fix: infinite loop spikes CPU at midnight

[abdelhalim97]

closes #1547

Root cause

setupUI calls refresh.
refresh set a timer to call setupUI every 1 second.
This resulted infinite loop.

At midnight this gets worst, because date changes, which will trigger calculatePrayerTimes and calculatePrayerTimes also calls setupUI...
Multiple infinite loops explains cpu spike at midnight.

Fix

Replaced refresh with a function startUpdateTimer that run once per second.
Added updateCountdown checks if day changed and recalculate prayer times at midnight.
UI will only be built when needed instead of every second

Same features without infinite loops

[github-actions]

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Found 1 potential issue(s):

⚠️ WARNING

⚠️ lang_bind

prayertimes@linworx.org/files/prayertimes@linworx.org/5.8/desklet.js:175

this._timeoutId = Mainloop.timeout_add_seconds(1, Lang.bind(this, this.updateCountdown));

Lang.bind() is deprecated. Use arrow functions (() => {}) or Function.prototype.bind() instead.

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[M-Hassand]

Great work!

In case the original author does not wish to change the original design, it is worth noting that removing the call to setupUI at the end of calculatePrayerTimes solves the problem as well (although of course, not as elegantly as the one above).

It is not needed as before the calculatePrayerTimes call, a call to setupUI was already scheduled. This way, there's only one loop that goes back and forth between setupUI and refresh rather than multiple loops spawning at midnight.