/***************************************************************************
 *   Copyright (C) 05/2011 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; 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, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <ctype.h>
#include <time.h>

#include "configfile.h"
#include "diskwatch.h"
#include "event.h"
#include "lcd.h"
#include "list.h"
#include "logging.h"

#include "sgio.h"
int verbose = 0;
int prefer_ata12 = 0;

#define F_PRESENT	0x0001
#define F_STANDBY	0x0002

struct disk_entry {
	struct list_head list;
	const char device[32];
	unsigned int timeout_sec;

	int flags;

	time_t standby_timeout;
	unsigned int sectors_rd;
	unsigned int sectors_wr;
};

struct diskwatch {
	struct list_head disk_list;
	struct lcddev *lcd;
	struct event_timeout *check_timeout;
};

static struct diskwatch diskwatch_glob;

static int diskwatch_check_standby(struct disk_entry *entry);

static int lcdpage_diskwatch(struct lcddev *lcd, int event, void *privdata)
{
	static struct disk_entry *entry;
	struct diskwatch *dwatch = (struct diskwatch *)privdata;

	if (entry == NULL) {
		if (list_empty(&dwatch->disk_list)) {
			return LCDPAGE_COMMAND_NEXT;
		}

		entry = list_entry(dwatch->disk_list.next, struct disk_entry, list);
	}

	switch (event) {
		case LCDPAGE_EVENT_BUTTON1:
			if (entry->list.next == &dwatch->disk_list) {
				entry = NULL;
				return LCDPAGE_COMMAND_NEXT;
			}

			entry = list_entry(entry->list.next, struct disk_entry, list);
			lcd_set_backlight(lcd, 1);
			break;

		case LCDPAGE_EVENT_ENTER:
			entry = list_entry(dwatch->disk_list.next, struct disk_entry, list);
			lcd_set_backlight(lcd, 1);
			break;

		case LCDPAGE_EVENT_BACKLIGHT:
		case LCDPAGE_EVENT_EXIT:
			return 0;

		default:
			break;
	}

	char line1[32];
	char line2[32];

	snprintf(line1, sizeof(line1), "DISK(%s):", entry->device);
	if (entry->flags & F_PRESENT) {
		diskwatch_check_standby(entry);

		if (entry->flags & F_STANDBY) {
			snprintf(line2, sizeof(line2), "STANDBY");
		} else {
			int timeout = entry->standby_timeout - time(NULL);
			int hours = timeout / 3600;
			timeout = timeout % 3600;
			int minutes = timeout / 60;
			timeout = timeout % 60;

			snprintf(line2, sizeof(line2), "RUN -%02d:%02d:%02d", hours, minutes, timeout);
		}

	} else {
		snprintf(line2, sizeof(line2), "not present");
	}

	lcd_setlines(lcd, line1, line2);

	return 1000;
}

static int diskwatch_check_standby(struct disk_entry *entry)
{
	if (!(entry->flags & F_PRESENT))
		return 0;

	int fd = open(entry->device, O_RDONLY | O_NONBLOCK);
	if (fd < 0) {
		log_print(LOG_ERROR, "%s(): failed to open %s", __FUNCTION__, entry->device);
		return -1;
	}

	unsigned char args[4] = { ATA_OP_CHECKPOWERMODE1, 0, 0, 0 };
	if (do_drive_cmd(fd, args)) {
		args[0] = ATA_OP_CHECKPOWERMODE2;
		if (do_drive_cmd(fd, args)) {
			log_print(LOG_WARN, "%s: do_drive_cmd(ATA_OP_CHECKPOWERMODEx) failed on %s", __FUNCTION__, entry->device);
			close(fd);
			return -1;
		}
	}

	time_t now = time(NULL);

	/* args[2]:
	 * 0x00 - standby
	 * 0x40 - NVcache_spindown
	 * 0x41 - NVcache_spinup
	 * 0x80 - idle
	 * 0xFF - active/idle
	 */
	/* drive is in standby */
	if (args[2] == 0x00) {
		entry->flags |= F_STANDBY;

	/* drive was in standby, and is now active */
	} else if (entry->flags & F_STANDBY) {
		entry->flags &= ~(F_STANDBY);
		entry->standby_timeout = now + entry->timeout_sec;

	/* drive is active, and timeout is up */
	} else if (now >= entry->standby_timeout) {
		unsigned char args[4] = { ATA_OP_STANDBYNOW1, 0, 0, 0};
		if (do_drive_cmd(fd, args)) {
			args[0] = ATA_OP_STANDBYNOW2;
			if (do_drive_cmd(fd, args)) {
				log_print(LOG_WARN, "%s: do_drive_cmd(ATA_OP_STANDBYNOWx) failed on %s", __FUNCTION__, entry->device);
				close(fd);
				return -1;
			}
		}
		entry->flags |= F_STANDBY;
	}

	close(fd);
	return 0;
}

static int diskwatch_check_stats(int timerid, void *privdata)
{
	struct diskwatch *dwatch = (struct diskwatch *)privdata;

	struct disk_entry *entry;
	list_for_each_entry(entry, &dwatch->disk_list, list) {
		entry->flags &= ~(F_PRESENT);
	}

