/*
     This file is part of GNUnet
     Copyright (C) 2012, 2013 GNUnet e.V.

     GNUnet 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 of the License,
     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
     Affero General Public License for more details.

     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */

/**
 * @author Martin Schanzenbach
 *
 * @file
 * Plugin API for reclaim attribute types
 *
 * @defgroup reclaim-attribute-plugin  reclaim plugin API for attributes/claims
 * @{
 */
#ifndef GNUNET_RECLAIM_PLUGIN_H
#define GNUNET_RECLAIM_PLUGIN_H

#include "gnunet_util_lib.h"
#include "gnunet_reclaim_lib.h"
#include "gnunet_identity_service.h"

#ifdef __cplusplus
extern "C" {
#if 0 /* keep Emacsens' auto-indent happy */
}
#endif
#endif


/**
 * Function called to convert the binary value @a data of an attribute of
 * type @a type to a human-readable string.
 *
 * @param cls closure
 * @param type type of the attribute
 * @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
 */
typedef char *(*GNUNET_RECLAIM_AttributeValueToStringFunction) (
  void *cls,
  uint32_t type,
  const void *data,
  size_t data_size);


/**
 * Function called to convert human-readable version of the value @a s
 * of an attribute of type @a type to the respective binary
 * representation.
 *
 * @param cls closure
 * @param type type of the attribute
 * @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
 */
typedef int (*GNUNET_RECLAIM_AttributeStringToValueFunction) (
  void *cls,
  uint32_t type,
  const char *s,
  void **data,
  size_t *data_size);


/**
 * Function called to convert a type name to the
 * corresponding number.
 *
 * @param cls closure
 * @param typename name to convert
 * @return corresponding number, UINT32_MAX on error
 */
typedef uint32_t (*GNUNET_RECLAIM_AttributeTypenameToNumberFunction) (
  void *cls,
  const char *typename);


/**
 * Function called to convert a type number (i.e. 1) to the
 * corresponding type string
 *
 * @param cls closure
 * @param type number of a type to convert
 * @return corresponding typestring, NULL on error
 */
typedef const char *(*GNUNET_RECLAIM_AttributeNumberToTypenameFunction) (
  void *cls,
  uint32_t type);

/**
 * Function called to convert the binary value @a data of an attribute of
 * type @a type to a human-readable string.
 *
 * @param cls closure
 * @param type type of the attribute
 * @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
 */
typedef char *(*GNUNET_RECLAIM_CredentialValueToStringFunction) (
  void *cls,
  uint32_t type,
  const void *data,
  size_t data_size);


/**
 * Function called to convert human-readable version of the value @a s
 * of an attribute of type @a type to the respective binary
 * representation.
 *
 * @param cls closure
 * @param type type of the attribute
 * @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
 */
typedef int (*GNUNET_RECLAIM_CredentialStringToValueFunction) (
  void *cls,
  uint32_t type,
  const char *s,
  void **data,
  size_t *data_size);


/**
 * Function called to convert a type name to the
 * corresponding number.
 *
 * @param cls closure
 * @param typename name to convert
 * @return corresponding number, UINT32_MAX on error
 */
typedef uint32_t (*GNUNET_RECLAIM_CredentialTypenameToNumberFunction) (
  void *cls,
  const char *typename);


/**
 * Function called to convert a type number (i.e. 1) to the
 * corresponding type string
 *
 * @param cls closure
 * @param type number of a type to convert
 * @return corresponding typestring, NULL on error
 */
typedef const char *(*GNUNET_RECLAIM_CredentialNumberToTypenameFunction) (
  void *cls,
  uint32_t type);

/**
 * Function called to extract attributes from a credential
 *
 * @param cls closure
 * @param cred the credential object
 * @return an attribute list
 */
typedef struct
  GNUNET_RECLAIM_AttributeList *(*
GNUNET_RECLAIM_CredentialGetAttributesFunction) (
  void *cls,
  const struct GNUNET_RECLAIM_Credential *cred);

/**
 * Function called to get the issuer of the credential (as string)
 *
 * @param cls closure
 * @param cred the credential object
 * @return corresponding issuer string
 */
typedef char *(*GNUNET_RECLAIM_CredentialGetIssuerFunction) (
  void *cls,
  const struct GNUNET_RECLAIM_Credential *cred);

/**
 * Function called to get the expiration of the credential
 *
 * @param cls closure
 * @param cred the credential object
 * @param where to write the value
 * @return GNUNET_OK if successful
 */
typedef int (*GNUNET_RECLAIM_CredentialGetExpirationFunction) (
  void *cls,
  const struct GNUNET_RECLAIM_Credential *cred,
  struct GNUNET_TIME_Absolute *expiration);

/**
 * Function called to convert the binary value @a data of an attribute of
 * type @a type to a human-readable string.
 *
 * @param cls closure
 * @param type type of the attribute
 * @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
 */
typedef char *(*GNUNET_RECLAIM_PresentationValueToStringFunction) (
  void *cls,
  uint32_t type,
  const void *data,
  size_t data_size);


/**
 * Function called to convert human-readable version of the value @a s
 * of an attribute of type @a type to the respective binary
 * representation.
 *
 * @param cls closure
 * @param type type of the attribute
 * @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
 */
typedef int (*GNUNET_RECLAIM_PresentationStringToValueFunction) (
  void *cls,
  uint32_t type,
  const char *s,
  void **data,
  size_t *data_size);


