/*
 * Copyright (C) 2012 STRATO.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * 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 021110-1307, USA.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <sys/stat.h>
#include <time.h>
#include <assert.h>
#include <inttypes.h>
#include <sys/wait.h>

#include "kerncompat.h"
#include "ctree.h"
#include "ioctl.h"
#include "utils.h"
#include "volumes.h"
#include "disk-io.h"

#include "commands.h"


static int print_replace_status(int fd, const char *path, int once);
static char *time2string(char *buf, size_t s, __u64 t);
static char *progress2string(char *buf, size_t s, int progress_1000);


static const char *replace_dev_result2string(__u64 result)
{
	switch (result) {
	case BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR:
		return "no error";
	case BTRFS_IOCTL_DEV_REPLACE_RESULT_NOT_STARTED:
		return "not started";
	case BTRFS_IOCTL_DEV_REPLACE_RESULT_ALREADY_STARTED:
		return "already started";
	default:
		return "<illegal result value>";
	}
}

static const char * const replace_cmd_group_usage[] = {
	"btrfs replace <command> [<args>]",
	NULL
};

static int is_numerical(const char *str)
{
	if (!(*str >= '0' && *str <= '9'))
		return 0;
	while (*str >= '0' && *str <= '9')
		str++;
	if (*str != '\0')
		return 0;
	return 1;
}

static int dev_replace_cancel_fd = -1;
static void dev_replace_sigint_handler(int signal)
{
	struct btrfs_ioctl_dev_replace_args args = {0};

	args.cmd = BTRFS_IOCTL_DEV_REPLACE_CMD_CANCEL;
	ioctl(dev_replace_cancel_fd, BTRFS_IOC_DEV_REPLACE, &args);
}

static int dev_replace_handle_sigint(int fd)
{
	struct sigaction sa = {
		.sa_handler = fd == -1 ? SIG_DFL : dev_replace_sigint_handler
	};

	dev_replace_cancel_fd = fd;
	return sigaction(SIGINT, &sa, NULL);
}

static const char *const cmd_start_replace_usage[] = {
	"btrfs replace start srcdev|devid targetdev [-Bfr] mount_point",
	"Replace device of a btrfs filesystem.",
	"On a live filesystem, duplicate the data to the target device which",
	"is currently stored on the source device. If the source device is not",
	"available anymore, or if the -r option is set, the data is built",
	"only using the RAID redundancy mechanisms. After completion of the",
	"operation, the source device is removed from the filesystem.",
	"If the srcdev is a numerical value, it is assumed to be the device id",
	"of the filesystem which is mounted at mount_point, otherwise it is",
	"the path to the source device. If the source device is disconnected,",
	"from the system, you have to use the devid parameter format.",
	"The targetdev needs to be same size or larger than the srcdev.",
	"",
	"-r     only read from srcdev if no other zero-defect mirror exists",
	"       (enable this if your drive has lots of read errors, the access",
	"       would be very slow)",
	"-f     force using and overwriting targetdev even if it looks like",
	"       containing a valid btrfs filesystem. A valid filesystem is",
	"       assumed if a btrfs superblock is found which contains a",
	"       correct checksum. Devices which are currently mounted are",
	"       never allowed to be used as the targetdev",
	"-B     do not background",
	NULL
};

static int cmd_start_replace(int argc, char **argv)
{
	struct btrfs_ioctl_dev_replace_args start_args = {0};
	struct btrfs_ioctl_dev_replace_args status_args = {0};
	int ret;
	int i;
	int c;
	int fdmnt = -1;
	int fdsrcdev = -1;
	int fddstdev = -1;
	char *path;
	char *srcdev;
	char *dstdev;
	int avoid_reading_from_srcdev = 0;
	int force_using_targetdev = 0;
	u64 total_devs = 1;
	struct btrfs_fs_devices *fs_devices_mnt = NULL;
	struct stat st;
	u64 dstdev_block_count;
	int do_not_background = 0;
	int mixed = 0;

	while ((c = getopt(argc, argv, "Brf")) != -1) {
		switch (c) {
		case 'B':
			do_not_background = 1;
			break;
		case 'r':
			avoid_reading_from_srcdev = 1;
			break;
		case 'f':
			force_using_targetdev = 1;
			break;
		case '?':
		default:
			usage(cmd_start_replace_usage);
		}
	}

	start_args.start.cont_reading_from_srcdev_mode =
		avoid_reading_from_srcdev ?
		 BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_AVOID :
		 BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_ALWAYS;
	if (check_argc_exact(argc - optind, 3))
		usage(cmd_start_replace_usage);
	path = argv[optind + 2];
	fdmnt = open_file_or_dir(path);
	if (fdmnt < 0) {
		fprintf(stderr, "ERROR: can't access \"%s\": %s\n",
			path, strerror(errno));
		goto leave_with_error;
	}

