configuration.rs

use crate::SubscriberEmail;
use config::{Config, File};
use secrecy::{ExposeSecret, Secret};
use serde::Deserialize;
use serde_aux::prelude::deserialize_number_from_string;

#[derive(Deserialize, Clone, Debug)]
pub struct Settings {
    pub database: DatabaseSettings,
    pub application: ApplicationSettings,
    pub email_client: EmailClientSettings,
    pub jwt_handler: JwtHandlerSettings,
}

pub enum Environment {
    Local,
    Test,
    Production,
}

#[derive(Deserialize, Clone, Debug)]
pub struct DatabaseSettings {
    pub username: String,
    pub password: Secret<String>,
    #[serde(deserialize_with = "deserialize_number_from_string")]
    pub port: u16,
    pub host: String,
    pub database_name: String,
}

#[derive(Deserialize, Clone, Debug)]
pub struct ApplicationSettings {
    #[serde(deserialize_with = "deserialize_number_from_string")]
    pub port: u16,
    pub base_url: String,
    pub logging_levels: Vec<String>,
    pub cors_base_url: Vec<String>,
}

#[derive(Deserialize, Clone, Debug)]
pub struct EmailClientSettings {
    pub base_url: String,
    pub sender_email: String,
    pub api_key: Secret<String>,
    #[serde(deserialize_with = "deserialize_number_from_string")]
    pub timeout_milliseconds: u64,
}

#[derive(Deserialize, Clone, Debug)]
pub struct JwtHandlerSettings {
    pub private_key: Secret<String>,
    pub public_key: String,
    #[serde(deserialize_with = "deserialize_number_from_string")]
    pub expiration_minutes: i64,
}

impl Environment {
    pub fn as_str(&self) -> &'static str {
        match self {
            Environment::Local => "local",
            Environment::Production => "production",
            Environment::Test => "test",
        }
    }
}

impl TryFrom<String> for Environment {
    type Error = String;
    fn try_from(s: String) -> Result<Self, Self::Error> {
        match s.to_lowercase().as_str() {
            "local" => Ok(Self::Local),
            "production" => Ok(Self::Production),
            "test" => Ok(Self::Test),
            other => Err(format!(
                "{} is not a supported environment. Use either `local` or `production`.",
                other
            )),
        }
    }
}

pub fn get_configuration() -> Result<Settings, config::ConfigError> {
    let base_path = std::env::current_dir().expect("Failed to determine the current directory");
    let configuration_directory = base_path.join("configuration");

    let environment: Environment = std::env::var("APP__ENVIRONMENT")
        .unwrap_or_else(|_| "local".into())
        .try_into()
        .expect("Failed to parse APP_ENVIRONMENT.");

    let settings = Config::builder()
        .add_source(File::from(configuration_directory.join("base")).required(true))
        .add_source(File::from(configuration_directory.join(environment.as_str())).required(true))
        .add_source(
            config::Environment::with_prefix("APP")
                .try_parsing(true)
                .separator("__"),
        )
        .build()?;

    settings.try_deserialize::<Settings>()
}

impl DatabaseSettings {
    pub fn connection_string(&self) -> Secret<String> {
        Secret::new(format!(
            "postgres://{}:{}@{}:{}/{}?sslmode=disable",
            self.username,
            self.password.expose_secret(),
            self.host,
            self.port,
            self.database_name
        ))
    }

    pub fn connection_string_without_db(&self) -> Secret<String> {
        Secret::new(format!(
            "postgres://{}:{}@{}:{}?sslmode=disable",
            self.username,
            self.password.expose_secret(),
            self.host,
            self.port
        ))
    }
}

impl EmailClientSettings {
    pub fn sender(&self) -> Result<SubscriberEmail, String> {
        SubscriberEmail::parse(self.sender_email.clone())
    }

    pub fn timeout(&self) -> std::time::Duration {
        std::time::Duration::from_millis(self.timeout_milliseconds)
    }
}