/* pop3client.c -- An application which demonstrates how to use the
   GNU Mailutils pop3 functions.  This application interactively allows users
   to contact a pop3 server.

   Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009, 2010 Free Software
   Foundation, Inc.

   GNU Mailutils 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, or (at your option)
   any later version.

   GNU Mailutils 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 GNU Mailutils; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
   MA 02110-1301 USA */

#ifdef HAVE_CONFIG_H
# include <config.h>  
#endif 
#include <sys/types.h>
#include <netinet/in.h>
#include <netdb.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <strings.h>
#include <stdlib.h>
#include <termios.h>
#include <signal.h>
#include <xalloc.h>

#ifdef WITH_READLINE
# include <readline/readline.h>
# include <readline/history.h>
#endif

#include <mailutils/pop3.h>
#include <mailutils/iterator.h>
#include <mailutils/error.h>
#include <mailutils/errno.h>
#include <mailutils/vartab.h>
#include <mailutils/argcv.h>
#include <mailutils/cctype.h>
#include <mailutils/cstr.h>
#include <mailutils/tls.h>

/* A structure which contains information on the commands this program
   can understand. */

typedef struct
{
  const char *name;		/* User printable name of the function. */
  int argmin;
  int argmax;
  int (*func) (int, char **);	/* Function to call to do the job. */
  const char *doc;		/* Documentation for this function.  */
}
COMMAND;

/* The names of functions that actually do the manipulation. */
int com_apop (int, char **);
int com_capa (int, char **);
int com_disconnect (int, char **);
int com_dele (int, char **);
int com_exit (int, char **);
int com_help (int, char **);
int com_list (int, char **);
int com_noop (int, char **);
int com_connect (int, char **);
int com_pass (int, char **);
int com_quit (int, char **);
int com_retr (int, char **);
int com_rset (int, char **);
int com_stat (int, char **);
int com_top (int, char **);
int com_uidl (int, char **);
int com_user (int, char **);
int com_verbose (int, char **);
int com_prompt (int, char **);
int com_stls (int, char **);

COMMAND *find_command (char *);

COMMAND commands[] = {
  { "apop",       3,  3, com_apop,
    "Authenticate with APOP: APOP user secret" },
  { "capa",       1, -1, com_capa,
    "List capabilities: capa [-reread] [names...]" },
  { "disconnect", 1, 1,
    com_disconnect, "Close connection: disconnect" },
  { "dele",       2, 2, com_dele,
    "Mark message: DELE msgno" },
  { "exit",       1, 1, com_exit,
    "exit program" },
  { "help",       1, 1, com_help,
    "Display this text" },
  { "?",          1, 1, com_help,
    "Synonym for `help'" },
  { "list",       1, 2, com_list,
    "List messages: LIST [msgno]" },
  { "noop",       1, 1, com_noop,
    "Send no operation: NOOP" },
  { "pass",       1, 2, com_pass,
    "Send passwd: PASS [passwd]" },
  { "prompt",     -1, -1, com_prompt,
    "Set command prompt" },
  { "connect",    1, 4, com_connect,
    "Open connection: connect [-tls] hostname port" },
  { "quit",       1, 1, com_quit,
    "Go to Update state : QUIT" },
  { "retr",       2, 2, com_retr,
    "Dowload message: RETR msgno" },
  { "rset",       1, 1, com_rset,
    "Unmark all messages: RSET" },
  { "stat",       1, 1, com_stat,
    "Get the size and count of mailbox : STAT" },
  { "stls",       1, 1, com_stls,
    "Start TLS negotiation" },
  { "top",        2, 3, com_top,
    "Get the header of message: TOP msgno [lines]" },
  { "uidl",       1, 2, com_uidl,
    "Get the unique id of message: UIDL [msgno]" },
  { "user",       2, 2, com_user,
    "send login: USER user" },
  { "verbose",    1, 2, com_verbose,
    "Enable Protocol tracing: verbose [on|off]" },
  { NULL }
};

/* Global handle for pop3.  */
mu_pop3_t pop3;

/* Flag if verbosity is needed.  */
int verbose;