	/* check for possible errors before backgrounding */
	status_args.cmd = BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS;
	ret = ioctl(fdmnt, BTRFS_IOC_DEV_REPLACE, &status_args);
	if (ret) {
		fprintf(stderr,
			"ERROR: ioctl(DEV_REPLACE_STATUS) failed on \"%s\": %s, %s\n",
			path, strerror(errno),
			replace_dev_result2string(status_args.result));
		goto leave_with_error;
	}

	if (status_args.result != BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR) {
		fprintf(stderr,
			"ERROR: ioctl(DEV_REPLACE_STATUS) on \"%s\" returns error: %s\n",
			path, replace_dev_result2string(status_args.result));
		goto leave_with_error;
	}

	if (status_args.status.replace_state ==
	    BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED) {
		fprintf(stderr,
			"ERROR: btrfs replace on \"%s\" already started!\n",
			path);
		goto leave_with_error;
	}

	srcdev = argv[optind];
	dstdev = argv[optind + 1];

	if (is_numerical(srcdev)) {
		struct btrfs_ioctl_fs_info_args fi_args;
		struct btrfs_ioctl_dev_info_args *di_args = NULL;

		if (atoi(srcdev) == 0) {
			fprintf(stderr, "Error: Failed to parse the numerical devid value '%s'\n",
				srcdev);
			goto leave_with_error;
		}
		start_args.start.srcdevid = (__u64)atoi(srcdev);

		ret = get_fs_info(fdmnt, path, &fi_args, &di_args);
		if (ret) {
			fprintf(stderr, "ERROR: getting dev info for devstats failed: "
					"%s\n", strerror(-ret));
			free(di_args);
			goto leave_with_error;
		}
		if (!fi_args.num_devices) {
			fprintf(stderr, "ERROR: no devices found\n");
			free(di_args);
			goto leave_with_error;
		}

		for (i = 0; i < fi_args.num_devices; i++)
			if (start_args.start.srcdevid == di_args[i].devid)
				break;
		if (i == fi_args.num_devices) {
			fprintf(stderr, "Error: '%s' is not a valid devid for filesystem '%s'\n",
				srcdev, path);
			goto leave_with_error;
		}
	} else {
		fdsrcdev = open(srcdev, O_RDWR);
		if (fdsrcdev < 0) {
			fprintf(stderr, "Error: Unable to open device '%s'\n",
				srcdev);
			goto leave_with_error;
		}
		ret = fstat(fdsrcdev, &st);
		if (ret) {
			fprintf(stderr, "Error: Unable to stat '%s'\n", srcdev);
			goto leave_with_error;
		}
		if (!S_ISBLK(st.st_mode)) {
			fprintf(stderr, "Error: '%s' is not a block device\n",
				srcdev);
			goto leave_with_error;
		}
		strncpy((char *)start_args.start.srcdev_name, srcdev,
			BTRFS_DEVICE_PATH_NAME_MAX);
		close(fdsrcdev);
		fdsrcdev = -1;
		start_args.start.srcdevid = 0;
	}

