Improve holiday management

[naveensingh]

Checklist

• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the request will be dismissed otherwise.
• This issue contains only one feature request.
• I have read and understood the contribution guidelines.

Feature description

Current user flow for adding and removing holidays:

• More options => Add holidays => Select country => Select holiday types => Import
• More options => Settings => Manage event types => Delete "Holidays" event type

Proposed:

• More options => Manage holidays => Select country => Select holiday types => Import.
• More options => Manage holidays => Deselect country or deselect holiday types => Deselected holidays are automatically deleted.

Why do you want this feature?

Improved UI/UX.

Additional information

• It should be possible to do this in-app using the importId field to store country, holiday type info.
• https://www.reddit.com/r/Fossify/comments/1ie6vx0/fossify_calendar_how_to_remove_public_holidays/

The UI could be similar to the following:

[VidathD]

Are holidays currently unavailable for some countries? When I tried importing for Sri Lanka, no holidays were imported

[naveensingh]

Yes, holidays for many countries are not yet added but Sri Lanka works for me.

[Aga-C]

@VidathD 4 countries are not supported by the holiday generator because of missing data in the upstream repo:

Calendar/.github/workflows/holiday-generator/config.js

Lines 73 to 78 in c1c0176

	export const UNSUPPORTED_COUNTRIES = {
	"IN": "India", // TODO: https://github.com/commenthol/date-holidays/issues/137
	"KZ": "Kazakhstan", // TODO: (no GH issue)
	"PK": "Pakistan", // TODO: https://github.com/commenthol/date-holidays/pull/138
	"LK": "Sri Lanka", // TODO: (no GH issue)
	};

Until it's supported, the best way is to manually add holidays for Sri Lanka by editing this ICS file: https://github.com/FossifyOrg/Calendar/blob/master/app/src/main/assets/holidays/LK/public.ics. We'll be happy if someone could contribute updated Sri Lankan holidays and also holidays for other unsupported countries.