package com.googlecode.gwt.test.assertions;

import com.google.gwt.user.client.ui.*;

import java.util.Iterator;

import static org.assertj.core.util.Objects.areEqual;

/**
 * Base class for all {@link Panel} assertions.
 *
 * @param <S> used to simulate "self types." For more information please read "<a href=
 *            "http://passion.forco.de/content/emulating-self-types-using-java-generics-simplify-fluent-api-implementation"
 *            target="_blank">Emulating 'self types' using Java Generics to simplify fluent API
 *            implementation</a>."
 * @param <A> the type of the "actual" value.
 * @author Gael Lazzari
 */
public class BasePanelAssert<S extends BasePanelAssert<S, A>, A extends Panel> extends
        BaseWidgetAssert<S, A> {

    /**
     * Creates a new <code>{@link BasePanelAssert}</code>.
     *
     * @param actual   the actual value to verify.
     * @param selfType the "self type."
     */
    protected BasePanelAssert(A actual, Class<S> selfType) {
        super(actual, selfType);
    }

    /**
     * Verifies that the actual {@link ComplexPanel} child widget count is equal to the given one.
     *
     * @param expected the expected widget count.
     * @return this assertion object.
     * @throws AssertionError if the actual widget count is not equal to the given one.
     * @see ComplexPanel#getWidgetCount()
     */
    public S widgetCountEquals(int expected) {
        int widgetCount = getWigetCount(actual);
        if (areEqual(widgetCount, expected))
            return myself;
        throw propertyComparisonFailed("WidgetCount", widgetCount, expected);
    }

    private int getWigetCount(A actual) {
        if (actual instanceof IndexedPanel) {
            return ((IndexedPanel) actual).getWidgetCount();
        } else if (actual instanceof SimplePanel) {
            return 1;
        }

        Iterator<Widget> it = actual.iterator();
        int count = 0;
        while (it.hasNext()) {
            count++;
            it.next();
        }

        return count;
    }

}