1 files changed, 54 insertions, 0 deletions
diff --git a/public/clock.js b/public/clock.js
new file mode 100644
index 000000000..ffb9beae8
--- /dev/null
+++ b/public/clock.js
@@ -0,0 +1,54 @@
+document.addEventListener("DOMContentLoaded", function(event) { 
+  updateClock();
+  setInterval(updateClock, 1000);
+});
+
+function getNextOpen(now) {
+    var days = [[0, 14], [4, 18], [8, 22], [12], [2, 16], [6, 20], [10]]
+    var nowday = now.getUTCDay();
+    var nour = now.getUTCHours();
+
+    var open_hour = -1;
+    var d = 0;
+
+    while (open_hour == -1) {
+        var times = days[(nowday + d) % 7];
+        for (var i = 0; i < times.length; ++i) {
+            var time = times[i];
+            if (time == nour) {
+                return "refresh";
+            } else if (time > nour || d > 0) {
+                open_hour = time;
+                break;
+            }
+        }
+        if (open_hour == -1) {
+            d += 1;
+            nour = -1;
+        }
+    }
+
+    var open = new Date(Date.UTC(now.getUTCFullYear(), now.getUTCMonth(), now.getUTCDate() + d));
+    var ts = open.setUTCHours(open_hour);
+    return open;
+}
+
+function updateClock() {
+    var clock = document.querySelector(".closed-registrations-message .clock");
+    var now = new Date();
+    var open = getNextOpen(now);
+
+    if (open == "refresh") {
+        location.reload();
+        return;
+    }
+
+    var until = open - now;
+    var ms = until % 1000;
+    var s =  Math.floor((until / 1000)) % 60;
+    var m =  Math.floor((until / 1000 / 60)) % 60;
+    var h =  Math.floor((until / 1000 / 60 / 60));
+    if (m < 10) m = "0" + m;
+    if (s < 10) s = "0" + s;
+    clock.innerHTML = h + ":" + m + ":" + s;
+}