/*
 * collectd - src/sigrok.c
 * Copyright (C) 2013 Bert Vermeulen
 *
 * 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 2 of the License, or
 * (at your option) 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/>.
 *
 * Authors:
 *   Bert Vermeulen <bert at biot.com>
 */

#include "collectd.h"
#include "common.h"
#include "plugin.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <pthread.h>

#include <glib.h>
#include <libsigrok/libsigrok.h>

/* Minimum interval between dispatches coming from this plugin. The RRD
 * plugin, at least, complains when written to with sub-second intervals.*/
#define DEFAULT_MIN_DISPATCH_INTERVAL TIME_T_TO_CDTIME_T(0)

static pthread_t sr_thread;
static int sr_thread_running = FALSE;
GSList *config_devices;
static int num_devices;
static int loglevel = SR_LOG_WARN;
static struct sr_context *sr_ctx;

struct config_device {
	char *name;
	char *driver;
	char *conn;
	char *serialcomm;
	struct sr_dev_inst *sdi;
	cdtime_t min_dispatch_interval;
	cdtime_t last_dispatch;
};


static int sigrok_log_callback(void*cb_data __attribute__((unused)),
		int msg_loglevel, const char *format, va_list args)
{
	char s[512];

	if (msg_loglevel <= loglevel) {
		vsnprintf(s, 512, format, args);
		plugin_log(LOG_INFO, "sigrok plugin: %s", s);
	}

	return 0;
}

static int sigrok_config_device(oconfig_item_t *ci)
{
	struct config_device *cfdev;
	int i;

	if (!(cfdev = malloc(sizeof(struct config_device)))) {
		ERROR("sigrok plugin: malloc() failed.");
		return -1;
	}
	memset(cfdev, 0, sizeof(*cfdev));
	if (cf_util_get_string(ci, &cfdev->name)) {
		free(cfdev);
		WARNING("sigrok plugin: Invalid device name.");
		return -1;
	}
	cfdev->min_dispatch_interval = DEFAULT_MIN_DISPATCH_INTERVAL;

	for (i = 0; i < ci->children_num; i++) {
		oconfig_item_t *item = ci->children + i;
		if (!strcasecmp(item->key, "driver"))
			cf_util_get_string(item, &cfdev->driver);
		else if (!strcasecmp(item->key, "conn"))
			cf_util_get_string(item, &cfdev->conn);
		else if (!strcasecmp(item->key, "serialcomm"))
			cf_util_get_string(item, &cfdev->serialcomm);
		else if (!strcasecmp(item->key, "minimuminterval"))
			cf_util_get_cdtime(item, &cfdev->min_dispatch_interval);
		else
			WARNING("sigrok plugin: Invalid keyword \"%s\".",
					item->key);
	}

	config_devices = g_slist_append(config_devices, cfdev);

	return 0;
}

static int sigrok_config(oconfig_item_t *ci)
{
	int i;

	for (i = 0; i < ci->children_num; i++) {
		oconfig_item_t *item = ci->children + i;
		if (strcasecmp("LogLevel", item->key) == 0) {
			int status;
			int tmp = -1;

			status = cf_util_get_int (item, &tmp);
			if (status != 0)
				continue;
			else if ((tmp < 0) || (tmp > 5)) {
				ERROR ("sigrok plugin: The \"LogLevel\" "
						"configuration option expects "
						"an integer between 0 and 5 "
						"(inclusive); you provided %i.",
						tmp);
				continue;
			}
			loglevel = tmp;
		} else if (!strcasecmp(item->key, "Device"))
			sigrok_config_device(item);
		else
			WARNING("sigrok plugin: Invalid keyword \"%s\".",
					item->key);
	}

	return 0;
}

static char *sigrok_value_type(const struct sr_datafeed_analog *analog)
{
	char *s;

