package com.onaro.sanscreen.client.view.selection;


import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import javax.swing.event.EventListenerList;

import org.eclipse.core.runtime.IAdaptable;


/**
 * Represents the current state of the selection for any object Models a selection
 * of objects of different types. Selection mode may be single or multiple selection.
 * Whenever the selection changes, an event is issued to all interested listeners.
 * <p>Objects are identified only by their id.
 */
public class ObjectSelectionModel {

    /**
     * The set of selected objects, indexed by the object's ID.
     */
    protected List<IAdaptable> selectedAdaptables = Collections.emptyList();
    
    protected final EventListenerList listeners = new EventListenerList();
    
    protected void fireListChanged() {
    	ObjectSelectionListener[] listenerList = listeners.getListeners(ObjectSelectionListener.class);
    	if (listenerList.length == 0) return;
    	
    	ObjectSelectionEvent objectSelectionEvent = new ObjectSelectionEvent(this);
    	for (ObjectSelectionListener listener : listenerList) {
			listener.selectionChanged(objectSelectionEvent);
		}
    }

    /**
     * Change the selection to the empty set.
     */
    public void clearSelection() {
        if (!selectedAdaptables.isEmpty()) {
        	selectedAdaptables.clear();
            fireListChanged();
        }
    }
    
    /**
     * @see #setSelectedAdaptables(Iterable)
     */
    public void setSelectedAdaptable(IAdaptable adaptable) {
    	if (adaptable == null) {
    		clearSelection();
    	} else {
    		setSelectedAdaptables(Collections.singletonList(adaptable));
    	}
    }
    

    /**
     * Sets the selected objects removing any previous selection. The selection is
     * always considered as changed.
     *
     * @param newSelection a list of <code>SelectedObject</code>s
     */
    public void setSelectedAdaptables(Iterable<? extends IAdaptable> newSelection) {
    	selectedAdaptables = new ArrayList<IAdaptable>();
    	
    	for (IAdaptable adaptable : newSelection) {
    		if (adaptable != null) {
    			selectedAdaptables.add(adaptable);
    		}
		}
    	
    	fireListChanged();
    }
//    public void setSelectedAdaptables(Iterable<? extends IAdaptable> newSelection) {
//    	selectedAdaptables = new ArrayList<IAdaptable>();
//
//    	for (IAdaptable adaptable : newSelection) {
//    		if (adaptable != null) {
//    			selectedAdaptables.add(adaptable);
//    		}
//		}
//
//    	fireListChanged();
//    }

    /**
     * Tests if there is any selected object.
     * @return true of no objects are selected
     */
    public boolean isSelectionEmpty() {
        return selectedAdaptables.isEmpty();
    }

    public List<IAdaptable> getSelectedAdaptables() {
    	return new ArrayList<IAdaptable>(selectedAdaptables);
    }
    
    /**
     * 
     * Gets a list of the current selected objects.
     * Returns a mutable copy of the selected object list.
     * @return a list of {@link SelectedObject} instances
     */
    @Deprecated
    public List<SelectedObject> getSelectedObjects() {
        List<IAdaptable> selectedAdaptables = getSelectedAdaptables();
		List<SelectedObject> selectedObjects = SelectedObjectUtils.getSelectedObjects(selectedAdaptables);
		return selectedObjects;
    }

    public IAdaptable getFirstSelectedAdaptable() {
    	if (selectedAdaptables.isEmpty()) return null;
    	
    	return selectedAdaptables.get(0);
    }
    
    /**
     * Gets the first selected object.
     * @return the first selected object or null if none are selected
     * 
     */
    @Deprecated
    public SelectedObject first() {
        for (IAdaptable adaptable : selectedAdaptables) {
        	if (adaptable instanceof SelectedObject) {
        		return (SelectedObject)adaptable;
        	}
        	SelectedObject selectedObject = SelectedObjectUtils.getSelectedObject(adaptable);
        	if (selectedObject != null) return selectedObject;
        }
        
        return null;
    }

    /**
     * Registers a listener for this job's state changes.
     *
     * @param listener the listener
     */
    public void addObjectSelectionListener(ObjectSelectionListener listener) {
        listeners.add(ObjectSelectionListener.class, listener);
    }

    /**
     * Removes a listener of this job's state changes.
     *
     * @param listener the listener
     */
    public void removeObjectSelectionListener(ObjectSelectionListener listener) {
        listeners.remove(ObjectSelectionListener.class, listener);
    }

    /**
     * Gets the number of selected objects.
     * @return the number of objects selected
     */
    public int size() {
        return selectedAdaptables.size();
    }

   
}