#define _GNU_SOURCE

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <errno.h>

#include <assert.h>

#include <argp.h>

#include <rpm/rpmlib.h>

#include <err.h>

typedef enum {

        RPMNVRCMP,

        VERSNVRCMP,

        RPMVERCMP,

        STRVERSCMP,

} comparitors;

static comparitors comparitor = RPMNVRCMP;

static inline void *xmalloc(size_t sz)

{

        void *ret = malloc(sz);

        assert(sz == 0 || ret != NULL);

        return ret;

}

static inline void *xrealloc(void *p, size_t sz)

{

        void *ret = realloc(p, sz);

        assert(sz == 0 || ret != NULL);

        return ret;

}

static inline char *xstrdup(const char * const s)

{

        void *ret = strdup(s);

        assert(s == NULL || ret != NULL);

        return ret;

}

static size_t

read_file (const char *input, char **ret)

{

  FILE *in;

  size_t s;

  size_t sz = 2048;

  size_t offset = 0;

  char *text;

  if (!strcmp(input, "-"))

    in = stdin;

  else

    in = fopen(input, "r");

  text = xmalloc (sz);

  if (!in)

    err(1, "cannot open `%s'", input);

  while ((s = fread (text + offset, 1, sz - offset, in)) != 0)

    {

      offset += s;

      if (sz - offset == 0)

	{

	  sz += 2048;

	  text = xrealloc (text, sz);

	}

    }

  text[offset] = '\0';

  *ret = text;

  if (in != stdin)

    fclose(in);

  return offset + 1;

}

/* returns name/version/release */

/* NULL string pointer returned if nothing found */

static void

split_package_string (char *package_string, char **name,

                     char **version, char **release)

{

  char *package_version, *package_release;

  /* Release */

  package_release = strrchr (package_string, '-');

  if (package_release != NULL)

      *package_release++ = '\0';

  *release = package_release;

  /* Version */

  package_version = strrchr(package_string, '-');

  if (package_version != NULL)

      *package_version++ = '\0';

  *version = package_version;

  /* Name */

  *name = package_string;

  /* Bubble up non-null values from release to name */

  if (*name == NULL)

    {

      *name = (*version == NULL ? *release : *version);

      *version = *release;

      *release = NULL;

    }

  if (*version == NULL)

    {

      *version = *release;

      *release = NULL;

    }

}

static int

cmprpmversp(const void *p1, const void *p2)

{

        return rpmvercmp(*(char * const *)p1, *(char * const *)p2);

}

static int

cmpstrversp(const void *p1, const void *p2)

{

        return strverscmp(*(char * const *)p1, *(char * const *)p2);

}

/*

 * package name-version-release comparator for qsort

 * expects p, q which are pointers to character strings (char *)

 * which will not be altered in this function

 */

static int

package_version_compare (const void *p, const void *q)

{

  char *local_p, *local_q;

  char *lhs_name, *lhs_version, *lhs_release;

  char *rhs_name, *rhs_version, *rhs_release;

  int vercmpflag = 0;

  int (*cmp)(const char *s1, const char *s2);

  switch(comparitor)

    {

    default: /* just to shut up -Werror=maybe-uninitialized */

    case RPMNVRCMP:

      cmp = rpmvercmp;

      break;

    case VERSNVRCMP:

      cmp = strverscmp;

      break;

    case RPMVERCMP:

      return cmprpmversp(p, q);

      break;

    case STRVERSCMP:

      return cmpstrversp(p, q);

      break;

    }

  local_p = alloca (strlen (*(char * const *)p) + 1);

  local_q = alloca (strlen (*(char * const *)q) + 1);

  /* make sure these allocated */

  assert (local_p);

  assert (local_q);

  strcpy (local_p, *(char * const *)p);

  strcpy (local_q, *(char * const *)q);

  split_package_string (local_p, &lhs_name, &lhs_version, &lhs_release);

  split_package_string (local_q, &rhs_name, &rhs_version, &rhs_release);

  /* Check Name and return if unequal */

  vercmpflag = cmp ((lhs_name == NULL ? "" : lhs_name),

                    (rhs_name == NULL ? "" : rhs_name));

  if (vercmpflag != 0)

    return vercmpflag;

  /* Check version and return if unequal */

  vercmpflag = cmp ((lhs_version == NULL ? "" : lhs_version),

                    (rhs_version == NULL ? "" : rhs_version));

  if (vercmpflag != 0)

    return vercmpflag;

  /* Check release and return the version compare value */

  vercmpflag = cmp ((lhs_release == NULL ? "" : lhs_release),

                    (rhs_release == NULL ? "" : rhs_release));

  return vercmpflag;

