/*

 * Copyright 1997-2002 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package javax.swing.text.html;

import java.awt.*;

import javax.swing.event.DocumentEvent;

import javax.swing.text.*;

import java.util.Enumeration;

import java.lang.Integer;

/**

 * A view implementation to display an html horizontal

 * rule.

 *

 * @author  Timothy Prinzing

 * @author  Sara Swanson

 */

class HRuleView extends View  {

    /**

     * Creates a new view that represents an <hr> element.

     *

     * @param elem the element to create a view for

     */

    public HRuleView(Element elem) {

        super(elem);

        setPropertiesFromAttributes();

    }

    /**

     * Update any cached values that come from attributes.

     */

    protected void setPropertiesFromAttributes() {

        StyleSheet sheet = ((HTMLDocument)getDocument()).getStyleSheet();

        AttributeSet eAttr = getElement().getAttributes();

        attr = sheet.getViewAttributes(this);

        alignment = StyleConstants.ALIGN_CENTER;

        size = 0;

        noshade = null;

        widthValue = null;

        if (attr != null) {

            // getAlignment() returns ALIGN_LEFT by default, and HR should

            // use ALIGN_CENTER by default, so we check if the alignment

            // attribute is actually defined

            if (attr.getAttribute(StyleConstants.Alignment) != null) {

            alignment = StyleConstants.getAlignment(attr);

            }

            noshade = (String)eAttr.getAttribute(HTML.Attribute.NOSHADE);

            Object value = eAttr.getAttribute(HTML.Attribute.SIZE);

            if (value != null && (value instanceof String))

                size = Integer.parseInt((String)value);

            value = attr.getAttribute(CSS.Attribute.WIDTH);

            if (value != null && (value instanceof CSS.LengthValue)) {

                widthValue = (CSS.LengthValue)value;

            }

            topMargin = getLength(CSS.Attribute.MARGIN_TOP, attr);

            bottomMargin = getLength(CSS.Attribute.MARGIN_BOTTOM, attr);

            leftMargin = getLength(CSS.Attribute.MARGIN_LEFT, attr);

            rightMargin = getLength(CSS.Attribute.MARGIN_RIGHT, attr);

        }

        else {

            topMargin = bottomMargin = leftMargin = rightMargin = 0;

        }

        size = Math.max(2, size);

    }

    // This will be removed and centralized at some point, need to unify this

    // and avoid private classes.

    private float getLength(CSS.Attribute key, AttributeSet a) {

        CSS.LengthValue lv = (CSS.LengthValue) a.getAttribute(key);

        float len = (lv != null) ? lv.getValue() : 0;

        return len;

    }

    // --- View methods ---------------------------------------------

    /**

     * Paints the view.

     *

     * @param g the graphics context

     * @param a the allocation region for the view

     * @see View#paint

     */

    public void paint(Graphics g, Shape a) {

        Rectangle alloc = (a instanceof Rectangle) ? (Rectangle)a :

                          a.getBounds();

        int x = 0;

        int y = alloc.y + SPACE_ABOVE + (int)topMargin;

        int width = alloc.width - (int)(leftMargin + rightMargin);

        if (widthValue != null) {

            width = (int)widthValue.getValue((float)width);

        }

        int height = alloc.height - (SPACE_ABOVE + SPACE_BELOW +

                                     (int)topMargin + (int)bottomMargin);

        if (size > 0)

                height = size;

        // Align the rule horizontally.

        switch (alignment) {

        case StyleConstants.ALIGN_CENTER:

            x = alloc.x + (alloc.width / 2) - (width / 2);

            break;

        case StyleConstants.ALIGN_RIGHT:

            x = alloc.x + alloc.width - width - (int)rightMargin;

            break;

        case StyleConstants.ALIGN_LEFT:

        default:

            x = alloc.x + (int)leftMargin;

            break;

        }

        // Paint either a shaded rule or a solid line.

        if (noshade != null) {

            g.setColor(Color.black);

            g.fillRect(x, y, width, height);

        }

        else {

            Color bg = getContainer().getBackground();

            Color bottom, top;

            if (bg == null || bg.equals(Color.white)) {

                top = Color.darkGray;

                bottom = Color.lightGray;

            }

            else {

                top = Color.darkGray;

                bottom = Color.white;

            }

            g.setColor(bottom);

            g.drawLine(x + width - 1, y, x + width - 1, y + height - 1);

            g.drawLine(x, y + height - 1, x + width - 1, y + height - 1);

            g.setColor(top);

            g.drawLine(x, y, x + width - 1, y);

            g.drawLine(x, y, x, y + height - 1);

        }

    }

    /**

     * Calculates the desired shape of the rule... this is

     * basically the preferred size of the border.

