/*
 * Copyright (c) 2011, 2016, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package javafx.scene.control.skin;

import com.sun.javafx.scene.control.behavior.BehaviorBase;
import com.sun.javafx.scene.control.behavior.TextAreaBehavior;
import com.sun.javafx.scene.control.behavior.TextInputControlBehavior;
import javafx.beans.binding.BooleanBinding;
import javafx.beans.binding.DoubleBinding;
import javafx.beans.binding.ObjectBinding;
import javafx.beans.binding.StringBinding;
import javafx.beans.property.DoubleProperty;
import javafx.beans.property.SimpleDoubleProperty;
import javafx.beans.value.ObservableBooleanValue;
import javafx.beans.value.ObservableDoubleValue;
import javafx.event.EventHandler;
import javafx.geometry.Bounds;
import javafx.geometry.HPos;
import javafx.geometry.Point2D;
import javafx.geometry.Rectangle2D;
import javafx.scene.AccessibleAttribute;
import javafx.scene.Group;
import javafx.scene.Node;
import javafx.scene.control.Accordion;
import javafx.scene.control.Button;
import javafx.scene.control.Control;
import javafx.scene.control.IndexRange;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.paint.Paint;
import javafx.scene.shape.Path;
import javafx.scene.shape.PathElement;
import javafx.scene.shape.Rectangle;
import javafx.scene.text.Text;
import javafx.scene.text.HitInfo;
import java.util.List;
import com.sun.javafx.scene.control.behavior.TextFieldBehavior;
import com.sun.javafx.scene.control.behavior.PasswordFieldBehavior;

/**
 * Default skin implementation for the {@link TextField} control.
 *
 * @see TextField
 * @since 9
 */
public class TextFieldSkin extends TextInputControlSkin<TextField> {

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

    private final TextFieldBehavior behavior;

    /**
     * This group contains the text, caret, and selection rectangle.
     * It is clipped. The textNode, selectionHighlightPath, and
     * caret are each translated individually when horizontal
     * translation is needed to keep the caretPosition visible.
     */
    private Pane textGroup = new Pane();
    private Group handleGroup;

    /**
     * The clip, applied to the textGroup. This makes sure that any
     * text / selection wandering off the text box is clipped
     */
    private Rectangle clip = new Rectangle();
    /**
     * The node actually displaying the text. Note that it has the
     * ability to render both the normal fill as well as the highlight
     * fill, to perform hit testing, fetching of the selection
     * highlight, and other such duties.
     */
    private Text textNode = new Text();
    /**
     *
     * The node used for showing the prompt text.
     */
    private Text promptNode;
    /**
     * A path, provided by the textNode, which represents the area
     * which is selected. The path elements which make up the
     * selection must be updated whenever the selection changes. We
     * don't need to keep track of text changes because those will
     * force the selection to be updated.
     */
    private Path selectionHighlightPath = new Path();

    private Path characterBoundingPath = new Path();
    private ObservableBooleanValue usePromptText;
    private DoubleProperty textTranslateX = new SimpleDoubleProperty(this, "textTranslateX");
    private double caretWidth;

    /**
     * Right edge of the text region sans padding
     */
    private ObservableDoubleValue textRight;

    private double pressX, pressY; // For dragging handles on embedded

    // For use with PasswordField
    static final char BULLET = '\u25cf';



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

    /**
     * Creates a new TextFieldSkin 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 TextFieldSkin(final TextField control) {
        super(control);

        // install default input map for the text field control
        this.behavior = (control instanceof PasswordField)
                ? new PasswordFieldBehavior((PasswordField)control)
                : new TextFieldBehavior(control);
        this.behavior.setTextFieldSkin(this);
//        control.setInputMap(behavior.getInputMap());

        control.caretPositionProperty().addListener((observable, oldValue, newValue) -> {
            if (control.getWidth() > 0) {
                updateTextNodeCaretPos(control.getCaretPosition());
                if (!isForwardBias()) {
                    setForwardBias(true);
                }
                updateCaretOff();
            }
        });

        forwardBiasProperty().addListener(observable -> {
            if (control.getWidth() > 0) {
                updateTextNodeCaretPos(control.getCaretPosition());
                updateCaretOff();
            }
        });

        textRight = new DoubleBinding() {
            { bind(textGroup.widthProperty()); }
            @Override protected double computeValue() {
                return textGroup.getWidth();
            }
        };

