/*
 * Copyright 2000-2018 Vaadin Ltd.
 *
 * 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.
 */

package com.vaadin.client.ui;

import com.google.gwt.core.client.Scheduler;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.Style.Visibility;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.Event;
import com.vaadin.client.ApplicationConnection;
import com.vaadin.client.BrowserInfo;
import com.vaadin.client.Util;
import com.vaadin.client.VTooltip;
import com.vaadin.client.WidgetUtil.ErrorUtil;
import com.vaadin.client.ui.aria.AriaHelper;
import com.vaadin.client.ui.aria.HandlesAriaInvalid;
import com.vaadin.client.ui.aria.HandlesAriaRequired;

public class VCheckBox extends com.google.gwt.user.client.ui.CheckBox
        implements Field, HandlesAriaInvalid, HandlesAriaRequired,
        HasErrorIndicatorElement {

    public static final String CLASSNAME = "v-checkbox";

    /** For internal use only. May be removed or replaced in the future. */
    public String id;

    /** For internal use only. May be removed or replaced in the future. */
    public ApplicationConnection client;

    /** For internal use only. May be removed or replaced in the future. */
    private Element errorIndicatorElement;

    /** For internal use only. May be removed or replaced in the future. */
    public Icon icon;

    public VCheckBox() {
        setStyleName(CLASSNAME);

        Element el = DOM.getFirstChild(getElement());
        while (el != null) {
            DOM.sinkEvents(el, DOM.getEventsSunk(el) | VTooltip.TOOLTIP_EVENTS);
            el = DOM.getNextSibling(el);
        }

        if (BrowserInfo.get().isWebkit() || BrowserInfo.get().isFirefox()) {
            // Webkit and Firefox do not focus non-text input elements on click
            // (#3944)
            addClickHandler(event -> setFocus(true));
        }
    }

    @Override
    public void onBrowserEvent(Event event) {
        if (icon != null && event.getTypeInt() == Event.ONCLICK
                && DOM.eventGetTarget(event) == icon.getElement()) {
            // Click on icon should do nothing if widget is disabled
            if (isEnabled()) {
                setValue(!getValue());
            }
        }
        super.onBrowserEvent(event);
        if (event.getTypeInt() == Event.ONLOAD) {
            Util.notifyParentOfSizeChange(this, true);
        }
    }

    /**
     * Gives access to the input element.
     *
     * @return Element of the CheckBox itself
     * @since 8.7
     */
    public Element getInputElement() {
        // public to allow CheckBoxState to access it.
        // FIXME: Would love to use a better way to access the checkbox element
        return getElement().getFirstChildElement();
    }

    /**
     * Gives access to the label element.
     *
     * @return Element of the Label itself
     * @since 8.7
     */
    public Element getLabelElement() {
        // public to allow CheckBoxState to access it.
        // FIXME: Would love to use a better way to access the label element
        return getInputElement().getNextSiblingElement();
    }

    @Override
    public void setAriaRequired(boolean required) {
        AriaHelper.handleInputRequired(getInputElement(), required);
    }

    @Override
    public void setAriaInvalid(boolean invalid) {
        AriaHelper.handleInputInvalid(getInputElement(), invalid);
    }

    @Override
    public Element getErrorIndicatorElement() {
        return errorIndicatorElement;
    }

    @Override
    public void setErrorIndicatorElementVisible(boolean visible) {
        if (visible) {
            if (errorIndicatorElement == null) {
                errorIndicatorElement = ErrorUtil.createErrorIndicatorElement();
                getElement().appendChild(errorIndicatorElement);
                DOM.sinkEvents(errorIndicatorElement,
                        VTooltip.TOOLTIP_EVENTS | Event.ONCLICK);
            }
        } else if (errorIndicatorElement != null) {
            getElement().removeChild(errorIndicatorElement);
            errorIndicatorElement = null;
        }
    }

    @Override
    protected void onAttach() {
        super.onAttach();

        if (BrowserInfo.get().isSafari()) {
            /*
             * Sometimes Safari does not render checkbox correctly when
             * attaching. Setting the visibility to hidden and a bit later
             * restoring will make everything just fine.
             */
            getElement().getStyle().setVisibility(Visibility.HIDDEN);
            Scheduler.get().scheduleFinally(() -> {
                getElement().getStyle().setVisibility(Visibility.VISIBLE);
            });
        }
    }
}