fix: Rename timer to stopwatch

Closes #392

client/src/utils/stopwatch.js

@@ -0,0 +1,47 @@
+const getFullSeconds = ({ startedAt, total }) => {
+  if (startedAt) {
+    return Math.floor((new Date() - startedAt) / 1000) + total;
+  }
+
+  return total;
+};
+
+export const createStopwatch = ({ hours, minutes, seconds }) => ({
+  startedAt: null,
+  total: hours * 60 * 60 + minutes * 60 + seconds,
+});
+
+export const updateStopwatch = ({ startedAt }, parts) => ({
+  ...createStopwatch(parts),
+  startedAt: startedAt && new Date(),
+});
+
+export const startStopwatch = (stopwatch) => ({
+  startedAt: new Date(),
+  total: stopwatch ? stopwatch.total : 0,
+});
+
+export const stopStopwatch = (stopwatch) => ({
+  startedAt: null,
+  total: getFullSeconds(stopwatch),
+});
+
+export const getStopwatchParts = (stopwatch) => {
+  const fullSeconds = getFullSeconds(stopwatch);
+
+  const hours = Math.floor(fullSeconds / 3600);
+  const minutes = Math.floor((fullSeconds - hours * 3600) / 60);
+  const seconds = fullSeconds - hours * 3600 - minutes * 60;
+
+  return {
+    hours,
+    minutes,
+    seconds,
+  };
+};
+
+export const formatStopwatch = (stopwatch) => {
+  const { hours, minutes, seconds } = getStopwatchParts(stopwatch);
+
+  return [hours, ...[minutes, seconds].map((part) => (part < 10 ? `0${part}` : part))].join(':');
+};