        // Once this was crucial for performance, not sure now.
        clip.setSmooth(false);
        clip.setX(0);
        clip.widthProperty().bind(textGroup.widthProperty());
        clip.heightProperty().bind(textGroup.heightProperty());

        // Add content
        textGroup.setClip(clip);
        // Hack to defeat the fact that otherwise when the caret blinks the parent group
        // bounds are completely invalidated and therefore the dirty region is much
        // larger than necessary.
        textGroup.getChildren().addAll(selectionHighlightPath, textNode, new Group(caretPath));
        getChildren().add(textGroup);
        if (SHOW_HANDLES) {
            handleGroup = new Group();
            handleGroup.setManaged(false);
            handleGroup.getChildren().addAll(caretHandle, selectionHandle1, selectionHandle2);
            getChildren().add(handleGroup);
        }

        // Add text
        textNode.setManaged(false);
        textNode.getStyleClass().add("text");
        textNode.fontProperty().bind(control.fontProperty());

        textNode.layoutXProperty().bind(textTranslateX);
        textNode.textProperty().bind(new StringBinding() {
            { bind(control.textProperty()); }
            @Override protected String computeValue() {
                return maskText(control.textProperty().getValueSafe());
            }
        });
        textNode.fillProperty().bind(textFillProperty());
        textNode.selectionFillProperty().bind(new ObjectBinding<Paint>() {
            { bind(highlightTextFillProperty(), textFillProperty(), control.focusedProperty()); }
            @Override protected Paint computeValue() {
                return control.isFocused() ? highlightTextFillProperty().get() : textFillProperty().get();
            }
        });
        // updated by listener on caretPosition to ensure order
        updateTextNodeCaretPos(control.getCaretPosition());
        control.selectionProperty().addListener(observable -> {
            updateSelection();
        });

        // Add selection
        selectionHighlightPath.setManaged(false);
        selectionHighlightPath.setStroke(null);
        selectionHighlightPath.layoutXProperty().bind(textTranslateX);
        selectionHighlightPath.visibleProperty().bind(control.anchorProperty().isNotEqualTo(control.caretPositionProperty()).and(control.focusedProperty()));
        selectionHighlightPath.fillProperty().bind(highlightFillProperty());
        textNode.selectionShapeProperty().addListener(observable -> {
            updateSelection();
        });

        // Add caret
        caretPath.setManaged(false);
        caretPath.setStrokeWidth(1);
        caretPath.fillProperty().bind(textFillProperty());
        caretPath.strokeProperty().bind(textFillProperty());

        // modifying visibility of the caret forces a layout-pass (RT-32373), so
        // instead we modify the opacity.
        caretPath.opacityProperty().bind(new DoubleBinding() {
            { bind(caretVisibleProperty()); }
            @Override protected double computeValue() {
                return caretVisibleProperty().get() ? 1.0 : 0.0;
            }
        });
        caretPath.layoutXProperty().bind(textTranslateX);
        textNode.caretShapeProperty().addListener(observable -> {
            caretPath.getElements().setAll(textNode.caretShapeProperty().get());
            if (caretPath.getElements().size() == 0) {
                // The caret pos is invalid.
                updateTextNodeCaretPos(control.getCaretPosition());
            } else if (caretPath.getElements().size() == 4) {
                // The caret is split. Ignore and keep the previous width value.
            } else {
                caretWidth = Math.round(caretPath.getLayoutBounds().getWidth());
            }
        });

        // Be sure to get the control to request layout when the font changes,
        // since this will affect the pref height and pref width.
        control.fontProperty().addListener(observable -> {
            // I do both so that any cached values for prefWidth/height are cleared.
            // The problem is that the skin is unmanaged and so calling request layout
            // doesn't walk up the tree all the way. I think....
            control.requestLayout();
            getSkinnable().requestLayout();
        });

        registerChangeListener(control.prefColumnCountProperty(), e -> getSkinnable().requestLayout());
        if (control.isFocused()) setCaretAnimating(true);

        control.alignmentProperty().addListener(observable -> {
            if (control.getWidth() > 0) {
                updateTextPos();
                updateCaretOff();
                control.requestLayout();
            }
        });

        usePromptText = new BooleanBinding() {
            { bind(control.textProperty(),
                   control.promptTextProperty(),
                   promptTextFillProperty()); }
            @Override protected boolean computeValue() {
                String txt = control.getText();
                String promptTxt = control.getPromptText();
                return ((txt == null || txt.isEmpty()) &&
                        promptTxt != null && !promptTxt.isEmpty() &&
                        !getPromptTextFill().equals(Color.TRANSPARENT));
            }
        };

