/*
 * svdrp.c: Simple Video Disk Recorder Protocol
 *
 * See the main source file 'vdr.c' for copyright information and
 * how to reach the author.
 *
 * The "Simple Video Disk Recorder Protocol" (SVDRP) was inspired
 * by the "Simple Mail Transfer Protocol" (SMTP) and is fully ASCII
 * text based. Therefore you can simply 'telnet' to your VDR port
 * and interact with the Video Disk Recorder - or write a full featured
 * graphical interface that sits on top of an SVDRP connection.
 *
 * $Id: svdrp.c 1.2 2000/07/24 16:43:51 kls Exp $
 */

#define _GNU_SOURCE

#include "svdrp.h"
#include <arpa/inet.h>
#include <ctype.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <unistd.h>
#include "config.h"
#include "interface.h"
#include "tools.h"

// --- cSocket ---------------------------------------------------------------

cSocket::cSocket(int Port, int Queue)
{
  port = Port;
  sock = -1;
}

cSocket::~cSocket()
{
  Close();
}

void cSocket::Close(void)
{
  if (sock >= 0) {
     close(sock);
     sock = -1;
     }
}

bool cSocket::Open(void)
{
  if (sock < 0) {
     // create socket:
     sock = socket(PF_INET, SOCK_STREAM, 0);
     if (sock < 0) {
        LOG_ERROR;
        port = 0;
        return false;
        }
     struct sockaddr_in name;
     name.sin_family = AF_INET;
     name.sin_port = htons(port);
     name.sin_addr.s_addr = htonl(INADDR_ANY);
     if (bind(sock, (struct sockaddr *)&name, sizeof(name)) < 0) {
        LOG_ERROR;
        Close();
        return false;
        }
     // make it non-blocking:
     int oldflags = fcntl(sock, F_GETFL, 0);
     if (oldflags < 0) {
        LOG_ERROR;
        return false;
        }
     oldflags |= O_NONBLOCK;
     if (fcntl(sock, F_SETFL, oldflags) < 0) {
        LOG_ERROR;
        return false;
        }
     // listen to the socket:
     if (listen(sock, queue) < 0) {
        LOG_ERROR;
        return false;
        }
     }
  return true;
}

int cSocket::Accept(void)
{
  if (Open()) {
     struct sockaddr_in clientname;
     uint size = sizeof(clientname);
     int newsock = accept(sock, (struct sockaddr *)&clientname, &size);
     if (newsock > 0)
        isyslog(LOG_INFO, "connect from %s, port %hd", inet_ntoa(clientname.sin_addr), ntohs(clientname.sin_port));
     else if (errno != EINTR)
        LOG_ERROR;
     return newsock;
     }
  return -1;
}

// --- cSVDRP ----------------------------------------------------------------

#define MAXCMDBUFFER 10000
#define MAXHELPTOPIC 10

const char *HelpPages[] = {
  "CHAN [ + | - | <number> | <name> ]\n"
  "    Switch channel up, down or to the given channel number or name.\n"
  "    Without option (or after successfully switching to the channel)\n"
  "    it returns the current channel number and name.",
  "DELC <number>\n"
  "    Delete channel.",
  "DELT <number>\n"
  "    Delete timer.",
  "HELP [ <topic> ]\n"
  "    The HELP command gives help info.",
  "LSTC [ <number> | <name> ]\n"
  "    List channels. Without option, all channels are listed. Otherwise\n"
  "    only the given channel is listed. If a name is given, all channels\n"
  "    containing the given string as part of their name are listed.",
  "LSTT [ <number> ]\n"
  "    List timers. Without option, all timers are listed. Otherwise\n"
  "    only the given timer is listed.",
  "MODC <number> <settings>\n"
  "    Modify a channel. Settings must be in the same format as returned\n"
  "    by the LSTC command.",
  "MODT <number> on | off | <settings>\n"
  "    Modify a timer. Settings must be in the same format as returned\n"
  "    by the LSTT command. The special keywords 'on' and 'off' can be\n"
  "    used to easily activate or deactivate a timer.",
  "MOVC <number> <to>\n"
  "    Move a channel to a new position.",
  "MOVT <number> <to>\n"
  "    Move a timer to a new position.",
  "NEWC <settings>\n"
  "    Create a new channel. Settings must be in the same format as returned\n"
  "    by the LSTC command.",
  "NEWT <settings>\n"
  "    Create a new timer. Settings must be in the same format as returned\n"
  "    by the LSTT command.",
  "QUIT\n"
  "    Exit vdr (SVDRP).\n"
  "    You can also hit Ctrl-D to exit.",
  NULL
  };

/* SVDRP Reply Codes:

 214 Help message
 220 VDR service ready
 221 VDR service closing transmission channel
 250 Requested VDR action okay, completed
 451 Requested action aborted: local error in processing
 500 Syntax error, command unrecognized
 501 Syntax error in parameters or arguments
 502 Command not implemented
 504 Command parameter not implemented
 550 Requested action not taken
 554 Transaction failed

*/

const char *GetHelpTopic(const char *HelpPage)
{
  static char topic[MAXHELPTOPIC];
  const char *q = HelpPage;
  while (*q) {
        if (isspace(*q)) {
           uint n = q - HelpPage;
           if (n >= sizeof(topic))
              n = sizeof(topic) - 1;
           strncpy(topic, HelpPage, n);
           topic[n] = 0;
           return topic;
           }
        q++;
        }
  return NULL;
}

const char *GetHelpPage(const char *Cmd)
{
  const char **p = HelpPages;
  while (*p) {
        const char *t = GetHelpTopic(*p);
        if (strcasecmp(Cmd, t) == 0)
           return *p;
        p++;
        }
  return NULL;
}

cSVDRP::cSVDRP(int Port)
:socket(Port)
{
  filedes = -1;
  isyslog(LOG_INFO, "SVDRP listening on port %d", Port);
}

cSVDRP::~cSVDRP()
{
  Close();
}

void cSVDRP::Close(void)
{
  if (filedes >= 0) {
     //TODO how can we get the *full* hostname?
     char buffer[MAXCMDBUFFER];
     gethostname(buffer, sizeof(buffer));
     Reply(221, "%s closing connection", buffer);
     isyslog(LOG_INFO, "closing connection"); //TODO store IP#???
     close(filedes);
     filedes = -1;
     }
}

bool cSVDRP::Send(const char *s, int length)
{
  if (length < 0)
     length = strlen(s);
  int wbytes = write(filedes, s, length);
  if (wbytes == length)
     return true;
  if (wbytes < 0)
     LOG_ERROR;
  else //XXX while...???
     esyslog(LOG_ERR, "Wrote %d bytes to client while expecting %d\n", wbytes, length);
  return false;
}

void cSVDRP::Reply(int Code, const char *fmt, ...)
{
  if (filedes >= 0) {
     if (Code != 0) {
        va_list ap;
        va_start(ap, fmt);
        char *buffer;
        vasprintf(&buffer, fmt, ap);
        char *nl = strchr(buffer, '\n');
        if (Code > 0 && nl && *(nl + 1)) // trailing newlines don't count!
           Code = -Code;
        char number[16];
        sprintf(number, "%03d%c", abs(Code), Code < 0 ? '-' : ' ');
        const char *s = buffer;
        while (s && *s) {
              const char *n = strchr(s, '\n');
              if (!(Send(number) && Send(s, n ? n - s : -1) && Send("\r\n"))) {
                 Close();
                 break;
                 }
              s = n ? n + 1 : NULL;
              }
        delete buffer;
        va_end(ap);
        }
     else {
        Reply(451, "Zero return code - looks like a programming error!");
        esyslog(LOG_ERR, "SVDRP: zero return code!");
        }
     }
}

void cSVDRP::CmdChan(const char *Option)
{
  if (*Option) {
     int n = -1;
     if (isnumber(Option)) {
        int o = strtol(Option, NULL, 10) - 1;
        if (o >= 0 && o < Channels.Count())
           n = o;
        }
     else if (strcmp(Option, "-") == 0) {
        n = CurrentChannel;
        if (CurrentChannel > 0)
           n--;
        }
     else if (strcmp(Option, "+") == 0) {
        n = CurrentChannel;
        if (CurrentChannel < Channels.Count() - 1)
           n++;
        }
     else {
        int i = 0;
        cChannel *channel;
        while ((channel = Channels.Get(i)) != NULL) {
              if (strcasecmp(channel->name, Option) == 0) {
                 n = i;
                 break;
                 }
              i++;
              }
        }
     if (n < 0) {
        Reply(501, "Undefined channel \"%s\"", Option);
        return;
        }
     if (Interface.Recording()) {
        Reply(550, "Can't switch channel, interface is recording");
        return;
        }
     cChannel *channel = Channels.Get(n);
     if (channel) {
        if (!channel->Switch()) {
           Reply(554, "Error switching to channel \"%d\"", channel->Index() + 1);
           return;
           }
        }
     else {
        Reply(550, "Unable to find channel \"%s\"", Option);
        return;
        }
     }
  cChannel *channel = Channels.Get(CurrentChannel);
  if (channel)
     Reply(250, "%d %s", CurrentChannel + 1, channel->name);
  else
     Reply(550, "Unable to find channel \"%d\"", CurrentChannel);
}

