//use crossbeam_channel::unbounded;
use socket2::SockAddr;
use tokio::{net::UdpSocket, sync::{Mutex, mpsc}, io::{BufReader, BufWriter, AsyncWriteExt, AsyncReadExt}, fs::File};
use tokio_util::sync::CancellationToken;
use base64::prelude::*;
use log::{error, info, warn};
use std::sync::Arc;
use std::net::Ipv4Addr;
use x25519_dalek::{PublicKey, StaticSecret};
use std::{
    io::{self, Read, Write},
    net::SocketAddr,
    process::Command,
    os::unix::io::FromRawFd,
};
use aes_gcm::{
    aead::{Aead, AeadCore, KeyInit, OsRng},
    Aes256Gcm, Nonce};

use crate::config::ClientConfiguration;
use crate::udp::{UDPVpnPacket, UDPVpnHandshake, UDPSerializable};
use network_interface::NetworkInterface;
use network_interface::NetworkInterfaceConfig;
use robusta_jni::jni::JNIEnv;
use crate::jni::FridaLib;

pub async fn client_mode(client_config: ClientConfiguration, fd: i32, close_token: CancellationToken) {
    info!("Starting client...");

    let sock = UdpSocket::bind("0.0.0.0:25565").await.unwrap();
    sock.connect(&client_config.server.endpoint).await.unwrap();
   
    info!("FD: {:?}", &fd);
    let mut dev = unsafe { File::from_raw_fd(fd) };
    let mut dev1 = unsafe { File::from_raw_fd(fd) };
    let mut dev_reader = BufReader::new(dev);
    let mut dev_writer = BufWriter::new(dev1);

    let sock_rec = Arc::new(sock);
    let sock_snd = sock_rec.clone();

    let (tx, mut rx) = mpsc::unbounded_channel::<Vec<u8>>();
    let (dx, mut mx) = mpsc::unbounded_channel::<Vec<u8>>();

    let cipher_shared: Arc<Mutex<Option<x25519_dalek::SharedSecret>>> = Arc::new(Mutex::new(None));

    let cancel_dr = close_token.clone();
    let dev_read_task = tokio::spawn(async move {
        let mut buf = vec![0; 1400]; // mtu
        loop {
            tokio::select! {
                _ = cancel_dr.cancelled() => {
                    info!("Cancellation token has been thrown dev_read_task");
                    return;
                }
                rr = dev_reader.read(&mut buf) => {
                    if let Ok(n) = rr {
                        info!("Read from tun."); // hex::encode(&buf[..n])
                        dx.send(buf[..n].to_vec()).unwrap();
                    }
                }
            };
        }
    });

    let priv_key = BASE64_STANDARD.decode(client_config.client.private_key).unwrap();
    
    let cipher_shared_clone = cipher_shared.clone();
    let cancel_sr = close_token.clone();
    let sock_read_task = tokio::spawn(async move {
        let mut buf = vec![0; 4096];

        loop {
            tokio::select! {
                _ = cancel_sr.cancelled() => {
                    info!("Cancellation token has been thrown sock_read_task");
                    return;
                }
                rr = sock_rec.recv(&mut buf) => {
                    if let Ok(l) = rr {
                        info!("Read from socket");
                        let mut s_cipher = cipher_shared_clone.lock().await;
                        match buf.first() {
                            Some(h) => {
                                match h {
                                    0 => {
                                        let handshake = UDPVpnHandshake::deserialize(&(buf[..l].to_vec()));
                                        let mut k = [0u8; 32];
                                        for (&x, p) in handshake.public_key.iter().zip(k.iter_mut()) {
                                            *p = x;
                                        }
                                        let mut k1 = [0u8; 32];
                                        for (&x, p) in priv_key.iter().zip(k1.iter_mut()) {
                                            *p = x;
                                        }
                                        *s_cipher = Some(StaticSecret::from(k1)
                                            .diffie_hellman(&PublicKey::from(k)));
                                    }, // handshake
                                    1 => {
                                        let wrapped_packet = UDPVpnPacket::deserialize(&(buf[..l].to_vec()));
                                        if s_cipher.is_some() {
                                            let aes = Aes256Gcm::new(s_cipher.as_ref().unwrap().as_bytes().into());
                                            let nonce = Nonce::clone_from_slice(&wrapped_packet.nonce);
                                            match aes.decrypt(&nonce, &wrapped_packet.data[..]) {
                                                Ok(decrypted) => { let _ = tx.send(decrypted); },
                                                Err(error) => { error!("Decryption error! {:?}", error); }
                                            }
                                        } else {
                                            warn!("There is no static_secret");
                                        }
                                    }, // payload
                                    2 => { info!("Got keepalive packet"); },
                                    _ => { error!("Unexpected header value."); }
                                }
                            },
                            None => { error!("There is no header."); }
                        }
                        drop(s_cipher);
                    }
                }
            };
        }
    });

    let pkey = BASE64_STANDARD.decode(client_config.client.public_key).unwrap();
    let handshake = UDPVpnHandshake{ public_key: pkey, request_ip: client_config.client.address.parse::<Ipv4Addr>().unwrap() };
    let mut nz = 0;
    while nz < 25 {
        sock_snd.send(&handshake.serialize()).await.unwrap();
        nz += 1
    }
    //sock_snd.send(&handshake.serialize()).await.unwrap();

    let s_cipher = cipher_shared.clone();
    loop {
        tokio::select! {
            _ = close_token.cancelled() => {
                info!("Cancellation token has been thrown");
                dev_read_task.join();
                sock_read_task.join();
                return;
            }
            rr = rx.recv() => {
                if let Some(bytes) = rr {
                    info!("Write to tun.");
                    if let Err(e) = dev_writer.write_all(&bytes).await {
                        error!("Writing error: {:?}", e);
                    }
                    if let Err(e) = dev_writer.flush().await {
                        error!("Flushing error: {:?}", e);
                    }
                }
            }
            rr2 = mx.recv() => {
                if let Some(bytes) = rr2 {
                    let s_c = s_cipher.lock().await;
                    
                    if s_c.is_some() {
                        let aes = Aes256Gcm::new(s_c.as_ref().unwrap().as_bytes().into());
                        let nonce = Aes256Gcm::generate_nonce(&mut OsRng);
                        let ciphered_data = aes.encrypt(&nonce, &bytes[..]);
                        
                        if let Ok(ciphered_d) = ciphered_data {
                            let vpn_packet = UDPVpnPacket{ data: ciphered_d, nonce: nonce.to_vec()};
                            let serialized_data = vpn_packet.serialize();
                            info!("Write to socket");
                            sock_snd.send(&serialized_data).await.unwrap();
                        } else {
                            error!("Socket encryption failed.");
                        }
                    } else {
                        error!("There is no shared_secret in main loop");
                    }
                }
            }
        };
    }
}