runique 3.0.2

//! Database engine detection and driver verification.
use serde::{Deserialize, Serialize};

/// Database engines supported by Runique.
///
/// Each variant corresponds to a database driver that must be
/// enabled via Cargo features.
///
/// # Required Features
///
/// - `sqlite` - For SQLite (enabled by default)
/// - `postgres` - For PostgreSQL
/// - `mysql` - For MySQL
/// - `mariadb` - For MariaDB (uses MySQL driver)
///
/// # Examples
///
/// ```
/// use runique::prelude::DatabaseEngine;
///
/// let engine = DatabaseEngine::detect_from_url("postgres://localhost/db")?;
/// assert_eq!(engine, DatabaseEngine::PostgreSQL);
/// # Ok::<(), String>(())
/// ```
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum DatabaseEngine {
    /// PostgreSQL database
    PostgreSQL,
    /// MySQL database
    MySQL,
    /// MariaDB database (MySQL-compatible)
    MariaDB,
    /// SQLite embedded database
    SQLite,
}

impl DatabaseEngine {
    /// Automatically detects the database type from a connection URL.
    ///
    /// # Examples
    ///
    /// ```
    /// use runique::prelude::DatabaseEngine;
    ///
    /// let engine = DatabaseEngine::detect_from_url("sqlite://db.sqlite")?;
    /// assert_eq!(engine, DatabaseEngine::SQLite);
    ///
    /// let engine = DatabaseEngine::detect_from_url("postgres://localhost/db")?;
    /// assert_eq!(engine, DatabaseEngine::PostgreSQL);
    /// # Ok::<(), String>(())
    /// ```
    ///
    /// # Errors
    ///
    /// Returns an error if the URL doesn't match any supported database.
    pub fn detect_from_url(url: &str) -> Result<Self, String> {
        if url.starts_with("postgres://") || url.starts_with("postgresql://") {
            Ok(DatabaseEngine::PostgreSQL)
        } else if url.starts_with("mysql://") {
            Ok(DatabaseEngine::MySQL)
        } else if url.starts_with("mariadb://") {
            Ok(DatabaseEngine::MariaDB)
        } else if url.starts_with("sqlite://") {
            Ok(DatabaseEngine::SQLite)
        } else {
            Err(format!("Unsupported database URL: {}", url))
        }
    }

    /// Returns the human-readable name of the database.
    ///
    /// # Examples
    ///
    /// ```
    /// use runique::prelude::DatabaseEngine;
    ///
    /// assert_eq!(DatabaseEngine::PostgreSQL.name(), "PostgreSQL");
    /// assert_eq!(DatabaseEngine::SQLite.name(), "SQLite");
    /// ```
    pub fn name(&self) -> &'static str {
        match self {
            DatabaseEngine::PostgreSQL => "PostgreSQL",
            DatabaseEngine::MySQL => "MySQL",
            DatabaseEngine::MariaDB => "MariaDB",
            DatabaseEngine::SQLite => "SQLite",
        }
    }
}

/// Verifies that the database driver is available.
///
/// # Errors
///
/// Returns a helpful error message if the corresponding Cargo feature is not enabled.
pub(super) fn verify_database_driver(engine: &DatabaseEngine) -> Result<(), String> {
    match engine {
        #[cfg(not(feature = "postgres"))]
        DatabaseEngine::PostgreSQL => Err(driver_not_enabled(engine, "postgres")),
        #[cfg(not(feature = "mysql"))]
        DatabaseEngine::MySQL => Err(driver_not_enabled(engine, "mysql")),
        // MariaDB goes through the MySQL driver: `all-databases` enables `mysql`, not `mariadb`.
        #[cfg(not(feature = "mysql"))]
        DatabaseEngine::MariaDB => Err(driver_not_enabled(engine, "mariadb")),
        #[cfg(not(feature = "sqlite"))]
        DatabaseEngine::SQLite => Err(driver_not_enabled(engine, "sqlite")),
        #[allow(unreachable_patterns)]
        _ => Ok(()),
    }
}

/// Both fixes: the dependency line for an app, `cargo install` for the CLI binary.
#[cfg(not(all(feature = "postgres", feature = "mysql", feature = "sqlite")))]
fn driver_not_enabled(engine: &DatabaseEngine, feature: &str) -> String {
    crate::utils::trad::tf(
        "build.driver_not_enabled",
        &[
            engine.name(),
            feature,
            env!("CARGO_PKG_VERSION"),
            feature,
            feature,
        ],
    )
}

#[cfg(test)]
mod tests {
    // Each test is compiled only for some features: the import lives in them.

    #[cfg(not(feature = "postgres"))]
    #[test]
    fn a_missing_driver_names_the_real_version_and_both_fixes() {
        use super::*;
        let msg = verify_database_driver(&DatabaseEngine::PostgreSQL).unwrap_err();
        assert!(msg.contains(env!("CARGO_PKG_VERSION")), "{msg}");
        assert!(msg.contains(r#"features = ["postgres"]"#), "{msg}");
        assert!(
            msg.contains("cargo install runique --features postgres --locked --force"),
            "{msg}"
        );
    }

    #[cfg(feature = "sqlite")]
    #[test]
    fn a_compiled_driver_passes() {
        use super::*;
        assert!(verify_database_driver(&DatabaseEngine::SQLite).is_ok());
    }
}