/*
 *  R : A Computer Language for Statistical Data Analysis

 *  Copyright (C) 1998-2017   The R Core Team
 *  Copyright (C) 1996, 1997  Robert Gentleman and Ross Ihaka
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, a copy is available at
 *  https://www.R-project.org/Licenses/
 */

/* <UTF8> chars are handled as a whole */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

extern void R_ProcessEvents(void);
#ifdef Win32
#define R_SelectEx(n,rfd,wrd,efd,tv,ih) select(n,rfd,wrd,efd,tv)
#endif

#ifdef HAVE_STRINGS_H
   /* may be needed to define bzero in FD_ZERO (eg AIX) */
  #include <strings.h>
#endif

#include <stdlib.h> /* for NULL */
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
/* #include <errno.h>*/
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "sock.h"

#include <R_ext/Print.h> // for REprintf
#include <Rmath.h> /* for ceil */

static int sock_inited = 0;

static struct Sock_error_t perr;

static int enter_sock(int fd)
{
#ifdef DEBUG
    printf("enter_sock(%d)\n", fd);
#endif
    if (fd == -1) return 0; else return fd;
}

static int close_sock(int fd)
{
    perr.error = 0;
    int res = Sock_close(fd, &perr);
    if (res == -1) {
	REprintf("socket error: %s\n", strerror(perr.error));
	return -1;
    }
    return 0;
}

static void check_init(void)
{
    if (! sock_inited) {
#ifdef DEBUG
	printf("initing\n");
#endif
	Sock_init();
	sock_inited = 1;
    }
}

void in_Rsockopen(int *port)
{
    check_init();
    perr.error = 0;
    *port = enter_sock(Sock_open((Sock_port_t)*port, &perr));
    if(perr.error) REprintf("socket error: %s\n", strerror(perr.error));
}

void in_Rsocklisten(int *sockp, char **buf, int *len)
{
    check_init();
    perr.error = 0;
    *sockp = enter_sock(Sock_listen(*sockp, *buf , *len, &perr));
    if(perr.error) REprintf("socket error: %s\n", strerror(perr.error));
}

void in_Rsockconnect(int *port, char **host)
{
    check_init();
#ifdef DEBUG
    printf("connect to %d at %s\n",*port, *host);
#endif
    perr.error = perr.h_error = 0;
    *port = enter_sock(Sock_connect((Sock_port_t)*port, *host, &perr));
//    if(perr.h_error) REprintf("host lookup error: %s\n", hstrerror(perr.h_error));
    if(perr.error)
	REprintf("socket error: %s\n", strerror(perr.error));
}

void in_Rsockclose(int *sockp)
{
    *sockp = close_sock(*sockp);
}

void in_Rsockread(int *sockp, char **buf, int *maxlen)
{
    check_init();
#ifdef DEBUG
    printf("Reading from %d\n",*sockp);
#endif
    perr.error = 0;
    *maxlen = (int) Sock_read(*sockp, *buf, *maxlen, &perr);
    if(perr.error) REprintf("socket error: %s\n", strerror(perr.error));
}

void in_Rsockwrite(int *sockp, char **buf, int *start, int *end, int *len)
{
    ssize_t n;
    if (*end > *len)
	*end = *len;
    if (*start < 0)
	*start = 0;
    if (*end < *start) {
	*len = -1;
	return;
    }
    check_init();
#ifdef DEBUG
    printf("writing %s to %d", *buf, *sockp);
#endif
    perr.error = 0;
    n = Sock_write(*sockp, *buf + *start, *end - *start, &perr);
    *len = (int) n;
    if(perr.error) REprintf("socket error: %s\n", strerror(perr.error));
}

/* --------- for use in socket connections ---------- */

#include <R_ext/R-ftp-http.h>

#ifdef Win32
#define FD_SETSIZE 1024
#include <winsock2.h>
#include <io.h>
#define EWOULDBLOCK             WSAEWOULDBLOCK
#define EINPROGRESS             WSAEINPROGRESS
#else
# include <netdb.h>
# include <sys/socket.h>
# include <netinet/in.h>
#endif

