/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <time.h>
#include <string.h>

#include "util.h"
#include "time-util.h"

usec_t now(clockid_t clock_id) {
        struct timespec ts;

        assert_se(clock_gettime(clock_id, &ts) == 0);

        return timespec_load(&ts);
}

dual_timestamp* dual_timestamp_get(dual_timestamp *ts) {
        assert(ts);

        ts->realtime = now(CLOCK_REALTIME);
        ts->monotonic = now(CLOCK_MONOTONIC);

        return ts;
}

dual_timestamp* dual_timestamp_from_realtime(dual_timestamp *ts, usec_t u) {
        int64_t delta;
        assert(ts);

        if (u == (usec_t) -1) {
                ts->realtime = ts->monotonic = (usec_t) -1;
                return ts;
        }

        ts->realtime = u;

        if (u == 0)
                ts->monotonic = 0;
        else {
                delta = (int64_t) now(CLOCK_REALTIME) - (int64_t) u;

                ts->monotonic = now(CLOCK_MONOTONIC);

                if ((int64_t) ts->monotonic > delta)
                        ts->monotonic -= delta;
                else
                        ts->monotonic = 0;
        }

        return ts;
}

dual_timestamp* dual_timestamp_from_monotonic(dual_timestamp *ts, usec_t u) {
        int64_t delta;
        assert(ts);

        if (u == (usec_t) -1) {
                ts->realtime = ts->monotonic = (usec_t) -1;
                return ts;
        }

        ts->monotonic = u;
        delta = (int64_t) now(CLOCK_MONOTONIC) - (int64_t) u;

        ts->realtime = now(CLOCK_REALTIME);
        if ((int64_t) ts->realtime > delta)
                ts->realtime -= delta;
        else
                ts->realtime = 0;

        return ts;
}

usec_t timespec_load(const struct timespec *ts) {
        assert(ts);

        if (ts->tv_sec == (time_t) -1 &&
            ts->tv_nsec == (long) -1)
                return (usec_t) -1;

        if ((usec_t) ts->tv_sec > (UINT64_MAX - (ts->tv_nsec / NSEC_PER_USEC)) / USEC_PER_SEC)
                return (usec_t) -1;

        return
                (usec_t) ts->tv_sec * USEC_PER_SEC +
                (usec_t) ts->tv_nsec / NSEC_PER_USEC;
}

struct timespec *timespec_store(struct timespec *ts, usec_t u)  {
        assert(ts);

        if (u == (usec_t) -1) {
                ts->tv_sec = (time_t) -1;
                ts->tv_nsec = (long) -1;
                return ts;
        }

        ts->tv_sec = (time_t) (u / USEC_PER_SEC);
        ts->tv_nsec = (long int) ((u % USEC_PER_SEC) * NSEC_PER_USEC);

        return ts;
}

usec_t timeval_load(const struct timeval *tv) {
        assert(tv);

        if (tv->tv_sec == (time_t) -1 &&
            tv->tv_usec == (suseconds_t) -1)
                return (usec_t) -1;

        if ((usec_t) tv->tv_sec > (UINT64_MAX - tv->tv_usec) / USEC_PER_SEC)
                return (usec_t) -1;

        return
                (usec_t) tv->tv_sec * USEC_PER_SEC +
                (usec_t) tv->tv_usec;
}

struct timeval *timeval_store(struct timeval *tv, usec_t u) {
        assert(tv);

        if (u == (usec_t) -1) {
                tv->tv_sec = (time_t) -1;
                tv->tv_usec = (suseconds_t) -1;
                return tv;
        }

        tv->tv_sec = (time_t) (u / USEC_PER_SEC);
        tv->tv_usec = (suseconds_t) (u % USEC_PER_SEC);

        return tv;
}

char *format_timestamp(char *buf, size_t l, usec_t t) {
        struct tm tm;
        time_t sec;

        assert(buf);
        assert(l > 0);

        if (t <= 0)
                return NULL;

        sec = (time_t) (t / USEC_PER_SEC);

        if (strftime(buf, l, "%a %Y-%m-%d %H:%M:%S %Z", localtime_r(&sec, &tm)) <= 0)
                return NULL;

        return buf;
}

char *format_timestamp_relative(char *buf, size_t l, usec_t t) {
        usec_t n, d;

        n = now(CLOCK_REALTIME);

        if (t <= 0 || t > n || t + USEC_PER_DAY*7 <= t)
                return NULL;

        d = n - t;