        promptTextFillProperty().addListener(observable -> {
            updateTextPos();
        });

        control.textProperty().addListener(observable -> {
            if (!behavior.isEditing()) {
                // Text changed, but not by user action
                updateTextPos();
            }
        });

        if (usePromptText.get()) {
            createPromptNode();
        }

        usePromptText.addListener(observable -> {
            createPromptNode();
            control.requestLayout();
        });

        if (SHOW_HANDLES) {
            selectionHandle1.setRotate(180);

            EventHandler<MouseEvent> handlePressHandler = e -> {
                pressX = e.getX();
                pressY = e.getY();
                e.consume();
            };

            caretHandle.setOnMousePressed(handlePressHandler);
            selectionHandle1.setOnMousePressed(handlePressHandler);
            selectionHandle2.setOnMousePressed(handlePressHandler);

            caretHandle.setOnMouseDragged(e -> {
                Point2D p = new Point2D(caretHandle.getLayoutX() + e.getX() + pressX - textNode.getLayoutX(),
                                        caretHandle.getLayoutY() + e.getY() - pressY - 6);
                HitInfo hit = textNode.hitTest(p);
                positionCaret(hit, false);
                e.consume();
            });

            selectionHandle1.setOnMouseDragged(new EventHandler<MouseEvent>() {
                @Override public void handle(MouseEvent e) {
                    TextField control = getSkinnable();
                    Point2D tp = textNode.localToScene(0, 0);
                    Point2D p = new Point2D(e.getSceneX() - tp.getX() + 10/*??*/ - pressX + selectionHandle1.getWidth() / 2,
                                            e.getSceneY() - tp.getY() - pressY - 6);
                    HitInfo hit = textNode.hitTest(p);
                    if (control.getAnchor() < control.getCaretPosition()) {
                        // Swap caret and anchor
                        control.selectRange(control.getCaretPosition(), control.getAnchor());
                    }
                    int pos = hit.getInsertionIndex();
                    if (pos >= 0) {
                        if (pos >= control.getAnchor() - 1) {
                            pos = Math.max(0, control.getAnchor() - 1);
                        }
                        positionCaret(pos, hit.isLeading(), true);
                    }
                    e.consume();
                }
            });

            selectionHandle2.setOnMouseDragged(new EventHandler<MouseEvent>() {
                @Override public void handle(MouseEvent e) {
                    TextField control = getSkinnable();
                    Point2D tp = textNode.localToScene(0, 0);
                    Point2D p = new Point2D(e.getSceneX() - tp.getX() + 10/*??*/ - pressX + selectionHandle2.getWidth() / 2,
                                            e.getSceneY() - tp.getY() - pressY - 6);
                    HitInfo hit = textNode.hitTest(p);
                    if (control.getAnchor() > control.getCaretPosition()) {
                        // Swap caret and anchor
                        control.selectRange(control.getCaretPosition(), control.getAnchor());
                    }
                    int pos = hit.getInsertionIndex();
                    if (pos > 0) {
                        if (pos <= control.getAnchor()) {
                            pos = Math.min(control.getAnchor() + 1, control.getLength());
                        }
                        positionCaret(pos, hit.isLeading(), true);
                    }
                    e.consume();
                }
            });
        }
    }



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

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

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

    /** {@inheritDoc} */
    @Override protected double computePrefWidth(double height, double topInset, double rightInset, double bottomInset, double leftInset) {
        TextField textField = getSkinnable();

        double characterWidth = fontMetrics.get().computeStringWidth("W");

        int columnCount = textField.getPrefColumnCount();

        return columnCount * characterWidth + leftInset + rightInset;
    }

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

    /** {@inheritDoc} */
    @Override protected double computePrefHeight(double width, double topInset, double rightInset, double bottomInset, double leftInset) {
        return topInset + textNode.getLayoutBounds().getHeight() + bottomInset;
    }

    /** {@inheritDoc} */
    @Override protected double computeMaxHeight(double width, double topInset, double rightInset, double bottomInset, double leftInset) {
        return getSkinnable().prefHeight(width);
    }

    /** {@inheritDoc} */
    @Override public double computeBaselineOffset(double topInset, double rightInset, double bottomInset, double leftInset) {
        return topInset + textNode.getBaselineOffset();
    }

