@node clock
@subsection clock.js

@deftp {abstract class} Clock
Interface for ``things'' which wants to get updated on a human timescale.

@defmethod Clock update now
@c abstract method
Called every now and then, with @var{now} being the current time.
@end defmethod
@end deftp

@deftp {class} Timebar @extends{Clock}
The (blue) vertical line which show the current time in the current day.

@c @defmethod Timebar constructor ∅
@c @end defmethod
@c 
@c @defmethod Timebar update now
@c @end defmethod
@end deftp

@deftp {class} SmallcalCellHighlight @extends{Clock}
Highlights the current date in the small calendar to the side.
Currently directly sets a border
@TODO{but should preferably set a class instead}.

@defmethod SmallcalCellHighlight constructor small_cal
@var{small_cal} is the DOM-node of the calendar.
(it should support querySelector).
@end defmethod

@c @defmethod SmallcalCellHighlight update now
@c @end defmethod
@end deftp

@deftp {class} ButtonUpdater @extends{Clock}
Updates the ``Today'' link in the side panel to point directly to the
correct web-address. The link works without JavaScript, but then
requires a redirect from the server.

All actual updating logic is already abstracted away. It would be
desirable if something more was done with this.

@defmethod ButtonUpdater el proc
Takes the element @var{el} to be updated, and the procedure @var{proc}
which will be called with the element, and the current time.
@end defmethod
@end deftp


As of commit
@githash{c9719ce7937f0f0f2aa371ced1d585f67af22457,static/script.js,231} 
all objects required manual setup. See static/script.js:

@verbatim
   231	    let start_time = document.querySelector("meta[name='start-time']").content;
   232	    let end_time = document.querySelector("meta[name='end-time']").content;
   233	
   234	    const button_updater = new ButtonUpdater(
   235	        document.getElementById("today-button"),
   236	        (e, d) => e.href = d.format('~Y-~m-~d') + ".html"
   237	    );
   238	
   239	    const sch = new SmallcalCellHighlight(
   240	        document.querySelector('.small-calendar'))
   241	
   242	    const timebar = new Timebar(start_time, end_time);
   243	
   244	    timebar.update(new Date);
   245	    window.setInterval(() => {
   246	        let d = new Date;
   247	        timebar.update(d);
   248	        button_updater.update(d);
   249	        sch.update(d);
   250	    }, 1000 * 60);
   251	
@end verbatim