/* sexp-conv.c
 *
 * Conversion tool for handling the different flavours of sexp
 * syntax. */

/* nettle, low-level cryptographics library
 *
 * Copyright (C) 2002 Niels Möller
 *  
 * The nettle library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 * 
 * The nettle library 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 Lesser General Public
 * License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with the nettle library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02111-1301, USA.
 */

#if HAVE_CONFIG_H
# include "config.h"
#endif

#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#if HAVE_FCNTL_LOCKING
# if HAVE_SYS_TYPES_H
#  include <sys/types.h>
# endif
# if HAVE_UNISTD_H
#  include <unistd.h>
# endif
# include <fcntl.h>
#endif

#include "buffer.h"
#include "nettle-meta.h"

#include "getopt.h"

#include "input.h"
#include "output.h"
#include "parse.h"

#define BUG_ADDRESS "nettle-bugs@lists.lysator.liu.se"


/* Conversion functions. */

/* Should be called with input->token being the first token of the
 * expression, to be converted, and return with input->token being the
 * last token of the expression. */
static void
sexp_convert_item(struct sexp_parser *parser,
		  struct sexp_compound_token *token,
		  struct sexp_output *output, enum sexp_mode mode_out,
		  unsigned indent)
{
  if (mode_out == SEXP_TRANSPORT)
    {
      sexp_put_char(output, '{');
      sexp_put_code_start(output, &nettle_base64);
      sexp_convert_item(parser, token, output, SEXP_CANONICAL, 0);
      sexp_put_code_end(output);
      sexp_put_char(output, '}');
    }
  else switch(token->type)
    {
    case SEXP_LIST_END:
      die("Unmatched end of list.\n");
    case SEXP_EOF:
      die("Unexpected end of file.\n");
    case SEXP_CODING_END:
      die("Unexpected end of coding.\n");

    case SEXP_LIST_START:
      {
	unsigned item;

	sexp_put_char(output, '(');
  
	for (item = 0;
	     sexp_parse(parser, token), token->type != SEXP_LIST_END;
	     item++)
	  {
	    if (mode_out == SEXP_ADVANCED)
	      {
		/* FIXME: Adapt pretty printing to handle a big first
		 * element. */
		switch (item)
		  {
		  case 0:
		    if (token->type == SEXP_COMMENT)
		      {
			indent = output->pos;
			/* Disable the indentation setup for next item */
			item++;
		      }
		    break;
		    
		  case  1:
		    sexp_put_char(output, ' ');
		    indent = output->pos;
		    break;

		  default:
		    sexp_put_newline(output, indent);
		    break;
		  }
	      }

	    sexp_convert_item(parser, token, output, mode_out, indent);
	  }
	sexp_put_char(output, ')');

	break;
      }      
      
    case SEXP_STRING:
      sexp_put_string(output, mode_out, &token->string);
      break;

    case SEXP_DISPLAY:
      sexp_put_char(output, '[');
      sexp_put_string(output, mode_out, &token->display);
      sexp_put_char(output, ']');
      sexp_put_string(output, mode_out, &token->string);      
      break;

    case SEXP_COMMENT:
      if (mode_out == SEXP_ADVANCED)
	{
	  sexp_put_data(output, token->string.size, token->string.contents);
	  sexp_put_soft_newline(output, indent);
	}
      break;
    default:
      /* Internal error */
      abort();
    }
}


