/*
 * Copyright 2000-2016 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.testbench.elements;

import java.util.List;
import java.util.NoSuchElementException;

import org.openqa.selenium.By;
import org.openqa.selenium.Point;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.interactions.Actions;

import com.vaadin.testbench.elementsbase.ServerClass;

@ServerClass("com.vaadin.ui.MenuBar")
public class MenuBarElement extends AbstractComponentElement {

    private Point lastItemLocationMovedTo = null;

    /**
     * Clicks on a visible item.<br>
     * If the item is a top level menu, the submenu is opened if it was closed,
     * or closed if it was opened.<br>
     * If the item is another submenu, that submenu is opened.<br>
     * If the item is not a submenu, it will be clicked and trigger any actions
     * associated to it.
     *
     * @param item
     *            name of the item to click
     * @throws NullPointerException
     *             if item does not exist or is not visible
     */
    private void clickItem(String item) {
        WebElement webElement = getVisibleItem("#" + item);
        if (webElement == null) {
            throw new NoSuchElementException(
                    "Menu item " + item + " is not available.");
        }
        activateOrOpenSubmenu(webElement, true);
    }

    /**
     * Clicks the item specified by a full path given as variable arguments.<br>
     * Fails if path given is not full (ie: last submenu is already opened, and
     * path given is last item only).
     * <p>
     * Example:
     * </p>
     *
     * <pre>
     * // clicks on "File" item
     * menuBarElement.click("File");
     * // clicks on "Copy" item in "File" top level menu.
     * menuBarElement.click("File", "Copy");
     * </pre>
     *
     * @param path
     *            Array of items to click through
     */
    public void clickItem(String... path) {
        if (path.length > 1) {
            closeAll();
        }
        for (String itemName : path) {
            clickItem(itemName);
        }
    }

    /**
     * Closes all submenus, if any is open.<br>
     * This is done by clicking on the currently selected top level item.
     */
    private void closeAll() {
        lastItemLocationMovedTo = null;
        WebElement selectedItem = getSelectedTopLevelItem();
        if (selectedItem != null) {
            activateOrOpenSubmenu(selectedItem, true);
        }
    }

    private WebElement getSelectedTopLevelItem() {
        List<WebElement> selectedItems = findElements(
                By.className("v-menubar-menuitem-selected"));
        if (selectedItems.size() == 0) {
            return null;
        }
        return selectedItems.get(0);
    }

    private WebElement getVisibleItem(String item) {
        return findElement(com.vaadin.testbench.By.vaadin(item));
    }

    private void activateOrOpenSubmenu(WebElement item, boolean alwaysClick) {

        if (lastItemLocationMovedTo == null || !isAnySubmenuVisible()) {
            item.click();
            if (hasSubmenu(item)) {
                lastItemLocationMovedTo = item.getLocation();
            }
            return;
        }

        // Assumes mouse is still at position of last clicked element
        Actions action = new Actions(getDriver());
        action.moveToElement(item);
        action.build().perform();

        if (isLeaf(item) || isSelectedTopLevelItem(item)) {
            lastItemLocationMovedTo = null;
        } else {
            lastItemLocationMovedTo = item.getLocation();
        }

        if (alwaysClick || isLeaf(item) || !isAnySubmenuVisible()) {
            action = new Actions(getDriver());
            action.click();
            action.build().perform();
        }
    }

    private boolean isSelectedTopLevelItem(WebElement item) {
        WebElement selectedItem = getSelectedTopLevelItem();
        if (selectedItem == null) {
            return false;
        }

        String itemCaption = item
                .findElements(By.className("v-menubar-menuitem-caption")).get(0)
                .getAttribute("innerHTML");
        String selectedItemCaption = selectedItem
                .findElements(By.className("v-menubar-menuitem-caption")).get(0)
                .getAttribute("innerHTML");
        return itemCaption.equals(selectedItemCaption);
    }

    private boolean isAnySubmenuVisible() {
        WebElement selectedItem = getSelectedTopLevelItem();
        if (selectedItem == null) {
            return false;
        }
        return hasSubmenu(selectedItem);
    }

    private boolean hasSubmenu(WebElement item) {
        List<WebElement> submenuIndicatorElements = item
                .findElements(By.className("v-menubar-submenu-indicator"));
        return submenuIndicatorElements.size() != 0;
    }

    private boolean isLeaf(WebElement item) {
        return !hasSubmenu(item);
    }

}