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

#include "libsodium_request.h"
#include "libsodium_api.h"

static void	libsodium_request_badarg(libsodium_request_t *request);

static void	libsodium_async_call(libsodium_request_t **request, char *buf, ErlDrvSizeT len);
static void	libsodium_async_call_invoke(void *async_data);
static void	libsodium_async_call_free(void *async_data);

libsodium_request_t *
libsodium_request_alloc(libsodium_port_t *port, ErlDrvTermData caller, unsigned int command)
{
	ErlDrvSizeT x;
	void *p;
	libsodium_request_t *request;

	x = (ErlDrvSizeT)((sizeof (libsodium_request_t)));
	p = driver_alloc(x);

	if (p == NULL) {
		return NULL;
	}

	request = (libsodium_request_t *)(p);
	request->port = port;
	request->caller = caller;
	request->command = NULL;
	request->tag.buff = NULL;
	request->tag.buffsz = 0;
	request->tag.index = 0;
	request->argc = -1;
	request->argv = NULL;
	request->execute = NULL;
	request->error = 0;
	request->reply.buff = NULL;
	request->reply.buffsz = 0;
	request->reply.index = 0;

	switch (command) {
	case LIBSODIUM_ASYNC_CALL:
		request->command = libsodium_async_call;
		break;
	default:
		(void) libsodium_request_badarg(request);
		break;
	}

	return request;
}

void
libsodium_request_free(libsodium_request_t *request)
{
	if (request == NULL) {
		return;
	}
	if (request->tag.buff != NULL) {
		(void) driver_free(request->tag.buff);
		request->tag.buff = NULL;
		request->tag.buffsz = 0;
		request->tag.index = 0;
	}
	if (request->argv != NULL) {
		(void) driver_free(request->argv);
		request->argv = NULL;
	}
	if (request->reply.buff != NULL) {
		(void) driver_free(request->reply.buff);
		request->reply.buff = NULL;
		request->reply.buffsz = 0;
		request->reply.index = 0;
	}
	(void) driver_free(request);
	request = NULL;
}

static void
libsodium_request_badarg(libsodium_request_t *request)
{
	request->error = (int)(ERL_DRV_ERROR_BADARG);
}

static void
libsodium_async_call(libsodium_request_t **request, char *buf, ErlDrvSizeT len)
{
	libsodium_request_t *req;
	libsodium_request_t *sync_req;
	char *buffer;
	int version;
	int version_beg;
	int version_end;
	int index;
	int tag_beg;
	int tag_end;
	int type;
	int type_length;
	int arity;
	libsodium_function_t *function;
	void *async_data;

	(void) len; // unused

	req = *request;
	buffer = buf;
	index = 0;

	version_beg = index;

	if (ei_decode_version(buffer, &index, &version) < 0) {
		(void) libsodium_request_badarg(req);
		return;
	}

	version_end = index;

	if (ei_decode_tuple_header(buffer, &index, &arity) < 0 || arity != 4) {
		(void) libsodium_request_badarg(req);
		return;
	}

	if (ei_get_type(buffer, &index, &type, &type_length) < 0
			|| (type != ERL_REFERENCE_EXT
			&& type != ERL_NEW_REFERENCE_EXT)) {
		(void) libsodium_request_badarg(req);
		return;
	}

	tag_beg = index;

	if (ei_skip_term(buffer, &index) < 0) {
		(void) libsodium_request_badarg(req);
		return;
	}

	tag_end = index;

	req->tag.buffsz = (version_end - version_beg) + (tag_end - tag_beg);
	req->tag.index = req->tag.buffsz;
	req->tag.buff = (char *)(driver_alloc(req->tag.buffsz));

	if (req->tag.buff == NULL) {
		(void) libsodium_request_badarg(req);
		LS_FAIL_OOM(req->port->drv_port);
		return;
	}

