/*
 * Copyright (c) 2010, 2017, 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 javafx.scene.control.skin;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.WeakHashMap;

import com.sun.javafx.scene.control.behavior.BehaviorBase;
import javafx.beans.InvalidationListener;
import javafx.beans.Observable;
import javafx.beans.property.DoubleProperty;
import javafx.beans.value.WritableValue;
import javafx.geometry.HPos;
import javafx.geometry.VPos;
import javafx.scene.Node;
import javafx.scene.control.Control;
import javafx.scene.control.ListView;
import javafx.scene.control.TreeCell;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeView;
import javafx.css.StyleableDoubleProperty;
import javafx.css.StyleableProperty;
import javafx.css.CssMetaData;

import javafx.css.converter.SizeConverter;
import com.sun.javafx.scene.control.behavior.TreeCellBehavior;

import javafx.css.Styleable;

/**
 * Default skin implementation for the {@link TreeCell} control.
 *
 * @see TreeCell
 * @since 9
 */
public class TreeCellSkin<T> extends CellSkinBase<TreeCell<T>> {

    /***************************************************************************
     *                                                                         *
     * Static fields                                                           *
     *                                                                         *
     **************************************************************************/

    /*
     * This is rather hacky - but it is a quick workaround to resolve the
     * issue that we don't know maximum width of a disclosure node for a given
     * TreeView. If we don't know the maximum width, we have no way to ensure
     * consistent indentation for a given TreeView.
     *
     * To work around this, we create a single WeakHashMap to store a max
     * disclosureNode width per TreeView. We use WeakHashMap to help prevent
     * any memory leaks.
     *
     * RT-19656 identifies a related issue, which is that we may not provide
     * indentation to any TreeItems because we have not yet encountered a cell
     * which has a disclosureNode. Once we scroll and encounter one, indentation
     * happens in a displeasing way.
     */
    private static final Map<TreeView<?>, Double> maxDisclosureWidthMap = new WeakHashMap<TreeView<?>, Double>();



    /***************************************************************************
     *                                                                         *
     * Private fields                                                          *
     *                                                                         *
     **************************************************************************/

    private boolean disclosureNodeDirty = true;
    private TreeItem<?> treeItem;
    private final BehaviorBase<TreeCell<T>> behavior;

    private double fixedCellSize;
    private boolean fixedCellSizeEnabled;



    /***************************************************************************
     *                                                                         *
     * Constructors                                                            *
     *                                                                         *
     **************************************************************************/

    /**
     * Creates a new TreeCellSkin instance, installing the necessary child
     * nodes into the Control {@link Control#getChildren() children} list, as
     * well as the necessary input mappings for handling key, mouse, etc events.
     *
     * @param control The control that this skin should be installed onto.
     */
    public TreeCellSkin(TreeCell<T> control) {
        super(control);

        // install default input map for the TreeCell control
        behavior = new TreeCellBehavior<>(control);
//        control.setInputMap(behavior.getInputMap());

        updateTreeItem();

        registerChangeListener(control.treeItemProperty(), e -> {
            updateTreeItem();
            disclosureNodeDirty = true;
            getSkinnable().requestLayout();
        });
        registerChangeListener(control.textProperty(), e -> getSkinnable().requestLayout());

        setupTreeViewListeners();
    }

    private void setupTreeViewListeners() {
        TreeView<T> treeView = getSkinnable().getTreeView();
        if (treeView == null) {
            getSkinnable().treeViewProperty().addListener(new InvalidationListener() {
                @Override public void invalidated(Observable observable) {
                    getSkinnable().treeViewProperty().removeListener(this);
                    setupTreeViewListeners();
                }
            });
        } else {
            this.fixedCellSize = treeView.getFixedCellSize();
            this.fixedCellSizeEnabled = fixedCellSize > 0;
            registerChangeListener(treeView.fixedCellSizeProperty(), e -> {
                this.fixedCellSize = getSkinnable().getTreeView().getFixedCellSize();
                this.fixedCellSizeEnabled = fixedCellSize > 0;
            });
        }
    }



    /***************************************************************************
     *                                                                         *
     * Properties                                                              *
     *                                                                         *
     **************************************************************************/