void cSVDRP::CmdDelc(const char *Option)
{
  //TODO combine this with menu action (timers must be updated)
  Reply(502, "DELC not yet implemented");
}

void cSVDRP::CmdDelt(const char *Option)
{
  if (*Option) {
     if (isnumber(Option)) {
        cTimer *timer = Timers.Get(strtol(Option, NULL, 10) - 1);
        if (timer) {
           if (!timer->recording) {
              Timers.Del(timer);
              Timers.Save();
              isyslog(LOG_INFO, "timer %s deleted", Option);
              Reply(250, "Timer \"%s\" deleted", Option);
              }
           else
              Reply(550, "Timer \"%s\" is recording", Option);
           }
        else
           Reply(501, "Timer \"%s\" not defined", Option);
        }
     else
        Reply(501, "Error in timer number \"%s\"", Option);
     }
  else
     Reply(501, "Missing timer number");
}

void cSVDRP::CmdHelp(const char *Option)
{
  if (*Option) {
     const char *hp = GetHelpPage(Option);
     if (hp)
        Reply(214, hp);
     else {
        Reply(504, "HELP topic \"%s\" unknown", Option);
        return;
        }
     }
  else {
     Reply(-214, "This is VDR version 0.6"); //XXX dynamically insert version number
     Reply(-214, "Topics:");
     const char **hp = HelpPages;
     while (*hp) {
           //TODO multi-column???
           const char *topic = GetHelpTopic(*hp);
           if (topic)
              Reply(-214, "    %s", topic);
           hp++;
           }
     Reply(-214, "To report bugs in the implementation send email to");
     Reply(-214, "    vdr-bugs@cadsoft.de");
     }
  Reply(214, "End of HELP info");
}

void cSVDRP::CmdLstc(const char *Option)
{
  if (*Option) {
     if (isnumber(Option)) {
        cChannel *channel = Channels.Get(strtol(Option, NULL, 10) - 1);
        if (channel)
           Reply(250, "%d %s", channel->Index() + 1, channel->ToText());
        else
           Reply(501, "Channel \"%s\" not defined", Option);
        }
     else {
        int i = 0;
        cChannel *next = NULL;
        while (i < Channels.Count()) {
              cChannel *channel = Channels.Get(i);
              if (channel) {
                 if (strcasestr(channel->name, Option)) {
                    if (next)
                       Reply(-250, "%d %s", next->Index() + 1, next->ToText());
                    next = channel;
                    }
                 }
              else {
                 Reply(501, "Channel \"%d\" not found", i + 1);
                 return;
                 }
              i++;
              }
        if (next)
           Reply(250, "%d %s", next->Index() + 1, next->ToText());
        }
     }
  else {
     for (int i = 0; i < Channels.Count(); i++) {
         cChannel *channel = Channels.Get(i);
        if (channel)
           Reply(i < Channels.Count() - 1 ? -250 : 250, "%d %s", channel->Index() + 1, channel->ToText());
        else
           Reply(501, "Channel \"%d\" not found", i + 1);
         }
     }
}

void cSVDRP::CmdLstt(const char *Option)
{
  if (*Option) {
     if (isnumber(Option)) {
        cTimer *timer = Timers.Get(strtol(Option, NULL, 10) - 1);
        if (timer)
           Reply(250, "%d %s", timer->Index() + 1, timer->ToText());
        else
           Reply(501, "Timer \"%s\" not defined", Option);
        }
     else
        Reply(501, "Error in timer number \"%s\"", Option);
     }
  else {
     for (int i = 0; i < Timers.Count(); i++) {
         cTimer *timer = Timers.Get(i);
        if (timer)
           Reply(i < Timers.Count() - 1 ? -250 : 250, "%d %s", timer->Index() + 1, timer->ToText());
        else
           Reply(501, "Timer \"%d\" not found", i + 1);
         }
     }
}

void cSVDRP::CmdModc(const char *Option)
{
  if (*Option) {
     char *tail;
     int n = strtol(Option, &tail, 10);
     if (tail && tail != Option) {
        tail = skipspace(tail);
        cChannel *channel = Channels.Get(n - 1);
        if (channel) {
           cChannel c = *channel;
           if (!c.Parse(tail)) {
              Reply(501, "Error in channel settings");
              return;
              }
           *channel = c;
           Channels.Save();
           isyslog(LOG_INFO, "channel %d modified", channel->Index() + 1);
           Reply(250, "%d %s", channel->Index() + 1, channel->ToText());
           }
        else
           Reply(501, "Channel \"%d\" not defined", n);
        }
     else
        Reply(501, "Error in channel number");
     }
  else
     Reply(501, "Missing channel settings");
}

