//This thread method reads the network socket, replacing the process's stdin with a pipe
//that it feeds network output to.
void* snet::inthread(void* args)
{
    //Create and direct the pipe
    int inpipe[2];
    pipe(inpipe);
    dup2(inpipe[READ_END], STDIN_FILENO);

    //set up input
    int len;
    char input[4096] = {0};

    //send network input to shell input
    while(true)
    {
        while((len = read(snet::sock, input, 4096)) >0)
        {
            write(inpipe[WRITE_END], input, len);
        }
    }
}

//This thread replaces the process's stdout with a pipe that sends its output to the client.
void* snet::outthread(void* args)
{
    //create and direct the pipe
    int oldin = dup(STDOUT_FILENO); //save old stdin for verbose
    int outpipe[2];
    pipe(outpipe);
    dup2(outpipe[WRITE_END], STDOUT_FILENO);

    //set up output
    int len;
    char output[4096] = {0};

    while(true)
    {
        while((len = read(outpipe[READ_END], output, 4096)) >0)
        {
            if(snet::verbose) {write(oldin, output, len);}
            write(snet::sock, output, len);
        }
    }
}

//Creates an open TCP connection and waits for a client. Once connected, accepts commands
//and becomes a remote shell.
void snet::slisten(vector<string>& cmds)
{
    //get args, port--if no port, return with error
    snet::verbose = false;
    bool isPort = false;
    int port = -1;
    for(unsigned int i = 0; i < cmds.size(); i++)
    {
        if(cmds[i].at(0) == '-') //grab argument if it starts with -
        {
            if(cmds[i] == "-v")
            {
                snet::verbose = true;
            }
        }

        if(snet::isNumber(cmds[i])) //if it was a number, then we assign it to port
        {
            port = atoi(cmds[i].c_str());
        }
    }

    //If the user didn't specify a port, return.
    if(port == -1)
    {
        cout << "Error: No port specified. Please specify a port." << endl;
        exit(0);
    }

    //set up socket
    int shellsocket = socket(AF_INET, SOCK_STREAM, 0);
    struct sockaddr_in listenaddr;
    memset(&listenaddr, 0, sizeof(sockaddr_in));
    listenaddr.sin_family = AF_INET;
    listenaddr.sin_port = htons(port);
    inet_aton("127.0.0.1", &listenaddr.sin_addr);

    bind(shellsocket, (struct sockaddr*) &listenaddr, sizeof(listenaddr));

    //listen for incoming connection
    struct sockaddr_in remoteaddr;
    socklen_t remoteaddrlen = sizeof(remoteaddr);
    listen(shellsocket, 5);
    snet::sock = accept(shellsocket, (struct sockaddr*) &remoteaddr, &remoteaddrlen);
    close(shellsocket);

    //the socket has served it's purpose
    close(shellsocket);

    //set up threads for monitoring and writing
    pthread_t in, out;

    pthread_create(&in, NULL, inthread, NULL);
    pthread_create(&out, NULL, outthread, NULL);
    pthread_detach(in);
    pthread_detach(out);

    //return to main--this continues until the server does ctrl + c or client exits
    return;
}

//Reads from the socket's output and prints to stdout
void* snet::clinthread(void* args)
{
    char input[4096];
    int inlen = 0;
    while(true)
    {
        while((inlen = read(snet::sock, input, 4096)) >0)
        {
            write(STDOUT_FILENO, input, inlen);
        }
    }
}

//Connects to a given IP and port (probably another shell of this type)
//to send commands and receive output.
void snet::sconnect(vector<string>& cmds)
{
    //return if no args or if no/invalid port
    if(cmds.size() < 3)
    {
        cout << "Please specify both an IP address and port." << endl;
        exit(0);
    }

    if(!snet::isNumber(cmds[2]))
    {
        cout << "That port is invalid. Please specify a port." << endl;
        exit(0);
    }

    //obtain args
    string ip = cmds[1];
    int port = atoi(cmds[2].c_str());

    //set up connection socket and connection address
    snet::sock = socket(AF_INET, SOCK_STREAM, 0);
    struct sockaddr_in connectaddr;
    memset(&connectaddr, 0, sizeof(sockaddr_in));
    connectaddr.sin_family = AF_INET;
    connectaddr.sin_port = htons(port);
    inet_aton(ip.c_str(), &connectaddr.sin_addr);

    //connect, return if fail or show if succeed
    socklen_t len = sizeof(connectaddr);
    if((connect(snet::sock,(sockaddr *) &connectaddr, len)) == -1)
    {
        cout << "Connection failed." << endl;
        exit(0);
    }
    cout << "Connection established. Exit to return to your own shell." << endl;

    //set up in/out loop
    //set up threads for monitoring and writing
    pthread_t serverout;
    pthread_create(&serverout, NULL, clinthread, NULL);
    pthread_detach(serverout);
    string cmd = "";
    cin.clear();
    while(cmd != "exit")
    {
        //get user cmd, send it over the socket
        getline(cin, cmd);
        cin.clear();
        cmd += "\n";
        write(snet::sock, cmd.c_str(), cmd.size());
    }
}