}

static void

add_input (const char *filename, char ***package_names, size_t *n_package_names)

{

  char *orig_input_buffer = NULL;

  char *input_buffer;

  char *position_of_newline;

  char **names = *package_names;

  char **new_names = NULL;

  size_t n_names = *n_package_names;

  if (!*package_names)

    new_names = names = xmalloc (sizeof (char *) * 2);

  if (read_file (filename, &orig_input_buffer) < 2)

    {

      if (new_names)

	free (new_names);

      if (orig_input_buffer)

	free (orig_input_buffer);

      return;

    }

  input_buffer = orig_input_buffer;

  while (input_buffer && *input_buffer &&

	 (position_of_newline = strchrnul (input_buffer, '\n')))

    {

      size_t sz = position_of_newline - input_buffer;

      char *new;

      if (sz == 0)

	{

	  input_buffer = position_of_newline + 1;

	  continue;

	}

      new = xmalloc (sz+1);

      strncpy (new, input_buffer, sz);

      new[sz] = '\0';

      names = xrealloc (names, sizeof (char *) * (n_names + 1));

      names[n_names] = new;

      n_names++;

      /* move buffer ahead to next line */

      input_buffer = position_of_newline + 1;

      if (*position_of_newline == '\0')

	input_buffer = NULL;

    }

  free (orig_input_buffer);

  *package_names = names;

  *n_package_names = n_names;

}

static char *

help_filter (int key, const char *text, void *input __attribute__ ((unused)))

{

  return (char *)text;

}

static struct argp_option options[] = {

  { "comparitor", 'c', "COMPARITOR", 0, "[rpm-nvr-cmp|vers-nvr-cmp|rpmvercmp|strverscmp]", 0},

  { 0, }

};

struct arguments

{

  size_t ninputs;

  size_t input_max;

  char **inputs;

};

static error_t

argp_parser (int key, char *arg, struct argp_state *state)

{

  struct arguments *arguments = state->input;

  switch (key)

    {

    case 'c':

      if (!strcmp(arg, "rpm-nvr-cmp") || !strcmp(arg, "rpmnvrcmp"))

        comparitor = RPMNVRCMP;

      else if (!strcmp(arg, "vers-nvr-cmp") || !strcmp(arg, "versnvrcmp"))

        comparitor = VERSNVRCMP;

      else if (!strcmp(arg, "rpmvercmp"))

        comparitor = RPMVERCMP;

      else if (!strcmp(arg, "strverscmp"))

        comparitor = STRVERSCMP;

      else

        err(1, "Invalid comparitor \"%s\"", arg);

      break;

    case ARGP_KEY_ARG:

      assert (arguments->ninputs < arguments->input_max);

      arguments->inputs[arguments->ninputs++] = xstrdup (arg);

      break;

    default:

      return ARGP_ERR_UNKNOWN;

    }

  return 0;

}

static struct argp argp = {

  options, argp_parser, "[INPUT_FILES]",

  "Sort a list of strings in RPM version sort order.",

  NULL, help_filter, NULL

};

int

main (int argc, char *argv[])

{

  struct arguments arguments;

  char **package_names = NULL;

  size_t n_package_names = 0;

  int i;

  memset (&arguments, 0, sizeof (struct arguments));

  arguments.input_max = argc+1;

  arguments.inputs = xmalloc ((arguments.input_max + 1)

			      * sizeof (arguments.inputs[0]));

  memset (arguments.inputs, 0, (arguments.input_max + 1)

	  * sizeof (arguments.inputs[0]));

  /* Parse our arguments */

  if (argp_parse (&argp, argc, argv, 0, 0, &arguments) != 0)

    errx(1, "%s", "Error in parsing command line arguments\n");

  /* If there's no inputs in argv, add one for stdin */

  if (!arguments.ninputs)

    {

      arguments.ninputs = 1;

      arguments.inputs[0] = xmalloc (2);

      strcpy(arguments.inputs[0], "-");

    }

  for (i = 0; i < arguments.ninputs; i++)

    add_input(arguments.inputs[i], &package_names, &n_package_names);

  if (package_names == NULL || n_package_names < 1)

    errx(1, "Invalid input");

  qsort (package_names, n_package_names, sizeof (char *),

	 package_version_compare);

  /* send sorted list to stdout */

  for (i = 0; i < n_package_names; i++)

    {

      fprintf (stdout, "%s\n", package_names[i]);

      free (package_names[i]);

    }

  free (package_names);

  for (i = 0; i < arguments.ninputs; i++)

    free (arguments.inputs[i]);

  free (arguments.inputs);

  return 0;

}