/*
 * Copyright (c) 2009 Kathryn Huxtable and Kenneth Orr.
 *
 * This file is part of the SeaGlass Pluggable Look and Feel.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * $Id$
 */
package com.seaglasslookandfeel.ui;

import java.awt.Dimension;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.Rectangle;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import javax.swing.AbstractButton;
import javax.swing.ButtonModel;
import javax.swing.Icon;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.LookAndFeel;
import javax.swing.plaf.ComponentUI;
import javax.swing.plaf.UIResource;
import javax.swing.plaf.basic.BasicButtonUI;
import javax.swing.plaf.basic.BasicHTML;
import javax.swing.plaf.synth.ColorType;
import javax.swing.plaf.synth.Region;
import javax.swing.plaf.synth.SynthConstants;
import javax.swing.plaf.synth.SynthContext;
import javax.swing.plaf.synth.SynthGraphicsUtils;
import javax.swing.plaf.synth.SynthLookAndFeel;
import javax.swing.plaf.synth.SynthStyle;
import javax.swing.text.View;

import com.seaglasslookandfeel.SeaGlassContext;
import com.seaglasslookandfeel.SeaGlassLookAndFeel;

/**
 * SeaGlassButtonUI implementation.
 *
 * <p>Based on SynthButtonUI by Scott Violet.</p>
 *
 * @see javax.swing.plaf.synth.SynthButtonUI
 */
public class SeaGlassButtonUI extends BasicButtonUI implements PropertyChangeListener, SeaglassUI {
    private static final String APPLE_PREFIX = "JButton.";
    private SynthStyle          style;

    /**
     * Create a new UI delegate.
     *
     * @param  c the component.
     *
     * @return the UI delegate.
     */
    public static ComponentUI createUI(JComponent c) {
        return new SeaGlassButtonUI();
    }

    /**
     * @see javax.swing.plaf.basic.BasicButtonUI#installDefaults(javax.swing.AbstractButton)
     */
    protected void installDefaults(AbstractButton b) {
        updateStyle(b);

        LookAndFeel.installProperty(b, "rolloverEnabled", Boolean.TRUE);
    }

    /**
     * @see javax.swing.plaf.basic.BasicButtonUI#installListeners(javax.swing.AbstractButton)
     */
    protected void installListeners(AbstractButton b) {
        super.installListeners(b);
        b.addPropertyChangeListener(this);
    }

    /**
     * Update the style of the button.
     *
     * @param b the button.
     */
    public void updateStyle(AbstractButton b) {
        SeaGlassContext context  = getContext(b, SynthConstants.ENABLED);
        SynthStyle      oldStyle = style;

        style = SeaGlassLookAndFeel.updateStyle(context, this);
        if (style != oldStyle) {
            if (b.getMargin() == null || (b.getMargin() instanceof UIResource)) {
                Insets margin = (Insets) style.get(context, getPropertyPrefix() + "margin");

                if (margin == null) {
                    // Some places assume margins are non-null.
                    margin = SeaGlassLookAndFeel.EMPTY_UIRESOURCE_INSETS;
                }

                b.setMargin(margin);
            }

            Object value = style.get(context, getPropertyPrefix() + "iconTextGap");

            if (value != null) {
                LookAndFeel.installProperty(b, "iconTextGap", value);
            }

            value = style.get(context, getPropertyPrefix() + "contentAreaFilled");
            LookAndFeel.installProperty(b, "contentAreaFilled", value != null ? value : Boolean.TRUE);

            value = b.getClientProperty(APPLE_PREFIX + "buttonType");
            if (value != null) {
                if ("segmented".equals(value)) {
                    b.setMargin(SeaGlassLookAndFeel.EMPTY_UIRESOURCE_INSETS);
                }
            }

            if (oldStyle != null) {
                uninstallKeyboardActions(b);
                installKeyboardActions(b);
            }
        }

        context.dispose();
    }

    /**
     * @see javax.swing.plaf.basic.BasicButtonUI#uninstallListeners(javax.swing.AbstractButton)
     */
    protected void uninstallListeners(AbstractButton b) {
        super.uninstallListeners(b);
        b.removePropertyChangeListener(this);
    }