#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif


#ifndef Win32
#define closesocket(s) close(s)
#define SOCKET int
#endif

static int socket_errno(void)
{
#ifdef Win32
    return(WSAGetLastError());
#else
    return(errno);
#endif
}


#ifdef Unix
#include <R_ext/eventloop.h>

/* modified from src/unix/sys-std.c  */
static int
setSelectMask(InputHandler *handlers, fd_set *readMask)
{
    int maxfd = -1;
    InputHandler *tmp = handlers;
    FD_ZERO(readMask);

    while(tmp) {
	if(tmp->fileDescriptor > 0) {
	    FD_SET(tmp->fileDescriptor, readMask);
	    maxfd = maxfd < tmp->fileDescriptor ? tmp->fileDescriptor : maxfd;
	}
	tmp = tmp->next;
    }

    return(maxfd);
}
#endif

static int R_SocketWait(int sockfd, int write, int timeout)
{
    fd_set rfd, wfd;
    struct timeval tv;
    double used = 0.0;

    while(1) {
	int maxfd = 0, howmany;
	R_ProcessEvents();
#ifdef Unix
	if(R_wait_usec > 0) {
	    tv.tv_sec = 0;
	    tv.tv_usec = R_wait_usec;
	} else {
	    tv.tv_sec = timeout;
	    tv.tv_usec = 0;
	}
#elif defined(Win32)
	tv.tv_sec = 0;
	tv.tv_usec = 2e5;
#else
	tv.tv_sec = timeout;
	tv.tv_usec = 0;
#endif


#ifdef Unix
	maxfd = setSelectMask(R_InputHandlers, &rfd);
#else
	FD_ZERO(&rfd);
#endif
	FD_ZERO(&wfd);
	if(write) FD_SET(sockfd, &wfd); else FD_SET(sockfd, &rfd);
	if(maxfd < sockfd) maxfd = sockfd;

	/* increment used value _before_ the select in case select
	   modifies tv (as Linux does) */
	used += tv.tv_sec + 1e-6 * tv.tv_usec;

	howmany = R_SelectEx(maxfd+1, &rfd, &wfd, NULL, &tv, NULL);

	if (howmany < 0) {
	    return -socket_errno();
	}
	if (howmany == 0) {
	    if(used >= timeout) return 1;
	    continue;
	}

#ifdef Unix
	if((!write && !FD_ISSET(sockfd, &rfd)) ||
	   (write && !FD_ISSET(sockfd, &wfd)) || howmany > 1) {
	    /* was one of the extras */
	    InputHandler *what;
	    what = getSelectedHandler(R_InputHandlers, &rfd);
	    if(what != NULL) what->handler((void*) NULL);
	    continue;
	}
#endif
	/* the socket was ready */
	break;
    }
    return 0;
}

/**** FIXME: merge with R_SocketWait */
/**** FIXME: add timeout argument instead of using global?? */
int R_SocketWaitMultiple(int nsock, int *insockfd, int *ready, int *write,
			 double mytimeout)
{
    fd_set rfd, wfd;
    struct timeval tv;
    double used = 0.0;
    int nready = 0;

    while(1) {
	int maxfd = 0, howmany, i;
	R_ProcessEvents();
#ifdef Unix
	if(R_wait_usec > 0) {
	    int delta;
	    if (mytimeout < 0 || R_wait_usec / 1e-6 < mytimeout - used)
		delta = R_wait_usec;
	    else
		delta = (int)ceil(1e6 * (mytimeout - used));
	    tv.tv_sec = 0;
	    tv.tv_usec = delta;
	} else if (mytimeout >= 0) {
	    tv.tv_sec = (int)(mytimeout - used);
	    tv.tv_usec = (int)ceil(1e6 * (mytimeout - used - tv.tv_sec));
	} else {  /* always poll occationally--not really necessary */
	    tv.tv_sec = 60;
	    tv.tv_usec = 0;
	}
#elif defined(Win32)
	tv.tv_sec = 0;
	tv.tv_usec = 2e5;
#else
	if (mytimeout >= 0) {
	    tv.tv_sec = mytimeout - used;
	    tv.tv_usec = ceil(1e6 * (mytimeout - used - tv.tv_sec));
	} else {  /* always poll occasionally--not really necessary */
	    tv.tv_sec = timeout;
	    tv.tv_usec = 0;
	}
#endif