        if (d >= USEC_PER_YEAR)
                snprintf(buf, l, "%llu years %llu months ago",
                         (unsigned long long) (d / USEC_PER_YEAR),
                         (unsigned long long) ((d % USEC_PER_YEAR) / USEC_PER_MONTH));
        else if (d >= USEC_PER_MONTH)
                snprintf(buf, l, "%llu months %llu days ago",
                         (unsigned long long) (d / USEC_PER_MONTH),
                         (unsigned long long) ((d % USEC_PER_MONTH) / USEC_PER_DAY));
        else if (d >= USEC_PER_WEEK)
                snprintf(buf, l, "%llu weeks %llu days ago",
                         (unsigned long long) (d / USEC_PER_WEEK),
                         (unsigned long long) ((d % USEC_PER_WEEK) / USEC_PER_DAY));
        else if (d >= 2*USEC_PER_DAY)
                snprintf(buf, l, "%llu days ago", (unsigned long long) (d / USEC_PER_DAY));
        else if (d >= 25*USEC_PER_HOUR)
                snprintf(buf, l, "1 day %lluh ago",
                         (unsigned long long) ((d - USEC_PER_DAY) / USEC_PER_HOUR));
        else if (d >= 6*USEC_PER_HOUR)
                snprintf(buf, l, "%lluh ago",
                         (unsigned long long) (d / USEC_PER_HOUR));
        else if (d >= USEC_PER_HOUR)
                snprintf(buf, l, "%lluh %llumin ago",
                         (unsigned long long) (d / USEC_PER_HOUR),
                         (unsigned long long) ((d % USEC_PER_HOUR) / USEC_PER_MINUTE));
        else if (d >= 5*USEC_PER_MINUTE)
                snprintf(buf, l, "%llumin ago",
                         (unsigned long long) (d / USEC_PER_MINUTE));
        else if (d >= USEC_PER_MINUTE)
                snprintf(buf, l, "%llumin %llus ago",
                         (unsigned long long) (d / USEC_PER_MINUTE),
                         (unsigned long long) ((d % USEC_PER_MINUTE) / USEC_PER_SEC));
        else if (d >= USEC_PER_SEC)
                snprintf(buf, l, "%llus ago",
                         (unsigned long long) (d / USEC_PER_SEC));
        else if (d >= USEC_PER_MSEC)
                snprintf(buf, l, "%llums ago",
                         (unsigned long long) (d / USEC_PER_MSEC));
        else if (d > 0)
                snprintf(buf, l, "%lluus ago",
                         (unsigned long long) d);
        else
                snprintf(buf, l, "now");

        buf[l-1] = 0;
        return buf;
}

char *format_timespan(char *buf, size_t l, usec_t t) {
        static const struct {
                const char *suffix;
                usec_t usec;
        } table[] = {
                { "w", USEC_PER_WEEK },
                { "d", USEC_PER_DAY },
                { "h", USEC_PER_HOUR },
                { "min", USEC_PER_MINUTE },
                { "s", USEC_PER_SEC },
                { "ms", USEC_PER_MSEC },
                { "us", 1 },
        };

        unsigned i;
        char *p = buf;

        assert(buf);
        assert(l > 0);

        if (t == (usec_t) -1)
                return NULL;

        if (t == 0) {
                snprintf(p, l, "0");
                p[l-1] = 0;
                return p;
        }

        /* The result of this function can be parsed with parse_usec */

        for (i = 0; i < ELEMENTSOF(table); i++) {
                int k;
                size_t n;

                if (t < table[i].usec)
                        continue;

                if (l <= 1)
                        break;

                k = snprintf(p, l, "%s%llu%s", p > buf ? " " : "", (unsigned long long) (t / table[i].usec), table[i].suffix);
                n = MIN((size_t) k, l);

                l -= n;
                p += n;

                t %= table[i].usec;
        }

        *p = 0;

        return buf;
}

void dual_timestamp_serialize(FILE *f, const char *name, dual_timestamp *t) {

        assert(f);
        assert(name);
        assert(t);

        if (!dual_timestamp_is_set(t))
                return;

        fprintf(f, "%s=%llu %llu\n",
                name,
                (unsigned long long) t->realtime,
                (unsigned long long) t->monotonic);
}

void dual_timestamp_deserialize(const char *value, dual_timestamp *t) {
        unsigned long long a, b;

        assert(value);
        assert(t);

        if (sscanf(value, "%lli %llu", &a, &b) != 2)
                log_debug("Failed to parse finish timestamp value %s", value);
        else {
                t->realtime = a;
                t->monotonic = b;
        }
}

