refactor: unify progress bar logic

apps/client/src/common/utils/getProgress.ts

@@ -0,0 +1,23 @@
+import { MaybeNumber } from 'ontime-types';
+
+import { clamp } from './math';
+
+/**
+ * Returns completion percentage of a progress bar
+ * This code assumes the current time and duration have addedTime already applied
+ */
+export function getProgress(current: MaybeNumber, duration: MaybeNumber) {
+  if (current === null || duration === null) {
+    return 0;
+  }
+
+  if (current <= 0) {
+    return 100;
+  }
+
+  if (current >= duration) {
+    return 0;
+  }
+
+  return clamp(((duration - current) / duration) * 100, 0, 100);
+}