/* Argument parsing and main program */

/* The old lsh sexp-conv program took the following options:
 *
 * Usage: sexp-conv [OPTION...]
 *             Conversion: sexp-conv [options] <INPUT-SEXP >OUTPUT
 *   or:  sexp-conv [OPTION...]
 *             Fingerprinting: sexp-conv --raw-hash [ --hash=ALGORITHM ]
 *             <PUBLIC-KEY
 * Reads an s-expression on stdin, and outputs the same s-expression on stdout,
 * possibly using a different encoding. By default, output uses the advanced
 * encoding. 
 * 
 *       --hash=Algorithm       Hash algorithm (default sha1).
 *       --once                 Process exactly one s-expression.
 *       --raw-hash             Output the hash for the canonical representation
 *                              of the object, in hexadecimal.
 *       --replace=Substitution An expression `/before/after/' replaces all
 *                              occurances of the atom `before' with `after'. The
 *                              delimiter `/' can be any single character.
 *       --select=Operator      Select a subexpression (e.g `caddr') for
 *                              processing.
 *       --spki-hash            Output an SPKI hash for the object.
 *       --debug                Print huge amounts of debug information
 *       --log-file=File name   Append messages to this file.
 *   -q, --quiet                Suppress all warnings and diagnostic messages
 *       --trace                Detailed trace
 *   -v, --verbose              Verbose diagnostic messages
 * 
 *  Valid sexp-formats are transport, canonical, advanced, and international.
 * 
 *  Valid sexp-formats are transport, canonical, advanced, advanced-hex and
 *  international.
 *   -f, --output-format=format Variant of the s-expression syntax to generate.
 *   -i, --input-format=format  Variant of the s-expression syntax to accept.
 * 
 *   -?, --help                 Give this help list
 *       --usage                Give a short usage message
 *   -V, --version              Print program version
 */ 

struct conv_options
{
  /* Output mode */
  enum sexp_mode mode;
  int prefer_hex;
  int once;
  int lock;
  unsigned width;
  const struct nettle_hash *hash;
};

enum { OPT_ONCE = 300, OPT_HASH, OPT_LOCK, OPT_HELP };

static int
match_argument(const char *given, const char *name)
{
  /* FIXME: Allow abbreviations */
  return !strcmp(given, name);
}

static void
parse_options(struct conv_options *o,
	      int argc, char **argv)
{  
  o->mode = SEXP_ADVANCED;
  o->prefer_hex = 0;
  o->once = 0;
  o->lock = 0;
  o->hash = NULL;
  o->width = 72;
  
  for (;;)
    {
      static const struct nettle_hash *hashes[] =
	{ &nettle_md5, &nettle_sha1, &nettle_sha256, NULL };
  
      static const struct option options[] =
	{
	  /* Name, args, flag, val */
	  { "help", no_argument, NULL, OPT_HELP },
	  { "version", no_argument, NULL, 'V' },
	  { "once", no_argument, NULL, OPT_ONCE },
	  { "syntax", required_argument, NULL, 's' },
	  { "hash", optional_argument, NULL, OPT_HASH },
	  { "raw-hash", optional_argument, NULL, OPT_HASH },
	  { "width", required_argument, NULL, 'w' },
#if HAVE_FCNTL_LOCKING
	  { "lock", no_argument, NULL, OPT_LOCK },
#endif
#if 0
	  /* Not yet implemented */
	  { "replace", required_argument, NULL, OPT_REPLACE },
	  { "select", required_argument, NULL, OPT_SELECT },
	  { "spki-hash", optional_argument, NULL, OPT_SPKI_HASH },
#endif
	  { NULL, 0, NULL, 0 }
	};
      int c;
      int option_index = 0;
      unsigned i;
     
      c = getopt_long(argc, argv, "Vs:w:", options, &option_index);

      switch (c)
	{
	default:
	  abort();
	  
	case -1:
	  if (optind != argc)
	    die("sexp-conv: Command line takes no arguments, only options.\n");
	  return;

	case '?':
	  exit(EXIT_FAILURE);
	  
	case 'w':
	  {
	    char *end;
	    int width = strtol(optarg, &end , 0);
	    if (!*optarg || *end || width < 0)
	      die("sexp-conv: Invalid width `%s'.\n", optarg);

	    o->width = width;
	    break;
	  }
	case 's':
	  if (o->hash)
	    werror("sexp-conv: Combining --hash and -s usually makes no sense.\n");
	  if (match_argument(optarg, "advanced"))
	    o->mode = SEXP_ADVANCED;
	  else if (match_argument(optarg, "transport"))
	    o->mode = SEXP_TRANSPORT;
	  else if (match_argument(optarg, "canonical"))
	    o->mode = SEXP_CANONICAL;
	  else if (match_argument(optarg, "hex"))
	    {
	      o->mode = SEXP_ADVANCED;
	      o->prefer_hex = 1;
	    }
	  else
	    die("Available syntax variants: advanced, transport, canonical\n");
	  break;

	case OPT_ONCE:
	  o->once = 1;
	  break;
	
