/*

 * Copyright (c) 2003, 2014, Oracle and/or its affiliates. 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.  Oracle designates this

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

 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package sun.awt.X11;

import java.awt.*;

import java.awt.event.MouseEvent;

import java.awt.event.MouseWheelEvent;

import java.awt.event.AdjustmentEvent;

import java.util.ArrayList;

import java.util.Iterator;

import sun.util.logging.PlatformLogger;

// FIXME: implement multi-select

/*

 * Class to paint a list of items, possibly with scrollbars

 * This class paints all items with the same font

 * For now, this class manages the list of items and painting thereof, but not

 * posting of Item or ActionEvents

 */

final class ListHelper implements XScrollbarClient {

    private static final PlatformLogger log = PlatformLogger.getLogger("sun.awt.X11.ListHelper");

    private final int FOCUS_INSET = 1;

    private final int BORDER_WIDTH; // Width of border drawn around the list

                                    // of items

    private final int ITEM_MARGIN;  // Margin between the border of the list

                                    // of items and and item's bg, and between

                                    // items

    private final int TEXT_SPACE;   // Space between the edge of an item and

                                    // the text

    private final int SCROLLBAR_WIDTH;  // Width of a scrollbar

    private java.util.List<String> items;        // List of items

    // TODO: maybe this would be better as a simple int[]

    private java.util.List<Integer> selected;     // List of selected items

    private boolean multiSelect;         // Can multiple items be selected

                                         // at once?

    private int focusedIndex;

    private int maxVisItems;             // # items visible without a vsb

    private XVerticalScrollbar vsb;      // null if unsupported

    private boolean vsbVis;

    private XHorizontalScrollbar hsb;    // null if unsupported

    private boolean hsbVis;

    private Font font;

    private FontMetrics fm;

    private XWindow peer;   // So far, only needed for painting

                            // on notifyValue()

    private Color[] colors; // Passed in for painting on notifyValue()

    // Holds the true if mouse is dragging outside of the area of the list

    // The flag is used at the moment of the dragging and releasing mouse

    // See 6243382 for more information

    private boolean mouseDraggedOutVertically = false;

    private volatile boolean vsbVisibilityChanged = false;

    /*

     * Comment

     */

    ListHelper(XWindow peer, Color[] colors, int initialSize,

               boolean multiSelect, boolean scrollVert, boolean scrollHoriz,

               Font font, int maxVisItems, int SPACE, int MARGIN, int BORDER,

               int SCROLLBAR) {

        this.peer = peer;

        this.colors = colors;

        this.multiSelect = multiSelect;

        items = new ArrayList<>(initialSize);

        selected = new ArrayList<>(1);

        selected.add(Integer.valueOf(-1));

        this.maxVisItems = maxVisItems;

        if (scrollVert) {

            vsb = new XVerticalScrollbar(this);

            vsb.setValues(0, 0, 0, 0, 1, maxVisItems - 1);

        }

        if (scrollHoriz) {

            hsb = new XHorizontalScrollbar(this);

            hsb.setValues(0, 0, 0, 0, 1, 1);

        }

        setFont(font);

        TEXT_SPACE = SPACE;

        ITEM_MARGIN = MARGIN;

        BORDER_WIDTH = BORDER;

        SCROLLBAR_WIDTH = SCROLLBAR;

    }

    @Override

    public Component getEventSource() {

        return peer.getEventSource();

    }

    /**********************************************************************/

    /* List management methods                                            */

    /**********************************************************************/

    void add(String item) {

        items.add(item);

        updateScrollbars();

    }

    void add(String item, int index) {

        items.add(index, item);

        updateScrollbars();

    }

    void remove(String item) {

        // FIXME: need to clean up select list, too?

        items.remove(item);

        updateScrollbars();

        // Is vsb visible now?

    }

    void remove(int index) {

        // FIXME: need to clean up select list, too?

        items.remove(index);

        updateScrollbars();

        // Is vsb visible now?

    }

    void removeAll() {

        items.removeAll(items);

        updateScrollbars();

    }

    void setMultiSelect(boolean ms) {

        multiSelect = ms;

    }

    /*

     * docs.....definitely docs

     * merely keeps internal track of which items are selected for painting

     * dealing with target Components happens elsewhere

     */

    void select(int index) {

        if (index > getItemCount() - 1) {

            index = (isEmpty() ? -1 : 0);

        }

        if (multiSelect) {

            assert false : "Implement ListHelper.select() for multiselect";

        }

        else if (getSelectedIndex() != index) {

            selected.remove(0);

            selected.add(Integer.valueOf(index));

            makeVisible(index);

        }

    }

    /* docs */

    void deselect(int index) {

        assert(false);

    }

    /* docs */

    /* if called for multiselect, return -1 */

    int getSelectedIndex() {

        if (!multiSelect) {

            Integer val = selected.get(0);

            return val.intValue();

        }

        return -1;

    }

    int[] getSelectedIndexes() { assert(false); return null;}

    /*

     * A getter method for XChoicePeer.

