/***************************************************************************
 *   Copyright (C) 05/2009 by Olaf Rempel                                  *
 *   razzor@kopf-tisch.de                                                  *
 *                                                                         *
 *   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; version 2 of the License                *
 *                                                                         *
 *   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, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#include <stdio.h>
#include <unistd.h>
#include <string.h>

#include <sys/socket.h>

#include "configfile.h"
#include "event.h"
#include "logging.h"
#include "unixsocket.h"
#include "usvdevice.h"

#define DEFAULT_SOCKET "alix-usvd.sock"
#define SENDMAIL "/usr/sbin/sendmail -t"

enum {
	STATE_IDLE	= 0x01,
	STATE_TEST	= 0x02,
	STATE_CHARGE	= 0x04,
	STATE_DISCHARGE	= 0x08,
	STATE_POWEROFF	= 0x10,
};

static struct event_fd *listen_event;
static struct event_timeout *timeout_event;

static const char *mail_from;
static const char *mail_to;

static char * state2str(int state)
{
	switch (state) {
	case STATE_IDLE:
		return "IDLE";

	case STATE_TEST:
		return "TEST";

	case STATE_CHARGE:
		return "CHARGE";

	case STATE_DISCHARGE:
		return "DISCHARGE";

	case STATE_POWEROFF:
		return "POWEROFF";

	default:
		return "UNKNOWN";
	}
}

static int str2state(char *buf)
{
	int state = -1;
	if (strncasecmp(buf, "IDLE", 4) == 0)
		state = STATE_IDLE;

	else if (strncasecmp(buf, "TEST", 4) == 0)
		state = STATE_TEST;

	else if (strncasecmp(buf, "CHARGE", 6) == 0)
		state = STATE_CHARGE;

	else if (strncasecmp(buf, "DISCHARGE", 9) == 0)
		state = STATE_DISCHARGE;

	else if (strncasecmp(buf, "POWEROFF", 8) == 0)
		state = STATE_POWEROFF;

	return state;
}

static int usvstate_update(int state, struct usvdev_status *status)
{
	static int old_state;

	if (status != NULL)
		state = status->state;

	if (state == old_state)
		return state;

	log_print(LOG_INFO, "usv state changed: %s => %s", state2str(old_state), state2str(state));

	if (mail_to != NULL) {
		FILE *mail = popen(SENDMAIL, "w");
		if (mail != NULL) {
			fprintf(mail, "From: %s\n", mail_from);
			fprintf(mail, "To: %s\n", mail_to);
			fprintf(mail, "Subject: alix-usvd state change: %s => %s\n\n",
				state2str(old_state), state2str(state));

			if (status != NULL) {
				fprintf(mail, "Current USV status:\n");
				fprintf(mail, "Ibat:  %1.3lf mA\nUbat: %2.3lf  V\nUin : %2.3lf  V\n\n",
					status->ibat / 1000.0, status->ubat / 1000.0, status->uin / 1000.0);
			}

			fprintf(mail, "Faithfully yours, etc.\n");
			fclose(mail);
		}
	}

	old_state = state;
	return state;
}

static int unix_read_cb(int fd, void *privdata)
{
	char buf[64];
	int len = read(fd, buf, sizeof(buf));
	if (len < 0)
		return -1;

	int new_state = str2state(buf);
	if (new_state != -1) {
		usvdev_setstate(new_state);
		new_state = usvstate_update(new_state, NULL);

		int len = snprintf(buf, sizeof(buf), "%s", state2str(new_state));
		write(fd, buf, len);

	} else if (strncasecmp(buf, "status", 6) == 0) {

		struct usvdev_status status;
		if (usvdev_getstatus(&status) == 0)
			usvstate_update(-1, &status);

		int len = snprintf(buf, sizeof(buf), "%s:%d:%d:%d",
					state2str(status.state),
					(short)status.ibat, status.ubat, status.uin);
		write(fd, buf, len);
	}

	close(fd);
	return -1;
}

static int status_interval(void *privdata)
{
	struct usvdev_status status;
	if (usvdev_getstatus(&status) < 0)
		return 0;

	usvstate_update(-1, &status);
	return 0;
}

static int unix_accept_cb(int fd, void *privdata)
{
	int con = accept(fd, NULL, NULL);
	if (con < 0) {
		log_print(LOG_ERROR, "unix_accept_cb: accept()");
		return 0;
	}

	event_add_readfd(NULL, con, unix_read_cb, NULL);
	return 0;
}

int usvstate_init(void)
{
	const char *socket_path = config_get_string("global", "socket", DEFAULT_SOCKET);
	int sockfd = unix_listen(socket_path);
	if (sockfd < 0)
		return -1;

	listen_event = event_add_readfd(NULL, sockfd, unix_accept_cb, NULL);
	if (listen_event == NULL) {
		close(sockfd);
		return -1;
	}

	int interval = config_get_int("global", "check-interval", 60);
	struct timeval tv = { .tv_sec = interval, .tv_usec = 0 };

	timeout_event = event_add_timeout(&tv, status_interval, NULL);

	mail_from = config_get_string("alerts", "mail-from", NULL);
	mail_to = config_get_string("alerts", "mail-to", NULL);

	usvstate_update(-1, NULL);
	return 0;
}

int usvstate_close(void)
{
	event_remove_timeout(timeout_event);

	event_remove_fd(listen_event);
	close(event_get_fd(listen_event));

	return 0;
}