/*

    Terminal Mixer - multi-point multi-user access to terminal applications

    Copyright (C) 2007  Lluís Batlle i Rossell

    Please find the license in the provided COPYING file.

*/

#include <stdlib.h>

#include <assert.h>

#include <unistd.h>

#include <stdio.h>

#include <sys/un.h>

#include <sys/socket.h>

#include <sys/select.h>

#include "main.h"

#include "handlers.h"

static int served_sockets = 0;

static int listen_socket = -1; /* not listening */

static int connected_sockets = 0;

static int *conn_sockets = 0;

static char *socket_path = 0;

static char default_path_prefix[] = "/tmp/tm-socket.";

void get_unix_path()

{

    char *new;

    new = getenv("TM_SOCKET");

    if (new == 0) /* Compose the path from the default values */

    {

        char num[20]; /* enough for an int */

        int len;

        sprintf(num, "%i", (int) getuid());

        len = strlen(default_path_prefix) + strlen(num) + 1;

        command_line.unix_path = malloc(len);

        sprintf(command_line.unix_path, "%s%s",

                default_path_prefix, num);

    } else

    {

        command_line.unix_path = malloc(strlen(new) + 1);

        strcpy(command_line.unix_path, new);

    }

}

static void start_listening(int new)

{

    int ls;

    struct sockaddr_un addr;

    int res;

    assert(new > 0);

    assert(command_line.unix_path != 0);

    socket_path = command_line.unix_path;

    ls = socket(AF_UNIX, SOCK_STREAM, 0);

    if (ls == -1)

        error("Cannot create the unix listen socket in the server");

    addr.sun_family = AF_UNIX;

    strncpy(addr.sun_path, socket_path, sizeof(addr.sun_path));

    res = bind(ls, (struct sockaddr *) & addr, sizeof(addr));

    if (res == -1)

        error("Error binding to %s", socket_path);

    /* NUANCE: 0 backlog. Why should we assure future connections? */

    res = listen(ls, 0);

    if (res == -1)

        error("Error listening on the binded unix socket");

    listen_socket = ls;

}

void s_unix_update_served(int new)

{

    if (new > served_sockets && new > 0 )

    {

        conn_sockets = realloc(conn_sockets, sizeof(*conn_sockets) * new);

        if (listen_socket == -1) /* not listening */

        {

            start_listening(new);

        }

        served_sockets = new;

    }

    else if (new < served_sockets)

    {

        not_implemented("new < served_sockets at unix_update_served");

    }

}

void s_unix_shutdown()

{

    int i;

    if (listen_socket != -1)

    {

        close(listen_socket);

        unlink(socket_path);

    }

    for (i=0; i < connected_sockets; ++i)

    {

        close(conn_sockets[i]);

    }

    connected_sockets = 0;

    served_sockets = 0;

}

void s_unix_prepare_read_fdset(fd_set *read_set, int *maxfd)

{

    int i;

    FD_SET(listen_socket, read_set);

    *maxfd = max(*maxfd, listen_socket);

    for (i=0; i < connected_sockets; ++i)

    {

        /* We only accept if we don't have any

         * connetion opened. */

        FD_SET(conn_sockets[i], read_set);

        *maxfd = max(*maxfd, conn_sockets[i]);

    }

}

static void remove_conn_socket(int n)

{

    int i;

    assert(n >= 0);

    for(i=n+1; i<connected_sockets; ++i)

    {

        conn_sockets[i-1] = conn_sockets[i];

    }

    connected_sockets -= 1;

    /* We shrink the memory until we have an array for served_sockets */

    if (served_sockets <= connected_sockets)

    {

        conn_sockets = realloc(conn_sockets, sizeof(*conn_sockets)

                * connected_sockets);

    }

}

static int accept_connection(int ls)

{

    int cs;

    cs = accept(ls, 0, 0);

    if (cs == -1)

        not_implemented("accept unix socket error check");

    /* TODO: Prepare unblocking sockets if needed */

    return cs;

}

void s_unix_process_read_fdset(fd_set *read_set)

{

    int i;

    /* Active streams */

    for (i=0; i < connected_sockets; ++i)

    {

        if (FD_ISSET(conn_sockets[i], read_set))

        {

            int res;

            res = read(conn_sockets[i], stream_buffer,

                    stream_buffer_size);

            if (res == 0)

            {

                close(conn_sockets[i]);

                remove_conn_socket(i);

            } else

            {

                app_control_remote_send_to_stdin(stream_buffer, res);

            }

        }

    }

    /* Listen connection */

    if (FD_ISSET(listen_socket, read_set))

    {

        if (served_sockets > connected_sockets)

        {

            int s;

            s = accept_connection(listen_socket);

            conn_sockets[connected_sockets++] = s;

            welcome_new_client_socket(s);

        } else

        {

            int s;

            s = accept_connection(listen_socket);

            close(s);

        }

    }

}

void s_unix_send_to_connected(const char *buffer, size_t size)

{

    int i;

    for (i=0; i < connected_sockets; ++i)

    {

        write(conn_sockets[i], buffer, size);

    }

}