use std::sync::LazyLock;

pub struct Settings {
    /// Base directory for config and cache files.
    /// Controlled by `MDRS_CLIENT_CONFIG_DIRNAME` env var (default: `~/.mdrs-client`).
    pub config_dirname: std::path::PathBuf,
    /// Maximum number of concurrent MDRS API requests used by upload/download.
    /// Controlled by `MDRS_CLIENT_CONCURRENT` env var (default: 10).
    pub concurrent: usize,
}

impl Settings {
    fn load() -> Self {
        let config_dirname = std::env::var("MDRS_CLIENT_CONFIG_DIRNAME")
            .ok()
            .map(|s| {
                if s.starts_with("~/") {
                    dirs::home_dir()
                        .unwrap_or_else(|| std::path::PathBuf::from("."))
                        .join(&s[2..])
                } else {
                    std::path::PathBuf::from(&s)
                }
            })
            .unwrap_or_else(|| {
                dirs::home_dir()
                    .unwrap_or_else(|| std::path::PathBuf::from("."))
                    .join(".mdrs-client")
            });

        let concurrent = std::env::var("MDRS_CLIENT_CONCURRENT")
            .ok()
            .and_then(|s| s.parse::<usize>().ok())
            .unwrap_or(10);

        Settings {
            config_dirname,
            concurrent,
        }
    }
}

pub static SETTINGS: LazyLock<Settings> = LazyLock::new(Settings::load);