    // Public for behavior
    /**
     * Replaces a range of characters with the given text.
     *
     * Call this implementation from behavior classes instead of the
     * one provided on TextInputControl to ensure that the text
     * scrolls as needed.
     *
     * @param start The starting index in the range, inclusive. This must be &gt;= 0 and &lt; the end.
     * @param end The ending index in the range, exclusive. This is one-past the last character to
     *            delete (consistent with the String manipulation methods). This must be &gt; the start,
     *            and &lt;= the length of the text.
     * @param text The text that is to replace the range. This must not be null.
     * @see TextField#replaceText(int, int, String)
     */
    public void replaceText(int start, int end, String txt) {
        final double textMaxXOld = textNode.getBoundsInParent().getMaxX();
        final double caretMaxXOld = caretPath.getLayoutBounds().getMaxX() + textTranslateX.get();
        getSkinnable().replaceText(start, end, txt);
        scrollAfterDelete(textMaxXOld, caretMaxXOld);
    }

    // Public for behavior
    /**
     * Deletes the character that follows or precedes the current
     * caret position from the text if there is no selection, or
     * deletes the selection if there is one.
     *
     * Call this implementation from behavior classes instead of the
     * one provided on TextInputControl to ensure that the text
     * scrolls as needed.
     *
     * @param previous whether to delete the preceding character.
     */
    public void deleteChar(boolean previous) {
        final double textMaxXOld = textNode.getBoundsInParent().getMaxX();
        final double caretMaxXOld = caretPath.getLayoutBounds().getMaxX() + textTranslateX.get();
        if (previous ? getSkinnable().deletePreviousChar() : getSkinnable().deleteNextChar()) {
            scrollAfterDelete(textMaxXOld, caretMaxXOld);
        }
    }

    // Public for behavior
    /**
     * Performs a hit test, mapping point to index in the content.
     *
     * @param x the x coordinate of the point.
     * @param y the y coordinate of the point.
     * @return a {@code HitInfo} object describing the index and forward bias.
     */
    public HitInfo getIndex(double x, double y) {
        // adjust the event to be in the same coordinate space as the
        // text content of the textInputControl
        Point2D p = new Point2D(x - textTranslateX.get() - snappedLeftInset(),
                                y - snappedTopInset());
        return textNode.hitTest(p);
    }

    // Public for behavior
    /**
     * Moves the caret to the specified position.
     *
     * @param hit the new position and forward bias of the caret.
     * @param select whether to extend selection to the new position.
     */
    public void positionCaret(HitInfo hit, boolean select) {
        positionCaret(hit.getInsertionIndex(), hit.isLeading(), select);
    }

    private void positionCaret(int pos, boolean leading, boolean select) {
        TextField textField = getSkinnable();
        if (select) {
            textField.selectPositionCaret(pos);
        } else {
            textField.positionCaret(pos);
        }
        setForwardBias(leading);
    }

    /** {@inheritDoc} */
    @Override public Rectangle2D getCharacterBounds(int index) {
        double x, y;
        double width, height;
        if (index == textNode.getText().length()) {
            Bounds textNodeBounds = textNode.getBoundsInLocal();
            x = textNodeBounds.getMaxX();
            y = 0;
            width = 0;
            height = textNodeBounds.getMaxY();
        } else {
            characterBoundingPath.getElements().clear();
            characterBoundingPath.getElements().addAll(textNode.rangeShape(index, index + 1));
            characterBoundingPath.setLayoutX(textNode.getLayoutX());
            characterBoundingPath.setLayoutY(textNode.getLayoutY());

            Bounds bounds = characterBoundingPath.getBoundsInLocal();

            x = bounds.getMinX();
            y = bounds.getMinY();
            // Sometimes the bounds is empty, in which case we must ignore the width/height
            width  = bounds.isEmpty() ? 0 : bounds.getWidth();
            height = bounds.isEmpty() ? 0 : bounds.getHeight();
        }

        Bounds textBounds = textGroup.getBoundsInParent();

        return new Rectangle2D(x + textBounds.getMinX() + textTranslateX.get(),
                y + textBounds.getMinY(), width, height);
    }

    /** {@inheritDoc} */
    @Override protected PathElement[] getUnderlineShape(int start, int end) {
        return textNode.underlineShape(start, end);
    }

