/*
    irchack, a simple application to reuse IRC clients as user interfaces for tc_client
    Copyright (C) 2014-2015  <email hidden>
    Copyright (C) 2015  Jade Lea

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published by
    the Free Software Foundation, version 3 of the License.

    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 Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
#include <netinet/in.h>
#include <unistd.h>
#include <poll.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/socket.h>
#include <ctype.h>
#include <signal.h>

#ifdef __ANDROID__
// Android has no dprintf, so we make our own
#include <stdarg.h>
size_t dprintf(int fd, const char* fmt, ...)
{
  va_list va;
  va_start(va, fmt);
  int len=vsnprintf(0, 0, fmt, va);
  va_end(va);
  char buf[len+1];
  va_start(va, fmt);
  vsnprintf(buf, len+1, fmt, va);
  va_end(va);
  buf[len]=0;
  write(fd, buf, len);
  return len;
}
#endif

// ANSI colors and their IRC equivalents
struct color{const char* ansi; const char* irc;};
struct color colortable[]={
  {"31",   "\x03""05"},
  {"31;1", "\x03""04"},
  {"33",   "\x03""07"},
  {"33",   "\x03""07"},
  {"33;1", "\x03""08"},
  {"32;1", "\x03""09"},
  {"32;1", "\x03""09"},
  {"32",   "\x03""03"},
  {"36",   "\x03""10"},
  {"34;1", "\x03""12"},
  {"34;1", "\x03""12"},
  {"34",   "\x03""02"},
  {"35",   "\x03""06"},
  {"35;1", "\x03""13"},
  {"35;1", "\x03""13"},
  {"35;1", "\x03""13"}
};

const char* findcolor_irc(const char* ansi)
{
  int len;
  for(len=0; ansi[len]&&ansi[len]!='m'; ++len);
  int i;
  for(i=0; i<16; ++i)
  {
    if(!strncmp(colortable[i].ansi, ansi, len) && !colortable[i].ansi[len])
    {
      return colortable[i].irc;
    }
  }
  return 0;
}

int findcolor_ansi(char* irc, char** end)
{
  char color[4];
  strncpy(color, irc, 3);
  color[3]=0;
  if(!isdigit(color[1])){*end=&irc[1]; return -1;}
  if(!isdigit(color[2])){*end=&irc[2]; color[2]=color[1]; color[1]='0';}else{*end=&irc[3];}
  int i;
  for(i=0; i<16; ++i)
  {
    if(!strcmp(colortable[i].irc, color))
    {
      return i;
    }
  }
  return -1;
}

extern char session(int sock, const char* nick, const char* channel, const char* pass, const char* acc_user, const char* acc_pass);

int main(int argc, char** argv)
{
  int port=(argc>1?atoi(argv[1]):6667);
  struct sockaddr_in addr;
  memset(&addr, 0, sizeof(addr));
  addr.sin_family=AF_INET;
  addr.sin_addr.s_addr=htonl(0x7f000001); // 127.0.0.1
  addr.sin_port=htons(port);
  int lsock=socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
  if(bind(lsock, (struct sockaddr*)&addr, sizeof(addr))){perror("bind"); return 1;}
  listen(lsock, 1);
  printf("Done! Open an IRC client and connect to localhost on port %i\n", port);
  signal(SIGCHLD, SIG_IGN);
  int sock;
  while((sock=accept(lsock, 0, 0))>-1)
  {
    if(fork()){continue;}
    char buf[2048];
    char* nick=0;
    char* channel=0;
    char* pass=0;
    char* acc_user=0;
    char* acc_pass=0;
    int len;
    while(1)
    {
      len=0;
      int r;
      while(len<2047)
      {
        if((r=read(sock, &buf[len], 1))!=1 || buf[len]=='\r' || buf[len]=='\n'){break;}
        ++len;
      }
      if(r!=1){break;}
      buf[len]=0;
      if(!strncmp(buf, "USER ", 5))
      {
        acc_user=&buf[5];
        char* end=strchr(acc_user, ' ');
        if(end){end[0]=0;}
        acc_user=strdup(acc_user);
      }
      else if(!strncmp(buf, "PASS ", 5))
      {
        acc_pass=&buf[5];
        if(acc_pass[0]==':'){acc_pass=&acc_pass[1];}
        acc_pass=strdup(acc_pass);
      }
      else if(!strncmp(buf, "NICK ", 5))
      {
        char* newnick=&buf[5];
        if(newnick[0]==':'){newnick=&nick[1];}
        if(!nick)
        {
          dprintf(sock, ":irchack 001 %s :Welcome\n", newnick);
        }else{
          dprintf(sock, ":%s!user@host NICK :%s\n", nick, newnick);
        }
        free(nick);
        nick=strdup(newnick);
      }
      else if(nick && !strncmp(buf, "JOIN ", 5))
      {
        free(channel);
        channel=&buf[5];
        if(channel[0]==':'){channel=&channel[1];}
        free(pass);
        pass=strchr(channel, ' ');
        if(pass)
        {
          pass[0]=0;
          pass=&pass[1];
          if(pass[0]==':'){pass=strdup(&pass[1]);}
        }
        if(channel[0]=='#'){channel=&channel[1];}
        channel=strdup(channel);
        if(!session(sock, nick, channel, pass, acc_user, acc_pass)){break;}
      }
      else if(!strncmp(buf, "PING ", 5))
      {
        dprintf(sock, ":irchack PONG %s\n", &buf[5]);
      }
    }
    shutdown(sock, SHUT_RDWR);
    _exit(0);
  }
  close(lsock);
  return 0;
}

