/*
 * lsclocks(1) - display system clocks
 *
 * Copyright (C) 2023 Thomas Weißschuh <thomas@t-8ch.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 would 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <stdio.h>
#include <stdbool.h>
#include <time.h>
#include <inttypes.h>
#include <getopt.h>

#include <libsmartcols.h>

#include "c.h"
#include "nls.h"
#include "strutils.h"
#include "timeutils.h"
#include "closestream.h"
#include "xalloc.h"

#define CLOCKFD 3
#define FD_TO_CLOCKID(fd) ((~(clockid_t) (fd) << 3) | CLOCKFD)

#ifndef CLOCK_REALTIME
#define CLOCK_REALTIME			0
#endif

#ifndef CLOCK_MONOTONIC
#define CLOCK_MONOTONIC			1
#endif

#ifndef CLOCK_MONOTONIC_RAW
#define CLOCK_MONOTONIC_RAW		4
#endif

#ifndef CLOCK_REALTIME_COARSE
#define CLOCK_REALTIME_COARSE		5
#endif

#ifndef CLOCK_MONOTONIC_COARSE
#define CLOCK_MONOTONIC_COARSE		6
#endif

#ifndef CLOCK_BOOTTIME
#define CLOCK_BOOTTIME			7
#endif

#ifndef CLOCK_REALTIME_ALARM
#define CLOCK_REALTIME_ALARM		8
#endif

#ifndef CLOCK_BOOTTIME_ALARM
#define CLOCK_BOOTTIME_ALARM		9
#endif

#ifndef CLOCK_TAI
#define CLOCK_TAI			11
#endif

struct clockinfo {
	clockid_t id;
	const char * const id_name;
	const char * const name;
};

static const struct clockinfo clocks[] = {
	{ CLOCK_REALTIME,         "CLOCK_REALTIME",         "realtime"         },
	{ CLOCK_MONOTONIC,        "CLOCK_MONOTONIC",        "monotonic"        },
	{ CLOCK_MONOTONIC_RAW,    "CLOCK_MONOTONIC_RAW",    "monotonic-raw"    },
	{ CLOCK_REALTIME_COARSE,  "CLOCK_REALTIME_COARSE",  "realtime-coarse"  },
	{ CLOCK_MONOTONIC_COARSE, "CLOCK_MONOTONIC_COARSE", "monotonic-coarse" },
	{ CLOCK_BOOTTIME,         "CLOCK_BOOTTIME",         "boottime"         },
	{ CLOCK_REALTIME_ALARM,   "CLOCK_REALTIME_ALARM",   "realtime-alarm"   },
	{ CLOCK_BOOTTIME_ALARM,   "CLOCK_BOOTTIME_ALARM",   "boottime-alarm"   },
	{ CLOCK_TAI,              "CLOCK_TAI",              "tai"              },
};

/* column IDs */
enum {
	COL_ID,
	COL_CLOCK,
	COL_NAME,
	COL_TIME,
	COL_ISO_TIME,
	COL_RESOLUTION,
};

/* column names */
struct colinfo {
	const char * const	name; /* header */
	double			whint; /* width hint (N < 1 is in percent of termwidth) */
	int			flags; /* SCOLS_FL_* */
	int			json_type; /* SCOLS_JSON_* */
	const char * const	help;
};

/* columns descriptions */
static const struct colinfo infos[] = {
	[COL_ID]         = { "ID",         1, SCOLS_FL_RIGHT, SCOLS_JSON_NUMBER, N_("numeric id") },
	[COL_CLOCK]      = { "CLOCK",      1, 0,              SCOLS_JSON_STRING, N_("symbolic name") },
	[COL_NAME]       = { "NAME",       1, 0,              SCOLS_JSON_STRING, N_("readable name") },
	[COL_TIME]       = { "TIME",       1, SCOLS_FL_RIGHT, SCOLS_JSON_NUMBER, N_("numeric time") },
	[COL_ISO_TIME]   = { "ISO_TIME",   1, SCOLS_FL_RIGHT, SCOLS_JSON_STRING, N_("human readable ISO time") },
	[COL_RESOLUTION] = { "RESOLUTION", 1, SCOLS_FL_RIGHT, SCOLS_JSON_NUMBER, N_("resolution") },
};