int parse_timestamp(const char *t, usec_t *usec) {
        static const struct {
                const char *name;
                const int nr;
        } day_nr[] = {
                { "Sunday",    0 },
                { "Sun",       0 },
                { "Monday",    1 },
                { "Mon",       1 },
                { "Tuesday",   2 },
                { "Tue",       2 },
                { "Wednesday", 3 },
                { "Wed",       3 },
                { "Thursday",  4 },
                { "Thu",       4 },
                { "Friday",    5 },
                { "Fri",       5 },
                { "Saturday",  6 },
                { "Sat",       6 },
        };

        const char *k;
        struct tm tm, copy;
        time_t x;
        usec_t plus = 0, minus = 0, ret;
        int r, weekday = -1;
        unsigned i;

        /*
         * Allowed syntaxes:
         *
         *   2012-09-22 16:34:22
         *   2012-09-22 16:34     (seconds will be set to 0)
         *   2012-09-22           (time will be set to 00:00:00)
         *   16:34:22             (date will be set to today)
         *   16:34                (date will be set to today, seconds to 0)
         *   now
         *   yesterday            (time is set to 00:00:00)
         *   today                (time is set to 00:00:00)
         *   tomorrow             (time is set to 00:00:00)
         *   +5min
         *   -5days
         *
         */

        assert(t);
        assert(usec);

        x = time(NULL);
        assert_se(localtime_r(&x, &tm));
        tm.tm_isdst = -1;

        if (streq(t, "now"))
                goto finish;

        else if (streq(t, "today")) {
                tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
                goto finish;

        } else if (streq(t, "yesterday")) {
                tm.tm_mday --;
                tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
                goto finish;

        } else if (streq(t, "tomorrow")) {
                tm.tm_mday ++;
                tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
                goto finish;

        } else if (t[0] == '+') {

                r = parse_usec(t+1, &plus);
                if (r < 0)
                        return r;

                goto finish;
        } else if (t[0] == '-') {

                r = parse_usec(t+1, &minus);
                if (r < 0)
                        return r;

                goto finish;

        } else if (endswith(t, " ago")) {
                _cleanup_free_ char *z;

                z = strndup(t, strlen(t) - 4);
                if (!z)
                        return -ENOMEM;

                r = parse_usec(z, &minus);
                if (r < 0)
                        return r;

                goto finish;
        }

        for (i = 0; i < ELEMENTSOF(day_nr); i++) {
                size_t skip;

                if (!startswith_no_case(t, day_nr[i].name))
                        continue;

                skip = strlen(day_nr[i].name);
                if (t[skip] != ' ')
                        continue;

                weekday = day_nr[i].nr;
                t += skip + 1;
                break;
        }

        copy = tm;
        k = strptime(t, "%y-%m-%d %H:%M:%S", &tm);
        if (k && *k == 0)
                goto finish;

        tm = copy;
        k = strptime(t, "%Y-%m-%d %H:%M:%S", &tm);
        if (k && *k == 0)
                goto finish;

        tm = copy;
        k = strptime(t, "%y-%m-%d %H:%M", &tm);
        if (k && *k == 0) {
                tm.tm_sec = 0;
                goto finish;
        }

        tm = copy;
        k = strptime(t, "%Y-%m-%d %H:%M", &tm);
        if (k && *k == 0) {
                tm.tm_sec = 0;
                goto finish;
        }

        tm = copy;
        k = strptime(t, "%y-%m-%d", &tm);
        if (k && *k == 0) {
                tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
                goto finish;
        }

        tm = copy;
        k = strptime(t, "%Y-%m-%d", &tm);
        if (k && *k == 0) {
                tm.tm_sec = tm.tm_min = tm.tm_hour = 0;
                goto finish;
        }

        tm = copy;
        k = strptime(t, "%H:%M:%S", &tm);
        if (k && *k == 0)
                goto finish;

        tm = copy;
        k = strptime(t, "%H:%M", &tm);
        if (k && *k == 0) {
                tm.tm_sec = 0;
                goto finish;
        }

        return -EINVAL;

finish:
        x = mktime(&tm);
        if (x == (time_t) -1)
                return -EINVAL;

        if (weekday >= 0 && tm.tm_wday != weekday)
                return -EINVAL;

        ret = (usec_t) x * USEC_PER_SEC;

        ret += plus;
        if (ret > minus)
                ret -= minus;
        else
                ret = 0;

