/** Signal meta data.
 *
 * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
 * @copyright 2014-2020, Institute for Automation of Complex Power Systems, EONERC
 * @license GNU General Public License (version 3)
 *
 * VILLASnode
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************************/

#include <cstring>
#include <cinttypes>
#include <villas/signal.h>
#include <villas/list.h>
#include <villas/utils.hpp>
#include <villas/node.h>
#include <villas/mapping.h>

using namespace villas;
using namespace villas::utils;

int signal_init(struct signal *s)
{
	s->enabled = true;

	s->name = nullptr;
	s->unit = nullptr;
	s->type = SignalType::INVALID;

	s->refcnt = ATOMIC_VAR_INIT(1);

	return 0;
}

int signal_init_from_mapping(struct signal *s, const struct mapping_entry *me, unsigned index)
{
	int ret;

	ret = signal_init(s);
	if (ret)
		return ret;

	ret = mapping_to_str(me, index, &s->name);
	if (ret)
		return ret;

	switch (me->type) {
		case MappingType::STATS:
			s->type = Stats::types[me->stats.type].signal_type;
			break;

		case MappingType::HEADER:
			switch (me->header.type) {
				case MappingHeaderType::LENGTH:
				case MappingHeaderType::SEQUENCE:
					s->type = SignalType::INTEGER;
					break;
			}
			break;

		case MappingType::TIMESTAMP:
			s->type = SignalType::INTEGER;
			break;

		case MappingType::DATA:
			s->type = me->data.signal->type;
			s->init = me->data.signal->init;
			s->enabled = me->data.signal->enabled;

			if (me->data.signal->name)
				s->name = strdup(me->data.signal->name);

			if (me->data.signal->unit)
				s->name = strdup(me->data.signal->unit);
			break;
	}

	return 0;
}

int signal_destroy(struct signal *s)
{
	if (s->name)
		free(s->name);

	if (s->unit)
		free(s->unit);

	return 0;
}

struct signal * signal_create(const char *name, const char *unit, enum SignalType fmt)
{
	int ret;
	struct signal *sig;

	sig = new struct signal;
	if (!sig)
		return nullptr;

	ret = signal_init(sig);
	if (ret)
		return nullptr;

	if (name)
		sig->name = strdup(name);

	if (unit)
		sig->unit = strdup(unit);

	sig->type = fmt;

	return sig;
}

int signal_free(struct signal *s)
{
	int ret;

	ret = signal_destroy(s);
	if (ret)
		 return ret;

	delete s;

	return 0;
}

int signal_incref(struct signal *s)
{
	return atomic_fetch_add(&s->refcnt, 1) + 1;
}

int signal_decref(struct signal *s)
{
	int prev = atomic_fetch_sub(&s->refcnt, 1);

	/* Did we had the last reference? */
	if (prev == 1)
		signal_free(s);

	return prev - 1;
}

struct signal * signal_copy(struct signal *s)
{
	struct signal *ns;

	ns = new struct signal;
	if (!ns)
		return nullptr;

	signal_init(ns);

	ns->type = s->type;
	ns->init = s->init;
	ns->enabled = s->enabled;

	if (s->name)
		ns->name = strdup(s->name);

	if (s->unit)
		ns->name = strdup(s->unit);

	return ns;
}

int signal_parse(struct signal *s, json_t *cfg)
{
	int ret;
	json_error_t err;
	json_t *json_init = nullptr;
	const char *name = nullptr;
	const char *unit = nullptr;
	const char *type = nullptr;

	ret = json_unpack_ex(cfg, &err, 0, "{ s?: s, s?: s, s?: s, s?: o, s?: b }",
		"name", &name,
		"unit", &unit,
		"type", &type,
		"init", &json_init,
		"enabled", &s->enabled
	);
	if (ret)
		return -1;

	if (name)
		s->name = strdup(name);

	if (unit)
		s->unit = strdup(unit);

	if (type) {
		s->type = signal_type_from_str(type);
		if (s->type == SignalType::INVALID)
			return -1;
	}

	if (json_init) {
		ret = signal_data_parse_json(&s->init, s, json_init);
		if (ret)
			return ret;
	}
	else
		signal_data_set(&s->init, s, 0);

	return 0;
}

/* Signal list */

int signal_list_init(struct vlist *list)
{
	int ret;

	ret = vlist_init(list);
	if (ret)
		return ret;

	return 0;
}

int signal_list_destroy(struct vlist *list)
{
	int ret;

	ret = vlist_destroy(list, (dtor_cb_t) signal_decref, false);
	if (ret)
		return ret;