    /**
     * The amount of space to multiply by the treeItem.level to get the left
     * margin for this tree cell. This is settable from CSS
     */
    private DoubleProperty indent = null;
    public final void setIndent(double value) { indentProperty().set(value); }
    public final double getIndent() { return indent == null ? 10.0 : indent.get(); }
    public final DoubleProperty indentProperty() {
        if (indent == null) {
            indent = new StyleableDoubleProperty(10.0) {
                @Override public Object getBean() {
                    return TreeCellSkin.this;
                }

                @Override public String getName() {
                    return "indent";
                }

                @Override public CssMetaData<TreeCell<?>,Number> getCssMetaData() {
                    return StyleableProperties.INDENT;
                }
            };
        }
        return indent;
    }



    /***************************************************************************
     *                                                                         *
     * Public API                                                              *
     *                                                                         *
     **************************************************************************/

    /** {@inheritDoc} */
    @Override public void dispose() {
        super.dispose();

        if (behavior != null) {
            behavior.dispose();
        }
    }

    /** {@inheritDoc} */
    @Override protected void updateChildren() {
        super.updateChildren();
        updateDisclosureNode();
    }

    /** {@inheritDoc} */
    @Override protected void layoutChildren(double x, final double y,
                                            double w, final double h) {
        // RT-25876: can not null-check here as this prevents empty rows from
        // being cleaned out.
        // if (treeItem == null) return;

        TreeView<T> tree = getSkinnable().getTreeView();
        if (tree == null) return;

        if (disclosureNodeDirty) {
            updateDisclosureNode();
            disclosureNodeDirty = false;
        }

        Node disclosureNode = getSkinnable().getDisclosureNode();

        int level = tree.getTreeItemLevel(treeItem);
        if (! tree.isShowRoot()) level--;
        double leftMargin = getIndent() * level;

        x += leftMargin;

        // position the disclosure node so that it is at the proper indent
        boolean disclosureVisible = disclosureNode != null && treeItem != null && ! treeItem.isLeaf();

        final double defaultDisclosureWidth = maxDisclosureWidthMap.containsKey(tree) ?
                maxDisclosureWidthMap.get(tree) : 18;   // RT-19656: default width of default disclosure node
        double disclosureWidth = defaultDisclosureWidth;

        if (disclosureVisible) {
            if (disclosureNode == null || disclosureNode.getScene() == null) {
                updateChildren();
            }

            if (disclosureNode != null) {
                disclosureWidth = disclosureNode.prefWidth(h);
                if (disclosureWidth > defaultDisclosureWidth) {
                    maxDisclosureWidthMap.put(tree, disclosureWidth);
                }

                double ph = disclosureNode.prefHeight(disclosureWidth);

                disclosureNode.resize(disclosureWidth, ph);
                positionInArea(disclosureNode, x, y,
                        disclosureWidth, ph, /*baseline ignored*/0,
                        HPos.CENTER, VPos.CENTER);
            }
        }

        // determine starting point of the graphic or cell node, and the
        // remaining width available to them
        final int padding = treeItem != null && treeItem.getGraphic() == null ? 0 : 3;
        x += disclosureWidth + padding;
        w -= (leftMargin + disclosureWidth + padding);

        // Rather ugly fix for RT-38519, where graphics are disappearing in
        // certain circumstances
        Node graphic = getSkinnable().getGraphic();
        if (graphic != null && !getChildren().contains(graphic)) {
            getChildren().add(graphic);
        }

        layoutLabelInArea(x, y, w, h);
    }

    /** {@inheritDoc} */
    @Override protected double computeMinHeight(double width, double topInset, double rightInset, double bottomInset, double leftInset) {
        if (fixedCellSizeEnabled) {
            return fixedCellSize;
        }

        double pref = super.computeMinHeight(width, topInset, rightInset, bottomInset, leftInset);
        Node d = getSkinnable().getDisclosureNode();
        return (d == null) ? pref : Math.max(d.minHeight(-1), pref);
    }

    /** {@inheritDoc} */
    @Override protected double computePrefHeight(double width, double topInset, double rightInset, double bottomInset, double leftInset) {
        if (fixedCellSizeEnabled) {
            return fixedCellSize;
        }

        final TreeCell<T> cell = getSkinnable();

        final double pref = super.computePrefHeight(width, topInset, rightInset, bottomInset, leftInset);
        final Node d = cell.getDisclosureNode();
        final double prefHeight = (d == null) ? pref : Math.max(d.prefHeight(-1), pref);

