/*
     This file is part of GNUnet
     Copyright (C) 2013 GNUnet e.V.

     GNUnet 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.

     GNUnet 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 GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
*/

/**
 * @file credential/plugin_gnsrecord_credential.c
 * @brief gnsrecord plugin to provide the API for CREDENTIAL records
 * @author Adnan Husain
 */

#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_gnsrecord_lib.h"
#include "gnunet_credential_service.h"
#include "gnunet_gnsrecord_plugin.h"
#include "gnunet_signatures.h"
#include "credential_serialization.h"


/**
 * Convert the 'value' of a record to a string.
 *
 * @param cls closure, unused
 * @param type type of the record
 * @param data value in binary encoding
 * @param data_size number of bytes in @a data
 * @return NULL on error, otherwise human-readable representation of the value
 */
static char *
credential_value_to_string (void *cls,
                              uint32_t type,
                              const void *data,
                              size_t data_size)
{

  const char *cdata;

  switch (type)
  {
   case GNUNET_GNSRECORD_TYPE_ATTRIBUTE:
   {
    struct GNUNET_CREDENTIAL_DelegationRecordData sets;
    char *attr_str;
    char *subject_pkey;
    char *tmp_str;
    int i;
    if (data_size < sizeof (struct GNUNET_CREDENTIAL_DelegationRecordData))
      return NULL; /* malformed */
    memcpy (&sets,
            data,
            sizeof (sets));
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "SIZE %llu needed: %llu + %llu\n", 
                data_size,
                GNUNET_ntohll (sets.data_size),
                sizeof (sets));

    cdata = data;
    struct GNUNET_CREDENTIAL_DelegationSetRecord set[ntohl(sets.set_count)];
    if (GNUNET_OK != GNUNET_CREDENTIAL_delegation_set_deserialize (GNUNET_ntohll (sets.data_size),
                                                                   &cdata[sizeof (sets)],
                                                                   ntohl (sets.set_count),
                                                                   set))
      return NULL;

    for (i=0;i<ntohl(sets.set_count);i++)
    {
      subject_pkey = GNUNET_CRYPTO_ecdsa_public_key_to_string (&set[i].subject_key);
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  "%d len attr\n", set[i].subject_attribute_len);
      if (0 == set[i].subject_attribute_len)
      {
        if (0 == i)
        {
          GNUNET_asprintf (&attr_str,
                           "%s",
                           subject_pkey);
        } else {
          GNUNET_asprintf (&tmp_str,
                           "%s,%s",
                           attr_str,
                           subject_pkey);
          GNUNET_free (attr_str);
          attr_str = tmp_str;
        }
      } else {
        if (0 == i)
        {
          GNUNET_asprintf (&attr_str,
                           "%s %s",
                           subject_pkey,
                           set[i].subject_attribute);
        } else {
          GNUNET_asprintf (&tmp_str,
                           "%s,%s %s",
                           attr_str,
                           subject_pkey,
                           set[i].subject_attribute);
          GNUNET_free (attr_str);
          attr_str = tmp_str;
        }
      }
      GNUNET_free (subject_pkey);
    }
    return attr_str;
   }
   case GNUNET_GNSRECORD_TYPE_CREDENTIAL:
   {
     struct GNUNET_CREDENTIAL_CredentialRecordData cred;
     struct GNUNET_TIME_Absolute etime_abs;
     char *cred_str;
     char *subject_pkey;
     char *issuer_pkey;
     char *signature;
     const char *expiration;


     if (data_size < sizeof (struct GNUNET_CREDENTIAL_CredentialRecordData))
       return NULL; /* malformed */
     memcpy (&cred,
             data,
             sizeof (cred));
     cdata = data;  
     subject_pkey = GNUNET_CRYPTO_ecdsa_public_key_to_string (&cred.subject_key);
     issuer_pkey = GNUNET_CRYPTO_ecdsa_public_key_to_string (&cred.issuer_key);
     etime_abs.abs_value_us = GNUNET_ntohll(cred.expiration);
     expiration = GNUNET_STRINGS_absolute_time_to_string (etime_abs);
     GNUNET_STRINGS_base64_encode ((char*)&cred.signature,
                                   sizeof (struct GNUNET_CRYPTO_EcdsaSignature),
                                   &signature);
     GNUNET_asprintf (&cred_str,
                      "%s.%s -> %s | %s | %s",
                      issuer_pkey,
                      &cdata[sizeof (cred)],
                      subject_pkey,
                      signature,
                      expiration);
     GNUNET_free (subject_pkey);
     GNUNET_free (issuer_pkey);
     GNUNET_free (signature);
     return cred_str;
   }
   default:
   return NULL;
  }
}