static int column_name_to_id(const char *name, size_t namesz)
{
	size_t i;

	for (i = 0; i < ARRAY_SIZE(infos); i++) {
		const char *cn = infos[i].name;

		if (!strncasecmp(name, cn, namesz) && !*(cn + namesz))
			return i;
	}
	warnx(_("unknown column: %s"), name);

	return -1;
}

static void __attribute__((__noreturn__)) usage(void)
{
	FILE *out = stdout;
	size_t i;

	fputs(USAGE_HEADER, out);
	fprintf(out, _(" %s [options]\n"), program_invocation_short_name);

	fputs(USAGE_OPTIONS, out);
	fputs(_(" -J, --json              use JSON output format\n"), out);
	fputs(_(" -n, --noheadings        don't print headings\n"), out);
	fputs(_(" -o, --output <list>     output columns\n"), out);
	fputs(_(" -r, --raw               use raw output format\n"), out);
	fputs(_(" -t, --time <clock>      show current time of single clock\n"), out);

	fputs(USAGE_SEPARATOR, out);
	printf(USAGE_HELP_OPTIONS(25));

	fprintf(out, USAGE_COLUMNS);

	for (i = 0; i < ARRAY_SIZE(infos); i++)
		fprintf(out, " %16s  %-10s%s\n", infos[i].name,
			infos[i].json_type == SCOLS_JSON_STRING?  "<string>":
			infos[i].json_type == SCOLS_JSON_ARRAY_STRING?  "<string>":
			infos[i].json_type == SCOLS_JSON_ARRAY_NUMBER?  "<string>":
			infos[i].json_type == SCOLS_JSON_NUMBER?  "<number>":
			"<boolean>",
			_(infos[i].help));

	printf(USAGE_MAN_TAIL("lslocks(1)"));

	exit(EXIT_SUCCESS);
}

__attribute__ ((__format__ (__printf__, 3, 4)))
static void scols_line_asprintf(struct libscols_line *ln, size_t n, const char *format, ...)
{
	char *data;
	va_list args;

	va_start(args, format);
	xvasprintf(&data, format, args);
	va_end(args);

	scols_line_refer_data(ln, n, data);
}

static void scols_line_format_timespec(struct libscols_line *ln, size_t n, const struct timespec *ts)
{
	scols_line_asprintf(ln, n, "%ju.%09" PRId32, (uintmax_t) ts->tv_sec, (uint32_t) ts->tv_nsec);
}

static clockid_t parse_clock(const char *name)
{
	size_t i;
	uint32_t id = -1;
	int rc;

	rc = ul_strtou32(name, &id, 10);

	for (i = 0; i < ARRAY_SIZE(clocks); i++) {
		if (!strcmp(name, clocks[i].id_name)
		    || !strcmp(name, clocks[i].name))
			return clocks[i].id;
		if (rc == 0 && (clockid_t) id == clocks[i].id)
			return id;
	}

	errx(EXIT_FAILURE, _("Unknown clock: %s"), name);
}

int main(int argc, char **argv)
{
	size_t i, j;
	char c;
	int rc;
	const struct colinfo *colinfo;
	const struct clockinfo *clockinfo;

	struct libscols_table *tb;
	struct libscols_line *ln;
	struct libscols_column *col;

	bool noheadings = false, raw = false, json = false;
	const char *outarg = NULL;
	int columns[ARRAY_SIZE(infos) * 2];
	size_t ncolumns = 0;
	clockid_t clock = -1;

	struct timespec resolution, now;
	char buf[FORMAT_TIMESTAMP_MAX];

	static const struct option longopts[] = {
		{ "noheadings", no_argument,       NULL, 'n' },
		{ "output",     required_argument, NULL, 'o' },
		{ "version",    no_argument,       NULL, 'V' },
		{ "help",	no_argument,       NULL, 'h' },
		{ "json",       no_argument,       NULL, 'J' },
		{ "raw",        no_argument,       NULL, 'r' },
		{ "time",       required_argument, NULL, 't' },
		{ 0 }
	};

