mod config;
mod error;

use std::env::args;
use std::net::UdpSocket;

use crate::config::{Config, Mac};
use crate::error::EResult;

fn main() -> EResult<()> {
    let config = Config::create()?;

    let arg_1 = args().nth(1);
    let Some(arg_1) = arg_1 else {
        print_usage();
        return Ok(());
    };

    let mac = config.get_mac(&arg_1)?;
    let mut magic_bytes = [0u8; 102];
    get_magic_pkt(&mac, &mut magic_bytes);

    let socket = UdpSocket::bind("0.0.0.0:0").expect("couldnt' bind socket");
    socket.set_broadcast(true).expect("couldn't set broadcast");
    socket
        .send_to(&magic_bytes, "255.255.255.255:9")
        .expect("couldn't send data");
    println!("Magic packet sent to 255.255.255.255:9 for Mac {:}", mac);
    Ok(())
}

fn get_magic_pkt(mac: &Mac, magic_bytes: &mut [u8; 102]) {
    magic_bytes[..6].fill(0xFF);
    for i in 0..16 {
        let start = 6 + i * 6;
        magic_bytes[start..start + 6].copy_from_slice(&mac.mac_bytes);
    }
}

fn print_usage() {
    println!(
        "{}",
        r#"usage: woly ARG

Options:
    ARG     Either the mac address of the device to send the wol magic
            packet to, or a nickname specified in woly.conf to lookup
            the mac.
            Eg: woly aa:bb:cc:dd:ee:ff
            Eg: woly potato
                where potato is configured in the woly.conf file as
                potato=aa:bb:cc:dd:ee:ff

Config file:
    Filename   woly.conf
    Location   $WOLY_CONFIG_DIR/woly.conf, then $XDG_CONFIG_DIR/woly.conf,
               then $HOME/woly.conf
    Format     one KEY=VALUE per line without spaces
    Example    potato=aa:bb:cc:dd:ee:ff
               idly=12:34:23:e2:3d:ff
"#
    );
}

#[cfg(test)]
mod tests {
    use crate::{config::Mac, get_magic_pkt};

    #[test]
    fn test_magic_bytes_for_mac() {
        let mut magic_bytes = [0u8; 102];
        let mac = Mac::create("32:1a:ff:3e:10:ef").expect("Test data is curated to be valid");
        get_magic_pkt(&mac, &mut magic_bytes);

        #[rustfmt::skip]
        let expected = [
            255, 255, 255, 255, 255, 255,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
             50,  26, 255,  62,  16, 239,
        ];

        assert_eq!(
            magic_bytes, expected,
            "Magic bytes are not created correctly"
        );
    }
}