	return 0;
}

int signal_list_parse(struct vlist *list, json_t *cfg)
{
	int ret;
	struct signal *s;

	if (!json_is_array(cfg))
		return -1;

	size_t i;
	json_t *json_signal;
	json_array_foreach(cfg, i, json_signal) {
		s = new struct signal;
		if (!s)
			return -1;

		ret = signal_init(s);
		if (ret)
			return ret;

		ret = signal_parse(s, json_signal);
		if (ret)
			return ret;

		vlist_push(list, s);
	}

	return 0;
}

int signal_list_generate(struct vlist *list, unsigned len, enum SignalType typ)
{
	char name[32];

	for (unsigned i = 0; i < len; i++) {
		snprintf(name, sizeof(name), "signal%d", i);

		struct signal *sig = signal_create(name, nullptr, typ);
		if (!sig)
			return -1;

		vlist_push(list, sig);
	}

	return 0;
}

int signal_list_generate2(struct vlist *list, const char *dt)
{
	int len, i = 0;
	char name[32], *e;
	enum SignalType typ;

	for (const char *t = dt; *t; t = e + 1) {
		len = strtoul(t, &e, 10);
		if (t == e)
			len = 1;

		typ = signal_type_from_fmtstr(*e);
		if (typ == SignalType::INVALID)
			return -1;

		for (int j = 0; j < len; j++) {
			snprintf(name, sizeof(name), "signal%d", i++);

			struct signal *sig = signal_create(name, nullptr, typ);
			if (!sig)
				return -1;

			vlist_push(list, sig);
		}
	}

	return 0;
}

void signal_list_dump(const struct vlist *list, const union signal_data *data, unsigned len)
{
	debug(5, "  Signals:");

	for (size_t i = 0; i < vlist_length(list); i++) {
		struct signal *sig = (struct signal *) vlist_at(list, i);

		char *buf = strf("    %d:", i);

		if (sig->name)
			strcatf(&buf, " %s", sig->name);

		if (sig->unit)
			strcatf(&buf, " [%s]", sig->unit);

		strcatf(&buf, "(%s)", signal_type_to_str(sig->type));

		if (data && i < len) {
			char val[32];

			signal_data_print_str(&data[i], sig, val, sizeof(val));

			strcatf(&buf, " = %s", val);
		}

		debug(5, "%s", buf);
		free(buf);
	}
}

int signal_list_copy(struct vlist *dst, const struct vlist *src)
{
	assert(src->state == State::INITIALIZED);
	assert(dst->state == State::INITIALIZED);

	for (size_t i = 0; i < vlist_length(src); i++) {
		struct signal *s = (struct signal *) vlist_at_safe(src, i);

		signal_incref(s);

		vlist_push(dst, s);
	}

	return 0;
}

/* Signal type */

enum SignalType signal_type_from_str(const char *str)
{
	if      (!strcmp(str, "boolean"))
		return SignalType::BOOLEAN;
	else if (!strcmp(str, "complex"))
		return SignalType::COMPLEX;
	else if (!strcmp(str, "float"))
		return SignalType::FLOAT;
	else if (!strcmp(str, "integer"))
		return SignalType::INTEGER;
	else
		return SignalType::INVALID;
}

enum SignalType signal_type_from_fmtstr(char c)
{
	switch (c) {
		case 'f':
			return SignalType::FLOAT;

		case 'i':
			return SignalType::INTEGER;

		case 'c':
			return SignalType::COMPLEX;

		case 'b':
			return SignalType::BOOLEAN;

		default:
			return SignalType::INVALID;
	}
}

const char * signal_type_to_str(enum SignalType fmt)
{
	switch (fmt) {
		case SignalType::BOOLEAN:
			return "boolean";

		case SignalType::COMPLEX:
			return "complex";

		case SignalType::FLOAT:
			return "float";

		case SignalType::INTEGER:
			return "integer";

		case SignalType::INVALID:
			return "invalid";
	}

	return nullptr;
}

enum SignalType signal_type_detect(const char *val)
{
	const char *brk;
	int len;

	debug(LOG_IO | 5, "Attempt to detect type of value: %s", val);

	brk = strchr(val, 'i');
	if (brk)
		return SignalType::COMPLEX;

	brk = strchr(val, '.');
	if (brk)
		return SignalType::FLOAT;

	len = strlen(val);
	if (len == 1 && (val[0] == '1' || val[0] == '0'))
		return SignalType::BOOLEAN;

	return SignalType::INTEGER;
}

/* Signal data */

void signal_data_set(union signal_data *data, const struct signal *sig, double val)
{
	switch (sig->type) {
		case SignalType::BOOLEAN:
			data->b = val;
			break;