    /**
     * @see javax.swing.plaf.basic.BasicButtonUI#uninstallDefaults(javax.swing.AbstractButton)
     */
    protected void uninstallDefaults(AbstractButton b) {
        SeaGlassContext context = getContext(b, ENABLED);

        style.uninstallDefaults(context);
        context.dispose();
        style = null;
    }

    /**
     * @see SeaglassUI#getContext(javax.swing.JComponent)
     */
    public SeaGlassContext getContext(JComponent c) {
        return getContext(c, getComponentState(c));
    }

    /**
     * Get the Synth context.
     *
     * @param  c     the component.
     * @param  state the state.
     *
     * @return the Synth context.
     */
    SeaGlassContext getContext(JComponent c, int state) {
        Region region = getRegion(c);

        return SeaGlassContext.getContext(SeaGlassContext.class, c, region, style, state);
    }

    /**
     * Get the region.
     *
     * @param  c the component.
     *
     * @return the region.
     */
    private Region getRegion(JComponent c) {
        return SynthLookAndFeel.getRegion(c);
    }

    /**
     * Returns the current state of the passed in <code>AbstractButton</code>.
     *
     * @param  c the button component.
     *
     * @return the button's state.
     */
    private int getComponentState(JComponent c) {
        int state = ENABLED;

        if (!c.isEnabled()) {
            state = DISABLED;
        }

        if (SeaGlassLookAndFeel.selectedUI == this) {
            return SeaGlassLookAndFeel.selectedUIState | SynthConstants.ENABLED;
        }

        AbstractButton button = (AbstractButton) c;
        ButtonModel    model  = button.getModel();

        if (model.isPressed()) {
            if (model.isArmed()) {
                state = PRESSED;
            } else {
                state = MOUSE_OVER;
            }
        }

        if (model.isRollover()) {
            state |= MOUSE_OVER;
        }

        if (model.isSelected()) {
            state |= SELECTED;
        }

        if (c.isFocusOwner() && button.isFocusPainted()) {
            state |= FOCUSED;
        }

        if ((c instanceof JButton) && ((JButton) c).isDefaultButton()) {
            state |= DEFAULT;
        }
        
        return state;
    }

    /**
     * @see javax.swing.plaf.basic.BasicButtonUI#getBaseline(javax.swing.JComponent,
     *      int, int)
     */
    public int getBaseline(JComponent c, int width, int height) {
        if (c == null) {
            throw new NullPointerException("Component must be non-null");
        }

        if (width < 0 || height < 0) {
            throw new IllegalArgumentException("Width and height must be >= 0");
        }

        AbstractButton b    = (AbstractButton) c;
        String         text = b.getText();

        if (text == null || "".equals(text)) {
            return -1;
        }

        Insets    i        = b.getInsets();
        Rectangle viewRect = new Rectangle();
        Rectangle textRect = new Rectangle();
        Rectangle iconRect = new Rectangle();

        viewRect.x      = i.left;
        viewRect.y      = i.top;
        viewRect.width  = width - (i.right + viewRect.x);
        viewRect.height = height - (i.bottom + viewRect.y);

        // layout the text and icon
        SeaGlassContext context = getContext(b);
        FontMetrics     fm = context.getComponent().getFontMetrics(context.getStyle().getFont(context));

        context.getStyle().getGraphicsUtils(context).layoutText(context, fm, b.getText(), b.getIcon(), b.getHorizontalAlignment(),
                                                                b.getVerticalAlignment(), b.getHorizontalTextPosition(),
                                                                b.getVerticalTextPosition(), viewRect, iconRect, textRect,
                                                                b.getIconTextGap());
        View view     = (View) b.getClientProperty(BasicHTML.propertyKey);
        int  baseline;

        if (view != null) {
            baseline = BasicHTML.getHTMLBaseline(view, textRect.width, textRect.height);
            if (baseline >= 0) {
                baseline += textRect.y;
            }
        } else {
            baseline = textRect.y + fm.getAscent();
        }

        context.dispose();
        return baseline;
    }

    // ********************************
    // Paint Methods
    // ********************************