/**
 * Convert human-readable version of a 'value' of a record to the binary
 * representation.
 *
 * @param cls closure, unused
 * @param type type of the record
 * @param s human-readable string
 * @param data set to value in binary encoding (will be allocated)
 * @param data_size set to number of bytes in @a data
 * @return #GNUNET_OK on success
 */
static int
credential_string_to_value (void *cls,
                            uint32_t type,
                            const char *s,
                            void **data,
                            size_t *data_size)
{
  if (NULL == s)
    return GNUNET_SYSERR;
  switch (type)
  {
    case GNUNET_GNSRECORD_TYPE_ATTRIBUTE:
      {
        struct GNUNET_CREDENTIAL_DelegationRecordData *sets;
        char attr_str[253 + 1];
        char subject_pkey[52 + 1];
        char *token;
        char *tmp_str;
        int matches = 0;
        int entries;
        size_t tmp_data_size;
        int i;

        tmp_str = GNUNET_strdup (s);
        token = strtok (tmp_str, ",");
        entries = 0;
        tmp_data_size = 0;
        *data_size = sizeof (struct GNUNET_CREDENTIAL_DelegationRecordData);
        while (NULL != token)
        {
          matches = SSCANF (token,
                            "%s %s",
                            subject_pkey,
                            attr_str);
          if (0 == matches)
          {
            GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                        _("Unable to parse ATTR record string `%s'\n"),
                        s);
            GNUNET_free (tmp_str);
            return GNUNET_SYSERR;
          }
          if (1 == matches) {
            tmp_data_size += sizeof (struct GNUNET_CREDENTIAL_DelegationSetRecord);
          } else if (2 == matches) {
            tmp_data_size += sizeof (struct GNUNET_CREDENTIAL_DelegationSetRecord) + strlen (attr_str) + 1;
          }
          entries++;
          token = strtok (NULL, ",");
        }
        GNUNET_free (tmp_str);
        tmp_str = GNUNET_strdup (s);
        token = strtok (tmp_str, ",");
        struct GNUNET_CREDENTIAL_DelegationSetRecord *set;
        set = GNUNET_malloc (entries * sizeof (struct GNUNET_CREDENTIAL_DelegationSetRecord));
        for (i=0;i<entries;i++)
        {
          matches = SSCANF (token,
                            "%s %s",
                            subject_pkey,
                            attr_str);
          GNUNET_CRYPTO_ecdsa_public_key_from_string (subject_pkey,
                                                      strlen (subject_pkey),
                                                      &set[i].subject_key);
          if (2 == matches) {
            GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                        "Adding %s (data size %llu)\n",
                        attr_str,
                        tmp_data_size);
            /*GNUNET_memcpy (&set[1],
                           attr_str,
                           strlen (attr_str)+1);*/
            set[i].subject_attribute_len = strlen (attr_str) + 1;
            set[i].subject_attribute = GNUNET_strdup (attr_str);//(const char*)&set[1];
          }
          token = strtok (NULL , ",");
        }
        tmp_data_size = GNUNET_CREDENTIAL_delegation_set_get_size (entries,
                                                                   set);
        if (-1 == tmp_data_size)
          return GNUNET_SYSERR;
        *data_size += tmp_data_size;
        *data = sets = GNUNET_malloc (*data_size);
        GNUNET_CREDENTIAL_delegation_set_serialize (entries,
                                                    set,
                                                    tmp_data_size,
                                                    (char*)&sets[1]);
        sets->set_count = htonl (entries);
        sets->data_size = GNUNET_htonll (tmp_data_size);

