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package net.sf.cuf.state.ui;

import java.awt.Color;
import java.util.HashMap;
import java.util.Map;

import javax.swing.JComponent;

import net.sf.cuf.state.AbstractStateAdapter;
import net.sf.cuf.state.State;

/**
 * A SwingBackgroundAdapter adapts the "enabled" state to setting the
 * original background color of a JComponent, the "disabled" state is mapped
 * to setting the background Color supplied in the adapter's constructor
 * or in the setDisabledBackground method.
 */
public class SwingBackgroundAdapter extends AbstractStateAdapter
{
    /** the "disabled" background color, never null */
    private Color                   mDisabledColor;
    /** key= JComponent, value= original background Color, map is never null */
    private Map  mOriginalBackground;

    /**
     * Create a new adapter with a state and a default background Color.
     * @param pState the state we adapt
     */
    public SwingBackgroundAdapter(final State pState)
    {
        super(pState);
        Color disabledColor= Color.PINK;
        init(disabledColor);
    }

    /**
     * Create a new adapter with no state associated.
     * @param pDisabledColor the Color for the disabled state, must not be null
     * @throws IllegalArgumentException if pDisabledColor is null
     */
    public SwingBackgroundAdapter(final Color pDisabledColor)
    {
        super();
        init(pDisabledColor);
    }

    /**
     * Create a new adapter.
     * @param pState the state we adapt
     * @param pDisabledColor the Color for the disabled state, must not be null
     * @throws IllegalArgumentException if pDisabledColor is null
     */
    public SwingBackgroundAdapter(final State pState, final Color pDisabledColor)
    {
        super(pState);
        init(pDisabledColor);
    }

    /**
     * Small helper for the constructors.
     * @param pDisabledColor the background Color for the disabled state, must not be null
     */
    private void init(final Color pDisabledColor)
    {
        if (pDisabledColor==null)
        {
            throw new IllegalArgumentException("Color must not be null");
        }
        mOriginalBackground= new HashMap<>(1);
        mDisabledColor= pDisabledColor;
    }

    /**
     * Sets the disabled Color for the background, the new Color will be shown at the next
     * state change.
     * @param pDisabledColor the Color for the disabled state, must not be null
     */
    public void setDisabledBackgound(final Color pDisabledColor)
    {
        if (pDisabledColor==null)
        {
            throw new IllegalArgumentException("Color must not be null");
        }
        mDisabledColor= pDisabledColor;
    }

    /**
     * We store the original Color of the background of the component, and call processStateChange()
     * afterwards.
     * @param pTarget the target we should adjust
     * @param pEnabled the state for the target
     */
    protected void adjustInitialState(final Object pTarget, final boolean pEnabled)
    {
        if (pTarget instanceof JComponent)
        {
            JComponent component = (JComponent) pTarget;
            mOriginalBackground.put(component, component.getBackground());
            processStateChange(pTarget, pEnabled);
        }
        else
        {
            // you can add any objects but we won't handle them ;-)
            throw new IllegalStateException("we cant handle that object:"+pTarget);
        }
    }

    /**
     * We map the pEnabled boolean to the setting/re-setting of a background Color
     * on a JComponent.
     * @param pTarget  target object, must be a JComponent
     * @param pEnabled true if the target object should get "enabled"
     * @throws IllegalStateException if pTarget is not a JComponent
     */
    protected void processStateChange(final Object pTarget, final boolean pEnabled)
    {
        if (pTarget instanceof JComponent)
        {
            JComponent component = (JComponent) pTarget;
            if (pEnabled)
            {
                component.setBackground(mOriginalBackground.get(component));
            }
            else
            {
                component.setBackground(mDisabledColor);
            }
        }
        else
        {
            // you can add any objects but we won't handle them ;-)
            throw new IllegalStateException("we cant handle that object:"+pTarget);
        }
    }
}