use std::env;
use std::net::SocketAddr;
use std::str::FromStr;

#[derive(Clone)]
pub struct Config {
    pub auth_secret: String,
    pub db_path: String,
    pub mock_mails: bool,
    pub secure_cookies: bool,
    pub socket_address: SocketAddr,
}

pub fn from_env() -> Result<Config, String> {
    Ok(Config {
        auth_secret: read_string("AUTH_SECRET")?,
        db_path: read_string("DB_PATH")?,
        mock_mails: read_bool("MOCK_MAILS")?,
        secure_cookies: read_bool("SECURE_COOKIES")?,
        socket_address: read_socket_address("SOCKET_ADDRESS")?,
    })
}

fn read_socket_address(key: &str) -> Result<SocketAddr, String> {
    SocketAddr::from_str(&read_string(key)?).map_err(|err| {
        format!("environment variable '{key}' is not a socket address: {err}")
    })
}

fn read_bool(key: &str) -> Result<bool, String> {
    read_string(key).and_then(|v| match v.as_str() {
        "true" => Ok(true),
        "false" => Ok(false),
        _ => Err(format!(
            "environment variable '{key}' is not a boolean: '{v}'"
        )),
    })
}

fn read_string(key: &str) -> Result<String, String> {
    env::var(key).map_err(|_| format!("missing environment variable '{key}'"))
}