path: root/src/donau/donau-httpd_batch-issue.c

/*
  This file is part of TALER
  Copyright (C) 2024 Taler Systems SA

  TALER is free software; you can redistribute it and/or modify it under the
  terms of the GNU Affero General Public License as published by the Free Software
  Foundation; either version 3, or (at your option) any later version.

  TALER 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 Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License along with
  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
*/
/**
 * @file donau-httpd_batch-issue.c
 * @brief Handle request to issue receipts.
 * @author Lukas Matyja
 */
#include <taler/platform.h>
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_json_lib.h>
#include <jansson.h>
#include <microhttpd.h>
#include <pthread.h>
#include <taler/taler_json_lib.h>
#include <taler/taler_mhd_lib.h>
#include <taler/taler_signatures.h>
#include "donaudb_plugin.h"
#include "donau-httpd_batch-issue.h"
#include "donau-httpd_db.h"
#include "donau-httpd_metrics.h"
#include "donau_json_lib.h"
#include "donau-httpd_keys.h"


/**
 * Parse a bkp encoded in JSON.
 *
 * @param[out] bkp where to return the result
 * @param bkp_key_obj json to parse
 * @return #GNUNET_OK if all is fine, #GNUNET_SYSERR if @a bkp_key_obj
 * is malformed.
 */
static enum GNUNET_GenericReturnValue
parse_json_bkp (struct DONAU_BlindedUniqueDonorIdentifierKeyPair *bkp,
                const json_t *bkp_key_obj)
{
  struct GNUNET_JSON_Specification spec[] = {
    GNUNET_JSON_spec_fixed_auto ("h_du_pub",
                                 &bkp->h_donation_unit_pub),
    DONAU_JSON_spec_blinded_donation_identifier ("blinded_udi",
                                                 &bkp->blinded_udi),
    GNUNET_JSON_spec_end ()
  };

  if (GNUNET_OK !=
      GNUNET_JSON_parse (bkp_key_obj,
                         spec,
                         NULL, NULL))
  {
    GNUNET_break_op (0);
    return GNUNET_SYSERR;
  }
  /* TODO: Check for duplicate blinded UDIs.*/
  return GNUNET_OK;
}


/**
 * Parse signatures to JSON.
 *
 * @param num_sig number of signatures
 * @param signatures
 * @param[out] j_signatures JSON object
 * @return #GNUNET_OK if all is fine, #GNUNET_SYSERR if we could not parse
 * is malformed.
 */
static void
signatures_to_JSON (const size_t num_sig,
                    struct DONAU_BlindedDonationUnitSignature *signatures,
                    json_t *j_signatures)
{
  for (size_t i = 0; i < num_sig; i++)
  {
    struct DONAU_BlindedDonationUnitSignature *signature = &signatures[i];
    GNUNET_assert (
      0 == json_array_append (
        j_signatures,
        GNUNET_JSON_PACK (
          DONAU_JSON_pack_blinded_donation_unit_sig ("blinded_signature",
                                                     signature))));
  }
}


MHD_RESULT
DH_handler_issue_receipts_post (struct DH_RequestContext *rc,
                                const json_t *root,
                                const char *const args[1])
{
  struct DONAU_CharitySignatureP charity_sig;
  uint64_t year;
  bool second_time = false;
  unsigned long long charity_id;
  char dummy;

  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "issue receipts request! \n");

  if ( (NULL == args[0]) ||
       (1 != sscanf (args[0],
                     "%llu%c",
                     &charity_id,
                     &dummy)) )
  {
    GNUNET_break_op (0);
    return TALER_MHD_reply_with_error (rc->connection,
                                       MHD_HTTP_BAD_REQUEST,
                                       TALER_EC_GENERIC_PARAMETER_MALFORMED,
                                       "charity_id");
  }
  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "issue receipts for charity id: %llu\n",
              charity_id);

  const json_t *budikeypairs;
  struct GNUNET_JSON_Specification spec[] = {
    GNUNET_JSON_spec_array_const ("budikeypairs",
                                  &budikeypairs),
    GNUNET_JSON_spec_fixed_auto ("charity_sig",
                                 &charity_sig),
    GNUNET_JSON_spec_uint64 ("year",
                             &year),
    GNUNET_JSON_spec_end ()
  };

  {
    enum GNUNET_GenericReturnValue res;

    res = TALER_MHD_parse_json_data (rc->connection,
                                     root,
                                     spec);
    if (GNUNET_SYSERR == res)
      return MHD_NO; /* hard failure */
    if (GNUNET_NO == res)
    {
      GNUNET_break_op (0);
      return MHD_YES; /* failure */
    }
  }

