex(ScrollableDataTableUtils.getClientRowIndex(grid));
		
		final Selection gridSelection = 
			grid.getSelection() == null ? 
					new SimpleSelection() : 
						grid.getSelection();
		final ClientSelection clientSelection = new ClientSelection();
		
		grid.walk(context, 
			new DataVisitor() {
				public void process(FacesContext context, Object rowKey,
						Object argument) throws IOException {
				
					if (gridSelection.isSelected(rowKey)) {

						int i = state.getRowIndex();
						
						clientSelection.addIndex(i);
					}
					
					
					state.nextRow();
					
				}
			}, 
		state);
		
		
		ScrollableDataTableRendererState.restoreState(context);
		
		grid.getAttributes().put(CLIENT_SELECTION, clientSelection);
	}
	
	/**
	 * Get client selection from the component, transform it into string form,
	 * and write it as hidden input
	 * @param context
	 * @param grid
	 * @throws IOException
	 */
	public void writeSelection(FacesContext context, UIScrollableDataTable grid) 
		throws IOException {
		
		Application application = context.getApplication();
		
		Converter converter = 
			application.createConverter(ClientSelection.class);
		
		String string = 
			converter.getAsString(context, grid, grid.getAttributes().get(CLIENT_SELECTION));
		
		if (string == null) {
			string = "";
		}
		
		String id = getSelectionInputName(context, grid);
		
		
		ResponseWriter writer = context.getResponseWriter();
		writer.startElement(HTML.INPUT_ELEM, grid);
		writer.writeAttribute(HTML.TYPE_ATTR, "hidden", null);
		writer.writeAttribute(HTML.id_ATTRIBUTE, id, null);
		writer.writeAttribute(HTML.NAME_ATTRIBUTE, id, null);
		writer.writeAttribute(HTML.value_ATTRIBUTE, string, null);
		writer.endElement(HTML.INPUT_ELEM);
		
		AjaxContext ajaxContext = AjaxContext.getCurrentInstance(context);
		
		if (ajaxContext.isAjaxRequest()) {
			ajaxContext.addRenderedArea(id);
		}
		
	}


}
