<!DOCTYPE html>
<html>
<head>
<style>
.scrollable_region {
    width: 680px;
}

.scrolled-content {
    height: 1036px;
    width: 100%;
    background-image: repeating-linear-gradient(silver, white 120px);
}
</style>
<script src="../../resources/js-test-pre.js"></script>
<script src="../../resources/ui-helper.js"></script>
<script>
    window.jsTestIsAsync = true;

    var divTarget;
    var pageScrollPositionBefore;
    var divScrollPositionBefore;
    var continueCount = 5;

    var wheelCount = 0;
    function onScrollWheel(evt)
    {
        wheelCount = wheelCount + 1;
    }

    function checkForScroll()
    {
        // The div should not have scrolled at all.
        var pageScrollPositionAfter = document.scrollingElement.scrollTop;
        var divScrollPositionAfter = divTarget.scrollTop;

        if (pageScrollPositionBefore != pageScrollPositionAfter)
            testFailed("Page received wheel events.");
        else
            testPassed("Page did not receive wheel events.");

        if (window.internals) {
            document.getElementById('layers').innerText = internals.layerTreeAsText(document,
                internals.LAYER_TREE_INCLUDES_VISIBLE_RECTS | internals.LAYER_TREE_INCLUDES_TILE_CACHES);
        }

        finishJSTest();
    }

    async function scrollTest()
    {
        pageScrollPositionBefore = document.scrollingElement.scrollTop;

        divTarget = document.getElementById('target');
        divTarget.scrollTop = divTarget.scrollHeight - divTarget.clientHeight - 100;

        divScrollPositionBefore = divTarget.scrollTop;

        // Scroll the #source until we reach the #target.
        const startPosX = Math.round(divTarget.offsetLeft) + 20;
        const startPosY = Math.round(divTarget.offsetTop) + 100; // One wheel turn before end.

        const events = [
            {
                type : "wheel",
                viewX : startPosX,
                viewY : startPosY,
                deltaY : -10,
                phase : "began"
            },
            {
                type : "wheel",
                deltaY : -10,
                phase : "changed"
            },
            {
                type : "wheel",
                deltaY : -10,
                phase : "changed"
            },
            {
                type : "wheel",
                phase : "ended"
            },
            {
                type : "wheel",
                deltaY : -10,
                momentumPhase : "began"
            },
            {
                type : "wheel",
                deltaY : -10,
                momentumPhase : "changed"
            },
            {
                type : "wheel",
                momentumPhase : "ended"
            }
        ];

        await UIHelper.mouseWheelSequence({ events: events });
        checkForScroll();
    }

    function setupTopLevel()
    {
        if (window.eventSender) {
            setTimeout(scrollTest, 0);
        } else {
            var messageLocation = document.getElementById('parent');
            var message = document.createElement('div');
            message.innerHTML = "<p>This test is better run under DumpRenderTree. To manually test it, place the mouse pointer<br/>"
                + "near the bottom of the scrollable region, and then use the mouse wheel or a two-finger swipe to scroll up.<br/></br/>"
                + "The page should not scroll.</p>";
            messageLocation.appendChild(message);
        }
    }

    window.addEventListener('load', () => {
        document.addEventListener("mousewheel", onScrollWheel);
        setupTopLevel();
    }, false);
</script>
</head>
<body>
<div id="parent" style="height: 2000px; width: 2000px;">
    <div id="source" style="height: 100px; width: 500px;">
        Put mouse here and flick downwards
    </div>
    <div class="scrollable_region">
        <h3>Scrollable Region</h3>
        <div id="target" style='overflow-y: auto; overflow-x: hidden; max-height: 350px;'>
            <div class="scrolled-content">Scrolled content</div>
        </div>
    </div>
</div>
<div id="console"></div>
<script>
description("Tests that a scrollable div doesn't pass wheel events to main frame when scrolling at bottom");
</script>
<pre id="layers">Layer tree goes here</p>
<script src="../../resources/js-test-post.js"></script>
</body>
</html>