<!DOCTYPE HTML>
<html>
    <head>
        <style>
            html {
                scroll-snap-type: x proximity;
            }
            .horizontalGallery {
                width: 600vw;
                height: 100vh;
                margin: 0;
                padding: 0;
            }
            .colorBox {
                height: 100vh;
                width: 100vw;
                float: left;
                scroll-snap-align: start;
            }
            #item0 { background-color: red; }
            #item1 { background-color: green; }
            #item2 { background-color: blue; }
            #item3 { background-color: aqua; }
            #item4 { background-color: yellow; }
            #item5 { background-color: fuchsia; }
        </style>
        <script src="../../../resources/js-test.js"></script>
        <script src="../../../resources/ui-helper.js"></script>
        <script>
        window.jsTestIsAsync = true;

        async function runTests()
        {
            try {
                await UIHelper.delayFor(0);

                let scrollPositionBeforeSnap = document.scrollingElement.scrollLeft;
                eventSender.keyDown("rightArrow");
                eventSender.keyDown("rightArrow");
                eventSender.keyDown("rightArrow");
                var betweenFirstScrollPositionAndSecond =
                    document.scrollingElement.scrollLeft > scrollPositionBeforeSnap
                    && document.scrollingElement.scrollLeft < window.innerWidth;
                expectTrue(betweenFirstScrollPositionAndSecond, "arrow keys didn't scroll to second div.");

                // We reset the scrolling position because changing the DOM when we are not on
                // a snap point can reset our scroll position.
                document.scrollingElement.scrollLeft = scrollPositionBeforeSnap;
                eventSender.keyDown("rightArrow");
                eventSender.keyDown("rightArrow");
                eventSender.keyDown("rightArrow");
                eventSender.keyDown("leftArrow");

                // Reversing directions should snap back.
                expectTrue(document.scrollingElement.scrollLeft == scrollPositionBeforeSnap, "left arrow snapped back.");
            } catch (e) {
                console.log(e);
            } finally {
                finishJSTest();
            }
        }

        function onLoad()
        {
            if (window.eventSender) {
                runTests();
            } else {
                var messageLocation = document.getElementById('item0');
                var message = document.createElement('div');
                message.innerHTML = "<p>To run this test manually, scroll the page horizontally with the keyboard.</p>";
                messageLocation.appendChild(message);
            }
        }
        </script>
    </head>
    <body onload="onLoad();" class="horizontalGallery">
        <div id="item0" class="colorBox"><div id="console"></div></div>
        <div id="item1" class="colorBox"></div>
        <div id="item2" class="colorBox"></div>
        <div id="item3" class="colorBox"></div>
        <div id="item4" class="colorBox"></div>
        <div id="item5" class="colorBox"></div>
    </body>
</html>