<!DOCTYPE HTML>
<title>Test VisibleStateEntry</title>
<link rel="author" title="Noam Rosenthal"  href="mailto:nrosenthal@chromium.org">
<link rel="help" href="https://html.spec.whatwg.org/multipage/interaction.html#page-visibility">
<meta name="timeout" content="long">
<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="resources/window_state_context.js"></script>
<script>

setup(() => {
    assert_implements(window.VisibilityStateEntry, 'VisibilityStateEntry is not supported.');
});

promise_test(async t => {
    const {minimizeAndWait, restoreAndWait} = window_state_context(t);
    const all = performance.getEntries();
    let entries = performance.getEntriesByType("visibility-state");
    assert_equals(entries.length, 1);
    assert_equals(entries[0].name, "visible");
    assert_equals(entries[0].startTime, 0);
    assert_equals(entries[0].duration, 0);
    await minimizeAndWait();
    entries = performance.getEntriesByType("visibility-state");
    assert_equals(entries.length, 2);
    assert_equals(entries[1].name, "hidden");
    assert_equals(entries[1].duration, 0);
    await restoreAndWait();
    entries = performance.getEntriesByType("visibility-state");
    assert_equals(entries.length, 3);
    assert_equals(entries[2].name, "visible");
    assert_equals(entries[2].duration, 0);
}, "Hiding/showing the page should create visibility-state entries");

promise_test(async t => {
    const {minimizeAndWait} = window_state_context(t);
    await minimizeAndWait();
    const iframe = document.createElement("iframe");
    iframe.src = "resources/blank_page_green.html";
    const loaded = new Promise(resolve => iframe.addEventListener("load", resolve));
    t.add_cleanup(() => iframe.remove());
    document.body.appendChild(iframe);
    await loaded;
    const entries = iframe.contentWindow.performance.getEntriesByType("visibility-state");
    assert_equals(entries[0].name, "hidden");
    assert_equals(entries[0].startTime, 0);
}, "If a page starts as hidden, the first visibility-state entry should be hidden");

promise_test(async t => {
    const {minimize, restore} = window_state_context(t);
    const observed = new Promise(resolve => new PerformanceObserver(list => {
      if (list.getEntries()[0].name === "visible")
        resolve();
    }).observe({entryTypes: ['visibility-state']}));
    await minimize();
    await restore();
    await observed;
}, "Visibility state entries should be queued to performance observers");

promise_test(async t => {
    const entry = await new Promise(resolve => new PerformanceObserver(
      (list, observer) => {
        observer.disconnect();
        resolve(list.getEntries()[0]);
      }).observe({type: "visibility-state", buffered: true}));
    assert_equals(entry.name, "visible");
}, "Visibility state observers should respect the buffered flag");
</script>
