// -*- mode: c; tab-width: 8; indent-tabs-mode: 1; st-rulers: [70] -*-
// vim: ts=8 sw=8 ft=c noet

#include "libsodium_api_randombytes.h"

static int	LS_API_INIT(randombytes, buf);
static void	LS_API_EXEC(randombytes, buf);
static void	LS_API_EXEC(randombytes, random);
static int	LS_API_INIT(randombytes, uniform);
static void	LS_API_EXEC(randombytes, uniform);
static void	LS_API_EXEC(randombytes, stir);
static void	LS_API_EXEC(randombytes, close);
static int	LS_API_INIT(randombytes, set_implementation);
static void	LS_API_EXEC(randombytes, set_implementation);
static void	LS_API_EXEC(randombytes, implementation_name);
static int	LS_API_INIT(randombytes, randombytes);
static void	LS_API_EXEC(randombytes, randombytes);

libsodium_function_t	libsodium_functions_randombytes[] = {
	LS_API_R_ARGV(randombytes, buf, 1),
	LS_API_R_ARG0(randombytes, random),
	LS_API_R_ARGV(randombytes, uniform, 1),
	LS_API_R_ARG0(randombytes, stir),
	LS_API_R_ARG0(randombytes, close),
	LS_API_R_ARGV(randombytes, set_implementation, 1),
	LS_API_R_ARG0(randombytes, implementation_name),
	LS_API_R_ARGV(randombytes, randombytes, 1),
	{NULL}
};

/* randombytes_buf/1 */

typedef struct LS_API_F_ARGV(randombytes, buf) {
	const size_t	size;
} LS_API_F_ARGV_T(randombytes, buf);

static int
LS_API_INIT(randombytes, buf)
{
	LS_API_F_ARGV_T(randombytes, buf) *argv;
	LS_API_INIT_ARGV(randombytes, buf);

	if (ei_decode_ulong(buffer, index, (unsigned long *)&(argv->size)) < 0) {
		(void) driver_free(argv);
		return -1;
	}
	request->argv = (void *)(argv);
	return 0;
}

static void
LS_API_EXEC(randombytes, buf)
{
	LS_API_F_ARGV_T(randombytes, buf) *argv;
	LS_API_READ_ARGV(randombytes, buf);
	void *buf;

	buf = (void *)(driver_alloc((ErlDrvSizeT)(argv->size)));

	if (buf == NULL) {
		LS_FAIL_OOM(request->port->drv_port);
		return;
	}

	(void) randombytes_buf(buf, argv->size);

	ErlDrvTermData spec[] = {
		LS_RES_TAG(request),
		ERL_DRV_BUF2BINARY, (ErlDrvTermData)(buf), argv->size,
		ERL_DRV_TUPLE, 2
	};

	LS_RESPOND(request, spec, __FILE__, __LINE__);

	(void) driver_free(buf);
}

/* randombytes_random/0 */

static void
LS_API_EXEC(randombytes, random)
{
	uint32_t n;

	n = randombytes_random();

	ErlDrvTermData spec[] = {
		LS_RES_TAG(request),
		ERL_DRV_UINT, (ErlDrvUInt)(n),
		ERL_DRV_TUPLE, 2
	};

	LS_RESPOND(request, spec, __FILE__, __LINE__);
}

/* randombytes_uniform/1 */

typedef struct LS_API_F_ARGV(randombytes, uniform) {
	const uint32_t	upper_bound;
} LS_API_F_ARGV_T(randombytes, uniform);

static int
LS_API_INIT(randombytes, uniform)
{
	LS_API_F_ARGV_T(randombytes, uniform) *argv;
	LS_API_INIT_ARGV(randombytes, uniform);

	if (ei_decode_ulong(buffer, index, (unsigned long *)&(argv->upper_bound)) < 0) {
		return -1;
	}
	request->argv = (void *)(argv);
	return 0;
}

static void
LS_API_EXEC(randombytes, uniform)
{
	LS_API_F_ARGV_T(randombytes, uniform) *argv;
	LS_API_READ_ARGV(randombytes, uniform);
	uint32_t n;

	n = randombytes_uniform(argv->upper_bound);

	ErlDrvTermData spec[] = {
		LS_RES_TAG(request),
		ERL_DRV_UINT, (ErlDrvUInt)(n),
		ERL_DRV_TUPLE, 2
	};

	LS_RESPOND(request, spec, __FILE__, __LINE__);
}

/* randombytes_stir/0 */

static void
LS_API_EXEC(randombytes, stir)
{
	(void) randombytes_stir();

	ErlDrvTermData spec[] = {
		LS_RES_TAG(request),
		ERL_DRV_ATOM, LS_ATOM(ok),
		ERL_DRV_TUPLE, 2
	};

	if (erl_drv_send_term(request->port->term_port, request->caller, spec, sizeof(spec) / sizeof(spec[0])) < 0) {
		TRACE_F("error sending term\n");
	}

	LS_RESPOND(request, spec, __FILE__, __LINE__);
}

/* randombytes_close/0 */

static void
LS_API_EXEC(randombytes, close)
{
	int r;

	r = randombytes_close();

