#pragma once

/*!
 * \file
 */

#ifdef __cplusplus
extern "C" {
#endif

#include <stdbool.h>

#include "groupelement.h"
#include "keypair.h"
#include "sharedkey.h"

typedef void(*Initializer)(void);

/*! 
 * \brief Defines how a KeyPair create function should look like.
 *        Used to store a pointer to function to a implementation.
 */
typedef struct KeyPair (*KeyPairCreator)(void);

/*!
 * \brief Defines how a KeyPair deleter function should look like.
 *        Used to store a pointer to function to a implementation.
 */
typedef void (*KeyPairDeleter)(struct KeyPair*);

/*!
 * \brief Defines how a Derived Shared Key function should look like.
 *        Used to store a pointer to function to a implementation.
 */
typedef GroupElement (*SharedKeyDeriver)(struct KeyPair, unsigned char const*, size_t, unsigned char const*, size_t, GroupElement, bool);

/*!
 * \brief Defines how a Derived Shared Key deleter function should look like.
 *        Used to store a pointer to function to a implementation.
 */
typedef void (*SharedKeyDeleter)(struct SharedKey*);

/*!
 * \brief Defines how the crypto library deinitialization should look.
 */
typedef void(*Deinitializer)(void);

/*!
 * \brief PubKeyArrayGetter typedef
 */
typedef void(*ElementToArray)(unsigned char**, size_t* size, GroupElement);

/*!
 *
 */
typedef void(*BufferDeleter)(void*);

/*!
 *
 */
typedef GroupElement(*ArrayToElement)(char const*, size_t size, bool);

/*!
 *
 */
typedef GroupElement(*MessageToElement)(char const*, size_t size, bool);

/*!
 *
 */
typedef void(*ElementToMessage)(unsigned char** message, const GroupElement element);

/*!
 *
 */
typedef void(*PubKeyHashGetter)(char** buffer, size_t* len, GroupElement const pub);

/*!
 *
 */
typedef size_t(*PubKeyHashLengthGetter)();

/*!
 * \brief PublicShareAdder typedef
 */
typedef void(*PublicShareAdder)(GroupElement*, char const*, size_t, GroupElement);

/*!
 *
 */
typedef GroupElement(*GroupElementGetter)(bool);

/*!
 * 
 */
typedef GroupElement(*KeyExchangeValueGetter)(GroupElement);

/*!
 *
 */
typedef GroupElement(*GroupElementCombiner)(GroupElement, GroupElement, bool);

/*!
 *
 */
typedef GroupElement(*GroupElementUncombiner)(GroupElement, GroupElement, bool);

/*!
 *
 */
typedef size_t(*GroupElementArraySizeGetter)();

/*!
 *
 */
typedef size_t(*MessageSizeGetter)();

/*!
 *
 */
typedef void(*GroupElementDeleter)(GroupElement);

/*!
 *
 */
typedef void (*Encrypter)(GroupElement*, GroupElement*, GroupElement, GroupElement);

/*!
 *
 */
typedef GroupElement (*Inverter)(GroupElement);

/*!
 *
 */
typedef unsigned int (*UniformIntGetter)(unsigned int);

/*!
 *
 */
typedef GroupElement (*DecryptionShareGetter)(GroupElement, GroupElement);

/*!
 * \brief The Api struct stores pointers to functions of a specific implementation. Like a Curve25519 specific one.
 */
struct Api {
	Initializer initialize; ///< Function that will initialize the crypto library.
	KeyPairCreator create_keypair; ///< Pointer to keypair creation function
	KeyPairDeleter free_keypair; ///< Pointer to keypair deletor function
	ElementToArray element_to_array; ///< Get the array representation of a public key
	BufferDeleter free_buffer; ///< frees library allocated buffers.
	ArrayToElement array_to_element; ///< The the GroupElement representation of this array.
	MessageToElement message_to_element; ///< Convert Message to element.
	ElementToMessage element_to_message; ///< Convert Element to message.
	PubKeyHashGetter get_pub_key_hash; ///< Get the hash of the public key.
	PubKeyHashLengthGetter get_pub_key_hash_length; ///< Get the length of the pubkey hash.
	GroupElementGetter get_group_element; ///< get group element
	GroupElementArraySizeGetter get_group_element_array_size; ///< Return the size required to store a groupelement in an array;
	MessageSizeGetter get_message_size; ///< Retrieve how large a message can be.
	GroupElementDeleter free_group_element; ///< frees a base type of the cryptolibrary.
	KeyExchangeValueGetter get_key_exchange_value; ///< get generator *op* group element.
	GroupElementCombiner combine; ///< Combines two groupelements modulo group.
	GroupElementUncombiner uncombine; ///< Uncombines two groupelements;
	DecryptionShareGetter get_decryption_share; ///< calculates the first argument to the power of Inverse second argument;
	PublicShareAdder add_public_share; ///< Adds the public key stored in void* to the existing share.
	SharedKeyDeriver derive_shared_key; ///< Pointer to shared key derivation function
	SharedKeyDeleter free_shared_key; ///< Pointer to shared key deleter function
	Encrypter encrypt; ///< encrypt value with key;
	Inverter invert; ///< Invert the group element;
	UniformIntGetter get_uniform_int; ///< Get a uniform int [0 .. argument);
	Deinitializer deinitialize; ///< Function that will deinitialize the crypto library.
};

/*!
 * A Pointer to function typedef to facilitate multiple implementations.
 */
typedef struct Api(*ImplementationGetter)(void);

/*!
 * \brief get_implementation The pointer to member function variable to implement when
 * defining a an implementation
 */
extern ImplementationGetter get_implementation;

#ifdef __cplusplus
}
#endif