//! PostgreSQL connection pool configuration.
//!
//! Reads settings from environment variables with sensible defaults.

use std::env;

/// PostgreSQL connection configuration, sourced from environment variables.
#[derive(Debug, Clone)]
pub struct DatabaseConfig {
    /// PostgreSQL connection URL (e.g. `postgres://user:pass@host/db`).
    pub url: String,
    /// Maximum number of connections in the pool.
    pub max_connections: u32,
    /// Minimum number of idle connections maintained.
    pub min_connections: u32,
    /// Timeout for acquiring a new connection (seconds).
    pub connect_timeout_secs: u64,
    /// Timeout for idle connections before they are closed (seconds).
    pub idle_timeout_secs: u64,
}

impl DatabaseConfig {
    /// Build config by reading environment variables, falling back to defaults.
    pub fn from_env() -> Self {
        Self {
            url: env::var("DATABASE_URL")
                .unwrap_or_else(|_| "postgres://localhost/imks".to_string()),
            max_connections: env::var("DATABASE_MAX_CONNECTIONS")
                .ok()
                .and_then(|v| v.parse().ok())
                .unwrap_or(10),
            min_connections: env::var("DATABASE_MIN_CONNECTIONS")
                .ok()
                .and_then(|v| v.parse().ok())
                .unwrap_or(2),
            connect_timeout_secs: env::var("DATABASE_CONNECT_TIMEOUT")
                .ok()
                .and_then(|v| v.parse().ok())
                .unwrap_or(30),
            idle_timeout_secs: env::var("DATABASE_IDLE_TIMEOUT")
                .ok()
                .and_then(|v| v.parse().ok())
                .unwrap_or(600),
        }
    }
}

impl Default for DatabaseConfig {
    fn default() -> Self {
        Self::from_env()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_default_config_has_sane_values() {
        // Without env vars set, defaults should be applied.
        let cfg = DatabaseConfig {
            url: "postgres://localhost/test".to_string(),
            max_connections: 10,
            min_connections: 2,
            connect_timeout_secs: 30,
            idle_timeout_secs: 600,
        };
        assert_eq!(cfg.max_connections, 10);
        assert_eq!(cfg.min_connections, 2);
    }
}