/* When non-zero, this global means the user is done using this program. */
int done;

enum pop_session_status
  {
    pop_session_disconnected,
    pop_session_connected,
    pop_session_logged_in
  };

enum pop_session_status pop_session_status;

int connect_argc;
char **connect_argv;

/* Host we are connected to. */
#define host connect_argv[0]
int port = 110;
char *username;

/* Command line prompt */
#define DEFAULT_PROMPT "pop3> "
char *prompt;

const char *
pop_session_str (enum pop_session_status stat)
{
  switch (stat)
    {
    case pop_session_disconnected:
      return "disconnected";
      
    case pop_session_connected:
      return "connected";
      
    case pop_session_logged_in:
      return "logged in";
    }
  return "unknown";
}

char *
expand_prompt ()
{
  mu_vartab_t vtab;
  char *str;
  
  if (mu_vartab_create (&vtab))
    return strdup (prompt);
  mu_vartab_define (vtab, "user",
		    (pop_session_status == pop_session_logged_in) ?
		      username : "not logged in", 1);
  mu_vartab_define (vtab, "host",
		    (pop_session_status != pop_session_disconnected) ?
		      host : "not connected", 1);
  mu_vartab_define (vtab, "program-name", mu_program_name, 1);
  mu_vartab_define (vtab, "canonical-program-name", "pop3client", 1);
  mu_vartab_define (vtab, "package", PACKAGE, 1);
  mu_vartab_define (vtab, "version", PACKAGE_VERSION, 1);
  mu_vartab_define (vtab, "status", pop_session_str (pop_session_status), 1);
  
  if (mu_vartab_expand (vtab, prompt, &str))
    str = strdup (prompt);
  mu_vartab_destroy (&vtab);
  return str;
}



#ifdef WITH_READLINE
/* Interface to Readline Completion */

char *command_generator (const char *, int);
char **pop_completion (char *, int, int);

/* Tell the GNU Readline library how to complete.  We want to try to complete
   on command names if this is the first word in the line, or on filenames
   if not. */
void
initialize_readline ()
{
  /* Allow conditional parsing of the ~/.inputrc file. */
  rl_readline_name = (char *) "pop3";

  /* Tell the completer that we want a crack first. */
  rl_attempted_completion_function = (CPPFunction *) pop_completion;
}

/* Attempt to complete on the contents of TEXT.  START and END bound the
   region of rl_line_buffer that contains the word to complete.  TEXT is
   the word to complete.  We can use the entire contents of rl_line_buffer
   in case we want to do some simple parsing.  Return the array of matches,
   or NULL if there aren't any. */
char **
pop_completion (char *text, int start, int end MU_ARG_UNUSED)
{
  char **matches;

  matches = (char **) NULL;

  /* If this word is at the start of the line, then it is a command
     to complete.  Otherwise it is the name of a file in the current
     directory. */
  if (start == 0)
    matches = rl_completion_matches (text, command_generator);

  return (matches);
}

/* Generator function for command completion.  STATE lets us know whether
   to start from scratch; without any state (i.e. STATE == 0), then we
   start at the top of the list. */
char *
command_generator (const char *text, int state)
{
  static int list_index, len;
  const char *name;

  /* If this is a new word to complete, initialize now.  This includes
     saving the length of TEXT for efficiency, and initializing the index
     variable to 0. */
  if (!state)
    {
      list_index = 0;
      len = strlen (text);
    }

  /* Return the next name which partially matches from the command list. */
  while ((name = commands[list_index].name))
    {
      list_index++;

      if (strncmp (name, text, len) == 0)
	return xstrdup (name);
    }

  /* If no names matched, then return NULL. */
  return NULL;
}

#else
void
initialize_readline ()
{
}

char *
readline (char *prompt)
{
  char buf[255];

