#[derive(Debug, thiserror::Error)]
pub enum AppTransportError {
    #[error("invalid session")]
    InvalidSession,
    #[error("unauthorized")]
    Unauthorized,
    #[error("token invalid or expired")]
    TokenInvalidOrExpired,
    #[error("renewal limit exceeded")]
    RenewalLimitExceeded,
    #[error("rate limit exceeded")]
    RateLimitExceeded,
    #[error("room not found")]
    RoomNotFound,
    #[error("access denied")]
    AccessDenied,
    #[error("internal error")]
    Internal,
}

impl From<room::error::RoomError> for AppTransportError {
    fn from(e: room::error::RoomError) -> Self {
        match e {
            room::error::RoomError::Unauthorized => AppTransportError::Unauthorized,
            room::error::RoomError::NoPower => AppTransportError::AccessDenied,
            room::error::RoomError::NotFound(_) => AppTransportError::RoomNotFound,
            room::error::RoomError::RateLimited(_) => AppTransportError::RateLimitExceeded,
            room::error::RoomError::BadRequest(_) => AppTransportError::Internal,
            room::error::RoomError::Database(_) => AppTransportError::Internal,
            room::error::RoomError::RoleParseError => AppTransportError::Internal,
            room::error::RoomError::Internal(_) => AppTransportError::Internal,
        }
    }
}

impl AppTransportError {
    /// Map error to a (code, error_type) pair for WS error messages.
    /// Frontend can use these to distinguish auth vs rate-limit vs internal errors.
    pub fn ws_error_code(&self) -> (u16, &'static str) {
        match self {
            AppTransportError::Unauthorized => (401, "unauthorized"),
            AppTransportError::TokenInvalidOrExpired => (401, "token_invalid"),
            AppTransportError::AccessDenied => (403, "access_denied"),
            AppTransportError::RateLimitExceeded => (429, "rate_limit_exceeded"),
            AppTransportError::RoomNotFound => (404, "not_found"),
            AppTransportError::InvalidSession => (401, "invalid_session"),
            AppTransportError::RenewalLimitExceeded => (429, "renewal_limit"),
            AppTransportError::Internal => (500, "internal_error"),
        }
    }
}