refactor: ETA calculation (#2055)

* Refactor ETA calculation

* Update src/renderer/pages/player-page.js

Co-authored-by: Alex <alxmorais8@msn.com>

* Fix lint issue

Co-authored-by: Alex <alxmorais8@msn.com>

src/renderer/lib/time.js

@@ -0,0 +1,20 @@
+module.exports = {
+  calculateEta
+}
+
+function calculateEta (missing, downloadSpeed) {
+  if (downloadSpeed === 0 || missing === 0) return
+
+  const rawEta = missing / downloadSpeed
+  const hours = Math.floor(rawEta / 3600) % 24
+  const minutes = Math.floor(rawEta / 60) % 60
+  const seconds = Math.floor(rawEta % 60)
+
+  // Only display hours and minutes if they are greater than 0 but always
+  // display minutes if hours is being displayed
+  const hoursStr = hours ? hours + ' h' : ''
+  const minutesStr = (hours || minutes) ? minutes + ' min' : ''
+  const secondsStr = seconds + ' s'
+
+  return `${hoursStr} ${minutesStr} ${secondsStr} remaining`
+}