//! This module provides the functionality to generate random user agent string.

use std::sync::OnceLock;

use fake_useragent::{Browsers, UserAgents, UserAgentsBuilder};

/// A static variable which stores the initially build `UserAgents` struct. So as it can be resused
/// again and again without the need of reinitializing the `UserAgents` struct.
static USER_AGENTS: OnceLock<UserAgents> = OnceLock::new();

/// A function to generate random user agent to improve privacy of the user.
///
/// # Returns
///
/// A randomly generated user agent string.
pub fn random_user_agent() -> &'static str {
    USER_AGENTS
        .get_or_init(|| {
            UserAgentsBuilder::new()
                .cache(false)
                .dir("/tmp")
                .thread(1)
                .set_browsers(
                    Browsers::new()
                        .set_chrome()
                        .set_safari()
                        .set_edge()
                        .set_firefox()
                        .set_mozilla(),
                )
                .build()
        })
        .random()
}