	ret = check_mounted(dstdev);
	if (ret < 0) {
		fprintf(stderr, "Error checking %s mount status\n", dstdev);
		goto leave_with_error;
	}
	if (ret == 1) {
		fprintf(stderr,
			"Error, target device %s is in use and currently mounted!\n",
			dstdev);
		goto leave_with_error;
	}
	fddstdev = open(dstdev, O_RDWR);
	if (fddstdev < 0) {
		fprintf(stderr, "Unable to open %s\n", dstdev);
		goto leave_with_error;
	}
	ret = btrfs_scan_one_device(fddstdev, dstdev, &fs_devices_mnt,
				    &total_devs, BTRFS_SUPER_INFO_OFFSET);
	if (ret >= 0 && !force_using_targetdev) {
		fprintf(stderr,
			"Error, target device %s contains filesystem, use '-f' to force overwriting.\n",
			dstdev);
		goto leave_with_error;
	}
	ret = fstat(fddstdev, &st);
	if (ret) {
		fprintf(stderr, "Error: Unable to stat '%s'\n", dstdev);
		goto leave_with_error;
	}
	if (!S_ISBLK(st.st_mode)) {
		fprintf(stderr, "Error: '%s' is not a block device\n", dstdev);
		goto leave_with_error;
	}
	strncpy((char *)start_args.start.tgtdev_name, dstdev,
		BTRFS_DEVICE_PATH_NAME_MAX);
	if (btrfs_prepare_device(fddstdev, dstdev, 1, &dstdev_block_count, 0,
				 &mixed, 0)) {
		fprintf(stderr, "Error: Failed to prepare device '%s'\n",
			dstdev);
		goto leave_with_error;
	}
	close(fddstdev);
	fddstdev = -1;

	dev_replace_handle_sigint(fdmnt);
	if (!do_not_background) {
		if (daemon(0, 0) < 0) {
			fprintf(stderr, "ERROR, backgrounding failed: %s\n",
				strerror(errno));
			goto leave_with_error;
		}
	}

	start_args.cmd = BTRFS_IOCTL_DEV_REPLACE_CMD_START;
	ret = ioctl(fdmnt, BTRFS_IOC_DEV_REPLACE, &start_args);
	if (do_not_background) {
		if (ret) {
			fprintf(stderr,
				"ERROR: ioctl(DEV_REPLACE_START) failed on \"%s\": %s, %s\n",
				path, strerror(errno),
				replace_dev_result2string(start_args.result));
			goto leave_with_error;
		}

		if (start_args.result !=
		    BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR) {
			fprintf(stderr,
				"ERROR: ioctl(DEV_REPLACE_START) on \"%s\" returns error: %s\n",
				path,
				replace_dev_result2string(start_args.result));
			goto leave_with_error;
		}
	}
	close(fdmnt);
	return 0;

leave_with_error:
	if (fdmnt != -1)
		close(fdmnt);
	if (fdsrcdev != -1)
		close(fdsrcdev);
	if (fddstdev != -1)
		close(fddstdev);
	return -1;
}

static const char *const cmd_status_replace_usage[] = {
	"btrfs replace status mount_point [-1]",
	"Print status and progress information of a running device replace",
	"operation",
	"",
	"-1     print once instead of print continously until the replace",
	"       operation finishes (or is canceled)",
	NULL
};

static int cmd_status_replace(int argc, char **argv)
{
	int fd;
	int e;
	int c;
	char *path;
	int once = 0;
	int ret;

	while ((c = getopt(argc, argv, "1")) != -1) {
		switch (c) {
		case '1':
			once = 1;
			break;
		case '?':
		default:
			usage(cmd_status_replace_usage);
		}
	}

	if (check_argc_exact(argc - optind, 1))
		usage(cmd_status_replace_usage);

	path = argv[optind];
	fd = open_file_or_dir(path);
	e = errno;
	if (fd < 0) {
		fprintf(stderr, "ERROR: can't access \"%s\": %s\n",
			path, strerror(e));
		return -1;
	}

	ret = print_replace_status(fd, path, once);
	close(fd);
	return ret;
}

static int print_replace_status(int fd, const char *path, int once)
{
	struct btrfs_ioctl_dev_replace_args args = {0};
	struct btrfs_ioctl_dev_replace_status_params *status;
	int ret;
	int prevent_loop = 0;
	int skip_stats;
	int num_chars;
	char string1[80];
	char string2[80];
	char string3[80];

	for (;;) {
		args.cmd = BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS;
		ret = ioctl(fd, BTRFS_IOC_DEV_REPLACE, &args);
		if (ret) {
			fprintf(stderr, "ERROR: ioctl(DEV_REPLACE_STATUS) failed on \"%s\": %s, %s\n",
				path, strerror(errno),
				replace_dev_result2string(args.result));
			return ret;
		}

		status = &args.status;
		if (args.result != BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR) {
			fprintf(stderr, "ERROR: ioctl(DEV_REPLACE_STATUS) on \"%s\" returns error: %s\n",
				path,
				replace_dev_result2string(args.result));
			return -1;
		}