    /** {@inheritDoc} */
    @Override protected PathElement[] getRangeShape(int start, int end) {
        return textNode.rangeShape(start, end);
    }

    /** {@inheritDoc} */
    @Override protected void addHighlight(List<? extends Node> nodes, int start) {
        textGroup.getChildren().addAll(nodes);
    }

    /** {@inheritDoc} */
    @Override protected void removeHighlight(List<? extends Node> nodes) {
        textGroup.getChildren().removeAll(nodes);
    }

    /** {@inheritDoc} */
    @Override public void moveCaret(TextUnit unit, Direction dir, boolean select) {
        switch (unit) {
            case CHARACTER:
                switch (dir) {
                    case LEFT:
                    case RIGHT:
                        nextCharacterVisually(dir == Direction.RIGHT);
                        break;
                    default:
                        throw new IllegalArgumentException(""+dir);
                }
                break;
            default:
                throw new IllegalArgumentException(""+unit);
        }
    }

    private void nextCharacterVisually(boolean moveRight) {
        if (isRTL()) {
            // Text node is mirrored.
            moveRight = !moveRight;
        }

        Bounds caretBounds = caretPath.getLayoutBounds();
        if (caretPath.getElements().size() == 4) {
            // The caret is split
            // TODO: Find a better way to get the primary caret position
            // instead of depending on the internal implementation.
            // See RT-25465.
            caretBounds = new Path(caretPath.getElements().get(0), caretPath.getElements().get(1)).getLayoutBounds();
        }
        double hitX = moveRight ? caretBounds.getMaxX() : caretBounds.getMinX();
        double hitY = (caretBounds.getMinY() + caretBounds.getMaxY()) / 2;
        HitInfo hit = textNode.hitTest(new Point2D(hitX, hitY));
        boolean leading = hit.isLeading();
        Path charShape = new Path(textNode.rangeShape(hit.getCharIndex(), hit.getCharIndex() + 1));
        if ((moveRight && charShape.getLayoutBounds().getMaxX() > caretBounds.getMaxX()) ||
                (!moveRight && charShape.getLayoutBounds().getMinX() < caretBounds.getMinX())) {
            leading = !leading;
        }
        positionCaret(hit.getInsertionIndex(), leading, false);
    }

    /** {@inheritDoc} */
    @Override protected void layoutChildren(final double x, final double y,
                                            final double w, final double h) {
        super.layoutChildren(x, y, w, h);

        if (textNode != null) {
            double textY;
            final Bounds textNodeBounds = textNode.getLayoutBounds();
            final double ascent = textNode.getBaselineOffset();
            final double descent = textNodeBounds.getHeight() - ascent;

            switch (getSkinnable().getAlignment().getVpos()) {
                case TOP:
                    textY = ascent;
                    break;

                case CENTER:
                    textY = (ascent + textGroup.getHeight() - descent) / 2;
                    break;

                case BOTTOM:
                default:
                    textY = textGroup.getHeight() - descent;
            }
            textNode.setY(textY);
            if (promptNode != null) {
                promptNode.setY(textY);
            }

            if (getSkinnable().getWidth() > 0) {
                updateTextPos();
                updateCaretOff();
            }
        }

        if (SHOW_HANDLES) {
            handleGroup.setLayoutX(x + caretWidth / 2);
            handleGroup.setLayoutY(y);

            // Resize handles for caret and anchor.
//            IndexRange selection = textField.getSelection();
            selectionHandle1.resize(selectionHandle1.prefWidth(-1),
                    selectionHandle1.prefHeight(-1));
            selectionHandle2.resize(selectionHandle2.prefWidth(-1),
                    selectionHandle2.prefHeight(-1));
            caretHandle.resize(caretHandle.prefWidth(-1),
                    caretHandle.prefHeight(-1));

            Bounds b = caretPath.getBoundsInParent();
            caretHandle.setLayoutY(b.getMaxY() - 1);
            //selectionHandle1.setLayoutY(b.getMaxY() - 1);
            selectionHandle1.setLayoutY(b.getMinY() - selectionHandle1.getHeight() + 1);
            selectionHandle2.setLayoutY(b.getMaxY() - 1);
        }
    }

    private HPos getHAlignment() {
        HPos hPos = getSkinnable().getAlignment().getHpos();
        return hPos;
    }