        // RT-30212: TreeCell does not honor minSize of cells.
        // snapSize for RT-36460
        return snapSizeY(Math.max(cell.getMinHeight(), prefHeight));
    }

    /** {@inheritDoc} */
    @Override protected double computeMaxHeight(double width, double topInset, double rightInset, double bottomInset, double leftInset) {
        if (fixedCellSizeEnabled) {
            return fixedCellSize;
        }

        return super.computeMaxHeight(width, topInset, rightInset, bottomInset, leftInset);
    }

    /** {@inheritDoc} */
    @Override protected double computePrefWidth(double height, double topInset, double rightInset, double bottomInset, double leftInset) {
        double labelWidth = super.computePrefWidth(height, topInset, rightInset, bottomInset, leftInset);

        double pw = snappedLeftInset() + snappedRightInset();

        TreeView<T> tree = getSkinnable().getTreeView();
        if (tree == null) return pw;

        if (treeItem == null) return pw;

        pw = labelWidth;

        // determine the amount of indentation
        int level = tree.getTreeItemLevel(treeItem);
        if (! tree.isShowRoot()) level--;
        pw += getIndent() * level;

        // include the disclosure node width
        Node disclosureNode = getSkinnable().getDisclosureNode();
        double disclosureNodePrefWidth = disclosureNode == null ? 0 : disclosureNode.prefWidth(-1);
        final double defaultDisclosureWidth = maxDisclosureWidthMap.containsKey(tree) ?
                maxDisclosureWidthMap.get(tree) : 0;
        pw += Math.max(defaultDisclosureWidth, disclosureNodePrefWidth);

        return pw;
    }



    /***************************************************************************
     *                                                                         *
     * Private implementation                                                  *
     *                                                                         *
     **************************************************************************/

    private void updateTreeItem() {
        treeItem = getSkinnable().getTreeItem();
    }

    private void updateDisclosureNode() {
        if (getSkinnable().isEmpty()) return;

        Node disclosureNode = getSkinnable().getDisclosureNode();
        if (disclosureNode == null) return;

        boolean disclosureVisible = treeItem != null && ! treeItem.isLeaf();
        disclosureNode.setVisible(disclosureVisible);

        if (! disclosureVisible) {
            getChildren().remove(disclosureNode);
        } else if (disclosureNode.getParent() == null) {
            getChildren().add(disclosureNode);
            disclosureNode.toFront();
        } else {
            disclosureNode.toBack();
        }

        // RT-26625: [TreeView, TreeTableView] can lose arrows while scrolling
        // RT-28668: Ensemble tree arrow disappears
        if (disclosureNode.getScene() != null) {
            disclosureNode.applyCss();
        }
    }



    /***************************************************************************
     *                                                                         *
     *                         Stylesheet Handling                             *
     *                                                                         *
     **************************************************************************/

    private static class StyleableProperties {

        private static final CssMetaData<TreeCell<?>,Number> INDENT =
            new CssMetaData<TreeCell<?>,Number>("-fx-indent",
                SizeConverter.getInstance(), 10.0) {

            @Override public boolean isSettable(TreeCell<?> n) {
                DoubleProperty p = ((TreeCellSkin<?>) n.getSkin()).indentProperty();
                return p == null || !p.isBound();
            }

            @Override public StyleableProperty<Number> getStyleableProperty(TreeCell<?> n) {
                final TreeCellSkin<?> skin = (TreeCellSkin<?>) n.getSkin();
                return (StyleableProperty<Number>)(WritableValue<Number>)skin.indentProperty();
            }
        };

        private static final List<CssMetaData<? extends Styleable, ?>> STYLEABLES;
        static {
            final List<CssMetaData<? extends Styleable, ?>> styleables =
                new ArrayList<CssMetaData<? extends Styleable, ?>>(CellSkinBase.getClassCssMetaData());
            styleables.add(INDENT);
            STYLEABLES = Collections.unmodifiableList(styleables);
        }
    }

    /**
     * Returns the CssMetaData associated with this class, which may include the
     * CssMetaData of its superclasses.
     * @return the CssMetaData associated with this class, which may include the
     * CssMetaData of its superclasses
     */
    public static List<CssMetaData<? extends Styleable, ?>> getClassCssMetaData() {
        return StyleableProperties.STYLEABLES;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public List<CssMetaData<? extends Styleable, ?>> getCssMetaData() {
        return getClassCssMetaData();
    }
}
