torrust-index-backend 2.0.0-alpha.3

//! User services.
use std::sync::Arc;

use argon2::password_hash::SaltString;
use argon2::{Argon2, PasswordHasher};
use jsonwebtoken::{decode, Algorithm, DecodingKey, Validation};
use log::{debug, info};
use pbkdf2::password_hash::rand_core::OsRng;

use crate::config::{Configuration, EmailOnSignup};
use crate::databases::database::{Database, Error};
use crate::errors::ServiceError;
use crate::mailer;
use crate::mailer::VerifyClaims;
use crate::models::user::{UserCompact, UserId, UserProfile};
use crate::utils::validation::validate_email_address;
use crate::web::api::v1::contexts::user::forms::RegistrationForm;

/// Since user email could be optional, we need a way to represent "no email"
/// in the database. This function returns the string that should be used for
/// that purpose.
fn no_email() -> String {
    String::new()
}

pub struct RegistrationService {
    configuration: Arc<Configuration>,
    mailer: Arc<mailer::Service>,
    user_repository: Arc<DbUserRepository>,
    user_profile_repository: Arc<DbUserProfileRepository>,
}

impl RegistrationService {
    #[must_use]
    pub fn new(
        configuration: Arc<Configuration>,
        mailer: Arc<mailer::Service>,
        user_repository: Arc<DbUserRepository>,
        user_profile_repository: Arc<DbUserProfileRepository>,
    ) -> Self {
        Self {
            configuration,
            mailer,
            user_repository,
            user_profile_repository,
        }
    }

    /// It registers a new user.
    ///
    /// # Errors
    ///
    /// This function will return a:
    ///
    /// * `ServiceError::EmailMissing` if email is required, but missing.
    /// * `ServiceError::EmailInvalid` if supplied email is badly formatted.
    /// * `ServiceError::PasswordsDontMatch` if the supplied passwords do not match.
    /// * `ServiceError::PasswordTooShort` if the supplied password is too short.
    /// * `ServiceError::PasswordTooLong` if the supplied password is too long.
    /// * `ServiceError::UsernameInvalid` if the supplied username is badly formatted.
    /// * `ServiceError::FailedToSendVerificationEmail` if unable to send the required verification email.
    /// * An error if unable to successfully hash the password.
    /// * An error if unable to insert user into the database.
    ///
    /// # Panics
    ///
    /// This function will panic if the email is required, but missing.
    pub async fn register_user(&self, registration_form: &RegistrationForm, api_base_url: &str) -> Result<UserId, ServiceError> {
        info!("registering user: {}", registration_form.username);

        let settings = self.configuration.settings.read().await;

        let opt_email = match settings.auth.email_on_signup {
            EmailOnSignup::Required => {
                if registration_form.email.is_none() {
                    return Err(ServiceError::EmailMissing);
                }
                registration_form.email.clone()
            }
            EmailOnSignup::None => None,
            EmailOnSignup::Optional => registration_form.email.clone(),
        };

        if let Some(email) = &registration_form.email {
            if !validate_email_address(email) {
                return Err(ServiceError::EmailInvalid);
            }
        }

        if registration_form.password != registration_form.confirm_password {
            return Err(ServiceError::PasswordsDontMatch);
        }

        let password_length = registration_form.password.len();

        if password_length <= settings.auth.min_password_length {
            return Err(ServiceError::PasswordTooShort);
        }

        if password_length >= settings.auth.max_password_length {
            return Err(ServiceError::PasswordTooLong);
        }

        let salt = SaltString::generate(&mut OsRng);

        // Argon2 with default params (Argon2id v19)
        let argon2 = Argon2::default();

        // Hash password to PHC string ($argon2id$v=19$...)
        let password_hash = argon2
            .hash_password(registration_form.password.as_bytes(), &salt)?
            .to_string();

        if registration_form.username.contains('@') {
            return Err(ServiceError::UsernameInvalid);
        }

        let user_id = self
            .user_repository
            .add(
                &registration_form.username,
                &opt_email.clone().unwrap_or(no_email()),
                &password_hash,
            )
            .await?;

        // If this is the first created account, give administrator rights
        if user_id == 1 {
            let _ = self.user_repository.grant_admin_role(&user_id).await;
        }

        if settings.mail.email_verification_enabled && opt_email.is_some() {
            let mail_res = self
                .mailer
                .send_verification_mail(
                    &opt_email.expect("variable `email` is checked above"),
                    &registration_form.username,
                    user_id,
                    api_base_url,
                )
                .await;

            if mail_res.is_err() {
                let _ = self.user_repository.delete(&user_id).await;
                return Err(ServiceError::FailedToSendVerificationEmail);
            }
        }

        Ok(user_id)
    }

    /// It verifies the email address of a user via the token sent to the
    /// user's email.
    ///
    /// # Errors
    ///
    /// This function will return a `ServiceError::DatabaseError` if unable to
    /// update the user's email verification status.
    pub async fn verify_email(&self, token: &str) -> Result<bool, ServiceError> {
        let settings = self.configuration.settings.read().await;

        let token_data = match decode::<VerifyClaims>(
            token,
            &DecodingKey::from_secret(settings.auth.secret_key.as_bytes()),
            &Validation::new(Algorithm::HS256),
        ) {
            Ok(token_data) => {
                if !token_data.claims.iss.eq("email-verification") {
                    return Ok(false);
                }

                token_data.claims
            }
            Err(_) => return Ok(false),
        };

        drop(settings);

        let user_id = token_data.sub;

        if self.user_profile_repository.verify_email(&user_id).await.is_err() {
            return Err(ServiceError::DatabaseError);
        };