    /** {@inheritDoc} */
    @Override public Point2D getMenuPosition() {
        Point2D p = super.getMenuPosition();
        if (p != null) {
            p = new Point2D(Math.max(0, p.getX() - textNode.getLayoutX() - snappedLeftInset() + textTranslateX.get()),
                    Math.max(0, p.getY() - textNode.getLayoutY() - snappedTopInset()));
        }
        return p;
    }

    /** {@inheritDoc} */
    @Override protected String maskText(String txt) {
        if (getSkinnable() instanceof PasswordField) {
            int n = txt.length();
            StringBuilder passwordBuilder = new StringBuilder(n);
            for (int i = 0; i < n; i++) {
                passwordBuilder.append(BULLET);
            }

            return passwordBuilder.toString();
        } else {
            return txt;
        }
    }

    /** {@inheritDoc} */
    @Override protected Object queryAccessibleAttribute(AccessibleAttribute attribute, Object... parameters) {
        switch (attribute) {
            case BOUNDS_FOR_RANGE:
            case OFFSET_AT_POINT:
                return textNode.queryAccessibleAttribute(attribute, parameters);
            default: return super.queryAccessibleAttribute(attribute, parameters);
        }
    }



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

    TextInputControlBehavior getBehavior() {
        return behavior;
    }

    private void updateTextNodeCaretPos(int pos) {
        if (pos == 0 || isForwardBias()) {
            textNode.setCaretPosition(pos);
        } else {
            textNode.setCaretPosition(pos - 1);
        }
        textNode.caretBiasProperty().set(isForwardBias());
    }

    private void createPromptNode() {
        if (promptNode != null || !usePromptText.get()) return;

        promptNode = new Text();
        textGroup.getChildren().add(0, promptNode);
        promptNode.setManaged(false);
        promptNode.getStyleClass().add("text");
        promptNode.visibleProperty().bind(usePromptText);
        promptNode.fontProperty().bind(getSkinnable().fontProperty());

        promptNode.textProperty().bind(getSkinnable().promptTextProperty());
        promptNode.fillProperty().bind(promptTextFillProperty());
        updateSelection();
    }

    private void updateSelection() {
        TextField textField = getSkinnable();
        IndexRange newValue = textField.getSelection();

        if (newValue == null || newValue.getLength() == 0) {
            textNode.selectionStartProperty().set(-1);
            textNode.selectionEndProperty().set(-1);
        } else {
            textNode.selectionStartProperty().set(newValue.getStart());
            // This intermediate value is needed to force selection shape layout.
            textNode.selectionEndProperty().set(newValue.getStart());
            textNode.selectionEndProperty().set(newValue.getEnd());
        }

        PathElement[] elements = textNode.selectionShapeProperty().get();
        if (elements == null) {
            selectionHighlightPath.getElements().clear();
        } else {
            selectionHighlightPath.getElements().setAll(elements);
        }

        if (SHOW_HANDLES && newValue != null && newValue.getLength() > 0) {
            int caretPos = textField.getCaretPosition();
            int anchorPos = textField.getAnchor();

            {
                // Position the handle for the anchor. This could be handle1 or handle2.
                // Do this before positioning the handle for the caret.
                updateTextNodeCaretPos(anchorPos);
                Bounds b = caretPath.getBoundsInParent();
                if (caretPos < anchorPos) {
                    selectionHandle2.setLayoutX(b.getMinX() - selectionHandle2.getWidth() / 2);
                } else {
                    selectionHandle1.setLayoutX(b.getMinX() - selectionHandle1.getWidth() / 2);
                }
            }

            {
                // Position handle for the caret. This could be handle1 or handle2.
                updateTextNodeCaretPos(caretPos);
                Bounds b = caretPath.getBoundsInParent();
                if (caretPos < anchorPos) {
                    selectionHandle1.setLayoutX(b.getMinX() - selectionHandle1.getWidth() / 2);
                } else {
                    selectionHandle2.setLayoutX(b.getMinX() - selectionHandle2.getWidth() / 2);
                }
            }
        }
    }