    /**
     * @see javax.swing.plaf.ComponentUI#update(java.awt.Graphics, javax.swing.JComponent)
     */
    public void update(Graphics g, JComponent c) {
        SeaGlassContext context = getContext(c);

        SeaGlassLookAndFeel.update(context, g);
        paintBackground(context, g, c);
        paint(context, g);
        context.dispose();
    }

    /**
     * @see javax.swing.plaf.basic.BasicButtonUI#paint(java.awt.Graphics, javax.swing.JComponent)
     */
    public void paint(Graphics g, JComponent c) {
        SeaGlassContext context = getContext(c);

        paint(context, g);
        context.dispose();
    }

    /**
     * Paint the button.
     *
     * @param context the Synth context.
     * @param g       the Graphics context.
     */
    protected void paint(SeaGlassContext context, Graphics g) {
        AbstractButton b = (AbstractButton) context.getComponent();

        g.setColor(context.getStyle().getColor(context, ColorType.TEXT_FOREGROUND));
        g.setFont(style.getFont(context));
        context.getStyle().getGraphicsUtils(context).paintText(context, g, b.getText(), getIcon(b), b.getHorizontalAlignment(),
                                                               b.getVerticalAlignment(), b.getHorizontalTextPosition(),
                                                               b.getVerticalTextPosition(), b.getIconTextGap(),
                                                               b.getDisplayedMnemonicIndex(), getTextShiftOffset(context));
    }

    /**
     * Paint the button background.
     *
     * @param context the Synth context.
     * @param g       the Graphics context.
     * @param c       the button component.
     */
    void paintBackground(SeaGlassContext context, Graphics g, JComponent c) {
        if (((AbstractButton) c).isContentAreaFilled()) {
            context.getPainter().paintButtonBackground(context, g, 0, 0, c.getWidth(), c.getHeight());
        }
    }

    /**
     * @see SeaglassUI#paintBorder(javax.swing.plaf.synth.SynthContext,
     *      java.awt.Graphics, int, int, int, int)
     */
    public void paintBorder(SynthContext context, Graphics g, int x, int y, int w, int h) {
        ((SeaGlassContext) context).getPainter().paintButtonBorder(context, g, x, y, w, h);
    }

    /**
     * Returns the default icon. This should NOT callback to the JComponent.
     *
     * @param  b AbstractButton the iocn is associated with.
     *
     * @return the default icon.
     */

    protected Icon getDefaultIcon(AbstractButton b) {
        SeaGlassContext context = getContext(b);
        Icon            icon    = context.getStyle().getIcon(context, getPropertyPrefix() + "icon");

        context.dispose();
        return icon;
    }

    /**
     * Returns the Icon to use in painting the button.
     *
     * @param  b the button.
     *
     * @return the icon.
     */
    protected Icon getIcon(AbstractButton b) {
        Icon        icon  = b.getIcon();
        ButtonModel model = b.getModel();

        if (!model.isEnabled()) {
            icon = getSynthDisabledIcon(b, icon);
        } else if (model.isPressed() && model.isArmed()) {
            icon = getPressedIcon(b, getSelectedIcon(b, icon));
        } else if (b.isRolloverEnabled() && model.isRollover()) {
            icon = getRolloverIcon(b, getSelectedIcon(b, icon));
        } else if (model.isSelected()) {
            icon = getSelectedIcon(b, icon);
        } else {
            icon = getEnabledIcon(b, icon);
        }