		skip_stats = 0;
		num_chars = 0;
		switch (status->replace_state) {
		case BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED:
			num_chars =
				printf("%s done",
				       progress2string(string3,
						       sizeof(string3),
						       status->progress_1000));
			break;
		case BTRFS_IOCTL_DEV_REPLACE_STATE_FINISHED:
			prevent_loop = 1;
			printf("Started on %s, finished on %s",
			       time2string(string1, sizeof(string1),
					   status->time_started),
			       time2string(string2, sizeof(string2),
					   status->time_stopped));
			break;
		case BTRFS_IOCTL_DEV_REPLACE_STATE_CANCELED:
			prevent_loop = 1;
			printf("Started on %s, canceled on %s at %s",
			       time2string(string1, sizeof(string1),
					   status->time_started),
			       time2string(string2, sizeof(string2),
					   status->time_stopped),
			       progress2string(string3, sizeof(string3),
					       status->progress_1000));
			break;
		case BTRFS_IOCTL_DEV_REPLACE_STATE_SUSPENDED:
			prevent_loop = 1;
			printf("Started on %s, suspended on %s at %s",
			       time2string(string1, sizeof(string1),
					   status->time_started),
			       time2string(string2, sizeof(string2),
					   status->time_stopped),
			       progress2string(string3, sizeof(string3),
					       status->progress_1000));
			break;
		case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
			prevent_loop = 1;
			skip_stats = 1;
			printf("Never started");
			break;
		default:
			prevent_loop = 1;
			assert(0);
			break;
		}

		if (!skip_stats)
			num_chars += printf(
				", %llu write errs, %llu uncorr. read errs",
				(unsigned long long)status->num_write_errors,
				(unsigned long long)
				 status->num_uncorrectable_read_errors);
		if (once || prevent_loop) {
			printf("\n");
			return 0;
		}

		fflush(stdout);
		sleep(1);
		while (num_chars > 0) {
			putchar('\b');
			num_chars--;
		}
	}

	return 0;
}

static char *
time2string(char *buf, size_t s, __u64 t)
{
	struct tm t_tm;
	time_t t_time_t;

	t_time_t = (time_t)t;
	assert((__u64)t_time_t == t);
	localtime_r(&t_time_t, &t_tm);
	strftime(buf, s, "%e.%b %T", &t_tm);
	return buf;
}

static char *
progress2string(char *buf, size_t s, int progress_1000)
{
	snprintf(buf, s, "%d.%01d%%", progress_1000 / 10, progress_1000 % 10);
	assert(s > 0);
	buf[s - 1] = '\0';
	return buf;
}

static const char *const cmd_cancel_replace_usage[] = {
	"btrfs replace cancel mount_point",
	"Cancel a running device replace operation.",
	NULL
};

static int cmd_cancel_replace(int argc, char **argv)
{
	struct btrfs_ioctl_dev_replace_args args = {0};
	int ret;
	int c;
	int fd;
	int e;
	char *path;

	while ((c = getopt(argc, argv, "")) != -1) {
		switch (c) {
		case '?':
		default:
			usage(cmd_cancel_replace_usage);
		}
	}

	if (check_argc_exact(argc - optind, 1))
		usage(cmd_cancel_replace_usage);

	path = argv[optind];
	fd = open_file_or_dir(path);
	if (fd < 0) {
		fprintf(stderr, "ERROR: can't access \"%s\": %s\n",
			path, strerror(errno));
		return -1;
	}

	args.cmd = BTRFS_IOCTL_DEV_REPLACE_CMD_CANCEL;
	ret = ioctl(fd, BTRFS_IOC_DEV_REPLACE, &args);
	e = errno;
	close(fd);
	if (ret) {
		fprintf(stderr, "ERROR: ioctl(DEV_REPLACE_CANCEL) failed on \"%s\": %s, %s\n",
			path, strerror(e),
			replace_dev_result2string(args.result));
		return ret;
	}

	return 0;
}

const struct cmd_group replace_cmd_group = {
	replace_cmd_group_usage, NULL, {
		{ "start", cmd_start_replace, cmd_start_replace_usage, NULL,
		  0 },
		{ "status", cmd_status_replace, cmd_status_replace_usage, NULL,
		  0 },
		{ "cancel", cmd_cancel_replace, cmd_cancel_replace_usage, NULL,
		  0 },
		{ 0, 0, 0, 0, 0 }
	}
};

int cmd_replace(int argc, char **argv)
{
	return handle_command_group(&replace_cmd_group, argc, argv);
}