char session(int sock, const char* nick, const char* channel, const char* pass, const char* acc_user, const char* acc_pass)
{
  printf("Nick: %s\n", nick);
  printf("Channel: %s\n", channel);
  printf("Password: %s\n", pass);
  int tc_in[2];
  int tc_out[2];
  pipe(tc_in);
  pipe(tc_out);
  if(!fork())
  {
    close(tc_in[1]);
    close(tc_out[0]);
    dup2(tc_in[0], 0);
    dup2(tc_out[1], 1);
    if(acc_user && acc_pass)
    {
      execl("./tc_client", "./tc_client", "-u", acc_user, "-p", acc_pass, channel, nick, pass, (char*)0);
    }else{
      execl("./tc_client", "./tc_client", channel, nick, pass, (char*)0);
    }
    perror("Failed to exec tc_client");
    _exit(1);
  }
  close(tc_in[0]);
  close(tc_out[1]);
  struct pollfd pfd[2];
  pfd[0].fd=tc_out[0];
  pfd[0].events=POLLIN;
  pfd[0].revents=0;
  pfd[1].fd=sock;
  pfd[1].events=POLLIN;
  pfd[1].revents=0;
  char buf[2048];
  int len;
  char joins=0;
  while(1)
  {
    poll(pfd, 2, -1);
    if(pfd[0].revents)
    {
      pfd[0].revents=0;
      len=0;
      while(len<2047)
      {
        if(read(tc_out[0], &buf[len], 1)!=1 || buf[len]=='\r' || buf[len]=='\n'){break;}
        ++len;
      }
      buf[len]=0;
printf("Got from tc_client: '%s'\n", buf);
      if(!strncmp(buf, "Currently online: ", 18))
      {
        dprintf(sock, ":irchack 353 %s = #%s :", nick, channel);
        char* user=&buf[18];
        while(user)
        {
          char* next=strchr(user, ',');
          if(next){next[0]=0; next=&next[2];}
          dprintf(sock, "%s%s", user, next?" ":"");
          user=next;
        }
        write(sock, "\n", 1);
        joins=1;
        continue;
      }
      else if(joins)
      {
        dprintf(sock, ":irchack 366 %s #%s :End of /NAMES list.\n", nick, channel);
        joins=0;
      }
      if(!strncmp(buf, "Room topic: ", 12))
      {
        dprintf(sock, ":irchack 332 %s #%s :%s\n", nick, channel, &buf[12]);
        continue;
      }
      if(!strcmp(buf, "Password required"))
      {
        dprintf(sock, ":irchack 475 %s :Cannot join %s without the correct password\n", channel, channel);
        close(tc_in[1]);
        close(tc_out[0]);
        return 1;
      }
      if(!strncmp(buf, "Guest ID: ", 10))
      {
        dprintf(sock, ":%s!user@host NICK :guest-%s\n", nick, &buf[10]);
        continue;
      }
      if(!strncmp(buf, "No such nick: ", 14))
      {
        dprintf(sock, ":irchack 401 %s %s :No such nick/channel\n", nick, &buf[14]);
        continue;
      }
      char* space=strchr(buf, ' ');
      if(space && !strcmp(space, " is a moderator."))
      {
        space[0]=0;
        dprintf(sock, ":irchack MODE #%s +o %s\n", channel, buf);
        continue;
      }
      if(space && !strcmp(space, " is no longer a moderator."))
      {
        space[0]=0;
        dprintf(sock, ":irchack MODE #%s -o %s\n", channel, buf);
        continue;
      }
      if(buf[0]!='['){continue;} // Beyond this we only care about timestamped lines
      // Translate ANSI escape codes to IRC color code instead
      char* ansi;
      const char* color="";
      while((ansi=strstr(buf, "\x1b[")))
      {
        int len;
        for(len=0; ansi[len]&&ansi[len]!='m'; ++len);
        if(ansi[len]=='m'){++len;}
        const char* c=findcolor_irc(&ansi[2]);
        if(c){color=c;}
        memmove(ansi, &ansi[len], strlen(&ansi[len])+1);
      }