        GNUNET_free (tmp_str);
        return GNUNET_OK;
      }
    case GNUNET_GNSRECORD_TYPE_CREDENTIAL:
      { 
        struct GNUNET_CREDENTIAL_CredentialRecordData *cred;

        size_t enclen = (sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey)) * 8;
        if (enclen % 5 > 0)
          enclen += 5 - enclen % 5;
        enclen /= 5; /* 260/5 = 52 */
        char subject_pkey[enclen + 1];
        char issuer_pkey[enclen + 1];
        char name[253 + 1];
        char signature[128]; //TODO max payload size
        char expiration[256];

        struct GNUNET_CRYPTO_EcdsaSignature *sig;
        struct GNUNET_TIME_Absolute etime_abs;

        if (5 != SSCANF (s,
                         "%52s.%253s -> %52s | %s | %255[0-9a-zA-Z: ]",
                         issuer_pkey,
                         name,
                         subject_pkey,
                         signature,
                         expiration))
        {
          GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                      _("Unable to parse CRED record string `%s'\n"),
                      s);
          return GNUNET_SYSERR;
        }
        *data_size = sizeof (struct GNUNET_CREDENTIAL_CredentialRecordData) + strlen (name) + 1;
        *data = cred = GNUNET_malloc (*data_size);
        GNUNET_CRYPTO_ecdsa_public_key_from_string (subject_pkey,
                                                    strlen (subject_pkey),
                                                    &cred->subject_key);
        GNUNET_CRYPTO_ecdsa_public_key_from_string (issuer_pkey,
                                                    strlen (issuer_pkey),
                                                    &cred->issuer_key);
        GNUNET_STRINGS_fancy_time_to_absolute (expiration,
                                               &etime_abs);
        GNUNET_STRINGS_base64_decode (signature,
                                      strlen (signature),
                                      (char**)&sig);
        cred->signature = *sig;
        cred->expiration = GNUNET_htonll (etime_abs.abs_value_us);
        cred->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_CREDENTIAL);
        cred->purpose.size = htonl (strlen (name) + 1 + sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose) +
                                    sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey) + sizeof (uint64_t));
        GNUNET_free (sig);
        GNUNET_memcpy (&cred[1],
                       name,
                       strlen (name));


        return GNUNET_OK;
      }
    default:
      return GNUNET_SYSERR;
  }
}


/**
 * Mapping of record type numbers to human-readable
 * record type names.
 */
static struct {
  const char *name;
  uint32_t number;
} name_map[] = {
  { "CRED", GNUNET_GNSRECORD_TYPE_CREDENTIAL },
  { "ATTR", GNUNET_GNSRECORD_TYPE_ATTRIBUTE },
  { NULL, UINT32_MAX }
};


/**
 * Convert a type name (i.e. "AAAA") to the corresponding number.
 *
 * @param cls closure, unused
 * @param gns_typename name to convert
 * @return corresponding number, UINT32_MAX on error
 */
static uint32_t
credential_typename_to_number (void *cls,
                               const char *gns_typename)
{
  unsigned int i;

  i=0;
  while ( (name_map[i].name != NULL) &&
          (0 != strcasecmp (gns_typename, name_map[i].name)) )
    i++;
  return name_map[i].number;
}


/**
 * Convert a type number (i.e. 1) to the corresponding type string (i.e. "A")
 *
 * @param cls closure, unused
 * @param type number of a type to convert
 * @return corresponding typestring, NULL on error
 */
static const char *
credential_number_to_typename (void *cls,
                               uint32_t type)
{
  unsigned int i;

  i=0;
  while ( (name_map[i].name != NULL) &&
          (type != name_map[i].number) )
    i++;
  return name_map[i].name;
}


/**
 * Entry point for the plugin.
 *
 * @param cls NULL
 * @return the exported block API
 */
void *
libgnunet_plugin_gnsrecord_credential_init (void *cls)
{
  struct GNUNET_GNSRECORD_PluginFunctions *api;

  api = GNUNET_new (struct GNUNET_GNSRECORD_PluginFunctions);
  api->value_to_string = &credential_value_to_string;
  api->string_to_value = &credential_string_to_value;
  api->typename_to_number = &credential_typename_to_number;
  api->number_to_typename = &credential_number_to_typename;
  return api;
}


/**
 * Exit point from the plugin.
 *
 * @param cls the return value from #libgnunet_plugin_block_test_init
 * @return NULL
 */
void *
libgnunet_plugin_gnsrecord_credential_done (void *cls)
{
  struct GNUNET_GNSRECORD_PluginFunctions *api = cls;

  GNUNET_free (api);
  return NULL;
}

/* end of plugin_gnsrecord_credential.c */