#ifdef Unix
	maxfd = setSelectMask(R_InputHandlers, &rfd);
#else
	FD_ZERO(&rfd);
#endif
	FD_ZERO(&wfd);
	for (i = 0; i < nsock; i++) {
	    if(write[i]) FD_SET(insockfd[i], &wfd);
	    else FD_SET(insockfd[i], &rfd);
	    if(maxfd < insockfd[i]) maxfd = insockfd[i];
	}

	/* increment used value _before_ the select in case select
	   modifies tv (as Linux does) */
	used += tv.tv_sec + 1e-6 * tv.tv_usec;

	howmany = R_SelectEx(maxfd+1, &rfd, &wfd, NULL, &tv, NULL);

	if (howmany < 0) {
	    return -socket_errno();
	}
	if (howmany == 0) {
	    if(mytimeout >= 0 && used >= mytimeout) {
		for (i = 0; i < nsock; i++)
		    ready[i] = 0; /* FALSE */
		return 0;
	    }
	    continue;
	}

	for (i = 0; i < nsock; i++)
	    if ((!write[i] && FD_ISSET(insockfd[i], &rfd)) ||
		(write[i] && FD_ISSET(insockfd[i], &wfd))) {
		ready[i] = 1; /* TRUE */
		nready++;
	    }
	    else ready[i] = 0; /* FALSE */

#ifdef Unix
	if(howmany > nready) {
	    /* one of the extras is ready */
	    InputHandler *what;
	    what = getSelectedHandler(R_InputHandlers, &rfd);
	    if(what != NULL) what->handler((void*) NULL);
	    continue;
	}
#endif
	/* some sockets are ready */
	break;
    }
    return nready;
}

int in_Rsockselect(int nsock, int *insockfd, int *ready, int *write,
		   double timeout)
{
    return R_SocketWaitMultiple(nsock, insockfd, ready, write, timeout);
}

int R_SockConnect(int port, char *host, int timeout)
{
    SOCKET s;
    fd_set wfd, rfd;
    struct timeval tv;
    int status = 0;
    double used = 0.0;
    struct sockaddr_in server;
    struct hostent *hp;

    check_init();
    s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (s == -1)  return -1;

#define CLOSE_N_RETURN(_ST_) { closesocket(s); return(_ST_); }

#ifdef Win32
    {
	u_long one = 1;
	status = ioctlsocket(s, FIONBIO, &one) == SOCKET_ERROR ? -1 : 0;
    }
#else
# ifdef HAVE_FCNTL
    if ((status = fcntl(s, F_GETFL, 0)) != -1) {
#  ifdef O_NONBLOCK
	status |= O_NONBLOCK;
#  else /* O_NONBLOCK */
#   ifdef F_NDELAY
	status |= F_NDELAY;
#   endif
#  endif /* !O_NONBLOCK */
	status = fcntl(s, F_SETFL, status);
    }
# endif // HAVE_FCNTL
    if (status < 0) {
	CLOSE_N_RETURN(-1);
    }
#endif

    if (! (hp = gethostbyname(host))) CLOSE_N_RETURN(-1);

    memcpy((char *)&server.sin_addr, hp->h_addr_list[0], hp->h_length);
    server.sin_port = htons((short)port);
    server.sin_family = AF_INET;

    if ((connect(s, (struct sockaddr *) &server, sizeof(server)) == -1)) {

	switch (socket_errno()) {
	case EINPROGRESS:
	case EWOULDBLOCK:
	    break;
	default:
	    CLOSE_N_RETURN(-1);
	}
    }

    while(1) {
	int maxfd = 0;
	R_ProcessEvents();
#ifdef Unix
	if(R_wait_usec > 0) {
	    R_PolledEvents();
	    tv.tv_sec = 0;
	    tv.tv_usec = R_wait_usec;
	} else {
	    tv.tv_sec = timeout;
	    tv.tv_usec = 0;
	}
#elif defined(Win32)
	tv.tv_sec = 0;
	tv.tv_usec = 2e5;
#else
	tv.tv_sec = timeout;
	tv.tv_usec = 0;
#endif