  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "parse some values!\n");
  /* parse the budikeypairs array */
  const size_t num_bkps
    = json_array_size (budikeypairs);
  struct DONAU_BlindedUniqueDonorIdentifierKeyPair *bkps;
  if (0 != num_bkps)
  {
    json_t *bkp_obj;
    size_t index;


    bkps = GNUNET_new_array
             (num_bkps,
             struct DONAU_BlindedUniqueDonorIdentifierKeyPair);
    json_array_foreach (budikeypairs, index, bkp_obj)
    {
      if (GNUNET_SYSERR ==
          parse_json_bkp (&bkps[index], bkp_obj))
      {
        GNUNET_break_op (0);
        return TALER_MHD_reply_with_error (rc->connection,
                                           MHD_HTTP_BAD_REQUEST,
                                           TALER_EC_GENERIC_PARAMETER_MALFORMED,
                                           "budikeypairs");
      }
    }
  }
  else
  {
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "Empty array of budi key pairs!\n");
    return TALER_MHD_reply_with_error (rc->connection,
                                       MHD_HTTP_BAD_REQUEST,
                                       TALER_EC_GENERIC_PARAMETER_MALFORMED,
                                       "budikeypairs");
  }

  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "budi key pairs array is parsed!\n");
  // Get charity pub
  struct DONAUDB_CharityMetaData charity_meta;
  enum GNUNET_DB_QueryStatus qs_charity;

  qs_charity = DH_plugin->lookup_charity (DH_plugin->cls,
                                          (uint64_t) charity_id,
                                          &charity_meta);
  switch (qs_charity)
  {
  case GNUNET_DB_STATUS_HARD_ERROR:
  case GNUNET_DB_STATUS_SOFT_ERROR:
	  GNUNET_break_op (0);
    return TALER_MHD_reply_with_error (rc->connection,
                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
                                       TALER_EC_GENERIC_DB_FETCH_FAILED,
                                       NULL);
  case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
	GNUNET_break_op (0);
    return TALER_MHD_reply_with_error (
      rc->connection,
      MHD_HTTP_NOT_FOUND,
      TALER_EC_DONAU_CHARITY_NOT_FOUND,
      NULL);
    break;
  case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
    break;
  }

  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "got charity from db!\n");
  /* verify charity signature */
  if (GNUNET_OK !=
      DONAU_charity_bkp_verify (num_bkps,
                                bkps,
                                &charity_meta.charity_pub,
                                &charity_sig))
  {
    GNUNET_break_op (0);
    return TALER_MHD_reply_with_error (
      rc->connection,
      MHD_HTTP_FORBIDDEN,
      TALER_EC_DONAU_CHARITY_SIGNATURE_INVALID,
      NULL);
  }

  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "charity signature valid!\n");
  /* request already made? -> idempotent */
  enum GNUNET_DB_QueryStatus qs_check_receipts;
  struct DONAUDB_IssuedReceiptsMetaData check_receipts_meta;
  struct DONAU_DonationReceiptHashP h_receipts = {0};
  json_t *blind_signatures = json_array ();
  GNUNET_assert (NULL != blind_signatures);

  struct GNUNET_HashContext *hc;
  hc = GNUNET_CRYPTO_hash_context_start ();
  for (unsigned int i = 0; i < num_bkps; i++)
  {
    GNUNET_CRYPTO_hash_context_read (hc,
                                     &bkps[i].h_donation_unit_pub,
                                     sizeof (bkps[i].h_donation_unit_pub));
    GNUNET_CRYPTO_hash_context_read (hc,
                                     bkps[i].blinded_udi.blinded_message,
                                     sizeof (bkps[i].blinded_udi.blinded_message
                                             ));
  }
  GNUNET_CRYPTO_hash_context_read (hc,
                                   &charity_sig,
                                   sizeof (struct DONAU_CharitySignatureP));
  GNUNET_CRYPTO_hash_context_read (hc,
                                   &year,
                                   sizeof (uint64_t));
  GNUNET_CRYPTO_hash_context_finish (hc,
                                     &h_receipts.hash);