  if (prompt)
    {
      printf ("%s", prompt);
      fflush (stdout);
    }

  if (!fgets (buf, sizeof (buf), stdin))
    return NULL;
  return strdup (buf);
}

void
add_history (const char *s MU_ARG_UNUSED)
{
}
#endif

int
get_bool (const char *str, int *pb)
{
  if (mu_c_strcasecmp (str, "yes") == 0
      || mu_c_strcasecmp (str, "on") == 0
      || mu_c_strcasecmp (str, "true") == 0)
    *pb = 1;
  else if (mu_c_strcasecmp (str, "no") == 0
      || mu_c_strcasecmp (str, "off") == 0
      || mu_c_strcasecmp (str, "false") == 0)
    *pb = 0;
  else
    {
      mu_error ("not a boolean: %s", str);
      return 1;
    }
  return 0;
}

int
get_port (const char *port_str, int *pn)
{
  short port_num;
  long num;
  char *p;
  
  num = port_num = strtol (port_str, &p, 0);
  if (*p == 0)
    {
      if (num != port_num)
	{
	  mu_error ("bad port number: %s", port_str);
	  return 1;
	}
    }
  else
    {
      struct servent *sp = getservbyname (port_str, "tcp");
      if (!sp)
	{
	  mu_error ("unknown port name");
	  return 1;
	}
      port_num = ntohs (sp->s_port);
    }
  *pn = port_num;
  return 0;
}

/* Parse and execute a command line. */
int
execute_line (char *line)
{
  int argc;
  char **argv;
  int status = 0;

  if (mu_argcv_get (line, NULL, "#", &argc, &argv))
    {
      mu_error("cannot parse input line");
      return 0;
    }

  if (argc >= 0)
    {
      COMMAND *command = find_command (argv[0]);
      
      if (!command)
	mu_error ("%s: no such command.", argv[0]);
      else if (command->argmin > 0 && argc < command->argmin)
	mu_error ("%s: too few arguments", argv[0]);
      else if (command->argmax > 0 && argc > command->argmax)
	mu_error ("%s: too many arguments", argv[0]);
      else
	{
	  if (command->argmin <= 0 && argc != 2)
	    {
	      char *word = mu_str_skip_class (line, MU_CTYPE_SPACE);
	      char *arg = mu_str_skip_class_comp (word, MU_CTYPE_SPACE);
	      if (*arg)
		{
		  *arg++ = 0;
		  arg = mu_str_skip_class (arg, MU_CTYPE_SPACE);
		}
	      
	      mu_argcv_free (argc, argv);
	      argc = 2;
	      argv = xcalloc (argc + 1, sizeof (argv[0]));
	      argv[0] = xstrdup (word);
	      argv[1] = xstrdup (arg);
	      argv[2] = NULL;
	    }
	  status = command->func (argc, argv);
	}
    }
  mu_argcv_free (argc, argv);
  return status;
}

/* Look up NAME as the name of a command, and return a pointer to that
   command.  Return a NULL pointer if NAME isn't a command name. */
COMMAND *
find_command (char *name)
{
  COMMAND *cp;

  for (cp = commands; cp->name; cp++)
    if (strcmp (cp->name, name) == 0)
      return cp;

  return NULL;
}

int
com_verbose (int argc, char **argv)
{
  if (argc == 1)
    {
      if (verbose)
	printf ("verbose is on\n");
      else
	printf ("verbose is off\n");
    }
  else
    {
      int bv;

      if (get_bool (argv[1], &bv) == 0)
	{
	  verbose = bv;
	  if (pop3 != NULL)
	    {
	      if (verbose == 1)
		mu_pop3_trace (pop3, MU_POP3_TRACE_SET);
	      else
		mu_pop3_trace (pop3, MU_POP3_TRACE_CLR);
	    }
	}
    }
  return 0;
}

int
com_user (int argc, char **argv)
{
  int status;
  
  status = mu_pop3_user (pop3, argv[1]);
  if (status == 0)
    username = strdup (argv[1]);
  return status;
}

int
com_apop (int argc, char **argv)
{
  int status;

  status = mu_pop3_apop (pop3, argv[1], argv[2]);
  if (status == 0)
    {
      username = strdup (argv[1]);
      pop_session_status = pop_session_logged_in;
    }
  return status;
}

int
com_capa (int argc, char **argv)
{
  mu_iterator_t iterator = NULL;
  int status = 0;
  int reread = 0;
  int i = 1;
  
