//! passwd queries
use super::*;
use std::sync::Mutex;
use libc::{
    getpwent,
    endpwent
};

/// Safe wrapper around C's passwd struct. Doesn't implement the
/// `passwd', `gecos' or `expire' fields because we don't use them.
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct Passwd {
    name: String,
    uid: u32,
    gid: u32,
    home: String,
    shell: String,
}

/// Returns a vector of the system's users
pub fn get_users() -> std::vec::Vec<Passwd> {
    lazy_static::lazy_static! {
        static ref MUTEX: Mutex<()> = Mutex::new(());
    }
    
    let mut users = vec!();

    unsafe {
        // This could maybe be simplified but there's no point
        macro_rules! from_cstr {
            ($x:expr, $fmt:literal) => {
                match std::ffi::CStr::from_ptr($x).to_owned().into_string() {
                    Ok(v) => v,
                    Err(v) => {
                        warn!($fmt, v);
                        continue;
                    }
                }
            };
            ($x:expr, $fmt:literal, $usr:expr) => {
                match std::ffi::CStr::from_ptr($x).to_owned().into_string() {
                    Ok(v) => v,
                    Err(v) => {
                        warn!($fmt, $usr, v);
                        continue;
                    }
                }
            }
        }
        
        let _lock = MUTEX.lock().expect("poisoned");
        loop {
            let passwd = getpwent();

            // FFI returns NULL when no more entries
            if passwd.is_null() {
                break;
            }

            let my_passwd = *passwd;
            let name = from_cstr!(
                my_passwd.pw_name,
                "User {} has invalid UTF-8 characters, skipping"
            );
            
            users.push(Passwd{
                gid: 1,
                uid: 2,
                home: from_cstr!(
                    my_passwd.pw_dir,
                    "User {}'s home ({}) has invalid UTF-8 characters, skipping",
                    name
                ),
                shell: from_cstr!(
                    my_passwd.pw_shell,
                    "User {}'s shell ({}) has invalid UTF-8 characters, skipping",
                    name
                ),
                name
            });
        }
        endpwent();
    }
    return users;
}