     *

     * @param axis may be either X_AXIS or Y_AXIS

     * @return the desired span

     * @see View#getPreferredSpan

     */

    public float getPreferredSpan(int axis) {

        switch (axis) {

        case View.X_AXIS:

            return 1;

        case View.Y_AXIS:

            if (size > 0) {

                return size + SPACE_ABOVE + SPACE_BELOW + topMargin +

                    bottomMargin;

            } else {

                if (noshade != null) {

                    return 2 + SPACE_ABOVE + SPACE_BELOW + topMargin +

                        bottomMargin;

                } else {

                    return SPACE_ABOVE + SPACE_BELOW + topMargin +bottomMargin;

                }

            }

        default:

            throw new IllegalArgumentException("Invalid axis: " + axis);

        }

    }

    /**

     * Gets the resize weight for the axis.

     * The rule is: rigid vertically and flexible horizontally.

     *

     * @param axis may be either X_AXIS or Y_AXIS

     * @return the weight

     */

    public int getResizeWeight(int axis) {

        if (axis == View.X_AXIS) {

                return 1;

        } else if (axis == View.Y_AXIS) {

                return 0;

        } else {

            return 0;

        }

    }

    /**

     * Determines how attractive a break opportunity in

     * this view is.  This is implemented to request a forced break.

     *

     * @param axis may be either View.X_AXIS or View.Y_AXIS

     * @param pos the potential location of the start of the

     *   broken view (greater than or equal to zero).

     *   This may be useful for calculating tab

     *   positions.

     * @param len specifies the relative length from <em>pos</em>

     *   where a potential break is desired. The value must be greater

     *   than or equal to zero.

     * @return the weight, which should be a value between

     *   ForcedBreakWeight and BadBreakWeight.

     */

    public int getBreakWeight(int axis, float pos, float len) {

        if (axis == X_AXIS) {

            return ForcedBreakWeight;

        }

        return BadBreakWeight;

    }

    public View breakView(int axis, int offset, float pos, float len) {

        return null;

    }

    /**

     * Provides a mapping from the document model coordinate space

     * to the coordinate space of the view mapped to it.

     *

     * @param pos the position to convert

     * @param a the allocated region to render into

     * @return the bounding box of the given position

     * @exception BadLocationException  if the given position does not

     * represent a valid location in the associated document

     * @see View#modelToView

     */

    public Shape modelToView(int pos, Shape a, Position.Bias b) throws BadLocationException {

        int p0 = getStartOffset();

        int p1 = getEndOffset();

        if ((pos >= p0) && (pos <= p1)) {

            Rectangle r = a.getBounds();

            if (pos == p1) {

                r.x += r.width;

            }

            r.width = 0;

            return r;

        }

        return null;

    }

    /**

     * Provides a mapping from the view coordinate space to the logical

     * coordinate space of the model.

     *

     * @param x the X coordinate

     * @param y the Y coordinate

     * @param a the allocated region to render into

     * @return the location within the model that best represents the

     *  given point of view

     * @see View#viewToModel

     */

    public int viewToModel(float x, float y, Shape a, Position.Bias[] bias) {

        Rectangle alloc = (Rectangle) a;

        if (x < alloc.x + (alloc.width / 2)) {

            bias[0] = Position.Bias.Forward;

            return getStartOffset();

        }

        bias[0] = Position.Bias.Backward;

        return getEndOffset();

    }

    /**

     * Fetches the attributes to use when rendering.  This is

     * implemented to multiplex the attributes specified in the

     * model with a StyleSheet.

     */

    public AttributeSet getAttributes() {

        return attr;

    }

    public void changedUpdate(DocumentEvent changes, Shape a, ViewFactory f) {

        super.changedUpdate(changes, a, f);

        int pos = changes.getOffset();

        if (pos <= getStartOffset() && (pos + changes.getLength()) >=

            getEndOffset()) {

            setPropertiesFromAttributes();

        }

    }

    // --- variables ------------------------------------------------

    private float topMargin;

    private float bottomMargin;

    private float leftMargin;

    private float rightMargin;

    private int alignment = StyleConstants.ALIGN_CENTER;

    private String noshade = null;

    private int size = 0;

    private CSS.LengthValue widthValue;

    private static final int SPACE_ABOVE = 3;

    private static final int SPACE_BELOW = 3;

    /** View Attributes. */

    private AttributeSet attr;

}