1 files changed, 106 insertions, 0 deletions
diff --git a/src/lib/stores/timer.svelte.js b/src/lib/stores/timer.svelte.js
new file mode 100644
index 0000000..dea1799
--- /dev/null
+++ b/src/lib/stores/timer.svelte.js
@@ -0,0 +1,106 @@
+import { Notyf } from "notyf";
+
+const DEFAULT_MINS = 12;
+const MIN_MINS = 0.5;
+
+const initialMins = Number(sessionStorage.getItem("mins")) || DEFAULT_MINS;
+const initialRunning = Boolean(Number(sessionStorage.getItem("running")));
+const initialDeadline = Number(sessionStorage.getItem("deadline")) || Date.now();
+const initialRemainingMs = initialRunning
+  ? Math.max(initialDeadline - Date.now(), 0)
+  : initialMins * 60 * 1000;
+
+let mins = $state(initialMins);
+let running = $state(initialRunning);
+let deadline = $state(initialDeadline);
+let remainingMs = $state(initialRemainingMs);
+
+let intervalId = null;
+
+function persist() {
+  sessionStorage.setItem("mins", mins);
+  sessionStorage.setItem("running", Number(running));
+  sessionStorage.setItem("deadline", deadline);
+}
+
+function showRoundCompletedToast() {
+  const notyf = new Notyf({
+    duration: 0,
+    position: { x: "center", y: "top" },
+    dismissible: true,
+  });
+  notyf.error("Round completed");
+}
+
+function stopInterval() {
+  if (intervalId !== null) clearInterval(intervalId);
+  intervalId = null;
+}
+
+function tick() {
+  const msToDeadline = deadline - Date.now();
+  if (msToDeadline > 0) {
+    remainingMs = msToDeadline;
+    return;
+  }
+  stopInterval();
+  running = false;
+  remainingMs = mins * 60 * 1000;
+  persist();
+  showRoundCompletedToast();
+}
+
+export function getMins() {
+  return mins;
+}
+
+export function getRunning() {
+  return running;
+}
+
+export function getRemainingMs() {
+  return remainingMs;
+}
+
+export function formatRemaining(ms) {
+  const m = Math.floor((ms % (1000 * 60 * 60)) / (1000 * 60));
+  const s = Math.floor((ms % (1000 * 60)) / 1000);
+  const pad = (n) => (n < 10 ? "0" + n : String(n));
+  return `${pad(m)}:${pad(s)}`;
+}
+
+export function getDisplay() {
+  return formatRemaining(remainingMs);
+}
+
+export function stopTimer() {
+  stopInterval();
+  running = false;
+  remainingMs = mins * 60 * 1000;
+  persist();
+}
+
+export function start(fresh = true) {
+  if (fresh && running) return;
+  if (fresh) {
+    deadline = Date.now() + mins * 60 * 1000;
+  }
+  running = true;
+  remainingMs = Math.max(deadline - Date.now(), 0);
+  persist();
+  stopInterval();
+  intervalId = setInterval(tick, 1000);
+}
+
+export function changeMinutes(delta) {
+  mins = Math.max(mins + delta, MIN_MINS);
+  stopTimer();
+}
+
+// Resume a timer that was still running across a page reload, otherwise
+// settle the display to the resting (not-running) state.
+if (initialRunning) {
+  start(false);
+} else {
+  stopTimer();
+}