use tun::Error;

// Here we will recieve bytes and try to get their destanation & apply Rules for them.
use crate::config::Config;

enum Protocol {
    TCP,
    UDP
}
type Ipv4 = [u8; 4];
type Ipv6 = [u8; 16];
type Port = u16;
enum PacketInfo {
    // <https://www.geeksforgeeks.org/computer-networks/what-is-ipv4/>
    V4 {
        src_ip: Ipv4,
        src_port: Port,
        dst_ip: Ipv4,
        dst_port: Port,
        protocol: Protocol
    },
    // <https://www.geeksforgeeks.org/computer-networks/internet-protocol-version-6-ipv6-header/>
    V6 {
        src_ip: Ipv6,
        src_port: Port,
        dst_ip: Ipv6,
        dst_port: Port,
        protocol: Protocol
    }
}
pub fn sniff_raw_packets(packet: &[u8]) -> Result<PacketInfo, Box<dyn std::error::Error + Send + Sync + 'static>> {
    let ver = packet[0] >> 4;
    match ver {
        4 => {
            PacketInfo::V4{
                src_ip: packet[12..16],
                src_port: u16::from_be_bytes([packet[20], packet[21]]),
                dst_ip: packet[16..20],
                dst_port: u16::from_be_bytes([packet[22], packet[23]]),
                protocol: match packet[9] {
                    6 => Protocol::TCP,
                    4 => Protocol::UDP,
                    _ => return Err(format!("unsuppiorted protocol: {p}").into())
                }
            }
        },
        6 => {
            PacketInfo::V6{
                src_ip: packet[8..24],
                src_port: u16::from_be_bytes([packet[40], packet[41]]),
                dst_ip: packet[24..40],
                dst_port: u16::from_be_bytes([packet[42], packet[43]]),
                protocol: match packet[6] {
                    6 => Protocol::TCP,
                    4 => Protocol::UDP,
                    _ => return Err(format!("unsuppiorted protocol: {p}").into())
                }
            }
        },
        ver => {
            panic!("unexpected packet ver: {ver}");
            Error
        }
    }
}

pub fn apply_rules(config: Config, pinfo: PacketInfo) {
    todo!()
}