Improve service errors adding more context

[josecelano]

In the ServiceError enum we only support a single error message with no extra data.

#[derive(Debug, Display, PartialEq, Eq, Error)]
#[allow(dead_code)]
pub enum ServiceError {
    #[display(fmt = "internal server error")]
    InternalServerError,

    #[display(fmt = "This server is is closed for registration. Contact admin if this is unexpected")]
    ClosedForRegistration,

    #[display(fmt = "Email is required")] //405j
    EmailMissing,
    #[display(fmt = "Please enter a valid email address")] //405j
    EmailInvalid,

    #[display(fmt = "The value you entered for URL is not a URL")] //405j
    NotAUrl,

    #[display(fmt = "Invalid username/email or password")]
    WrongPasswordOrUsername,
    #[display(fmt = "Username not found")]
    UsernameNotFound,
    #[display(fmt = "User not found")]
    UserNotFound,

    #[display(fmt = "Account not found")]
    AccountNotFound,

    /// when the value passed contains profanity
    #[display(fmt = "Can't allow profanity in usernames")]
    ProfanityError,
    /// when the value passed contains blacklisted words
    /// see [blacklist](https://github.com/shuttlecraft/The-Big-Username-Blacklist)
    #[display(fmt = "Username contains blacklisted words")]
    BlacklistError,
    /// when the value passed contains characters not present
    /// in [UsernameCaseMapped](https://tools.ietf.org/html/rfc8265#page-7)
    /// profile
    #[display(fmt = "username_case_mapped violation")]
    UsernameCaseMappedError,

    #[display(fmt = "Password too short")]
    PasswordTooShort,
    #[display(fmt = "Username too long")]
    PasswordTooLong,
    #[display(fmt = "Passwords don't match")]
    PasswordsDontMatch,

    /// when the a username is already taken
    #[display(fmt = "Username not available")]
    UsernameTaken,

    #[display(fmt = "Invalid username. Usernames must consist of 1-20 alphanumeric characters, dashes, or underscore")]
    UsernameInvalid,

    /// email is already taken
    #[display(fmt = "Email not available")]
    EmailTaken,

    #[display(fmt = "Please verify your email before logging in")]
    EmailNotVerified,

    /// when the a token name is already taken
    /// token not found
    #[display(fmt = "Token not found. Please sign in.")]
    TokenNotFound,

    /// token expired
    #[display(fmt = "Token expired. Please sign in again.")]
    TokenExpired,

    #[display(fmt = "Token invalid.")]
    /// token invalid
    TokenInvalid,

    #[display(fmt = "Uploaded torrent is not valid.")]
    InvalidTorrentFile,

    // ...

    #[display(fmt = "This torrent already exists in our database.")]
    InfoHashAlreadyExists,

    #[display(fmt = "A torrent with the same canonical infohash already exists in our database.")]
    CanonicalInfoHashAlreadyExists,

    // ...

    #[display(fmt = "Tracker unknown response. Unexpected response from tracker. For example, if it can be parsed.")]
    TrackerUnknownResponse,

    #[display(fmt = "Torrent not found in tracker.")]
    TorrentNotFoundInTracker,

    #[display(fmt = "Invalid tracker API token.")]
    InvalidTrackerToken,
    // End tracker errors
}

For some of them, it would be better if we add extra data. FOr example, the error:

    #[display(fmt = "A torrent with the same canonical infohash already exists in our database.")]
    CanonicalInfoHashAlreadyExists,

should give you the info-hash, so the user can search/navigate to see the pre-existing torrent.

We can do it like we do for other error enums with the thiserror crate.

use thiserror::Error;

#[derive(Debug, Error)]
pub enum ServiceError {
    #[error("internal server error: {0}")]
    InternalServerError(String),
    // other variants...
}