        *usec = ret;

        return 0;
}

int parse_usec(const char *t, usec_t *usec) {
        static const struct {
                const char *suffix;
                usec_t usec;
        } table[] = {
                { "seconds", USEC_PER_SEC },
                { "second", USEC_PER_SEC },
                { "sec", USEC_PER_SEC },
                { "s", USEC_PER_SEC },
                { "minutes", USEC_PER_MINUTE },
                { "minute", USEC_PER_MINUTE },
                { "min", USEC_PER_MINUTE },
                { "months", USEC_PER_MONTH },
                { "month", USEC_PER_MONTH },
                { "msec", USEC_PER_MSEC },
                { "ms", USEC_PER_MSEC },
                { "m", USEC_PER_MINUTE },
                { "hours", USEC_PER_HOUR },
                { "hour", USEC_PER_HOUR },
                { "hr", USEC_PER_HOUR },
                { "h", USEC_PER_HOUR },
                { "days", USEC_PER_DAY },
                { "day", USEC_PER_DAY },
                { "d", USEC_PER_DAY },
                { "weeks", USEC_PER_WEEK },
                { "week", USEC_PER_WEEK },
                { "w", USEC_PER_WEEK },
                { "years", USEC_PER_YEAR },
                { "year", USEC_PER_YEAR },
                { "y", USEC_PER_YEAR },
                { "usec", 1ULL },
                { "us", 1ULL },
                { "", USEC_PER_SEC }, /* default is sec */
        };

        const char *p;
        usec_t r = 0;

        assert(t);
        assert(usec);

        p = t;
        do {
                long long l;
                char *e;
                unsigned i;

                errno = 0;
                l = strtoll(p, &e, 10);

                if (errno != 0)
                        return -errno;

                if (l < 0)
                        return -ERANGE;

                if (e == p)
                        return -EINVAL;

                e += strspn(e, WHITESPACE);

                for (i = 0; i < ELEMENTSOF(table); i++)
                        if (startswith(e, table[i].suffix)) {
                                r += (usec_t) l * table[i].usec;
                                p = e + strlen(table[i].suffix);
                                break;
                        }

                if (i >= ELEMENTSOF(table))
                        return -EINVAL;

        } while (*p != 0);

        *usec = r;

        return 0;
}

int parse_nsec(const char *t, nsec_t *nsec) {
        static const struct {
                const char *suffix;
                nsec_t nsec;
        } table[] = {
                { "seconds", NSEC_PER_SEC },
                { "second", NSEC_PER_SEC },
                { "sec", NSEC_PER_SEC },
                { "s", NSEC_PER_SEC },
                { "minutes", NSEC_PER_MINUTE },
                { "minute", NSEC_PER_MINUTE },
                { "min", NSEC_PER_MINUTE },
                { "months", NSEC_PER_MONTH },
                { "month", NSEC_PER_MONTH },
                { "msec", NSEC_PER_MSEC },
                { "ms", NSEC_PER_MSEC },
                { "m", NSEC_PER_MINUTE },
                { "hours", NSEC_PER_HOUR },
                { "hour", NSEC_PER_HOUR },
                { "hr", NSEC_PER_HOUR },
                { "h", NSEC_PER_HOUR },
                { "days", NSEC_PER_DAY },
                { "day", NSEC_PER_DAY },
                { "d", NSEC_PER_DAY },
                { "weeks", NSEC_PER_WEEK },
                { "week", NSEC_PER_WEEK },
                { "w", NSEC_PER_WEEK },
                { "years", NSEC_PER_YEAR },
                { "year", NSEC_PER_YEAR },
                { "y", NSEC_PER_YEAR },
                { "usec", NSEC_PER_USEC },
                { "us", NSEC_PER_USEC },
                { "nsec", 1ULL },
                { "ns", 1ULL },
                { "", 1ULL }, /* default is nsec */
        };

        const char *p;
        nsec_t r = 0;

        assert(t);
        assert(nsec);

        p = t;
        do {
                long long l;
                char *e;
                unsigned i;

                errno = 0;
                l = strtoll(p, &e, 10);

                if (errno != 0)
                        return -errno;

                if (l < 0)
                        return -ERANGE;

                if (e == p)
                        return -EINVAL;

                e += strspn(e, WHITESPACE);

                for (i = 0; i < ELEMENTSOF(table); i++)
                        if (startswith(e, table[i].suffix)) {
                                r += (nsec_t) l * table[i].nsec;
                                p = e + strlen(table[i].suffix);
                                break;
                        }

                if (i >= ELEMENTSOF(table))
                        return -EINVAL;

        } while (*p != 0);

        *nsec = r;

        return 0;
}