/**
 * Function called to convert a type name to the
 * corresponding number.
 *
 * @param cls closure
 * @param typename name to convert
 * @return corresponding number, UINT32_MAX on error
 */
typedef uint32_t (*GNUNET_RECLAIM_PresentationTypenameToNumberFunction) (
  void *cls,
  const char *typename);


/**
 * Function called to convert a type number (i.e. 1) to the
 * corresponding type string
 *
 * @param cls closure
 * @param type number of a type to convert
 * @return corresponding typestring, NULL on error
 */
typedef const char *(*GNUNET_RECLAIM_PresentationNumberToTypenameFunction) (
  void *cls,
  uint32_t type);

/**
 * Function called to extract attributes from a credential
 *
 * @param cls closure
 * @param cred the credential object
 * @return an attribute list
 */
typedef struct
  GNUNET_RECLAIM_AttributeList *(*
GNUNET_RECLAIM_PresentationGetAttributesFunction) (
  void *cls,
  const struct GNUNET_RECLAIM_Presentation *cred);

/**
 * Function called to get the issuer of the credential (as string)
 *
 * @param cls closure
 * @param cred the credential object
 * @return corresponding issuer string
 */
typedef char *(*GNUNET_RECLAIM_PresentationGetIssuerFunction) (
  void *cls,
  const struct GNUNET_RECLAIM_Presentation *cred);

/**
 * Function called to get the expiration of the credential
 *
 * @param cls closure
 * @param cred the credential object
 * @param where to write the value
 * @return GNUNET_OK if successful
 */
typedef int (*GNUNET_RECLAIM_PresentationGetExpirationFunction) (
  void *cls,
  const struct GNUNET_RECLAIM_Presentation *cred,
  struct GNUNET_TIME_Absolute *expiration);

typedef int (*GNUNET_RECLAIM_CredentialToPresentation) (
  void *cls,
  const struct GNUNET_RECLAIM_Credential *cred,
  const struct GNUNET_RECLAIM_AttributeList *attrs,
  struct GNUNET_RECLAIM_Presentation **presentation);

/**
 * Each plugin is required to return a pointer to a struct of this
 * type as the return value from its entry point.
 */
struct GNUNET_RECLAIM_AttributePluginFunctions
{
  /**
   * Closure for all of the callbacks.
   */
  void *cls;

  /**
   * Conversion to string.
   */
  GNUNET_RECLAIM_AttributeValueToStringFunction value_to_string;

  /**
   * Conversion to binary.
   */
  GNUNET_RECLAIM_AttributeStringToValueFunction string_to_value;

  /**
   * Typename to number.
   */
  GNUNET_RECLAIM_AttributeTypenameToNumberFunction typename_to_number;

  /**
   * Number to typename.
   */
  GNUNET_RECLAIM_AttributeNumberToTypenameFunction number_to_typename;

};

/**
 * Each plugin is required to return a pointer to a struct of this
 * type as the return value from its entry point.
 */
struct GNUNET_RECLAIM_CredentialPluginFunctions
{
  /**
   * Closure for all of the callbacks.
   */
  void *cls;

  /**
   * Conversion to string.
   */
  GNUNET_RECLAIM_CredentialValueToStringFunction value_to_string;

  /**
   * Conversion to binary.
   */
  GNUNET_RECLAIM_CredentialStringToValueFunction string_to_value;

  /**
   * Typename to number.
   */
  GNUNET_RECLAIM_CredentialTypenameToNumberFunction typename_to_number;

  /**
   * Number to typename.
   */
  GNUNET_RECLAIM_CredentialNumberToTypenameFunction number_to_typename;

  /**
   * Attesation attributes.
   */
  GNUNET_RECLAIM_CredentialGetAttributesFunction get_attributes;

  /**
   * Attesation issuer.
   */
  GNUNET_RECLAIM_CredentialGetIssuerFunction get_issuer;

  /**
   * Expiration.
   */
  GNUNET_RECLAIM_CredentialGetExpirationFunction get_expiration;

  /**
   * Conversion to string.
   */
  GNUNET_RECLAIM_PresentationValueToStringFunction value_to_string_p;

  /**
   * Conversion to binary.
   */
  GNUNET_RECLAIM_PresentationStringToValueFunction string_to_value_p;

  /**
   * Typename to number.
   */
  GNUNET_RECLAIM_PresentationTypenameToNumberFunction typename_to_number_p;

  /**
   * Number to typename.
   */
  GNUNET_RECLAIM_PresentationNumberToTypenameFunction number_to_typename_p;

  /**
   * Attesation attributes.
   */
  GNUNET_RECLAIM_PresentationGetAttributesFunction get_attributes_p;

  /**
   * Attesation issuer.
   */
  GNUNET_RECLAIM_PresentationGetIssuerFunction get_issuer_p;

  /**
   * Expiration.
   */
  GNUNET_RECLAIM_PresentationGetExpirationFunction get_expiration_p;

  /**
   * Get presentation
   */
  GNUNET_RECLAIM_CredentialToPresentation create_presentation;

};


#if 0 /* keep Emacsens' auto-indent happy */
{
#endif
#ifdef __cplusplus
}
#endif

#endif

/** @} */ /* end of group */