void cSVDRP::CmdModt(const char *Option)
{
  if (*Option) {
     char *tail;
     int n = strtol(Option, &tail, 10);
     if (tail && tail != Option) {
        tail = skipspace(tail);
        cTimer *timer = Timers.Get(n - 1);
        if (timer) {
           cTimer t = *timer;
           if (strcasecmp(tail, "ON") == 0)
              t.active = 1;
           else if (strcasecmp(tail, "OFF") == 0)
              t.active = 0;
           else if (!t.Parse(tail)) {
              Reply(501, "Error in timer settings");
              return;
              }
           *timer = t;
           Timers.Save();
           isyslog(LOG_INFO, "timer %d modified (%s)", timer->Index() + 1, timer->active ? "active" : "inactive");
           Reply(250, "%d %s", timer->Index() + 1, timer->ToText());
           }
        else
           Reply(501, "Timer \"%d\" not defined", n);
        }
     else
        Reply(501, "Error in timer number");
     }
  else
     Reply(501, "Missing timer settings");
}

void cSVDRP::CmdMovc(const char *Option)
{
  //TODO combine this with menu action (timers must be updated)
  Reply(502, "MOVC not yet implemented");
}

void cSVDRP::CmdMovt(const char *Option)
{
  //TODO combine this with menu action
  Reply(502, "MOVT not yet implemented");
}

void cSVDRP::CmdNewc(const char *Option)
{
  if (*Option) {
     cChannel *channel = new cChannel;
     if (channel->Parse(Option)) {
        Channels.Add(channel);
        Channels.Save();
        isyslog(LOG_INFO, "channel %d added", channel->Index() + 1);
        Reply(250, "%d %s", channel->Index() + 1, channel->ToText());
        }
     else
        Reply(501, "Error in channel settings");
     }
  else
     Reply(501, "Missing channel settings");
}

void cSVDRP::CmdNewt(const char *Option)
{
  if (*Option) {
     cTimer *timer = new cTimer;
     if (timer->Parse(Option)) {
        Timers.Add(timer);
        Timers.Save();
        isyslog(LOG_INFO, "timer %d added", timer->Index() + 1);
        Reply(250, "%d %s", timer->Index() + 1, timer->ToText());
        }
     else
        Reply(501, "Error in timer settings");
     }
  else
     Reply(501, "Missing timer settings");
}

#define CMD(c) (strcasecmp(Cmd, c) == 0)

void cSVDRP::Execute(char *Cmd)
{
  // skip leading whitespace:
  Cmd = skipspace(Cmd);
  // find the end of the command word:
  char *s = Cmd;
  while (*s && !isspace(*s))
        s++;
  *s++ = 0;
  if      (CMD("CHAN"))  CmdChan(s);
  else if (CMD("DELC"))  CmdDelc(s);
  else if (CMD("DELT"))  CmdDelt(s);
  else if (CMD("HELP"))  CmdHelp(s);
  else if (CMD("LSTC"))  CmdLstc(s);
  else if (CMD("LSTT"))  CmdLstt(s);
  else if (CMD("MODC"))  CmdModc(s);
  else if (CMD("MODT"))  CmdModt(s);
  else if (CMD("MOVC"))  CmdMovc(s);
  else if (CMD("MOVT"))  CmdMovt(s);
  else if (CMD("NEWC"))  CmdNewc(s);
  else if (CMD("NEWT"))  CmdNewt(s);
  else if (CMD("QUIT")
       ||  CMD("\x04"))  Close();
  else                   Reply(500, "Command unrecognized: \"%s\"", Cmd);
}

void cSVDRP::Process(void)
{
  bool SendGreeting = filedes < 0;

  if (filedes >= 0 || (filedes = socket.Accept()) >= 0) {
     char buffer[MAXCMDBUFFER];
     if (SendGreeting) {
        //TODO how can we get the *full* hostname?
        gethostname(buffer, sizeof(buffer));
        time_t now = time(NULL);
        Reply(220, "%s SVDRP VideoDiskRecorder 0.6; %s", buffer, ctime(&now));//XXX dynamically insert version number
        }
     int rbytes = readstring(filedes, buffer, sizeof(buffer) - 1);
     if (rbytes > 0) {
        //XXX overflow check???
        // strip trailing whitespace:
        while (rbytes > 0 && strchr(" \t\r\n", buffer[rbytes - 1]))
              buffer[--rbytes] = 0;
        // make sure the string is terminated:
        buffer[rbytes] = 0;
        // showtime!
        Execute(buffer);
        }
     else if (rbytes < 0)
        Close();
     }
}

//TODO timeout???
//TODO more than one connection???