        Ok(true)
    }
}

pub struct BanService {
    user_repository: Arc<DbUserRepository>,
    user_profile_repository: Arc<DbUserProfileRepository>,
    banned_user_list: Arc<DbBannedUserList>,
}

impl BanService {
    #[must_use]
    pub fn new(
        user_repository: Arc<DbUserRepository>,
        user_profile_repository: Arc<DbUserProfileRepository>,
        banned_user_list: Arc<DbBannedUserList>,
    ) -> Self {
        Self {
            user_repository,
            user_profile_repository,
            banned_user_list,
        }
    }

    /// Ban a user from the Index.
    ///
    /// # Errors
    ///
    /// This function will return a:
    ///
    /// * `ServiceError::InternalServerError` if unable get user from the request.
    /// * An error if unable to get user profile from supplied username.
    /// * An error if unable to set the ban of the user in the database.
    pub async fn ban_user(&self, username_to_be_banned: &str, user_id: &UserId) -> Result<(), ServiceError> {
        debug!("user with ID {user_id} banning username: {username_to_be_banned}");

        let user = self.user_repository.get_compact(user_id).await?;

        // Check if user is administrator
        if !user.administrator {
            return Err(ServiceError::Unauthorized);
        }

        let user_profile = self
            .user_profile_repository
            .get_user_profile_from_username(username_to_be_banned)
            .await?;

        self.banned_user_list.add(&user_profile.user_id).await?;

        Ok(())
    }
}

pub struct DbUserRepository {
    database: Arc<Box<dyn Database>>,
}

impl DbUserRepository {
    #[must_use]
    pub fn new(database: Arc<Box<dyn Database>>) -> Self {
        Self { database }
    }

    /// It returns the compact user.
    ///
    /// # Errors
    ///
    /// It returns an error if there is a database error.
    pub async fn get_compact(&self, user_id: &UserId) -> Result<UserCompact, ServiceError> {
        // todo: persistence layer should have its own errors instead of
        // returning a `ServiceError`.
        self.database
            .get_user_compact_from_id(*user_id)
            .await
            .map_err(|_| ServiceError::UserNotFound)
    }

    /// It grants the admin role to the user.
    ///
    /// # Errors
    ///
    /// It returns an error if there is a database error.
    pub async fn grant_admin_role(&self, user_id: &UserId) -> Result<(), Error> {
        self.database.grant_admin_role(*user_id).await
    }

    /// It deletes the user.
    ///
    /// # Errors
    ///
    /// It returns an error if there is a database error.
    pub async fn delete(&self, user_id: &UserId) -> Result<(), Error> {
        self.database.delete_user(*user_id).await
    }

    /// It adds a new user.
    ///
    /// # Errors
    ///
    /// It returns an error if there is a database error.
    pub async fn add(&self, username: &str, email: &str, password_hash: &str) -> Result<UserId, Error> {
        self.database.insert_user_and_get_id(username, email, password_hash).await
    }
}

pub struct DbUserProfileRepository {
    database: Arc<Box<dyn Database>>,
}

impl DbUserProfileRepository {
    #[must_use]
    pub fn new(database: Arc<Box<dyn Database>>) -> Self {
        Self { database }
    }

    /// It marks the user's email as verified.
    ///
    /// # Errors
    ///
    /// It returns an error if there is a database error.
    pub async fn verify_email(&self, user_id: &UserId) -> Result<(), Error> {
        self.database.verify_email(*user_id).await
    }

    /// It get the user profile from the username.
    ///
    /// # Errors
    ///
    /// It returns an error if there is a database error.
    pub async fn get_user_profile_from_username(&self, username: &str) -> Result<UserProfile, Error> {
        self.database.get_user_profile_from_username(username).await
    }
}

pub struct DbBannedUserList {
    database: Arc<Box<dyn Database>>,
}

impl DbBannedUserList {
    #[must_use]
    pub fn new(database: Arc<Box<dyn Database>>) -> Self {
        Self { database }
    }

    /// It add a user to the banned users list.
    ///
    /// # Errors
    ///
    /// It returns an error if there is a database error.
    ///
    /// # Panics
    ///
    /// It panics if the expiration date cannot be parsed. It should never
    /// happen as the date is hardcoded for now.
    pub async fn add(&self, user_id: &UserId) -> Result<(), Error> {
        // todo: add reason and `date_expiry` parameters to request.

        // code-review: add the user ID of the user who banned the user.

        // For the time being, we will not use a reason for banning a user.
        let reason = "no reason".to_string();

        // User will be banned until the year 9999
        let date_expiry = chrono::NaiveDateTime::parse_from_str("9999-01-01 00:00:00", "%Y-%m-%d %H:%M:%S")
            .expect("Could not parse date from 9999-01-01 00:00:00.");

        self.database.ban_user(*user_id, &reason, date_expiry).await
    }
}