	if (analog->mq == SR_MQ_VOLTAGE)
		s = "voltage";
	else if (analog->mq == SR_MQ_CURRENT)
		s = "current";
	else if (analog->mq == SR_MQ_FREQUENCY)
		s = "frequency";
	else if (analog->mq == SR_MQ_POWER)
		s = "power";
	else if (analog->mq == SR_MQ_TEMPERATURE)
		s = "temperature";
	else if (analog->mq == SR_MQ_RELATIVE_HUMIDITY)
		s = "humidity";
	else if (analog->mq == SR_MQ_SOUND_PRESSURE_LEVEL)
		s = "spl";
	else
		s = "gauge";

	return s;
}

static void sigrok_feed_callback(const struct sr_dev_inst *sdi,
		const struct sr_datafeed_packet *packet, void *cb_data)
{
	const struct sr_datafeed_analog *analog;
	struct config_device *cfdev;
	GSList *l;
	value_t value;
	value_list_t vl = VALUE_LIST_INIT;

	/* Find this device's configuration. */
	cfdev = NULL;
	for (l = config_devices; l; l = l->next) {
		cfdev = l->data;
		if (cfdev->sdi == sdi) {
			/* Found it. */
			break;
		}
		cfdev = NULL;
	}

	if (!cfdev) {
		ERROR("sigrok plugin: Received data from driver \"%s\" but "
				"can't find a configuration / device matching "
				"it.", sdi->driver->name);
		return;
	}

	if (packet->type == SR_DF_END) {
		/* TODO: try to restart acquisition after a delay? */
		WARNING("sigrok plugin: acquisition for \"%s\" ended.",
				cfdev->name);
		return;
	}

	if (packet->type != SR_DF_ANALOG)
		return;

	if ((cfdev->min_dispatch_interval != 0)
			&& ((cdtime() - cfdev->last_dispatch)
				< cfdev->min_dispatch_interval))
		return;

	/* Ignore all but the first sample on the first probe. */
	analog = packet->payload;
	value.gauge = analog->data[0];
	vl.values = &value;
	vl.values_len = 1;
	sstrncpy(vl.host, hostname_g, sizeof(vl.host));
	sstrncpy(vl.plugin, "sigrok", sizeof(vl.plugin));
	ssnprintf(vl.plugin_instance, sizeof(vl.plugin_instance),
			"%s", cfdev->name);
	sstrncpy(vl.type, sigrok_value_type(analog), sizeof(vl.type));

	plugin_dispatch_values(&vl);
	cfdev->last_dispatch = cdtime();
}

static void sigrok_free_drvopts(struct sr_config *src)
{
	g_variant_unref(src->data);
	g_free(src);
}

static int sigrok_init_driver(struct config_device *cfdev,
		struct sr_dev_driver *drv)
{
	struct sr_config *src;
	GSList *devlist, *drvopts;
	char hwident[512];

	if (sr_driver_init(sr_ctx, drv) != SR_OK)
		/* Error was logged by libsigrok. */
		return -1;

	drvopts = NULL;
	if (cfdev->conn) {
		if (!(src = malloc(sizeof(struct sr_config))))
			return -1;
		src->key = SR_CONF_CONN;
		src->data = g_variant_new_string(cfdev->conn);
		drvopts = g_slist_append(drvopts, src);
	}
	if (cfdev->serialcomm) {
		if (!(src = malloc(sizeof(struct sr_config))))
			return -1;
		src->key = SR_CONF_SERIALCOMM;
		src->data = g_variant_new_string(cfdev->serialcomm);
		drvopts = g_slist_append(drvopts, src);
	}
	devlist = sr_driver_scan(drv, drvopts);
	g_slist_free_full(drvopts, (GDestroyNotify)sigrok_free_drvopts);
	if (!devlist) {
		/* Not an error, but the user should know about it. */
		WARNING("sigrok plugin: No device found for \"%s\".",
				cfdev->name);
		return 0;
	}

