/*
 * Copyright (C) 1997-2000 Thomas Roessler <roessler@guug.de>
 * 
 *     This program 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 2 of the License, or (at your option) any later
 *     version.
 * 
 *     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 General Public License for more
 *     details.
 * 
 *     You should have received a copy of the GNU General Public
 *     License along with this program; if not, write to the Free
 *     Software Foundation, Inc., 675 Mass Ave, Cambridge, MA
 *     02139, USA.
 */

/* Generally useful, pgp-related functions. */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <time.h>

#include "lib.h"
#include "pgplib.h"

const char *pgp_pkalgbytype (unsigned char type)
{
  switch (type)
  {
  case 1:
    return "RSA";
  case 2:
    return "RSA";
  case 3:
    return "RSA";
  case 16:
    return "ElG";
  case 17:
    return "DSA";
  case 20:
    return "ElG";
  default:
    return "unk";
  }
}


static struct
{
  char *pkalg;
  char *micalg;
}
pktomic[] =
{
  {
    "RSA", "pgp-md5"
  }
  ,
  {
    "ElG", "pgp-rmd160"
  }
  ,
  {
    "DSA", "pgp-sha1"
  }
  ,
  {
    NULL, "x-unknown"
  }
};


const char *pgp_pkalg_to_mic (const char *alg)
{
  int i;

  for (i = 0; pktomic[i].pkalg; i++)
  {
    if (!mutt_strcasecmp (pktomic[i].pkalg, alg))
      break;
  }

  return pktomic[i].micalg;
}


/* unused */

#if 0

static const char *hashalgbytype (unsigned char type)
{
  switch (type)
  {
  case 1:
    return "MD5";
  case 2:
    return "SHA1";
  case 3:
    return "RIPE-MD/160";
  case 4:
    return "HAVAL";
  default:
    return "unknown";
  }
}

#endif

short pgp_canencrypt (unsigned char type)
{
  switch (type)
  {
  case 1:
  case 2:
  case 16:
  case 20:
    return 1;
  default:
    return 0;
  }
}

short pgp_cansign (unsigned char type)
{
  switch (type)
  {
  case 1:
  case 3:
  case 17:
  case 20:
    return 1;
  default:
    return 0;
  }
}

/* return values: 

 * 1 = sign only
 * 2 = encrypt only
 * 3 = both
 */

short pgp_get_abilities (unsigned char type)
{
  return (pgp_canencrypt (type) << 1) | pgp_cansign (type);
}

void pgp_free_uid (pgp_uid_t ** upp)
{
  pgp_uid_t *up, *q;

  if (!upp || !*upp)
    return;
  for (up = *upp; up; up = q)
  {
    q = up->next;
    safe_free ((void **) &up->addr);
    safe_free ((void **) &up);
  }

  *upp = NULL;
}

pgp_uid_t *pgp_copy_uids (pgp_uid_t *up, pgp_key_t *parent)
{
  pgp_uid_t *l = NULL;
  pgp_uid_t **lp = &l;

  for (; up; up = up->next)
  {
    *lp = safe_calloc (1, sizeof (pgp_uid_t));
    (*lp)->trust  = up->trust;
    (*lp)->addr   = safe_strdup (up->addr);
    (*lp)->parent = parent;
    lp = &(*lp)->next;
  }

  return l;
}

static void _pgp_free_key (pgp_key_t ** kpp)
{
  pgp_key_t *kp;

  if (!kpp || !*kpp)
    return;

  kp = *kpp;

  pgp_free_uid (&kp->address);
  safe_free ((void **) &kp->keyid);
  safe_free ((void **) kpp);
}

pgp_key_t *pgp_remove_key (pgp_key_t ** klist, pgp_key_t * key)
{
  pgp_key_t **last;
  pgp_key_t *p, *q, *r;

  if (!klist || !*klist || !key)
    return NULL;

  if (key->parent && key->parent != key)
    key = key->parent;

  last = klist;
  for (p = *klist; p && p != key; p = p->next)
    last = &p->next;

  if (!p)
    return NULL;

  for (q = p->next, r = p; q && q->parent == p; q = q->next)
    r = q;

  if (r)
    r->next = NULL;

  *last = q;
  return q;
}

void pgp_free_key (pgp_key_t ** kpp)
{
  pgp_key_t *p, *q, *r;

  if (!kpp || !*kpp)
    return;

  if ((*kpp)->parent && (*kpp)->parent != *kpp)
    *kpp = (*kpp)->parent;
  
  /* Order is important here:
   *
   * - First free all children.
   * - If we are an orphan (i.e., our parent was not in the key list),
   *   free our parent.
   * - free ourselves.
   */

  for (p = *kpp; p; p = q)
  {
    for (q = p->next; q && q->parent == p; q = r)
    {
      r = q->next;
      _pgp_free_key (&q);
    }
    if (p->parent)
      _pgp_free_key (&p->parent);

    _pgp_free_key (&p);
  }

  *kpp = NULL;
}