    /**
     * Updates the textTranslateX value for the Text node position. This is
     * done for general layout, but care is taken to avoid resetting the
     * position when there's a need to scroll the text due to caret movement,
     * or when editing text that overflows on either side.
     */
    private void updateTextPos() {
        double oldX = textTranslateX.get();
        double newX;
        double textNodeWidth = textNode.getLayoutBounds().getWidth();

        switch (getHAlignment()) {
          case CENTER:
            double midPoint = textRight.get() / 2;
            if (usePromptText.get()) {
                // If a prompt is shown (which implies that the text is
                // empty), then we align the Text node so that the caret will
                // appear at the left of the centered prompt.
                newX = midPoint - promptNode.getLayoutBounds().getWidth() / 2;
                promptNode.setLayoutX(newX);
            } else {
                newX = midPoint - textNodeWidth / 2;
            }
            // Update if there is space on the right
            if (newX + textNodeWidth <= textRight.get()) {
                textTranslateX.set(newX);
            }
            break;

          case RIGHT:
            newX = textRight.get() - textNodeWidth - caretWidth / 2;
            // Update if there is space on the right
            if (newX > oldX || newX > 0) {
                textTranslateX.set(newX);
            }
            if (usePromptText.get()) {
                promptNode.setLayoutX(textRight.get() - promptNode.getLayoutBounds().getWidth() -
                                      caretWidth / 2);
            }
            break;

          case LEFT:
          default:
            newX = caretWidth / 2;
            // Update if there is space on either side.
            if (newX < oldX || newX + textNodeWidth <= textRight.get()) {
                textTranslateX.set(newX);
            }
            if (usePromptText.get()) {
                promptNode.layoutXProperty().set(newX);
            }
        }
    }

    // should be called when the padding changes, or the text box width, or
    // the dot moves
    private void updateCaretOff() {
        double delta = 0.0;
        double caretX = caretPath.getLayoutBounds().getMinX() + textTranslateX.get();
        // If the caret position is less than or equal to the left edge of the
        // clip then the caret will be clipped. We want the caret to end up
        // being positioned one pixel right of the clip's left edge. The same
        // applies on the right edge (but going the other direction of course).
        if (caretX < 0) {
            // I'll end up with a negative number
            delta = caretX;
        } else if (caretX > (textRight.get() - caretWidth)) {
            // I'll end up with a positive number
            delta = caretX - (textRight.get() - caretWidth);
        }

        // If delta is negative, then translate in the negative direction
        // to cause the text to scroll to the right. Vice-versa for positive.
        switch (getHAlignment()) {
          case CENTER:
            textTranslateX.set(textTranslateX.get() - delta);
            break;

          case RIGHT:
            textTranslateX.set(Math.max(textTranslateX.get() - delta,
                                        textRight.get() - textNode.getLayoutBounds().getWidth() -
                                        caretWidth / 2));
            break;

          case LEFT:
          default:
            textTranslateX.set(Math.min(textTranslateX.get() - delta,
                                        caretWidth / 2));
        }
        if (SHOW_HANDLES) {
            caretHandle.setLayoutX(caretX - caretHandle.getWidth() / 2);
        }
    }

    private void scrollAfterDelete(double textMaxXOld, double caretMaxXOld) {
        final Bounds textLayoutBounds = textNode.getLayoutBounds();
        final Bounds textBounds = textNode.localToParent(textLayoutBounds);
        final Bounds clipBounds = clip.getBoundsInParent();
        final Bounds caretBounds = caretPath.getLayoutBounds();

        switch (getHAlignment()) {
          case RIGHT:
            if (textBounds.getMaxX() > clipBounds.getMaxX()) {
                double delta = caretMaxXOld - caretBounds.getMaxX() - textTranslateX.get();
                if (textBounds.getMaxX() + delta < clipBounds.getMaxX()) {
                    if (textMaxXOld <= clipBounds.getMaxX()) {
                        delta = textMaxXOld - textBounds.getMaxX();
                    } else {
                        delta = clipBounds.getMaxX() - textBounds.getMaxX();
                    }
                }
                textTranslateX.set(textTranslateX.get() + delta);
            } else {
                updateTextPos();
            }
            break;

          case LEFT:
          case CENTER:
          default:
            if (textBounds.getMinX() < clipBounds.getMinX() + caretWidth / 2 &&
                textBounds.getMaxX() <= clipBounds.getMaxX()) {
                double delta = caretMaxXOld - caretBounds.getMaxX() - textTranslateX.get();
                if (textBounds.getMaxX() + delta < clipBounds.getMaxX()) {
                    if (textMaxXOld <= clipBounds.getMaxX()) {
                        delta = textMaxXOld - textBounds.getMaxX();
                    } else {
                        delta = clipBounds.getMaxX() - textBounds.getMaxX();
                    }
                }
                textTranslateX.set(textTranslateX.get() + delta);
            }
        }

        updateCaretOff();
    }
}