/*
 *  tvheadend, TCP common functions
 *  Copyright (C) 2007 Andreas Öman
 *
 *  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 3 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, see <http://www.gnu.org/licenses/>.
 */

#include <pthread.h>
#include <netdb.h>
#include <sys/epoll.h>
#include <poll.h>
#include <assert.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <fcntl.h>
#include <errno.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>

#include "tcp.h"


/**
 *
 */
int
tcp_connect(const char *hostname, int port, char *errbuf, size_t errbufsize,
	    int timeout)
{
  const char *errtxt;
  struct hostent hostbuf, *hp;
  char *tmphstbuf;
  size_t hstbuflen;
  int herr, fd, r, res, err;
  struct sockaddr_in6 in6;
  struct sockaddr_in in;
  socklen_t errlen = sizeof(int);

  hstbuflen = 1024;
  tmphstbuf = malloc(hstbuflen);

  while((res = gethostbyname_r(hostname, &hostbuf, tmphstbuf, hstbuflen,
			       &hp, &herr)) == ERANGE) {
    hstbuflen *= 2;
    tmphstbuf = realloc(tmphstbuf, hstbuflen);
  }
  
  if(res != 0) {
    snprintf(errbuf, errbufsize, "Resolver internal error");
    free(tmphstbuf);
    return -1;
  } else if(herr != 0) {
    switch(herr) {
    case HOST_NOT_FOUND:
      errtxt = "The specified host is unknown";
      break;
    case NO_ADDRESS:
      errtxt = "The requested name is valid but does not have an IP address";
      break;
      
    case NO_RECOVERY:
      errtxt = "A non-recoverable name server error occurred";
      break;
      
    case TRY_AGAIN:
      errtxt = "A temporary error occurred on an authoritative name server";
      break;
      
    default:
      errtxt = "Unknown error";
      break;
    }

    snprintf(errbuf, errbufsize, "%s", errtxt);
    free(tmphstbuf);
    return -1;
  } else if(hp == NULL) {
    snprintf(errbuf, errbufsize, "Resolver internal error");
    free(tmphstbuf);
    return -1;
  }
  fd = socket(hp->h_addrtype, SOCK_STREAM, 0);
  if(fd == -1) {
    snprintf(errbuf, errbufsize, "Unable to create socket: %s",
	     strerror(errno));
    free(tmphstbuf);
    return -1;
  }

  /**
   * Switch to nonblocking
   */
  fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) | O_NONBLOCK);

  switch(hp->h_addrtype) {
  case AF_INET:
    memset(&in, 0, sizeof(in));
    in.sin_family = AF_INET;
    in.sin_port = htons(port);
    memcpy(&in.sin_addr, hp->h_addr_list[0], sizeof(struct in_addr));
    r = connect(fd, (struct sockaddr *)&in, sizeof(struct sockaddr_in));
    break;

  case AF_INET6:
    memset(&in6, 0, sizeof(in6));
    in6.sin6_family = AF_INET6;
    in6.sin6_port = htons(port);
    memcpy(&in6.sin6_addr, hp->h_addr_list[0], sizeof(struct in6_addr));
    r = connect(fd, (struct sockaddr *)&in, sizeof(struct sockaddr_in6));
    break;

  default:
    snprintf(errbuf, errbufsize, "Invalid protocol family");
    free(tmphstbuf);
    return -1;
  }

  free(tmphstbuf);

  if(r == -1) {
    if(errno == EINPROGRESS) {
      struct pollfd pfd;

      pfd.fd = fd;
      pfd.events = POLLOUT;
      pfd.revents = 0;

      r = poll(&pfd, 1, timeout * 1000);
      if(r == 0) {
	/* Timeout */
	snprintf(errbuf, errbufsize, "Connection attempt timed out");
	close(fd);
	return -1;
      }
      
      if(r == -1) {
	snprintf(errbuf, errbufsize, "poll() error: %s", strerror(errno));
	close(fd);
	return -1;
      }

      getsockopt(fd, SOL_SOCKET, SO_ERROR, (void *)&err, &errlen);
    } else {
      err = errno;
    }
  } else {
    err = 0;
  }

  if(err != 0) {
    snprintf(errbuf, errbufsize, "%s", strerror(err));
    close(fd);
    return -1;
  }
  
  fcntl(fd, F_SETFL, fcntl(fd, F_GETFL) & ~O_NONBLOCK);
  return fd;
}


/**
 *
 */
int
tcp_write_queue(int fd, htsbuf_queue_t *q)
{
  htsbuf_data_t *hd;
  int l, r;

  while((hd = TAILQ_FIRST(&q->hq_q)) != NULL) {
    TAILQ_REMOVE(&q->hq_q, hd, hd_link);

    l = hd->hd_data_len - hd->hd_data_off;
    r = write(fd, hd->hd_data + hd->hd_data_off, l);
    free(hd->hd_data);
    free(hd);
  }
  q->hq_size = 0;
  return 0;
}


/**
 *
 */
static int
tcp_fill_htsbuf_from_fd(int fd, htsbuf_queue_t *hq)
{
  htsbuf_data_t *hd = TAILQ_LAST(&hq->hq_q, htsbuf_data_queue);
  int c;

  if(hd != NULL) {
    /* Fill out any previous buffer */
    c = hd->hd_data_size - hd->hd_data_len;

    if(c > 0) {

      c = read(fd, hd->hd_data + hd->hd_data_len, c);
      if(c < 1)
	return -1;

      hd->hd_data_len += c;
      hq->hq_size += c;
      return 0;
    }
  }
  
  hd = malloc(sizeof(htsbuf_data_t));
  
  hd->hd_data_size = 1000;
  hd->hd_data = malloc(hd->hd_data_size);

  c = read(fd, hd->hd_data, hd->hd_data_size);
  if(c < 1) {
    free(hd->hd_data);
    free(hd);
    return -1;
  }
  hd->hd_data_len = c;
  hd->hd_data_off = 0;
  TAILQ_INSERT_TAIL(&hq->hq_q, hd, hd_link);
  hq->hq_size += c;
  return 0;
}


