package org.litesoft.mgwt.client.widgets;

import org.litesoft.commonfoundation.annotations.*;
import org.litesoft.commonfoundation.base.*;
import org.litesoft.core.util.*;
import org.litesoft.core.util.externalization.*;

import com.google.gwt.event.logical.shared.*;
import com.google.gwt.user.client.*;
import com.google.gwt.user.client.ui.*;
import com.googlecode.mgwt.ui.client.widget.*;

import java.util.*;

public class RadioGroup<T> implements TakesValue<T> {
    protected final E13nResolver mResolver;
    private final SelectedListener<T> mSelectedListener;
    private final List<MRadioButton> mRadioButtons = new ArrayList<MRadioButton>();
    private final List<T> mOptions = new ArrayList<T>();
    private final String mGroupID = HTMLPanel.createUniqueId();
    private int mFirstEnabled = -1;

    public RadioGroup( @NotNull E13nResolver pResolver, @Nullable SelectedListener<T> pSelectedListener ) {
        mResolver = pResolver;
        mSelectedListener = pSelectedListener;
    }

    public MRadioButton addOption( @NotNull final T pOption ) {
        MRadioButton zRB = new MRadioButton( mGroupID );
        mRadioButtons.add( zRB );
        mOptions.add( pOption );
        zRB.setText( DisplayObject.resolve( mResolver, pOption ) );
        if ( !isSelectable( pOption ) ) {
            zRB.setEnabled( false );
        } else {
            if ( mFirstEnabled == -1 ) {
                mFirstEnabled = mRadioButtons.size() - 1;
                zRB.setValue( true );
            }
            zRB.addValueChangeHandler( new ValueChangeHandler<Boolean>() {
                @Override
                public void onValueChange( ValueChangeEvent<Boolean> event ) {
                    if ( pOption instanceof Runnable ) {
                        ((Runnable) pOption).run();
                    } else if ( mSelectedListener != null ) {
                        mSelectedListener.selected( pOption );
                    }
                }
            } );
        }
        return zRB;
    }

    @Override
    public T getValue() {
        int i = mRadioButtons.size();
        while ( --i > mFirstEnabled ) {
            if ( Boolean.TRUE.equals( mRadioButtons.get( i ).getValue() ) ) {
                return mOptions.get( i );
            }
        }
        return (mFirstEnabled > -1) ? mOptions.get( mFirstEnabled ) : null;
    }

    @Override
    public void setValue( T value ) {
        for ( int i = 0; i < mOptions.size(); i++ ) {
            if ( Currently.areEqual( value, mOptions.get( i ) ) ) {
                setIndex( i );
                return;
            }
        }
        setIndex( mFirstEnabled );
    }

    protected void setIndex( int pIndex ) {
        if ( (0 <= pIndex) && (pIndex < mRadioButtons.size()) ) {
            mRadioButtons.get( pIndex ).setValue( true );
        }
    }

    protected boolean isSelectable( T pOption ) {
        return !(pOption instanceof Selectable) || ((Selectable) pOption).isSelectable();
    }
}