// This Source Code is in the Public Domain per: http://unlicense.org
package org.litesoft.aokeyhole.swing;

import org.litesoft.aokeyhole.objects.*;
import org.litesoft.aokeyhole.objects.support.*;
import org.litesoft.aokeyhole.toolkit.*;

import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;

public class ObjectListAndSavePanel extends JPanel implements ObjectListUpdater,
                                                              ActionListener,
                                                              ListSelectionListener,
                                                              ChangeCallback {
    private static final int PREFERRED_CHAR_WIDTH = 32;
    private static final String CHAR_SAMPLE = "The quick brown fox jumped over the lazy moon.";
    private static final JLabel CHAR_SIZER = new JLabel( CHAR_SAMPLE );

    private static final String ATION_REFRESH = "Refresh";
    private static final String ATION_NEW = "New Object";
    private static final String ATION_SAVE = "Save All";

    private ObjectListClickListener mObjectListClickListener;
    private int mPreferredPixelWidth;
    private JList mList;
    private JButton mSaveButton;

    private ObjectMetaData mLastSelectedObject = null;

    public ObjectListAndSavePanel( ObjectListClickListener pObjectListClickListener ) {
        mObjectListClickListener = pObjectListClickListener;

        mPreferredPixelWidth = CHAR_SIZER.getPreferredSize().width * PREFERRED_CHAR_WIDTH / CHAR_SAMPLE.length();

        setLayout( new BorderLayout() );

        mList = new JList( new ObjectListModel() );
        mList.setSelectionMode( ListSelectionModel.SINGLE_SELECTION );
        mList.addListSelectionListener( this );

        JScrollPane scrollpane = new JScrollPane( mList );
        scrollpane.setHorizontalScrollBarPolicy( JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED );
        scrollpane.setVerticalScrollBarPolicy( JScrollPane.VERTICAL_SCROLLBAR_ALWAYS );

        add( createButton( mObjectListClickListener.createNewAllowed() ? ATION_NEW : ATION_REFRESH ), BorderLayout.NORTH );
        add( scrollpane );
        if ( mObjectListClickListener.requestSaveAllowed() ) {
            add( mSaveButton = createButton( ATION_SAVE ), BorderLayout.SOUTH );
            mSaveButton.setEnabled( false );
        }
    }

    private JButton createButton( String pAction ) {
        JButton button = new JButton( pAction );
        button.addActionListener( this );
        return button;
    }

    private ObjectMetaData getSelection() {
        return (ObjectMetaData) mList.getSelectedValue();
    }

    @Override
    public void changeStateUpdated( Changeable pChangeable ) {
        mSaveButton.setEnabled( pChangeable.isChanged() );
        mList.repaint();
    }

    @Override
    public void updateObjectList( ObjectMetaData[] pObjectMetaDatas ) {
        mList.clearSelection();
        ((ObjectListModel) mList.getModel()).setMembers( pObjectMetaDatas );
        mList.repaint();
        if ( mLastSelectedObject != null ) {
            for ( ObjectMetaData zObjectMetaData : pObjectMetaDatas ) {
                if ( mLastSelectedObject.equals( zObjectMetaData ) ) {
                    mList.setSelectedValue( zObjectMetaData, true );
                    return;
                }
            }
            mLastSelectedObject = null;
        }
    }

    @Override
    public void setSelectedObject( ObjectMetaData pObjectMetaData ) {
        if ( pObjectMetaData == null ) {
            clearSelectedObject();
        } else {
            mLastSelectedObject = pObjectMetaData;
            mList.setSelectedValue( pObjectMetaData, true );
        }
    }

    @Override
    public void clearSelectedObject() {
        mLastSelectedObject = null;
        mList.clearSelection();
    }

    @Override
    public void actionPerformed( ActionEvent e ) {
        if ( ATION_REFRESH.equals( e.getActionCommand() ) ) {
            mObjectListClickListener.refreshRequested();
        } else if ( ATION_NEW.equals( e.getActionCommand() ) ) {
            mObjectListClickListener.createNewRequested();
        } else if ( ATION_SAVE.equals( e.getActionCommand() ) ) {
            mObjectListClickListener.requestSave();
        }
    }

    @Override
    public void valueChanged( ListSelectionEvent e ) {
        ObjectMetaData selection = getSelection();
        if ( (selection != null) && !selection.equals( mLastSelectedObject ) ) {
            mLastSelectedObject = selection;
            mObjectListClickListener.selected( selection );
        }
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension( mPreferredPixelWidth, super.getPreferredSize().height );
    }

    private static class ObjectListModel extends AbstractListModel {
        private ObjectMetaData[] mMembers = ObjectMetaData.EMPTY_ARRAY;

        public void setMembers( ObjectMetaData[] pMembers ) {
            int oldLength = mMembers.length;
            mMembers = ObjectMetaData.EMPTY_ARRAY;
            if ( oldLength != 0 ) {
                fireIntervalRemoved( this, 0, oldLength - 1 );
            }
            int newLength = (pMembers == null) ? 0 : pMembers.length;
            if ( newLength != 0 ) {
                mMembers = pMembers;
                fireIntervalAdded( this, 0, newLength - 1 );
            }
        }

        @Override
        public int getSize() {
            return mMembers.length;
        }

        @Override
        public Object getElementAt( int index ) {
            return mMembers[index];
        }
    }
}