        if (icon == null) {
            return getDefaultIcon(b);
        }

        return icon;
    }

    /**
     * This method will return the icon that should be used for a button. We
     * only want to use the synth icon defined by the style if the specific icon
     * has not been defined for the button state and the backup icon is a
     * UIResource (we set it, not the developer).
     *
     * @param  b            button
     * @param  specificIcon icon returned from the button for the specific state
     * @param  defaultIcon  fallback icon
     * @param  state        the synth state of the button
     *
     * @return the icon.
     */
    private Icon getIcon(AbstractButton b, Icon specificIcon, Icon defaultIcon, int state) {
        Icon icon = specificIcon;

        if (icon == null) {
            if (defaultIcon instanceof UIResource) {
                icon = getSynthIcon(b, state);
                if (icon == null) {
                    icon = defaultIcon;
                }
            } else {
                icon = defaultIcon;
            }
        }

        return icon;
    }

    /**
     * DOCUMENT ME!
     *
     * @param  b             DOCUMENT ME!
     * @param  synthConstant DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    private Icon getSynthIcon(AbstractButton b, int synthConstant) {
        return style.getIcon(getContext(b, synthConstant), getPropertyPrefix() + "icon");
    }

    /**
     * DOCUMENT ME!
     *
     * @param  b           DOCUMENT ME!
     * @param  defaultIcon DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    private Icon getEnabledIcon(AbstractButton b, Icon defaultIcon) {
        if (defaultIcon == null) {
            defaultIcon = getSynthIcon(b, SynthConstants.ENABLED);
        }

        return defaultIcon;
    }

    /**
     * DOCUMENT ME!
     *
     * @param  b           DOCUMENT ME!
     * @param  defaultIcon DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    private Icon getSelectedIcon(AbstractButton b, Icon defaultIcon) {
        return getIcon(b, b.getSelectedIcon(), defaultIcon, SynthConstants.SELECTED);
    }

    /**
     * DOCUMENT ME!
     *
     * @param  b           DOCUMENT ME!
     * @param  defaultIcon DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    private Icon getRolloverIcon(AbstractButton b, Icon defaultIcon) {
        ButtonModel model = b.getModel();
        Icon        icon;

        if (model.isSelected()) {
            icon = getIcon(b, b.getRolloverSelectedIcon(), defaultIcon, SynthConstants.MOUSE_OVER | SynthConstants.SELECTED);
        } else {
            icon = getIcon(b, b.getRolloverIcon(), defaultIcon, SynthConstants.MOUSE_OVER);
        }

        return icon;
    }

    /**
     * DOCUMENT ME!
     *
     * @param  b           DOCUMENT ME!
     * @param  defaultIcon DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    private Icon getPressedIcon(AbstractButton b, Icon defaultIcon) {
        return getIcon(b, b.getPressedIcon(), defaultIcon, SynthConstants.PRESSED);
    }

    /**
     * DOCUMENT ME!
     *
     * @param  b           DOCUMENT ME!
     * @param  defaultIcon DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    private Icon getSynthDisabledIcon(AbstractButton b, Icon defaultIcon) {
        ButtonModel model = b.getModel();
        Icon        icon;

        if (model.isSelected()) {
            icon = getIcon(b, b.getDisabledSelectedIcon(), defaultIcon, SynthConstants.DISABLED | SynthConstants.SELECTED);
        } else {
            icon = getIcon(b, b.getDisabledIcon(), defaultIcon, SynthConstants.DISABLED);
        }

        return icon;
    }

    /**
     * Returns the amount to shift the text/icon when painting.
     *
     * @param  state DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    protected int getTextShiftOffset(SeaGlassContext state) {
        AbstractButton button = (AbstractButton) state.getComponent();
        ButtonModel    model  = button.getModel();

        if (model.isArmed() && model.isPressed() && button.getPressedIcon() == null) {
            return state.getStyle().getInt(state, getPropertyPrefix() + "textShiftOffset", 0);
        }

        return 0;
    }

    // ********************************
    // Layout Methods
    // ********************************
    /**
     * @see javax.swing.plaf.basic.BasicButtonUI#getMinimumSize(javax.swing.JComponent)
     */
    public Dimension getMinimumSize(JComponent c) {
        if (c.getComponentCount() > 0 && c.getLayout() != null) {
            return null;
        }

