<html>
<head>
    <script src="../../resources/js-test-pre.js"></script>
    <script>
        description('<a href="https://bugs.webkit.org/show_bug.cgi?id=98474">Bug 98474</a>: Throttle DOM timers on hidden pages.');

        var jsTestIsAsync = true;
        var previousTime = new Date().getTime();
        var timerCount = 0;
        var firstTimerWhileHidden = true;
        var isPageVisible = true;
        var timeoutInterval = 100;
        var tolerance = 20;
        var timerAlignmentInterval = 1000;

        function testTimer()
        {
            var date = new Date();
            var time = date.getTime();
            if (!isPageVisible) {
                if (firstTimerWhileHidden) {
                    firstTimerIntervalWhilePageHidden = time - previousTime;
                    var minValue = timeoutInterval - tolerance;
                    shouldBeGreaterThanOrEqual("firstTimerIntervalWhilePageHidden", minValue.toString());
                    var maxValue = timeoutInterval + timerAlignmentInterval + tolerance;
                    shouldBeTrue("firstTimerIntervalWhilePageHidden <= " + maxValue);
                    firstTimerWhileHidden = false;
                } else {
                    timerIntervalWhilePageHidden = time - previousTime;
                    shouldBeCloseTo("timerIntervalWhilePageHidden", timerAlignmentInterval, tolerance);
                }
            } else {
                timerIntervalWhilePageVisible = time - previousTime;
                shouldBeCloseTo("timerIntervalWhilePageVisible", timeoutInterval, tolerance);
            }

            timerCount++;
            previousTime = time;

            if (timerCount == 1) {
                testRunner.setPageVisibility("hidden");
                isPageVisible = false;
            } else if (timerCount == 3) {
                testRunner.resetPageVisibility();
                isPageVisible = true;
            } else if (timerCount >= 4){
                finishJSTest();
                return;
            }
            setTimeout(testTimer, timeoutInterval);
        }

        function runTest()
        {
            if (!window.testRunner) {
                debug('This test requires testRunner');
                return;
            }
            testRunner.overridePreference("WebKitHiddenPageDOMTimerThrottlingEnabled", 1);

            var timeoutIntervalSpans = document.getElementsByClassName('timeoutInterval');
            for (var i = 0; i < timeoutIntervalSpans.length; i++)
                timeoutIntervalSpans[i].innerText = timeoutInterval;

            document.getElementById('alignmentInterval').innerText = timerAlignmentInterval / 1000;

            testRunner.dumpAsText();
            setTimeout(testTimer, timeoutInterval);
        }
    </script>
</head>
<body onload="runTest()">
    <p>
    This test measures the time taken to fire a <span class="timeoutInterval"></span>ms DOM Timer when the page visibility is set to "visible", "hidden" and then back to "visible".  Due to hidden page timer throttling, the timer should fire close to <span id="alignmentInterval"></span>s when page is hidden.  And it should fire close to <span class="timeoutInterval"></span>ms, when the page is visible.
    </p>
    <script src="../../resources/js-test-post.js"></script>
</body>
</html>