	ErlDrvTermData spec[] = {
		LS_RES_TAG(request),
		ERL_DRV_INT, (ErlDrvSInt)(r),
		ERL_DRV_TUPLE, 2
	};

	LS_RESPOND(request, spec, __FILE__, __LINE__);
}

/* randombytes_set_implementation/1 */

typedef struct libsodium_api_randombytes_implementation {
	const char			*name;
	randombytes_implementation	*impl;
	ErlDrvTermData			am_name;
} libsodium_api_randombytes_implementation_t;

static libsodium_api_randombytes_implementation_t libsodium_api_randombytes_implementations[] = {
#ifdef __native_client__
	{"nativeclient", &randombytes_nativeclient_implementation},
#endif
	{"salsa20", &randombytes_salsa20_implementation},
	{"sysrandom", &randombytes_sysrandom_implementation},
	{NULL}
};

void
init_libsodium_api_randombytes_implementation(void)
{
	libsodium_api_randombytes_implementation_t *p = NULL;
	for (p = libsodium_api_randombytes_implementations; p->name; p++) {
		p->am_name = driver_mk_atom((char *)(p->name));
	}
}

static libsodium_api_randombytes_implementation_t *
get_libsodium_api_randombytes_implementation(const char *name)
{
	libsodium_api_randombytes_implementation_t *p = NULL;
	ErlDrvTermData am_name;
	(void) erl_drv_mutex_lock(libsodium_mutex);
	am_name = driver_mk_atom((char *)name);
	(void) erl_drv_mutex_unlock(libsodium_mutex);
	for (p = libsodium_api_randombytes_implementations; p->name; p++) {
		if (p->am_name == am_name) {
			return p;
		}
	}
	return NULL;
}

typedef struct LS_API_F_ARGV(randombytes, set_implementation) {
	randombytes_implementation	*impl;
} LS_API_F_ARGV_T(randombytes, set_implementation);

static int
LS_API_INIT(randombytes, set_implementation)
{
	LS_API_F_ARGV_T(randombytes, set_implementation) *argv;
	LS_API_INIT_ARGV(randombytes, set_implementation);
	int type;
	int type_length;
	ei_term term;
	libsodium_api_randombytes_implementation_t *p;

	if (ei_get_type(buffer, index, &type, &type_length) < 0 || type != ERL_ATOM_EXT) {
		return -1;
	}
	if (ei_decode_ei_term(buffer, index, &term) < 0) {
		return -1;
	}
	p = get_libsodium_api_randombytes_implementation(term.value.atom_name);
	if (p == NULL) {
		return -1;
	}
	argv->impl = p->impl;
	request->argv = (void *)(argv);
	return 0;
}

static void
LS_API_EXEC(randombytes, set_implementation)
{
	LS_API_F_ARGV_T(randombytes, set_implementation) *argv;
	LS_API_READ_ARGV(randombytes, set_implementation);
	int r;

	r = randombytes_set_implementation(argv->impl);

	ErlDrvTermData spec[] = {
		LS_RES_TAG(request),
		ERL_DRV_INT, (ErlDrvSInt)(r),
		ERL_DRV_TUPLE, 2
	};

	LS_RESPOND(request, spec, __FILE__, __LINE__);
}

/* randombytes_implementation_name/0 */

static void
LS_API_EXEC(randombytes, implementation_name)
{
	const char *implementation_name;

	implementation_name = randombytes_implementation_name();

	ErlDrvTermData spec[] = {
		LS_RES_TAG(request),
		ERL_DRV_ATOM, driver_mk_atom((char *)(implementation_name)),
		ERL_DRV_TUPLE, 2
	};

	LS_RESPOND(request, spec, __FILE__, __LINE__);
}

/* randombytes_randombytes/1 */

typedef struct LS_API_F_ARGV(randombytes, randombytes) {
	const unsigned long long	buf_len;
} LS_API_F_ARGV_T(randombytes, randombytes);

static int
LS_API_INIT(randombytes, randombytes)
{
	LS_API_F_ARGV_T(randombytes, randombytes) *argv;
	LS_API_INIT_ARGV(randombytes, randombytes);

	if (ei_decode_ulong(buffer, index, (unsigned long *)&(argv->buf_len)) < 0) {
		return -1;
	}
	request->argv = (void *)(argv);
	return 0;
}

static void
LS_API_EXEC(randombytes, randombytes)
{
	LS_API_F_ARGV_T(randombytes, randombytes) *argv;
	LS_API_READ_ARGV(randombytes, randombytes);
	unsigned char *buf;

	buf = (unsigned char *)(driver_alloc((ErlDrvSizeT)(argv->buf_len)));

	if (buf == NULL) {
		LS_FAIL_OOM(request->port->drv_port);
		return;
	}

	(void) randombytes((unsigned char * const)(buf), argv->buf_len);

	ErlDrvTermData spec[] = {
		LS_RES_TAG(request),
		ERL_DRV_BUF2BINARY, (ErlDrvTermData)(buf), (ErlDrvUInt)(argv->buf_len),
		ERL_DRV_TUPLE, 2
	};

	LS_RESPOND(request, spec, __FILE__, __LINE__);

	(void) driver_free(buf);
}