Initialize invokes the factory specified by the viper token "mailer" and returns the result of this call.

NewLetter creates a new letter with the from address filled in automatically.

Register is called by external implementations of the mailer interface to be made available in the registry.

RenderLetter loads a file containing the text of letters and templates it into the provided letter template.

UserToAddress composes the address for a user and returns filled in struct.

ErrInternal is a catch all for things that are unforseen.

ErrNoSuchLetter is returned if a templated letter is requested but isn't known to the system.

ErrUnknownMailer is returned if a mailer is requested but isn't known to the system.

A Letter here means the same thing it does in the real world.

A LetterContext is everything that's needed to pass into RenderLetter in order to generate a letter ready to send.

A Mailer implements the components needed to send email to a various persons.

A Factory returns a configured mailer that is ready to use.