      char* name=strchr(buf, ' ');
      if(!name){continue;}
      name[0]=0;
      name=&name[1];
      char* msg=name;
      while(msg[0]&&msg[0]!=':'&&msg[0]!=' '){msg=&msg[1];}
      if(msg[0]==':') // message
      {
        msg[0]=0;
        msg=&msg[2];
        if(!strncmp(msg, "/msg ", 5)) // PM
        {
          msg=strchr(&msg[5], ' ');
          if(!msg){continue;}
          msg=&msg[1];
          dprintf(sock, ":%s!user@host PRIVMSG %s :%s%s\n", name, nick, color, msg);
        }else{ // Regular channel message
          dprintf(sock, ":%s!user@host PRIVMSG #%s :%s%s\n", name, channel, color, msg);
        }
      }else{ // action, parse the actions and send them as JOINs, NICKs and QUITs etc. instead
        msg[0]=0;
        msg=&msg[1];
        if(!strcmp(msg, "entered the channel"))
        {
          dprintf(sock, ":%s!user@host JOIN #%s\n", name, channel);
        }
        else if(!strncmp(msg, "changed nickname to ", 20))
        {
          dprintf(sock, ":%s!user@host NICK :%s\n", name, &msg[20]);
        }
        else if(!strcmp(msg, "left the channel"))
        {
          dprintf(sock, ":%s!user@host QUIT :left the channel\n", name);
        }
        else // Unhandled action
        {
          dprintf(sock, ":%s!user@host PRIVMSG #%s :\x01""ACTION %s\x01\n", name, channel, msg);
        }
      }
    }
    if(pfd[1].revents)
    {
      pfd[1].revents=0;
      len=0;
      int r;
      while(len<2047)
      {
        if((r=read(sock, &buf[len], 1))!=1 || buf[len]=='\r' || buf[len]=='\n'){break;}
        ++len;
      }
      if(r!=1){break;}
      buf[len]=0;
printf("Got from IRC client: '%s'\n", buf);
      if(!strncmp(buf, "PRIVMSG ", 8))
      {
        char* target=&buf[8];
        char* msg=strchr(&buf[8], ' ');
        if(!msg){continue;}
        msg[0]=0;
        msg=&msg[1];
        if(msg[0]==':'){msg=&msg[1];}
        char* color;
        while((color=strchr(msg, '\x03')))
        {
          char* end;
          int c=findcolor_ansi(color, &end);
          if(c!=-1){dprintf(tc_in[1], "/color %i\n", c);}
          memmove(color, end, strlen(end)+1);
        }
        if(!strncmp(msg, "\x01""ACTION ", 8)) // Translate '/me'
        {
          msg=&msg[7];
          msg[0]='*';
          char* end=strchr(msg, '\x01');
          if(end){end[0]='*';}
        }
        if(target[0]=='#' && !strcmp(&target[1], channel))
        {
          dprintf(tc_in[1], "%s\n", msg);
        }else{
          dprintf(tc_in[1], "/msg %s %s\n", target, msg);
        }
      }
      else if(!strncmp(buf, "NICK ", 5))
      {
        char* nick=&buf[5];
        if(nick[0]==':'){nick=&nick[1];}
        dprintf(tc_in[1], "/nick %s\n", nick);
      }
      else if(!strncmp(buf, "PING ", 5))
      {
        dprintf(sock, ":irchack PONG %s\n", &buf[5]);
      }
      else if(!strncmp(buf, "QUIT ", 5)){break;}
    }
  }

  close(tc_in[1]);
  close(tc_out[0]);
  return 0;
}