	(void) memcpy((req->tag.buff) + version_beg, buf + version_beg, (version_end - version_beg));
	(void) memcpy((req->tag.buff) + (version_end - version_beg), buf + tag_beg, (tag_end - tag_beg));

	if (ei_get_type(buffer, &index, &type, &type_length) < 0 || type != ERL_ATOM_EXT) {
		(void) libsodium_request_badarg(req);
		return;
	}

	if (ei_decode_ei_term(buffer, &index, &(req->namespace)) < 0) {
		(void) libsodium_request_badarg(req);
		return;
	}

	if (ei_get_type(buffer, &index, &type, &type_length) < 0 || type != ERL_ATOM_EXT) {
		(void) libsodium_request_badarg(req);
		return;
	}

	if (ei_decode_ei_term(buffer, &index, &(req->function)) < 0) {
		(void) libsodium_request_badarg(req);
		return;
	}

	if (ei_decode_tuple_header(buffer, &index, &(req->argc)) < 0) {
		(void) libsodium_request_badarg(req);
		return;
	}

	function = get_libsodium_api(req->namespace.value.atom_name, req->function.value.atom_name);

	if (function == NULL || function->arity != req->argc) {
		(void) libsodium_request_badarg(req);
		return;
	}

	if (function->init != NULL && function->init(req, buffer, &index) < 0) {
		(void) libsodium_request_badarg(req);
		return;
	}

	req->execute = function->exec;

	sync_req = libsodium_request_alloc(req->port, req->caller, LIBSODIUM_ASYNC_CALL);

	if (sync_req == NULL) {
		(void) libsodium_request_badarg(req);
		LS_FAIL_OOM(req->port->drv_port);
		return;
	}

	sync_req->tag.buffsz = req->tag.buffsz;
	sync_req->tag.index = req->tag.index;
	sync_req->tag.buff = (char *)(driver_alloc(sync_req->tag.buffsz));

	if (sync_req->tag.buff == NULL) {
		(void) libsodium_request_free(sync_req);
		(void) libsodium_request_badarg(req);
		LS_FAIL_OOM(req->port->drv_port);
		return;
	}

	(void) memcpy(sync_req->tag.buff, req->tag.buff, sync_req->tag.buffsz);

	sync_req->reply.buffsz = sync_req->tag.buffsz;
	sync_req->reply.index = sync_req->tag.index;
	sync_req->reply.buff = (char *)(driver_alloc(sync_req->reply.buffsz));

	if (sync_req->reply.buff == NULL) {
		(void) libsodium_request_free(sync_req);
		(void) libsodium_request_badarg(req);
		LS_FAIL_OOM(req->port->drv_port);
		return;
	}

	(void) memcpy(sync_req->reply.buff, sync_req->tag.buff, sync_req->reply.buffsz);

	sync_req->namespace = req->namespace;
	sync_req->function = req->function;
	sync_req->argc = req->argc;
	sync_req->argv = NULL;
	sync_req->execute = req->execute;
	sync_req->error = req->error;

	async_data = (void *)(req);
	*request = sync_req;

	if (driver_async(req->port->drv_port, NULL, libsodium_async_call_invoke, async_data, libsodium_async_call_free) < 0) {
		(void) libsodium_request_badarg(sync_req);
		return;
	}
}

static void
libsodium_async_call_invoke(void *async_data)
{
	libsodium_request_t *request;

	request = (libsodium_request_t *)(async_data);

	if (request == NULL) {
		return;
	}

	// TRACE_F("(invoke) asynchronous call: %s\n", request->function.value.atom_name);

	(void) (request->execute)(request);
}

static void
libsodium_async_call_free(void *async_data)
{
	libsodium_request_t *request;

	request = (libsodium_request_t *)(async_data);

	if (request == NULL) {
		return;
	}

	// TRACE_F("(free) asynchronous call: %s\n", request->function.value.atom_name);

	(void) libsodium_request_free(request);
}