/**
 *
 */
int
tcp_read_line(int fd, char *buf, const size_t bufsize, htsbuf_queue_t *spill)
{
  int len;

  while(1) {
    len = htsbuf_find(spill, 0xa);

    if(len == -1) {
      if(tcp_fill_htsbuf_from_fd(fd, spill) < 0)
	return -1;
      continue;
    }
    
    if(len >= bufsize - 1)
      return -1;

    htsbuf_read(spill, buf, len);
    buf[len] = 0;
    while(len > 0 && buf[len - 1] < 32)
      buf[--len] = 0;
    htsbuf_drop(spill, 1); /* Drop the \n */
    return 0;
  }
}



/**
 *
 */
int
tcp_read_data(int fd, char *buf, const size_t bufsize, htsbuf_queue_t *spill)
{
  int x, tot = htsbuf_read(spill, buf, bufsize);

  if(tot == bufsize)
    return 0;

  x = recv(fd, buf + tot, bufsize - tot, MSG_WAITALL);
  if(x != bufsize - tot)
    return -1;

  return 0;
}

/**
 *
 */
int
tcp_read(int fd, void *buf, size_t len)
{
  int x = recv(fd, buf, len, MSG_WAITALL);

  if(x == -1)
    return errno;
  if(x != len)
    return ECONNRESET;
  return 0;

}

/**
 *
 */
static int tcp_server_epoll_fd;

typedef struct tcp_server {
  tcp_server_callback_t *start;
  void *opaque;
  int serverfd;
} tcp_server_t;

typedef struct tcp_server_launch_t {
  tcp_server_callback_t *start;
  void *opaque;
  int fd;
  struct sockaddr_in source;
} tcp_server_launch_t;


/**
 *
 */
static void *
tcp_server_start(void *aux)
{
  tcp_server_launch_t *tsl = aux;
  int val;

  val = 1;
  setsockopt(tsl->fd, SOL_SOCKET, SO_KEEPALIVE, &val, sizeof(val));
  
  val = 30;
  setsockopt(tsl->fd, SOL_TCP, TCP_KEEPIDLE, &val, sizeof(val));

  val = 15;
  setsockopt(tsl->fd, SOL_TCP, TCP_KEEPINTVL, &val, sizeof(val));

  val = 5;
  setsockopt(tsl->fd, SOL_TCP, TCP_KEEPCNT, &val, sizeof(val));

  val = 1;
  setsockopt(tsl->fd, SOL_TCP, TCP_NODELAY, &val, sizeof(val));


  tsl->start(tsl->fd, tsl->opaque, &tsl->source);
  free(tsl);

  return NULL;
}


/**
 *
 */
static void *
tcp_server_loop(void *aux)
{
  int r, i;
  struct epoll_event ev[1];
  tcp_server_t *ts;
  tcp_server_launch_t *tsl;
  pthread_attr_t attr;
  pthread_t tid;
  socklen_t slen;

  pthread_attr_init(&attr);
  pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);

  while(1) {
    r = epoll_wait(tcp_server_epoll_fd, ev, sizeof(ev) / sizeof(ev[0]), -1);
    if(r == -1) {
      perror("tcp_server: epoll_wait");
      continue;
    }

    for(i = 0; i < r; i++) {
      ts = ev[i].data.ptr;

      if(ev[i].events & EPOLLHUP) {
	close(ts->serverfd);
	free(ts);
	continue;
      }

      if(ev[i].events & EPOLLIN) {
	tsl = malloc(sizeof(tcp_server_launch_t));
	tsl->start  = ts->start;
	tsl->opaque = ts->opaque;
	slen = sizeof(struct sockaddr_in);

	tsl->fd = accept(ts->serverfd, 
			 (struct sockaddr *)&tsl->source, &slen);
	if(tsl->fd == -1) {
	  perror("accept");
	  free(tsl);
	  sleep(1);
	  continue;
	}

	pthread_create(&tid, &attr, tcp_server_start, tsl);
      }
    }
  }
}

/**
 *
 */
void *
tcp_server_create(int port, tcp_server_callback_t *start, void *opaque)
{
  int fd, x;
  struct epoll_event e;
  tcp_server_t *ts;
  struct sockaddr_in s;
  int one = 1;
  memset(&e, 0, sizeof(e));
  fd = socket(AF_INET, SOCK_STREAM, 0);
  if(fd == -1)
    return NULL;

  setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(int));

  memset(&s, 0, sizeof(s));
  s.sin_family = AF_INET;
  s.sin_port = htons(port);
  
  x = bind(fd, (struct sockaddr *)&s, sizeof(s));
  if(x < 0) {
    close(fd);
    return NULL;
  }

  listen(fd, 1);

  ts = malloc(sizeof(tcp_server_t));
  ts->serverfd = fd;
  ts->start = start;
  ts->opaque = opaque;

  
  e.events = EPOLLIN;
  e.data.ptr = ts;

  epoll_ctl(tcp_server_epoll_fd, EPOLL_CTL_ADD, fd, &e);
  printf("Adding fd %d, listening on port %d\n", fd, port);
  return ts;
}

/**
 *
 */
void
tcp_server_init(void)
{
  pthread_t tid;

  tcp_server_epoll_fd = epoll_create(10);
  pthread_create(&tid, NULL, tcp_server_loop, NULL);
}