	setlocale(LC_ALL, "");
	bindtextdomain(PACKAGE, LOCALEDIR);
	textdomain(PACKAGE);
	close_stdout_atexit();

	while ((c = getopt_long(argc, argv, "no:Jrt:Vh", longopts, NULL)) != -1) {
		switch (c) {
		case 'n':
			noheadings = true;
			break;
		case 'o':
			outarg = optarg;
			break;
		case 'J':
			json = true;
			break;
		case 'r':
			raw = true;
			break;
		case 't':
			clock = parse_clock(optarg);
			break;
		case 'V':
			print_version(EXIT_SUCCESS);
		case 'h':
			usage();
		default:
			errtryhelp(EXIT_FAILURE);
		}
	}

	if (argv[optind])
		errtryhelp(EXIT_FAILURE);

	if (clock != -1) {
		rc = clock_gettime(clock, &now);
		if (rc)
			err(EXIT_FAILURE, _("failed to get time"));
		printf("%ju.%09"PRId32"\n", (uintmax_t) now.tv_sec, (uint32_t) now.tv_nsec);
		return EXIT_SUCCESS;
	}

	if (!ncolumns) {
		columns[ncolumns++] = COL_ID;
		columns[ncolumns++] = COL_CLOCK;
		columns[ncolumns++] = COL_NAME;
		columns[ncolumns++] = COL_TIME;
		columns[ncolumns++] = COL_ISO_TIME;
		columns[ncolumns++] = COL_RESOLUTION;
	}

	if (outarg && string_add_to_idarray(outarg, columns, ARRAY_SIZE(columns),
					    &ncolumns, column_name_to_id) < 0)
		return EXIT_FAILURE;

	scols_init_debug(0);

	tb = scols_new_table();
	if (!tb)
		errx(EXIT_FAILURE, _("failed to allocate output table"));
	scols_table_set_name(tb, "clocks");

	for (i = 0; i < ncolumns; i++) {
		colinfo = &infos[columns[i]];

		col = scols_table_new_column(tb, colinfo->name, colinfo->whint, colinfo->flags);
		if (!col)
			errx(EXIT_FAILURE, _("failed to allocate output column"));

		scols_column_set_json_type(col, colinfo->json_type);
	}

	for (i = 0; i < ARRAY_SIZE(clocks); i++) {
		clockinfo = &clocks[i];

		ln = scols_table_new_line(tb, NULL);
		if (!ln)
			errx(EXIT_FAILURE, _("failed to allocate output line"));

		/* outside the loop to guarantee consistency between COL_TIME and COL_ISO_TIME */
		rc = clock_gettime(clockinfo->id, &now);
		if (rc)
			now.tv_nsec = -1;

		for (j = 0; j < ncolumns; j++) {
			switch (columns[j]) {
				case COL_ID:
					scols_line_asprintf(ln, j, "%ju", (uintmax_t) clockinfo->id);
					break;
				case COL_CLOCK:
					scols_line_set_data(ln, j, clockinfo->id_name);
					break;
				case COL_NAME:
					scols_line_set_data(ln, j, clockinfo->name);
					break;
				case COL_TIME:
					if (now.tv_nsec == -1)
						break;

					scols_line_format_timespec(ln, j, &now);
					break;
				case COL_ISO_TIME:
					if (now.tv_nsec == -1)
						break;

					rc = strtimespec_iso(&now,
							ISO_GMTIME | ISO_DATE | ISO_TIME | ISO_T | ISO_DOTNSEC | ISO_TIMEZONE,
							buf, sizeof(buf));
					if (rc)
						errx(EXIT_FAILURE, _("failed to format iso time"));
					scols_line_set_data(ln, j, buf);
					break;
				case COL_RESOLUTION:
					rc = clock_getres(clockinfo->id, &resolution);
					if (!rc)
						scols_line_format_timespec(ln, j, &resolution);
					break;
			}
		}
	}

	scols_table_enable_json(tb, json);
	scols_table_enable_raw(tb, raw);
	scols_table_enable_noheadings(tb, noheadings);
	scols_print_table(tb);
	scols_unref_table(tb);
}