  for (i = 1; i < argc; i++)
    {
      if (strcmp (argv[i], "-reread") == 0)
	reread = 1;
      else
	break;
    }

  if (i < argc)
    {
      if (reread)
	{
	  status = mu_pop3_capa (pop3, 1, NULL);
	  if (status)
	    return status;
	}
      for (; i < argc; i++)
	{
	  const char *elt;
	  int rc = pop3_capa_test (pop3, argv[i], &elt);
	  switch (rc)
	    {
	    case 0:
	      if (*elt)
		printf ("%s: %s\n", argv[i], elt);
	      else
		printf ("%s is set\n", argv[i]);
	      break;

	    case MU_ERR_NOENT:
	      printf ("%s is not set\n", argv[i]);
	      break;

	    default:
	      return rc;
	    }
	}
    }
  else
    {
      status = mu_pop3_capa (pop3, reread, &iterator);

      if (status == 0)
	{
	  for (mu_iterator_first (iterator);
	       !mu_iterator_is_done (iterator); mu_iterator_next (iterator))
	    {
	      char *capa = NULL;
	      mu_iterator_current (iterator, (void **) &capa);
	      printf ("CAPA: %s\n", capa ? capa : "");
	    }
	  mu_iterator_destroy (&iterator);
	}
    }
  return status;
}

int
com_uidl (int argc, char **argv)
{
  int status = 0;
  if (argc == 1)
    {
      mu_iterator_t uidl_iterator = NULL;
      status = mu_pop3_uidl_all (pop3, &uidl_iterator);
      if (status == 0)
	{
	  for (mu_iterator_first (uidl_iterator);
	       !mu_iterator_is_done (uidl_iterator);
	       mu_iterator_next (uidl_iterator))
	    {
	      char *uidl = NULL;
	      mu_iterator_current (uidl_iterator, (void **) &uidl);
	      printf ("UIDL: %s\n", uidl ? uidl : "");
	    }
	  mu_iterator_destroy (&uidl_iterator);
	}
    }
  else
    {
      char *uidl = NULL;
      unsigned int msgno = strtoul (argv[1], NULL, 10);
      status = mu_pop3_uidl (pop3, msgno, &uidl);
      if (status == 0)
	printf ("Msg: %d UIDL: %s\n", msgno, uidl ? uidl : "");
      free (uidl);
    }
  return status;
}

int
com_list (int argc, char **argv)
{
  int status = 0;
  if (argc == 1)
    {
      mu_iterator_t list_iterator;
      status = mu_pop3_list_all (pop3, &list_iterator);
      if (status == 0)
	{
	  for (mu_iterator_first (list_iterator);
	       !mu_iterator_is_done (list_iterator);
	       mu_iterator_next (list_iterator))
	    {
	      char *list = NULL;
	      mu_iterator_current (list_iterator, (void **) &list);
	      printf ("LIST: %s\n", (list) ? list : "");
	    }
	  mu_iterator_destroy (&list_iterator);
	}
    }
  else
    {
      size_t size = 0;
      unsigned int msgno = strtoul (argv[1], NULL, 10);
      status = mu_pop3_list (pop3, msgno, &size);
      if (status == 0)
	printf ("Msg: %u Size: %lu\n", msgno, (unsigned long) size);
    }
  return status;
}

int
com_noop (int argc MU_ARG_UNUSED, char **argv MU_ARG_UNUSED)
{
  return mu_pop3_noop (pop3);
}

static void
echo_off (struct termios *stored_settings)
{
  struct termios new_settings;
  tcgetattr (0, stored_settings);
  new_settings = *stored_settings;
  new_settings.c_lflag &= (~ECHO);
  tcsetattr (0, TCSANOW, &new_settings);
}

static void
echo_on (struct termios *stored_settings)
{
  tcsetattr (0, TCSANOW, stored_settings);
}

int
com_prompt (int argc, char **argv)
{
  int quote;
  size_t size;
  
  free (prompt);
  size = mu_argcv_quoted_length (argv[1], &quote);
  prompt = malloc (size + 1);
  if (!prompt)
    {
      mu_error ("Memory exhausted");
      exit (1);
    }
  mu_argcv_unquote_copy (prompt, argv[1], size);
  return 0;
}

