Hardcoded date formats used throughout game's code

[Susko3]

Type

Cosmetic

Bug description

Noticed while investigating https://github.com/ppy/osu/issues/21146.

Date formats are hardcoded throughout the code:

https://github.com/ppy/osu/blob/f8830c6850128456266c82de83273204f8b74ac0/osu.Game/Graphics/DateTooltip.cs#L72-L73

Using standard date format strings and properly utilising TranslatableString should help with this.

Screenshots or videos

Game:

Web:

Version

2022.1101.0

Logs

performance.log runtime.log updater.log database.log input.log network.log

[Susko3]

(continuation from https://github.com/ppy/osu-framework/pull/5538#discussion_r1039044155)

osu-web

osu-web uses custom date format strings for some usages, defined per-language: Japanese, English.

I don't know from where it gets regular date format strings, but they are (mostly) appropriate for the currently selected language. Example:

Not using culture-appropriate format:

There is also this formatter for relative time.

osu

Using regular .NET date time format strings doesn't work, as they don't exactly match osu-web.

• Something that also immediately sticks out when using .NET formatting is that en uses month/day/year and not day/month/year format that osu!web uses.
• the long date format D usually has the weekday (dddd): Monday, 15 June 2009
• while the year-month pattern Y does exist, there is no 'short' version

Someone using en-US might expect their dates to be formatted as June 15, 2009 and not 15 June 2009. osu! mostly uses the long date format with month names (where there is no ambiguity, at least in English), but there is one usage of the short date yyyy-MM-dd where the user might confuse the month and day.

So I though that re-using the existing localisation infrastructure and providing a custom format provider that formatted dates the same as osu-web could work. Using a format provider that respects not only the selected language in osu!, but also respects the user's date format (within reason) seemed like a good idea.