        AbstractButton   b      = (AbstractButton) c;
        SeaGlassContext  ss     = getContext(c);
        final SynthStyle style2 = ss.getStyle();
        Dimension        size   = style2.getGraphicsUtils(ss).getMinimumSize(ss, style2.getFont(ss), b.getText(), getSizingIcon(b),
                                                                             b.getHorizontalAlignment(), b.getVerticalAlignment(),
                                                                             b.getHorizontalTextPosition(), b.getVerticalTextPosition(),
                                                                             b.getIconTextGap(), b.getDisplayedMnemonicIndex());

        ss.dispose();
        return size;
    }

    /**
     * @see javax.swing.plaf.basic.BasicButtonUI#getPreferredSize(javax.swing.JComponent)
     */
    public Dimension getPreferredSize(JComponent c) {
        if (c.getComponentCount() > 0 && c.getLayout() != null) {
            return null;
        }

        AbstractButton     b             = (AbstractButton) c;
        SeaGlassContext    ss            = getContext(c);
        SynthStyle         style2        = ss.getStyle();
        SynthGraphicsUtils graphicsUtils = style2.getGraphicsUtils(ss);
        Dimension          size          = graphicsUtils.getPreferredSize(ss, style2.getFont(ss), b.getText(), getSizingIcon(b),
                                                                          b.getHorizontalAlignment(),
                                                                          b.getVerticalAlignment(), b.getHorizontalTextPosition(),
                                                                          b.getVerticalTextPosition(), b.getIconTextGap(),
                                                                          b.getDisplayedMnemonicIndex());

        ss.dispose();
        // Make height odd.
        size.height &= ~1;
        return size;
    }

    /**
     * @see javax.swing.plaf.basic.BasicButtonUI#getMaximumSize(javax.swing.JComponent)
     */
    public Dimension getMaximumSize(JComponent c) {
        if (c.getComponentCount() > 0 && c.getLayout() != null) {
            return null;
        }

        AbstractButton   b      = (AbstractButton) c;
        SeaGlassContext  ss     = getContext(c);
        final SynthStyle style2 = ss.getStyle();
        Dimension        size   = style2.getGraphicsUtils(ss).getMaximumSize(ss, style2.getFont(ss), b.getText(), getSizingIcon(b),
                                                                             b.getHorizontalAlignment(), b.getVerticalAlignment(),
                                                                             b.getHorizontalTextPosition(), b.getVerticalTextPosition(),
                                                                             b.getIconTextGap(), b.getDisplayedMnemonicIndex());

        ss.dispose();
        return size;
    }

    /**
     * Returns the Icon used in calculating the pref/min/max size.
     *
     * @param  b DOCUMENT ME!
     *
     * @return DOCUMENT ME!
     */
    protected Icon getSizingIcon(AbstractButton b) {
        // NOTE: this is slightly different than BasicButtonUI, where it
        // would just use getIcon, but this should be ok.
        Icon icon = (b.isEnabled() || b.getDisabledIcon() == null) ? b.getIcon() : b.getDisabledIcon();

        if (icon == null) {
            icon = getDefaultIcon(b);
        }

        return icon;
    }

    /**
     * @see java.beans.PropertyChangeListener#propertyChange(java.beans.PropertyChangeEvent)
     */
    public void propertyChange(PropertyChangeEvent e) {
        if (SeaGlassLookAndFeel.shouldUpdateStyle(e)) {
            updateStyle((AbstractButton) e.getSource());
        }
    }
}