     * Returns vsbVisiblityChanged value and sets it to false.

     */

    boolean checkVsbVisibilityChangedAndReset(){

        boolean returnVal = vsbVisibilityChanged;

        vsbVisibilityChanged = false;

        return returnVal;

    }

    boolean isEmpty() {

        return items.isEmpty();

    }

    int getItemCount() {

        return items.size();

    }

    String getItem(int index) {

        return items.get(index);

    }

    /**********************************************************************/

    /* GUI-related methods                                                */

    /**********************************************************************/

    void setFocusedIndex(int index) {

        focusedIndex = index;

    }

    private boolean isFocusedIndex(int index) {

        return index == focusedIndex;

    }

    void setFont(Font newFont) {

        if (newFont != font) {

            font = newFont;

            fm = Toolkit.getDefaultToolkit().getFontMetrics(font);

            // Also cache stuff like fontHeight?

        }

    }

    /*

     * Returns width of the text of the longest item

     */

    int getMaxItemWidth() {

        int m = 0;

        int end = getItemCount();

        for(int i = 0 ; i < end ; i++) {

            int l = fm.stringWidth(getItem(i));

            m = Math.max(m, l);

        }

        return m;

    }

    /*

     * Height of an item (this doesn't include ITEM_MARGIN)

     */

    int getItemHeight() {

        return fm.getHeight() + (2*TEXT_SPACE);

    }

    int y2index(int y) {

        if (log.isLoggable(PlatformLogger.Level.FINE)) {

            log.fine("y=" + y +", firstIdx=" + firstDisplayedIndex() +", itemHeight=" + getItemHeight()

                     + ",item_margin=" + ITEM_MARGIN);

        }

        // See 6243382 for more information

        int newIdx = firstDisplayedIndex() + ((y - 2*ITEM_MARGIN) / (getItemHeight() + 2*ITEM_MARGIN));

        return newIdx;

    }

    /* write these

    int index2y(int);

    public int numItemsDisplayed() {}

    */

    int firstDisplayedIndex() {

        if (vsbVis) {

            return vsb.getValue();

        }

        return 0;

    }

    int lastDisplayedIndex() {

        // FIXME: need to account for horiz scroll bar

        if (hsbVis) {

            assert false : "Implement for horiz scroll bar";

        }

        return vsbVis ? vsb.getValue() + maxVisItems - 1: getItemCount() - 1;

    }

    /*

     * If the given index is not visible in the List, scroll so that it is.

     */

    private void makeVisible(int index) {

        if (vsbVis) {

            if (index < firstDisplayedIndex()) {

                vsb.setValue(index);

            }

            else if (index > lastDisplayedIndex()) {

                vsb.setValue(index - maxVisItems + 1);

            }

        }

    }

    // FIXME: multi-select needs separate focused index

    void up() {

        int curIdx = getSelectedIndex();

        int numItems = getItemCount();

        int newIdx;

        assert curIdx >= 0;

        if (curIdx == 0) {

            newIdx = numItems - 1;

        }

        else {

            newIdx = --curIdx;

        }

        // focus(newIdx);

        select(newIdx);

    }

    void down() {

        int newIdx = (getSelectedIndex() + 1) % getItemCount();

        select(newIdx);

    }

    void pageUp() {

        // FIXME: for multi-select, move the focused item, not the selected item

        if (vsbVis && firstDisplayedIndex() > 0) {

            if (multiSelect) {

                assert false : "Implement pageUp() for multiSelect";

            }

            else {

                int selectionOffset = getSelectedIndex() - firstDisplayedIndex();

                // the vsb does bounds checking

                int newIdx = firstDisplayedIndex() - vsb.getBlockIncrement();

                vsb.setValue(newIdx);

                select(firstDisplayedIndex() + selectionOffset);

            }

        }

    }

    void pageDown() {

        if (vsbVis && lastDisplayedIndex() < getItemCount() - 1) {

            if (multiSelect) {

                assert false : "Implement pageDown() for multiSelect";

            }

            else {

                int selectionOffset = getSelectedIndex() - firstDisplayedIndex();

                // the vsb does bounds checking

                int newIdx = lastDisplayedIndex();

                vsb.setValue(newIdx);

                select(firstDisplayedIndex() + selectionOffset);

            }

        }

    }

    void home() {}

    void end() {}

    boolean isVSBVisible() { return vsbVis; }

    boolean isHSBVisible() { return hsbVis; }

    XVerticalScrollbar getVSB() { return vsb; }

    XHorizontalScrollbar getHSB() { return hsb; }

    boolean isInVertSB(Rectangle bounds, int x, int y) {

        if (vsbVis) {

            assert vsb != null : "Vert scrollbar is visible, yet is null?";

            int sbHeight = hsbVis ? bounds.height - SCROLLBAR_WIDTH : bounds.height;

            return (x <= bounds.width) &&

                   (x >= bounds.width - SCROLLBAR_WIDTH) &&

                   (y >= 0) &&

                   (y <= sbHeight);

        }

        return false;

