package org.csstudio.sds.ui.internal.properties.view;

import org.csstudio.sds.model.IOption;
import org.eclipse.jface.viewers.AbstractListViewer;
import org.eclipse.jface.viewers.ArrayContentProvider;
import org.eclipse.jface.viewers.CellEditor;
import org.eclipse.jface.viewers.ComboViewer;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.CCombo;
import org.eclipse.swt.events.FocusAdapter;
import org.eclipse.swt.events.FocusEvent;
import org.eclipse.swt.events.KeyAdapter;
import org.eclipse.swt.events.KeyEvent;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.TraverseEvent;
import org.eclipse.swt.events.TraverseListener;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

/**
 * Cell editor implementation that uses a combo box.
 * 
 * The editor displays a set of {@link IOption}�s. When one of the options is
 * chosen, the identifier of that option (see {@link IOption#getIdentifier()})
 * is returned as selected value for this cell editor.
 * 
 * @author Sven Wende
 * 
 */
public class OptionComboBoxCellEditor extends CellEditor {
	private AbstractListViewer _viewer;
	private CCombo _combobox; 
	private IOption[] _options;
	private IOption _selection;

	/**
	 * Constructor.
	 * 
	 * @param parent
	 *            the parent composite
	 * @param options
	 *            the options
	 * @param style
	 *            the style
	 */
	public OptionComboBoxCellEditor(Composite parent, IOption[] options,
			int style) {
		super(parent, style);
		assert options != null;
		_options = options;

		_viewer.setInput(_options);
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	protected Control createControl(Composite parent) {
		_combobox = new CCombo(parent, getStyle());
		_combobox.setEditable(false);
		_combobox.setVisibleItemCount(20);
		_viewer = new ComboViewer(_combobox);
		
		_viewer.setLabelProvider(new LabelProvider());
		_viewer.setContentProvider(new ArrayContentProvider());
		_combobox.setFont(parent.getFont());

		_combobox.addKeyListener(new KeyAdapter() {
            // hook key pressed - see PR 14201  
            @Override
			public void keyPressed(KeyEvent e) {
                keyReleaseOccured(e);
            }
        });
        
		_combobox.addSelectionListener(new SelectionAdapter() {
			@Override
			public void widgetDefaultSelected(SelectionEvent event) {
				applyEditorValueAndDeactivate();
			}
			
            @Override
			public void widgetSelected(SelectionEvent event) {
            	ISelection sel = _viewer.getSelection();
            	
            	if(sel instanceof IStructuredSelection) {
            		_selection = (IOption) ((IStructuredSelection) sel).getFirstElement();
            		applyEditorValueAndDeactivate();
            	}
            }
		});

		_combobox.addTraverseListener(new TraverseListener() {
			@Override
			public void keyTraversed(TraverseEvent e) {
				if (e.detail == SWT.TRAVERSE_ESCAPE
						|| e.detail == SWT.TRAVERSE_RETURN) {
					e.doit = false;
				}
			}
		});

		_combobox.addFocusListener(new FocusAdapter() {
			@Override
			public void focusLost(FocusEvent e) {
				OptionComboBoxCellEditor.this.focusLost();
			}
		});
		return _combobox;

	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	protected Object doGetValue() {
		String result = "";

		if (_selection != null) {
			result = _selection.getIdentifier();
		}

		return result;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	protected void doSetFocus() {
		_viewer.getControl().setFocus();
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	protected void doSetValue(Object value) {
		_viewer.setSelection(new StructuredSelection(value));
	}

	/**
	 * Applies the currently selected value and deactivates the cell editor.
	 */
	void applyEditorValueAndDeactivate() {
		Object newValue = doGetValue();
		markDirty();
		boolean isValid = isCorrect(newValue);
		setValueValid(isValid);

		fireApplyEditorValue();
		deactivate();
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	protected void focusLost() {
		if (isActivated()) {
			applyEditorValueAndDeactivate();
		}
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	protected void keyReleaseOccured(KeyEvent keyEvent) {
		if (keyEvent.character == '\u001b') { // Escape character
			fireCancelEditor();
		} else if (keyEvent.character == '\t') { // tab key
			applyEditorValueAndDeactivate();
		}
	}
}