int
com_pass (int argc, char **argv)
{
  int status;
  char pass[256];
  char *pwd;
  
  if (argc == 1)
    {
      struct termios stored_settings;

      printf ("passwd:");
      fflush (stdout);
      echo_off (&stored_settings);
      fgets (pass, sizeof pass, stdin);
      echo_on (&stored_settings);
      putchar ('\n');
      fflush (stdout);
      pass[strlen (pass) - 1] = '\0';	/* nuke the trailing line.  */
      pwd = pass;
    }
  else
    pwd = argv[1];
  status = mu_pop3_pass (pop3, pwd);
  if (status == 0)
    pop_session_status = pop_session_logged_in;
  return status;
}

int
com_stat (int argc MU_ARG_UNUSED, char **argv MU_ARG_UNUSED)
{
  unsigned count = 0;
  size_t size = 0;
  int status = 0;

  status = mu_pop3_stat (pop3, &count, &size);
  printf ("Mesgs: %lu Size %lu\n",
	  (unsigned long) count, (unsigned long) size);
  return status;
}

int
com_stls (int argc MU_ARG_UNUSED, char **argv MU_ARG_UNUSED)
{
  return mu_pop3_stls (pop3);
}

int
com_dele (int argc, char **argv)
{
  unsigned msgno;
  msgno = strtoul (argv[1], NULL, 10);
  return mu_pop3_dele (pop3, msgno);
}

/* Print out help for ARG, or for all of the commands if ARG is
   not present. */
int
com_help (int argc, char **argv)
{
  int i;
  int printed = 0;
  char *name = argv[1];
  
  for (i = 0; commands[i].name; i++)
    {
      if (!name || (strcmp (name, commands[i].name) == 0))
	{
	  printf ("%s\t\t%s.\n", commands[i].name, commands[i].doc);
	  printed++;
	}
    }

  if (!printed)
    {
      printf ("No commands match `%s'.  Possibilties are:\n", name);

      for (i = 0; commands[i].name; i++)
	{
	  /* Print in six columns. */
	  if (printed == 6)
	    {
	      printed = 0;
	      printf ("\n");
	    }

	  printf ("%s\t", commands[i].name);
	  printed++;
	}

      if (printed)
	printf ("\n");
    }
  return 0;
}

int
com_rset (int argc MU_ARG_UNUSED, char **argv MU_ARG_UNUSED)
{
  return mu_pop3_rset (pop3);
}

int
com_top (int argc, char **argv)
{
  mu_stream_t stream;
  unsigned int msgno;
  unsigned int lines;
  int status;

  msgno = strtoul (argv[1], NULL, 10);
  if (argc == 3)
    lines = strtoul (argv[2], NULL, 10);
  else
    lines = 5;

  status = mu_pop3_top (pop3, msgno, lines, &stream);

  if (status == 0)
    {
      size_t n = 0;
      char buf[128];
      while ((mu_stream_readline (stream, buf, sizeof buf, &n) == 0) && n)
	printf ("%s", buf);
      mu_stream_destroy (&stream);
    }
  return status;
}

int
com_retr (int argc, char **argv)
{
  mu_stream_t stream;
  unsigned int msgno;
  int status;

  msgno = strtoul (argv[1], NULL, 10);
  status = mu_pop3_retr (pop3, msgno, &stream);

  if (status == 0)
    {
      size_t n = 0;
      char buf[128];
      while ((mu_stream_readline (stream, buf, sizeof buf, &n) == 0) && n)
	printf ("%s", buf);
      mu_stream_destroy (&stream);
    }
  return status;
}

int
com_connect (int argc, char **argv)
{
  int status;
  int n = 0;
  int tls = 0;
  int i = 1;
  
  for (i = 1; i < argc; i++)
    {
      if (strcmp (argv[i], "-tls") == 0)
	{
	  if (WITH_TLS)
	    tls = 1;
	  else
	    {
	      mu_error ("TLS not supported");
	      return 0;
	    }
	}
      else
	break;
    }

  argc -= i;
  argv += i;
  