	case OPT_HASH:
	  o->mode = SEXP_CANONICAL;
	  if (!optarg)
	    o->hash = &nettle_sha1;
	  else
	    for (i = 0;; i++)
	      {
		if (!hashes[i])
		  die("sexp_conv: Unknown hash algorithm `%s'\n",
		      optarg);
	      
		if (match_argument(optarg, hashes[i]->name))
		  {
		    o->hash = hashes[i];
		    break;
		  }
	      }
	  break;
#if HAVE_FCNTL_LOCKING
	case OPT_LOCK:
	  o->lock = 1;
	  break;
#endif
	case OPT_HELP:
	  printf("Usage: sexp-conv [OPTION...]\n"
		 "  Conversion:     sexp-conv [OPTION...] <INPUT-SEXP\n"
		 "  Fingerprinting: sexp-conv --hash=HASH <INPUT-SEXP\n\n"
		 "Reads an s-expression on stdin, and outputs the same\n"
		 "sexp on stdout, possibly with a different syntax.\n\n"
		 "       --hash[=ALGORITHM]   Outputs only the hash of the expression.\n"
		 "                            Available hash algorithms:\n"
		 "                            ");
	  for(i = 0; hashes[i]; i++)
	    {
	      if (i) printf(", ");
	      printf("%s", hashes[i]->name);
	    }
	  printf(" (default is sha1).\n"
		 "   -s, --syntax=SYNTAX      The syntax used for the output. Available\n"
		 "                            variants: advanced, hex, transport, canonical\n"
		 "       --once               Process only the first s-expression.\n"
		 "   -w, --width=WIDTH        Linewidth for base64 encoded data.\n"
		 "                            Zero means no limit.\n"
#if HAVE_FCNTL_LOCKING
		 "       --lock               Lock output file.\n"
#endif
		 "       --raw-hash           Alias for --hash, for compatibility\n"
		 "                            with lsh-1.x.\n\n"
		 "Report bugs to " BUG_ADDRESS ".\n");
	  exit(EXIT_SUCCESS);

	case 'V':
	  printf("sexp-conv (" PACKAGE_STRING ")\n");
	  exit (EXIT_SUCCESS);
	}
    }
}

int
main(int argc, char **argv)
{
  struct conv_options options;
  struct sexp_input input;
  struct sexp_parser parser;
  struct sexp_compound_token token;
  struct sexp_output output;

  parse_options(&options, argc, argv);

  sexp_input_init(&input, stdin);
  sexp_parse_init(&parser, &input, SEXP_ADVANCED);
  sexp_compound_token_init(&token);
  sexp_output_init(&output, stdout,
		   options.width, options.prefer_hex);

#if HAVE_FCNTL_LOCKING
  if (options.lock)
    {
      struct flock fl;
  
      memset(&fl, 0, sizeof(fl));
      fl.l_type = F_WRLCK;
      fl.l_whence = SEEK_SET;
      fl.l_start = 0;
      fl.l_len = 0; /* Means entire file. */
      
      if (fcntl(STDOUT_FILENO, F_SETLKW, &fl) == -1)
	die("Locking output file failed: %s\n", strerror(errno));
    }
#endif /* HAVE_FCNTL_LOCKING */
  if (options.hash)
    {
      /* Leaks the context, but that doesn't matter */
      void *ctx = xalloc(options.hash->context_size);
      sexp_output_hash_init(&output, options.hash, ctx);
    }
  
  sexp_get_char(&input);
  
  sexp_parse(&parser, &token);
  
  if (token.type == SEXP_EOF)
    {
      if (options.once)
	die("sexp-conv: No input expression.\n");
      return EXIT_SUCCESS;
    }
  
  do 
    {
      sexp_convert_item(&parser, &token, &output, options.mode, 0);
      if (options.hash)
	{
	  sexp_put_digest(&output);
	  sexp_put_newline(&output, 0);
	}
      else if (options.mode != SEXP_CANONICAL)
	sexp_put_newline(&output, 0);
	  
      sexp_parse(&parser, &token);
    }
  while (!options.once && token.type != SEXP_EOF);

  sexp_compound_token_clear(&token);
  
  if (fflush(output.f) < 0)
    die("Final fflush failed: %s.\n", strerror(errno));
  
  return EXIT_SUCCESS;
}