    }

    boolean isInHorizSB(Rectangle bounds, int x, int y) {

        if (hsbVis) {

            assert hsb != null : "Horiz scrollbar is visible, yet is null?";

            int sbWidth = vsbVis ? bounds.width - SCROLLBAR_WIDTH : bounds.width;

            return (x <= sbWidth) &&

                   (x >= 0) &&

                   (y >= bounds.height - SCROLLBAR_WIDTH) &&

                   (y <= bounds.height);

        }

        return false;

    }

    void handleVSBEvent(MouseEvent e, Rectangle bounds, int x, int y) {

        int sbHeight = hsbVis ? bounds.height - SCROLLBAR_WIDTH : bounds.height;

        vsb.handleMouseEvent(e.getID(),

                             e.getModifiers(),

                             x - (bounds.width - SCROLLBAR_WIDTH),

                             y);

    }

    /*

     * Called when items are added/removed.

     * Update whether the scrollbar is visible or not, scrollbar values

     */

    private void updateScrollbars() {

        boolean oldVsbVis = vsbVis;

        vsbVis = vsb != null && items.size() > maxVisItems;

        if (vsbVis) {

            vsb.setValues(vsb.getValue(), getNumItemsDisplayed(),

                          vsb.getMinimum(), items.size());

        }

        // 6405689. If Vert Scrollbar gets disappeared from the dropdown menu we should repaint whole dropdown even if

        // no actual resize gets invoked. This is needed because some painting artifacts remained between dropdown items

        // but draw3DRect doesn't clear the area inside. Instead it just paints lines as borders.

        vsbVisibilityChanged = (vsbVis != oldVsbVis);

        // FIXME: check if added item makes a hsb necessary (if supported, that of course)

    }

    private int getNumItemsDisplayed() {

        return items.size() > maxVisItems ? maxVisItems : items.size();

    }

    @Override

    public void repaintScrollbarRequest(XScrollbar sb) {

        Graphics g = peer.getGraphics();

        Rectangle bounds = peer.getBounds();

        if ((sb == vsb) && vsbVis) {

            paintVSB(g, XComponentPeer.getSystemColors(), bounds);

        }

        else if ((sb == hsb) && hsbVis) {

            paintHSB(g, XComponentPeer.getSystemColors(), bounds);

        }

        g.dispose();

    }

    @Override

    public void notifyValue(XScrollbar obj, int type, int v, boolean isAdjusting) {

        if (obj == vsb) {

            int oldScrollValue = vsb.getValue();

            vsb.setValue(v);

            boolean needRepaint = (oldScrollValue != vsb.getValue());

            // See 6243382 for more information

            if (mouseDraggedOutVertically){

                int oldItemValue = getSelectedIndex();

                int newItemValue = getSelectedIndex() + v - oldScrollValue;

                select(newItemValue);

                needRepaint = needRepaint || (getSelectedIndex() != oldItemValue);

            }

            // FIXME: how are we going to paint!?

            Graphics g = peer.getGraphics();

            Rectangle bounds = peer.getBounds();

            int first = v;

            int last = Math.min(getItemCount() - 1,

                                v + maxVisItems);

            if (needRepaint) {

                paintItems(g, colors, bounds, first, last);

            }

            g.dispose();

        }

        else if ((XHorizontalScrollbar)obj == hsb) {

            hsb.setValue(v);

            // FIXME: how are we going to paint!?

        }

    }

    void updateColors(Color[] newColors) {

        colors = newColors;

    }

    /*

    public void paintItems(Graphics g,

                           Color[] colors,

                           Rectangle bounds,

                           Font font,

                           int first,

                           int last,

                           XVerticalScrollbar vsb,

                           XHorizontalScrollbar hsb) {

    */

    void paintItems(Graphics g,

                           Color[] colors,

                           Rectangle bounds) {

        // paint border

        // paint items

        // paint scrollbars

        // paint focus?

    }

    void paintAllItems(Graphics g,

                           Color[] colors,

                           Rectangle bounds) {

        paintItems(g, colors, bounds,

                   firstDisplayedIndex(), lastDisplayedIndex());

    }

    private void paintItems(Graphics g, Color[] colors, Rectangle bounds,

                            int first, int last) {

        peer.flush();

        int x = BORDER_WIDTH + ITEM_MARGIN;

        int width = bounds.width - 2*ITEM_MARGIN - 2*BORDER_WIDTH - (vsbVis ? SCROLLBAR_WIDTH : 0);

        int height = getItemHeight();

        int y = BORDER_WIDTH + ITEM_MARGIN;

        for (int i = first; i <= last ; i++) {

            paintItem(g, colors, getItem(i),

                      x, y, width, height,

                      isItemSelected(i),

                      isFocusedIndex(i));

            y += height + 2*ITEM_MARGIN;

        }

        if (vsbVis) {

            paintVSB(g, XComponentPeer.getSystemColors(), bounds);

        }

        if (hsbVis) {

            paintHSB(g, XComponentPeer.getSystemColors(), bounds);

        }

        peer.flush();