<!DOCTYPE html>
<title>
    Element#requestFullscreen() and Document#exitFullscreen() in iframe
</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<script src="../trusted-click.js"></script>
<div id="log"></div>
<iframe allowfullscreen></iframe>
<script>
    const iframe = document.querySelector("iframe");
    let iframeDoc;
    let iframeBody;

    promise_setup(async () => {
        const iframe = document.querySelector("iframe");
        await new Promise((resolve) => {
            iframe.onload = resolve;
            iframe.src = "about:blank";
        });
        iframeDoc = iframe.contentDocument;
        iframeBody = iframeDoc.body;
    });
    /**
     *
     * @param {Document} doc
     * @param {HTMLElement} value
     * @returns {Promise<Event>}
     */
    function makeChangeListener(doc) {
        return new Promise((resolve) => {
            doc.addEventListener("fullscreenchange", resolve, { once: true });
        });
    }

    // Both when entering and exiting, the fullscreenchange event is fired first
    // on the outer document and then on the iframe's document. This is because
    // the events are fired in animation frame tasks, which run in "frame tree"
    // order.
    promise_test(async (t) => {
        document.onfullscreenerror = t.unreached_func(
            "document fullscreenerror event"
        );
        iframeDoc.onfullscreenerror = t.unreached_func(
            "iframe fullscreenerror event"
        );
        const outerPromise = makeChangeListener(document);
        const innerPromise = makeChangeListener(iframeDoc);
        const request = trusted_request(iframeBody, iframeBody);

        const winningEvent = await Promise.race([outerPromise, innerPromise]);
        assert_equals(winningEvent.target, iframe);

        await Promise.allSettled([outerPromise, innerPromise, request]);

        assert_equals(
            document.fullscreenElement,
            iframe,
            "outer fullscreenElement"
        );

        assert_equals(
            iframeDoc.fullscreenElement,
            iframeBody,
            "inner fullscreenElement"
        );
    }, "Checks that the fullscreenchange events fire in right order when entering fullscreen");

    promise_test(async (t) => {
        document.onfullscreenerror = t.unreached_func(
            "document fullscreenerror event"
        );
        iframeDoc.onfullscreenerror = t.unreached_func(
            "iframe fullscreenerror event"
        );
        const outerPromise = makeChangeListener(document);
        const innerPromise = makeChangeListener(iframeDoc);
        const exitPromise = iframeDoc.exitFullscreen();

        const winningEvent = await Promise.race([outerPromise, innerPromise]);
        assert_equals(winningEvent.target, iframe);

        await Promise.allSettled([outerPromise, innerPromise, exitPromise]);
        assert_equals(
            document.fullscreenElement,
            null,
            "outer fullscreenElement"
        );
        assert_equals(
            iframeDoc.fullscreenElement,
            null,
            "inner fullscreenElement"
        );
    }, "Checks that the fullscreenchange events fire in right order when exiting fullscreen");
</script>