#ifdef Unix
	maxfd = setSelectMask(R_InputHandlers, &rfd);
#else
	FD_ZERO(&rfd);
#endif
	FD_ZERO(&wfd);
	FD_SET(s, &wfd);
	if(maxfd < s) maxfd = s;

	switch(R_SelectEx(maxfd+1, &rfd, &wfd, NULL, &tv, NULL))
	{
	case 0:
	    /* Time out */
	    used += tv.tv_sec + 1e-6 * tv.tv_usec;
	    if(used < timeout) continue;
	    CLOSE_N_RETURN(-1);
	case -1:
	    /* Ermm.. ?? */
	    CLOSE_N_RETURN(-1);
	}

	if ( FD_ISSET(s, &wfd) ) {
	    R_SOCKLEN_T len;
	    len = sizeof(status);
	    if (getsockopt(s, SOL_SOCKET, SO_ERROR, (char*)&status, &len) < 0){
		/* Solaris error code */
		return (-1);
	    }
	    if ( status ) {
		errno = status;
		CLOSE_N_RETURN(-1);
	    } else return(s);
#ifdef Unix
	} else { /* some other handler needed */
	    InputHandler *what;
	    what = getSelectedHandler(R_InputHandlers, &rfd);
	    if(what != NULL) what->handler((void*) NULL);
	    continue;
#endif
	}
    }
    /* not reached
    return(-1); */
}

int R_SockClose(int sockp)
{
    return closesocket(sockp);
}

ssize_t R_SockRead(int sockp, void *buf, size_t len, int blocking, int timeout)
{
    ssize_t res;

    if(blocking && (res = R_SocketWait(sockp, 0, timeout)) != 0)
        return res < 0 ? res : 0; /* socket error or timeout */
    res = recv(sockp, buf, len, 0);
    return (res >= 0) ? res : -socket_errno();
}

int R_SockOpen(int port)
{
    check_init();
    return Sock_open((Sock_port_t)port, NULL);
}

int R_SockListen(int sockp, char *buf, int len, int timeout)
{
    check_init();
    /* inserting a wait here will eliminate most blocking, but there
       are scenarios under which the Sock_listen call might block
       after the wait has completed. LT */
    int res = 0;
    do {
        res = R_SocketWait(sockp, 0, timeout);
    } while (res < 0 && -res == EINTR);
    if(res != 0)
        return -1;              /* socket error or timeout */
    return Sock_listen(sockp, buf, len, NULL);
}

ssize_t R_SockWrite(int sockp, const void *buf, size_t len, int timeout)
{
    ssize_t res, out = 0;

    /* Rprintf("socket %d writing |%s|\n", sockp, buf); */
    /* This function is not passed a `blocking' argument so the code
       here is equivalent to blocking == TRUE; it's not clear
       non-blocking writes make much sense with the current connection
       interface since there is no way to tell how much, if anything,
       has been written.  LT */
    do {
	if((res = R_SocketWait(sockp, 1, timeout)) != 0)
	    return res < 0 ? res : 0; /* socket error or timeout */
	res = send(sockp, buf, len, 0);
	if (res < 0 && socket_errno() != EWOULDBLOCK)
	    return -socket_errno();
	else {
	    { const char *cbuf = buf; cbuf += res; buf = cbuf; }
	    len -= res;
	    out += res;
	}
    } while (/* ! blocking && */len > 0);
    return out;
}