/*
  This file is part of TALER
  Copyright (C) 2014, 2015 Christian Grothoff (and other contributing authors)

  TALER 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.

  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 General Public License for more details.

  You should have received a copy of the GNU General Public License along with
  TALER; see the file COPYING.  If not, If not, see <http://www.gnu.org/licenses/>
*/
/**
 * @file include/taler_mintdb_lib.h
 * @brief IO operations for the mint's private keys
 * @author Florian Dold
 * @author Benedikt Mueller
 * @author Christian Grothoff
 */
#ifndef TALER_MINTDB_LIB_H
#define TALER_MINTDB_LIB_H

#include <gnunet/gnunet_util_lib.h>
#include "taler_signatures.h"

/**
 * Subdirectroy under the mint's base directory which contains
 * the mint's signing keys.
 */
#define TALER_MINTDB_DIR_SIGNING_KEYS "signkeys"

/**
 * Subdirectory under the mint's base directory which contains
 * the mint's denomination keys.
 */
#define TALER_MINTDB_DIR_DENOMINATION_KEYS "denomkeys"


GNUNET_NETWORK_STRUCT_BEGIN

/**
 * @brief On disk format used for a mint signing key.  Signing keys are used
 * by the mint to affirm its messages, but not to create coins.
 * Includes the private key followed by the public information about
 * the signing key.
 */
struct TALER_MINTDB_PrivateSigningKeyInformationP
{
  /**
   * Private key part of the mint's signing key.
   */
  struct TALER_MintPrivateKeyP signkey_priv;

  /**
   * Public information about a mint signing key.
   */
  struct TALER_MintSigningKeyValidityPS issue;
};


GNUNET_NETWORK_STRUCT_END


/**
 * @brief All information about a denomination key (which is used to
 * sign coins into existence).
 */
struct TALER_MINTDB_DenominationKeyIssueInformation
{
  /**
   * The private key of the denomination.  Will be NULL if the private
   * key is not available (this is the case after the key has expired
   * for signing coins, but is still valid for depositing coins).
   */
  struct TALER_DenominationPrivateKey denom_priv;

  /**
   * Decoded denomination public key (the hash of it is in
   * @e issue, but we sometimes need the full public key as well).
   */
  struct TALER_DenominationPublicKey denom_pub;

  /**
   * Signed public information about a denomination key.
   */
  struct TALER_DenominationKeyValidityPS issue;
};


/**
 * @brief Iterator over signing keys.
 *
 * @param cls closure
 * @param filename name of the file the key came from
 * @param ski the sign key
 * @return #GNUNET_OK to continue to iterate,
 *  #GNUNET_NO to stop iteration with no error,
 *  #GNUNET_SYSERR to abort iteration with error!
 */
typedef int
(*TALER_MINTDB_SigningKeyIterator)(void *cls,
                                   const char *filename,
                                   const struct TALER_MINTDB_PrivateSigningKeyInformationP *ski);


/**
 * @brief Iterator over denomination keys.
 *
 * @param cls closure
 * @param dki the denomination key
 * @param alias coin alias
 * @return #GNUNET_OK to continue to iterate,
 *  #GNUNET_NO to stop iteration with no error,
 *  #GNUNET_SYSERR to abort iteration with error!
 */
typedef int
(*TALER_MINTDB_DenominationKeyIterator)(void *cls,
                                        const char *alias,
                                        const struct TALER_MINTDB_DenominationKeyIssueInformation *dki);



/**
 * Call @a it for each signing key found in the @a mint_base_dir.
 *
 * @param mint_base_dir base directory for the mint,
 *                      the signing keys must be in the #TALER_MINTDB_DIR_SIGNING_KEYS
 *                      subdirectory
 * @param it function to call on each signing key
 * @param it_cls closure for @a it
 * @return number of files found (may not match
 *         number of keys given to @a it as malformed
 *         files are simply skipped), -1 on error
 */
int
TALER_MINTDB_signing_keys_iterate (const char *mint_base_dir,
                                   TALER_MINTDB_SigningKeyIterator it,
                                   void *it_cls);


/**
 * Call @a it for each denomination key found in the @a mint_base_dir.
 *
 * @param mint_base_dir base directory for the mint,
 *                      the signing keys must be in the #TALER_MINTDB_DIR_DENOMINATION_KEYS
 *                      subdirectory
 * @param it function to call on each denomination key found
 * @param it_cls closure for @a it
 * @return -1 on error, 0 if no files were found, otherwise
 *         a positive number (however, even with a positive
 *         number it is possible that @a it was never called
 *         as maybe none of the files were well-formed)
 */
int
TALER_MINTDB_denomination_keys_iterate (const char *mint_base_dir,
                                        TALER_MINTDB_DenominationKeyIterator it,
                                        void *it_cls);


/**
 * Exports a denomination key to the given file.
 *
 * @param filename the file where to write the denomination key
 * @param dki the denomination key
 * @return #GNUNET_OK upon success; #GNUNET_SYSERR upon failure.
 */
int
TALER_MINTDB_denomination_key_write (const char *filename,
                                     const struct TALER_MINTDB_DenominationKeyIssueInformation *dki);


/**
 * Import a denomination key from the given file.
 *
 * @param filename the file to import the key from
 * @param[out] dki set to the imported denomination key
 * @return #GNUNET_OK upon success; #GNUNET_SYSERR upon failure
 */
int
TALER_MINTDB_denomination_key_read (const char *filename,
                                    struct TALER_MINTDB_DenominationKeyIssueInformation *dki);


/**
 * Initialize the plugin.
 *
 * @param cfg configuration to use
 * @return NULL on failure
 */
struct TALER_MINTDB_Plugin *
TALER_MINTDB_plugin_load (const struct GNUNET_CONFIGURATION_Handle *cfg);


/**
 * Shutdown the plugin.
 *
 * @param plugin plugin to unload
 */
void
TALER_MINTDB_plugin_unload (struct TALER_MINTDB_Plugin *plugin);



#endif