use pcap::Capture;
use stable_eyre::eyre::{eyre, Result};

mod ieee80211 {
    use int_enum::IntEnum;
    use std::convert::TryFrom;

    // data/extension frames are irrelevant so just ignore their subtype
    #[derive(Clone, Copy, Debug, Eq, PartialEq)]
    pub enum FrameType {
        Management(ManagementSubtype),
        Control(ControlSubtype),
        Data,
        Extension
    }

    #[repr(u8)]
    #[derive(Clone, Copy, Debug, Eq, PartialEq, IntEnum)]
    pub enum ManagementSubtype {
        ProbeRequest = 0b0100,
        ProbeResponse = 0b0101,
        TimingAdvertisement = 0b0110,
        Beacon = 0b1000
    }

    #[repr(u8)]
    #[derive(Clone, Copy, Debug, Eq, PartialEq, IntEnum)]
    pub enum ControlSubtype {
        Rts = 0b1011,
        Cts = 0b1100,
        Ack = 0b1101
    }

    #[derive(Clone, Copy, Debug, Eq, PartialEq)]
    pub struct FrameControl {
        pub version: u8,
        pub ftype: FrameType
    }

    pub fn parse_frame_control(version_type_subtype: u8, flags: u8) -> Option<FrameControl> {
        let subtype = version_type_subtype >> 4 & 0b1111;
        let ftype = match version_type_subtype >> 2 & 0b11 {
            0b00 => FrameType::Management(ManagementSubtype::try_from(subtype).ok()?),
            0b01 => FrameType::Control(ControlSubtype::try_from(subtype).ok()?),
            0b10 => FrameType::Data,
            0b11 => FrameType::Extension,
            _ => unreachable!()
        };
        Some(FrameControl {
            version: version_type_subtype & 0b11,
            ftype: ftype
        })
    }

    pub struct MacAddress([u8; 12]);
}

fn main() -> Result<()> {
    let cap = Capture::from_device("mon0")?.immediate_mode(true);
    let mut cap = cap.open()?;
    if cap.get_datalink() != pcap::Linktype::IEEE802_11_RADIOTAP { return Err(eyre!("device link type wrong")) }

    while let Ok(packet) = cap.next() {
        //println!("{:?}", packet);
        match radiotap::parse(packet.data) {
            Ok(header) => {
                let data = &packet.data[header.length()..];
                match ieee80211::parse_frame_control(data[0], data[1]) {
                    Some(x) if x.ftype != ieee80211::FrameType::Data => {
                        println!("RTH={:?} FH={:?} MAC1={:?}", header, x, &data[4..10]);
                        if data.len() >= 16 { println!("MAC2={:?}", &data[10..16]); }
                        if data.len() >= 22 { println!("MAC3={:?}", &data[16..22]); }
                    },
                    _ => {}
                }
            },
            // This happens sometimes. I don't know why, since it really shouldn't (the radiotap headers are applied by the kernel). Thusly, just ignore it and hope it goes away.
            Err(e) => {
                eprintln!("header decoding failed: {:?}", e);
            }
        }
    }
    Ok(())
}