#include "saltywitch.h"

ERL_NIF_TERM saltywitch_secretbox_keygen(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
{
	ERL_NIF_TERM term;

	unsigned char *key = enif_make_new_binary(env, crypto_secretbox_KEYBYTES, &term);
	if (key == NULL) {
		return saltywitch_exception(env, atom_error, atom_err_nif_alloc);
	}

	crypto_secretbox_keygen(key);

	return term;
}

ERL_NIF_TERM saltywitch_secretbox_easy(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
{
	ErlNifBinary key, nonce, message;
	unsigned char *cipher;
	ERL_NIF_TERM term;

	ERL_NIF_TERM err    = atom_badarg;
	ERL_NIF_TERM reason = atom_err_opaque;

	if (enif_inspect_binary(env, argv[0], &key) == false) {
		reason = atom_err_invalid_type;
		goto badarg_FAULT;
	}

	if (key.size != crypto_secretbox_KEYBYTES) {
		reason = atom_err_invalid_key_size;
		goto badarg_FAULT;
	}

	if (enif_inspect_binary(env, argv[1], &nonce) == false) {
		reason = atom_err_invalid_type;
		goto badarg_FAULT;
	}

	if (nonce.size != crypto_secretbox_NONCEBYTES) {
		reason = atom_err_invalid_nonce_size;
		goto badarg_FAULT;
	}

	if (enif_inspect_binary(env, argv[2], &message) == false) {
		reason = atom_err_invalid_type;
		goto badarg_FAULT;
	}

	cipher = enif_make_new_binary(env, message.size + crypto_secretbox_MACBYTES, &term);
	if (cipher == NULL) {
		reason = atom_err_nif_alloc;
		goto error_FAULT;
	}

	crypto_secretbox_easy(cipher, message.data, message.size, nonce.data, key.data);

	return term;

error_FAULT:
	err = atom_error;
badarg_FAULT:
	return saltywitch_exception(env, err, reason);
}

ERL_NIF_TERM saltywitch_secretbox_open_easy(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
{
	ErlNifBinary key, nonce, cipher;
	unsigned char *message;
	ERL_NIF_TERM term;

	ERL_NIF_TERM err    = atom_badarg;
	ERL_NIF_TERM reason = atom_err_opaque;

	(void) argc;

	if (enif_inspect_binary(env, argv[0], &key) == false) {
		reason = atom_err_invalid_type;
		goto badarg_FAULT;
	}

	if (key.size != crypto_secretbox_KEYBYTES) {
		reason = atom_err_invalid_key_size;
		goto badarg_FAULT;
	}

	if (enif_inspect_binary(env, argv[1], &nonce) == false) {
		reason = atom_err_invalid_type;
		goto badarg_FAULT;
	}

	if (nonce.size != crypto_secretbox_NONCEBYTES) {
		reason = atom_err_invalid_nonce_size;
		goto badarg_FAULT;
	}

	if (enif_inspect_binary(env, argv[2], &cipher) == false) {
		reason = atom_err_invalid_type;
		goto badarg_FAULT;
	}

	if (cipher.size <= crypto_secretbox_MACBYTES) {
		reason = atom_err_ciphertext_too_small;
		goto badarg_FAULT;
	}

	message = enif_make_new_binary(env, cipher.size - crypto_secretbox_MACBYTES, &term);
	if (message == NULL) {
		reason = atom_err_nif_alloc;
		goto error_FAULT;
	}

	if (crypto_secretbox_open_easy(message, cipher.data, cipher.size, nonce.data, key.data) != 0) {
		reason = atom_err_invalid_type;
		goto error_FAULT;
	}

	return term;

error_FAULT:
	err = atom_error;
badarg_FAULT:
	return saltywitch_exception(env, err, reason);
}

ERL_NIF_TERM saltywitch_secretbox_detached(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
{
	ERL_NIF_TERM cipher_term, mac_term;
	ErlNifBinary key, message, nonce;
	unsigned char *cipher, *mac;

	ERL_NIF_TERM err    = atom_badarg;
	ERL_NIF_TERM reason = atom_err_opaque;

	if (enif_inspect_binary(env, argv[0], &key) == false) {
		reason = atom_err_invalid_type;
		goto badarg_FAULT;
	}

	if (key.size != crypto_secretbox_KEYBYTES) {
		reason = atom_err_invalid_key_size;
		goto badarg_FAULT;
	}

	if (enif_inspect_binary(env, argv[1], &nonce) == false) {
		reason = atom_err_invalid_type;
		goto badarg_FAULT;
	}

	if (nonce.size != crypto_secretbox_NONCEBYTES) {
		reason = atom_err_invalid_nonce_size;
		goto badarg_FAULT;
	}

	if (enif_inspect_binary(env, argv[2], &message) == false) {
		reason = atom_err_invalid_type;
		goto badarg_FAULT;
	}

	cipher = enif_make_new_binary(env, message.size, &cipher_term);
	if (cipher == NULL) {
		reason = atom_err_nif_alloc;
		goto error_FAULT;
	}

	mac = enif_make_new_binary(env, crypto_secretbox_MACBYTES, &mac_term);
	if (mac == NULL) {
		reason = atom_err_nif_alloc;
		goto error_FAULT;
	}

	crypto_secretbox_detached(cipher, mac, message.data, message.size, nonce.data, key.data);

	return enif_make_tuple2(env, cipher_term, mac_term);

error_FAULT:
	err = atom_error;
badarg_FAULT:
	return saltywitch_exception(env, err, reason);
}

ERL_NIF_TERM saltywitch_secretbox_open_detached(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
{
	ErlNifBinary key, nonce, cipher, mac;
	unsigned char *message;
	ERL_NIF_TERM term;

	ERL_NIF_TERM err    = atom_badarg;
	ERL_NIF_TERM reason = atom_err_opaque;

	if (enif_inspect_binary(env, argv[0], &key) == false) {
		reason = atom_err_invalid_type;
		goto FAULT;
	}

	if (key.size != crypto_secretbox_KEYBYTES) {
		goto FAULT;
	}

	if (enif_inspect_binary(env, argv[1], &nonce) == false) {
		reason = atom_err_invalid_type;
		goto FAULT;
	}

	if (nonce.size != crypto_secretbox_NONCEBYTES) {
		goto FAULT;
	}

	if (enif_inspect_binary(env, argv[2], &cipher) == false) {
		reason = atom_err_invalid_type;
		goto FAULT;
	}

	if (enif_inspect_binary(env, argv[3], &mac) == false) {
		reason = atom_err_invalid_type;
		goto FAULT;
	}

	if (mac.size != crypto_secretbox_MACBYTES) {
		goto FAULT;
	}

	message = enif_make_new_binary(env, cipher.size, &term);

	if (crypto_secretbox_open_detached(message, cipher.data, mac.data, cipher.size, nonce.data, key.data) != 0) {
		err = atom_error;
		goto FAULT;
	}

	return term;

FAULT:
	term = saltywitch_exception(env, err, reason);
	return term;
}

ERL_NIF_TERM saltywitch_secretbox_keybytes(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
{
	(void) argc;
	(void) argv;

	return enif_make_uint(env, crypto_secretbox_KEYBYTES);
}

ERL_NIF_TERM saltywitch_secretbox_macbytes(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
{
	(void) argc;
	(void) argv;

	return enif_make_uint(env, crypto_secretbox_MACBYTES);
}

ERL_NIF_TERM saltywitch_secretbox_noncebytes(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
{
	(void) argc;
	(void) argv;

	return enif_make_uint(env, crypto_secretbox_NONCEBYTES);
}