  if (argc >= 2)
    {
      if (get_port (argv[1], &n))
	return 0;
    }
  else if (tls)
    n = MU_POP3_DEFAULT_SSL_PORT;
  else
    n = MU_POP3_DEFAULT_PORT;
  
  if (pop_session_status != pop_session_disconnected)
    com_disconnect (0, NULL);
  
  status = mu_pop3_create (&pop3);
  if (status == 0)
    {
      mu_stream_t tcp;

      if (verbose)
	mu_pop3_trace (pop3, MU_POP3_TRACE_SET);
      status = mu_tcp_stream_create (&tcp, argv[0], n, MU_STREAM_READ);
      if (status == 0)
	{
#ifdef WITH_TLS
	  if (tls)
	    {
	      mu_stream_t tlsstream;
	      
	      status = mu_stream_open (tcp);
	      if (status)
		{
		  mu_error ("cannot open connection: %s",
			    mu_stream_strerror (tcp, status));
		  mu_stream_destroy (&tcp);
		  return 0;
		}

	      status = mu_tls_client_stream_create (&tlsstream, tcp, tcp, 0);
	      mu_stream_unref (tcp);
	      if (status)
		{
		  mu_error ("cannot create TLS stream: %s",
			    mu_strerror (status));
		  return 0;
		}
	      tcp = tlsstream;
	    }
#endif
	  mu_pop3_set_carrier (pop3, tcp);
	  status = mu_pop3_connect (pop3);
	}
      else
	{
	  mu_pop3_destroy (&pop3);
	  pop3 = NULL;
	}
    }

  if (status)
    mu_error ("Failed to create pop3: %s", mu_strerror (status));
  else
    {
      connect_argc = argc;
      connect_argv = xcalloc (argc, sizeof (*connect_argv));
      for (i = 0; i < argc; i++)
	connect_argv[i] = xstrdup (argv[i]);
      connect_argv[i] = NULL;
      port = n;
      pop_session_status = pop_session_connected;
    }
  
  return status;
}

int
com_disconnect (int argc MU_ARG_UNUSED, char **argv MU_ARG_UNUSED)
{
  if (pop3)
    {
      mu_pop3_disconnect (pop3);
      mu_pop3_destroy (&pop3);
      pop3 = NULL;
      
      mu_argcv_free (connect_argc, connect_argv);
      connect_argc = 0;
      connect_argv = NULL;
      pop_session_status = pop_session_disconnected;
    }
  return 0;
}

int
com_quit (int argc MU_ARG_UNUSED, char **argv MU_ARG_UNUSED)
{
  int status = 0;
  if (pop3)
    {
      if (mu_pop3_quit (pop3) == 0)
	{
	  status = com_disconnect (0, NULL);
	}
      else
	{
	  printf ("Try 'exit' to leave %s\n", mu_program_name);
	}
    }
  else
    printf ("Try 'exit' to leave %s\n", mu_program_name);
  return status;
}

int
com_exit (int argc MU_ARG_UNUSED, char **argv MU_ARG_UNUSED)
{
  if (pop3)
    {
      mu_pop3_disconnect (pop3);
      mu_pop3_destroy (&pop3);
    }
  done = 1;
  return 0;
}


int
main (int argc MU_ARG_UNUSED, char **argv)
{
  char *line, *s;

  mu_set_program_name (argv[0]);
  prompt = strdup (DEFAULT_PROMPT);
  initialize_readline ();	/* Bind our completer. */
#ifdef WITH_TLS
  mu_init_tls_libs ();
#endif  
  /* Loop reading and executing lines until the user quits. */
  while (!done)
    {
      char *p = expand_prompt ();
      line = readline (p);
      free (p);
      
      if (!line)
	break;

      /* Remove leading and trailing whitespace from the line.
         Then, if there is anything left, add it to the history list
         and execute it. */
      s = mu_str_stripws (line);

      if (*s)
	{
	  int status;
	  add_history (s);
	  status = execute_line (s);
	  if (status != 0)
	    mu_error ("Error: %s", mu_strerror (status));
	}

      free (line);
    }
  exit (0);
}