		case SignalType::FLOAT:
			data->f = val;
			break;

		case SignalType::INTEGER:
			data->i = val;
			break;

		case SignalType::COMPLEX:
			data->z = val;
			break;

		case SignalType::INVALID:
			*data = signal_data::nan();
			break;
	}
}

void signal_data_cast(union signal_data *data, const struct signal *from, const struct signal *to)
{
	if (from->type == to->type) /* Nothing to do */
		return;

	switch (to->type) {
		case SignalType::BOOLEAN:
			switch(from->type) {
				case SignalType::BOOLEAN:
					data->b = data->b;
					break;

				case SignalType::INTEGER:
					data->b = data->i;
					break;

				case SignalType::FLOAT:
					data->b = data->f;
					break;

				case SignalType::COMPLEX:
					data->b = std::real(data->z);
					break;

				default: { }
			}
			break;

		case SignalType::INTEGER:
			switch(from->type) {
				case SignalType::BOOLEAN:
					data->i = data->b;
					break;

				case SignalType::INTEGER:
					data->i = data->i;
					break;

				case SignalType::FLOAT:
					data->i = data->f;
					break;

				case SignalType::COMPLEX:
					data->i = std::real(data->z);
					break;

				default: { }
			}
			break;

		case SignalType::FLOAT:
			switch(from->type) {
				case SignalType::BOOLEAN:
					data->f = data->b;
					break;

				case SignalType::INTEGER:
					data->f = data->i;
					break;

				case SignalType::FLOAT:
					data->f = data->f;
					break;

				case SignalType::COMPLEX:
					data->f = std::real(data->z);
					break;

				default: { }
			}
			break;

		case SignalType::COMPLEX:
			switch(from->type) {
				case SignalType::BOOLEAN:
					data->z = data->b;
					break;

				case SignalType::INTEGER:
					data->z = data->i;
					break;

				case SignalType::FLOAT:
					data->z = data->f;
					break;

				case SignalType::COMPLEX:
					data->z = data->z;
					break;

				default: { }
			}
			break;

		default: { }
	}
}

int signal_data_parse_str(union signal_data *data, const struct signal *sig, const char *ptr, char **end)
{
	switch (sig->type) {
		case SignalType::FLOAT:
			data->f = strtod(ptr, end);
			break;

		case SignalType::INTEGER:
			data->i = strtol(ptr, end, 10);
			break;

		case SignalType::BOOLEAN:
			data->b = strtol(ptr, end, 10);
			break;

		case SignalType::COMPLEX: {
			float real, imag = 0;

			real = strtod(ptr, end);
			if (*end == ptr)
				return -1;

			ptr = *end;

			if (*ptr == 'i' || *ptr == 'j') {
				imag = real;
				real = 0;

				(*end)++;
			}
			else if (*ptr == '-' || *ptr == '+') {
				imag = strtod(ptr, end);
				if (*end == ptr)
					return -1;

				if (**end != 'i' && **end != 'j')
					return -1;

				(*end)++;
			}

			data->z = std::complex<float>(real, imag);
			break;
		}

		case SignalType::INVALID:
			return -1;
	}

	return 0;
}

int signal_data_parse_json(union signal_data *data, const struct signal *sig, json_t *cfg)
{
	int ret;

	switch (sig->type) {
		case SignalType::FLOAT:
			data->f = json_real_value(cfg);
			break;

		case SignalType::INTEGER:
			data->i = json_integer_value(cfg);
			break;

		case SignalType::BOOLEAN:
			data->b = json_boolean_value(cfg);
			break;

		case SignalType::COMPLEX: {
			double real, imag;

			json_error_t err;
			ret = json_unpack_ex(cfg, &err, 0, "{ s: F, s: F }",
				"real", &real,
				"imag", &imag
			);
			if (ret)
				return -2;

			data->z = std::complex<float>(real, imag);
			break;
		}

		case SignalType::INVALID:
			return -1;
	}

	return 0;
}

int signal_data_print_str(const union signal_data *data, const struct signal *sig, char *buf, size_t len)
{
	switch (sig->type) {
		case SignalType::FLOAT:
			return snprintf(buf, len, "%.6f", data->f);

		case SignalType::INTEGER:
			return snprintf(buf, len, "%" PRIi64, data->i);

		case SignalType::BOOLEAN:
			return snprintf(buf, len, "%u", data->b);

		case SignalType::COMPLEX:
			return snprintf(buf, len, "%.6f%+.6fi", std::real(data->z), std::imag(data->z));

		default:
			return 0;
	}
}