start:
  qs_check_receipts = DH_plugin->lookup_issued_receipts (DH_plugin->cls,
                                                         &h_receipts,
                                                         &check_receipts_meta);
  switch (qs_check_receipts)
  {
  case GNUNET_DB_STATUS_HARD_ERROR:
  case GNUNET_DB_STATUS_SOFT_ERROR:
    GNUNET_break (0);
    return TALER_MHD_reply_with_error (rc->connection,
                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
                                       TALER_EC_GENERIC_DB_FETCH_FAILED,
                                       NULL);
  case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "request has not been made yet (first time)!\n");
    break; // it's the first request from the charity, we can proceed
  case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "request has been made already!\n");
    signatures_to_JSON (num_bkps, check_receipts_meta.blinded_sig,
                        blind_signatures);
    return TALER_MHD_REPLY_JSON_PACK (
      rc->connection,
      MHD_HTTP_OK,
      GNUNET_JSON_pack_array_steal ("blind_signatures",
                                    blind_signatures));
  }
  /* calculate the sum of all receipts */
  struct TALER_Amount receipts_sum;

  GNUNET_assert (GNUNET_OK ==
                 TALER_amount_set_zero (DH_currency,
                                        &receipts_sum));
  for (size_t i = 0; i < num_bkps; i++)
  {
    struct DH_DonationUnitKey *dk;

    if (NULL == (dk = DH_keys_donation_unit_by_hash (
                   &bkps[i].h_donation_unit_pub))) {
      GNUNET_break_op (0);
      return TALER_MHD_reply_with_error (rc->connection,
                                         MHD_HTTP_NOT_FOUND,
                                         TALER_EC_DONAU_GENERIC_KEYS_MISSING,
                                         NULL);
    }
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "public key value: %lu.%u\n",
                dk->value.value, dk->value.fraction);
    GNUNET_assert (0 <= TALER_amount_add (&receipts_sum,
                                          &receipts_sum,
                                          &dk->value));
  }

  /* sign budis and send the signatures back */
  struct DONAU_BlindedDonationUnitSignature du_sigs[num_bkps];
  struct DONAU_BkpSignData bkps_sign_data[num_bkps];

  for (int i = 0; i < num_bkps; i++)
  {
    bkps_sign_data[i].h_donation_unit_pub = &bkps[i].h_donation_unit_pub;
    bkps_sign_data[i].budi = &bkps[i].blinded_udi;
  }
  enum TALER_ErrorCode batch_sign_ec;
  batch_sign_ec = DH_keys_donation_unit_batch_sign (num_bkps,
                                                    bkps_sign_data,
                                                    du_sigs);
  if (TALER_EC_NONE != batch_sign_ec) {
	GNUNET_break_op (0);
    return TALER_MHD_reply_with_error (rc->connection,
                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
                                       batch_sign_ec,   // TODO:other EC
                                       NULL);
  }
  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "made blind signatures!\n");
  /* save new receipts to date and save receipts Request (blinded signatures,
   * charity id, amount, hash over bkps) to make it idempotent*/
  enum GNUNET_DB_QueryStatus qs_insert_ir;
  bool smaller_than_max_per_year = false;
  qs_insert_ir = DH_plugin->insert_issued_receipt (
    DH_plugin->cls,
    num_bkps,
    du_sigs,
    (uint64_t) charity_id,
    &h_receipts,
    &receipts_sum,
    &smaller_than_max_per_year);
  switch (qs_insert_ir)
  {
  case GNUNET_DB_STATUS_HARD_ERROR:
  case GNUNET_DB_STATUS_SOFT_ERROR:
    GNUNET_break (0);
    return TALER_MHD_reply_with_error (rc->connection,
                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
                                       TALER_EC_GENERIC_DB_FETCH_FAILED,
                                       NULL);
  case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
    GNUNET_assert (! second_time);
    second_time = true;
    goto start;
  case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
    if (! smaller_than_max_per_year) {
      GNUNET_break_op (0);
      return TALER_MHD_reply_with_error (rc->connection,
                                         MHD_HTTP_BAD_REQUEST,
                                         TALER_EC_DONAU_EXCEEDING_DONATION_LIMIT,
                                         NULL);
    }
    break;
  }
  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "issue receipts request is saved! (idempotent)\n");

  signatures_to_JSON (num_bkps, du_sigs, blind_signatures);
  return TALER_MHD_REPLY_JSON_PACK (
    rc->connection,
    MHD_HTTP_CREATED,
    GNUNET_JSON_pack_array_steal ("blind_signatures",
                                  blind_signatures),
    TALER_JSON_pack_amount ("issued_amount",
                            &receipts_sum));
}


/* end of donau-httpd_batch-issue.c */