Add option to automate date based roles

[v-pan]

Current behaviour

Currently Whodis takes a few roles and assigns them to a user on verification

whodis/internal/api/verify.go

Lines 124 to 142 in 88bcbc3

	func addRoles(s *discordgo.Session, gid, uid string, rid []string) error {
	roles, err := s.GuildRoles(gid)
	if err != nil {
	return err
	}
	roleID := utils.GetRoleIDFromName(roles, viper.GetString("discord.member.role"))
	if roleID == "" {
	return errors.New("no role called: " + viper.GetString("discord.member.role"))
	}
	if err := s.GuildMemberRoleAdd(gid, uid, roleID); err != nil {
	return err
	}
	for _, additionalRoleID := range rid {
	if err := s.GuildMemberRoleAdd(gid, uid, additionalRoleID); err != nil {
	return err
	}
	}
	return nil
	}

This works for roles which do not change name over time, but requires manual management for assigning roles that may change by calling /setup again (eg. an @22/23 role).

Proposed Changes

Add an option to have Whodis manage a time-related role. This involves two things:

1. Whodis will check the existence of, and create roles based on the current date.
   • Permissions wise, this should already be covered by the Manage roles permission
   • A role check needs to occur on user verification, as the required role will change after /setup was called.
2. A method of configuring the role and how it should be updated needs to be provided.
   • By default this should not be enabled.

There's two ways we could add this:

Option 1

Allow a time format string in role names, in the style of the time command.

This would be easier to implement and flexible, but means that when /setup is called that we need to allow invalid roles as argument(s).

• This doesn't have to affect autocomplete, as discord allows bots to provide their own list of completions.
• To keep validating roles, it could instead be given a dedicated argument for dynamic roles.

Not all format options need to (or should, eg. seconds level accuracy) be provided.

Option 2

Fix the role as annual, and provide limited options to customise it.

It should check for the current academic year, probably by checking against a config provided cutoff date.

The role itself should be configured through extra arguments in /setup, or with a dedicated command for configuring dynamic roles.

With subcommands, setting up a dynamic role might look something like:

1. /setup welcome-message [announce-channel] [logging-channel] <given-role-1> <given-role-2>
   • The old setup, but moved to a subcommand
2. /setup date-role [date-format] <role-prefix> <role-suffix>
   • New subcommand. This will create and manage the role itself.

As before, we can provide auto-completions for the date formats, and don't have concerns with overloading existing arguments or commands.