	if (g_slist_length(devlist) > 1) {
		INFO("sigrok plugin: %d sigrok devices for device entry "
				"\"%s\": must be 1.",
				g_slist_length(devlist), cfdev->name);
		return -1;
	}
	cfdev->sdi = devlist->data;
	g_slist_free(devlist);
	ssnprintf(hwident, sizeof(hwident), "%s %s %s",
			cfdev->sdi->vendor ? cfdev->sdi->vendor : "",
			cfdev->sdi->model ? cfdev->sdi->model : "",
			cfdev->sdi->version ? cfdev->sdi->version : "");
	INFO("sigrok plugin: Device \"%s\" is a %s", cfdev->name, hwident);

	if (sr_dev_open(cfdev->sdi) != SR_OK)
		return -1;

	if (sr_session_dev_add(cfdev->sdi) != SR_OK)
		return -1;

	return 1;
}

static void *sigrok_read_thread(void *arg __attribute__((unused)))
{
	struct sr_dev_driver *drv, **drvlist;
	GSList *l;
	struct config_device *cfdev;
	int ret, i;

	sr_log_callback_set(sigrok_log_callback, NULL);
	sr_log_loglevel_set(loglevel);

	if ((ret = sr_init(&sr_ctx)) != SR_OK) {
		ERROR("sigrok plugin: Failed to initialize libsigrok: %s.",
				sr_strerror(ret));
		return NULL;
	}

	if (!sr_session_new())
		return NULL;

	num_devices = 0;
	drvlist = sr_driver_list();
	for (l = config_devices; l; l = l->next) {
		cfdev = l->data;
		drv = NULL;
		for (i = 0; drvlist[i]; i++) {
			if (!strcmp(drvlist[i]->name, cfdev->driver)) {
				drv = drvlist[i];
				break;
			}
		}
		if (!drv) {
			ERROR("sigrok plugin: Unknown driver \"%s\".",
					cfdev->driver);
			return NULL;
		}

		if ((ret = sigrok_init_driver(cfdev, drv)) < 0)
			/* Error was already logged. */
			return NULL;

		num_devices += ret;
	}

	if (num_devices > 0) {
		/* Do this only when we're sure there's hardware to talk to. */
		if (sr_session_datafeed_callback_add(sigrok_feed_callback, NULL)
				!= SR_OK)
			return NULL;

		/* Start acquisition on all devices. */
		if (sr_session_start() != SR_OK)
			return NULL;

		/* Main loop, runs forever. */
		sr_session_run();

		sr_session_stop();
		sr_session_dev_remove_all();
	}

	sr_session_destroy();

	sr_exit(sr_ctx);

	pthread_exit(NULL);
	sr_thread_running = FALSE;

	return NULL;
}

static int sigrok_init(void)
{
	int status;

	if (sr_thread_running) {
		ERROR("sigrok plugin: Thread already running.");
		return -1;
	}

	if ((status = plugin_thread_create(&sr_thread, NULL, sigrok_read_thread,
			NULL)) != 0) {
		ERROR("sigrok plugin: Failed to create thread: %s.",
				strerror(status));
		return -1;
	}
	sr_thread_running = TRUE;

	return 0;
}

static int sigrok_shutdown(void)
{
	struct config_device *cfdev;
	GSList *l;

	if (sr_thread_running) {
		pthread_cancel(sr_thread);
		pthread_join(sr_thread, NULL);
	}

	for (l = config_devices; l; l = l->next) {
		cfdev = l->data;
		free(cfdev->name);
		free(cfdev->driver);
		free(cfdev->conn);
		free(cfdev->serialcomm);
		free(cfdev);
	}
	g_slist_free(config_devices);

	return 0;
}

void module_register(void)
{
	plugin_register_complex_config("sigrok", sigrok_config);
	plugin_register_init("sigrok", sigrok_init);
	plugin_register_shutdown("sigrok", sigrok_shutdown);
}