	FILE *fp = fopen("/proc/diskstats", "r");
	if (fp == NULL) {
		log_print(LOG_WARN, "%s(): fopen()", __FUNCTION__);
		return -1;
	}

	time_t now = time(NULL);

	char buffer[256];
	while (fgets(buffer, sizeof(buffer), fp) != NULL) {
		int major, minor;
		char device[32];
		unsigned int val[11];

		/* field - description
		 *  1 - major number
		 *  2 - minor mumber
		 *  3 - device name
		 *  4 - reads completed successfully
		 *  5 - reads merged
		 *  6 - sectors read
		 *  7 - time spent reading (ms)
		 *  8 - writes completed
		 *  9 - writes merged
		 * 10 - sectors written
		 * 11 - time spent writing (ms)
		 * 12 - I/Os currently in progress
		 * 13 - time spent doing I/Os (ms)
		 * 14 - weighted time spent doing I/Os (ms)
		 */
		int cnt = sscanf(buffer, "%d %d %s %u %u %u %u %u %u %u %u %u %u %u",
					&major, &minor, device, &val[0],
					&val[1], &val[2], &val[3], &val[4],
					&val[5], &val[6], &val[7], &val[8],
					&val[9], &val[10]);

		if (cnt != 14) {
			log_print(LOG_WARN, "%s(): invalid diskstat line: '%s'", __FUNCTION__, buffer);
			continue;
		}

		struct disk_entry *entry;
		list_for_each_entry(entry, &dwatch->disk_list, list) {
			char *dev = strrchr(entry->device, '/');
			if (dev == NULL || *(dev +1) == '\0')
				continue;

			if (strncmp(dev +1, device, strlen(device)) != 0)
				continue;

			entry->flags |= F_PRESENT;

			if (entry->sectors_rd == val[2] && entry->sectors_wr == val[6])
				continue;

			/* sector counts changed, disk is not in standby */
			entry->flags &= ~(F_STANDBY);
			entry->sectors_rd = val[2];
			entry->sectors_wr = val[6];
			entry->standby_timeout = now + entry->timeout_sec;
		}
	}

	fclose(fp);

	list_for_each_entry(entry, &dwatch->disk_list, list) {
		diskwatch_check_standby(entry);
	}

	return 0;
}

static int diskwatch_add_disk(struct strtoken *tokens, void *privdata)
{
	struct diskwatch *dwatch = (struct diskwatch *)privdata;

	if (tokens->count != 2) {
		log_print(LOG_WARN, "%s(): invalid config line '%s'", __FUNCTION__, tokens->input);
		return -1;
	}

	struct disk_entry *entry = malloc(sizeof(struct disk_entry));
	if (entry == NULL) {
		log_print(LOG_WARN, "%s(): out of memory", __FUNCTION__);
		return -1;
	}

	memset(entry, 0x00, sizeof(struct disk_entry));

	strncpy((char *)entry->device, tokens->field[0], sizeof(entry->device));

	char *tmp;
	entry->timeout_sec = strtol(tokens->field[1], &tmp, 0);
	if (*tmp != '\0' && !isspace(*tmp)) {
		log_print(LOG_WARN, "%s(): invalid timeout value '%s'", __FUNCTION__, tokens->field[1]);
		free(entry);
		return -1;
	}

	log_print(LOG_INFO, "diskwatch: watching '%s' (standby timeout: %ds)", entry->device, entry->timeout_sec);
	list_add_tail(&entry->list, &dwatch->disk_list);
	return 0;
}

void diskwatch_exit(void)
{
	struct diskwatch *dwatch = &diskwatch_glob;
	struct disk_entry *entry, *tmp;

	list_for_each_entry_safe(entry, tmp, &dwatch->disk_list, list) {
		list_del(&entry->list);
		free(entry);
	}

	if (dwatch->check_timeout != NULL) {
		event_remove_timeout(dwatch->check_timeout);
		dwatch->check_timeout = NULL;
	}
}

int diskwatch_init(struct lcddev *lcd)
{
	struct diskwatch *dwatch = &diskwatch_glob;

	INIT_LIST_HEAD(&dwatch->disk_list);

	int diskcount = config_get_strtokens("diskwatch", "disk", ",", 2, diskwatch_add_disk, dwatch);
	if (diskcount <= 0)
		return 0;

	diskwatch_check_stats(0, dwatch);

	int check_interval = 0;
	config_get_int("diskwatch", "check_interval", &check_interval, 60);
	dwatch->check_timeout = event_add_timeout_ms(check_interval * 1000, diskwatch_check_stats, 0, dwatch);

	dwatch->lcd = lcd;
	if (dwatch->lcd != NULL) {
		lcd_addpage_cb(dwatch->lcd, 150, lcdpage_diskwatch, dwatch);
	}

	return 0;
}