// -*- mode: c++; c-basic-offset:4 -*-

// This file is part of libdap, A C++ implementation of the OPeNDAP Data

// Access Protocol.

// Copyright (c) 2002 OPeNDAP, Inc.

// Author: James Gallagher <jgallagher@opendap.org>

//

// This library 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.

//

// This library 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 this library; if not, write to the Free Software

// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

//

// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112

// This file was derived from the libwww source code of 1998/08/20. The

// copyright for the source of this derivative work can be found in the file

// COPYRIGHT_W3C.

#include "config.h"

#include <cstdio>

#include <cstring>

#include <cstdlib>

//#include <string>

#include <ctype.h>

#ifndef TM_IN_SYS_TIME

#include <time.h>

#else

#include <sys/time.h>

#endif

#include <sys/types.h>

#include <sys/stat.h>

#include <iostream>

#include "util_mit.h"

using std::cerr;

using std::endl;

using std::string;

#include "debug.h"

namespace libdap {

static const char * months[12] =

    {

        "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"

    };

#ifndef HAVE_STRFTIME

static const char * wkdays[7] =

    {

        "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"

    };

#endif

/* Upper- and Lowercase macros

   The problem here is that toupper(x) is not defined officially unless

   isupper(x) is. These macros are CERTAINLY needed on #if defined(pyr) ||

   define(mips) or BDSI platforms. For safety, we make them mandatory.

*/

#ifndef TOLOWER

#define TOLOWER(c) tolower((int) (c))

#define TOUPPER(c) toupper((int) (c))

#endif

static int

strncasecomp(const char *a, const char *b, int n)

{

    const char *p = a;

    const char *q = b;

    for (p = a, q = b;; p++, q++) {

        int diff;

        if (p == a + n) return 0; /*   Match up to n characters */

        if (!(*p && *q)) return *p - *q;

        diff = TOLOWER(*p) - TOLOWER(*q);

        if (diff) return diff;

    }

    /*NOTREACHED*/

    return -1; // silence gcc

}

static int

make_month(char * s, char ** ends)

{

    char * ptr = s;

    while (!isalpha((int) *ptr)) ptr++;

    if (*ptr) {

        int i;

        *ends = ptr + 3;

        for (i = 0; i < 12; i++)

            if (!strncasecomp(months[i], ptr, 3)) return i;

    }

    return 0;

}

/** Parse a string in GMT format to a local time time_t representation

    Four formats are accepted:

 Wkd, 00 Mon 0000 00:00:00 GMT  (rfc1123)

 Weekday, 00-Mon-00 00:00:00 GMT  (rfc850)

 Wkd Mon 00 00:00:00 0000 GMT  (ctime)

 1*DIGIT     (delta-seconds)

    Copied from libwww. 09/19/02 jhrg

    @param str The time string.

    @param expand If the time is given in delta seconds, adjust it to seconds

    since midnight 1 Jan 1970 if this is true. If false, simply convert the

    string to a time_t and return. The default value is true.

    @return The time in seconds since midnight 1 Jan 1970. */

time_t

parse_time(const char * str, bool expand)

{

    char * s;

    struct tm tm;

    time_t t;

    if (!str) return 0;

    if ((s = (char *)strchr(str, ','))) {  /* Thursday, 10-Jun-93 01:29:59 GMT */

        s++;    /* or: Thu, 10 Jan 1993 01:29:59 GMT */

        while (*s && *s == ' ') s++;

        if (strchr(s, '-')) {         /* First format */

            DBG(cerr << "Format...... Weekday, 00-Mon-00 00:00:00 GMT"

                << endl);

            if ((int)strlen(s) < 18) {

                DBG(cerr << "ERROR....... Not a valid time format \""

                    << s << "\"" << endl);

                return 0;

            }

            tm.tm_mday = strtol(s, &s, 10);

            tm.tm_mon = make_month(s, &s);

            ++s;

            tm.tm_year = strtol(s, &s, 10);

            tm.tm_hour = strtol(s, &s, 10);

            ++s;

            tm.tm_min = strtol(s, &s, 10);

            ++s;

            tm.tm_sec = strtol(s, &s, 10);

        }

        else {         /* Second format */

            DBG(cerr << "Format...... Wkd, 00 Mon 0000 00:00:00 GMT" << endl);

            if ((int)strlen(s) < 20) {

                DBG(cerr << "ERROR....... Not a valid time format \""

                    << s << "\"" << endl);

                return 0;

            }

            tm.tm_mday = strtol(s, &s, 10);

            tm.tm_mon = make_month(s, &s);

            tm.tm_year = strtol(s, &s, 10) - 1900;

            tm.tm_hour = strtol(s, &s, 10);

            ++s;

            tm.tm_min = strtol(s, &s, 10);

            ++s;

            tm.tm_sec = strtol(s, &s, 10);

        }

    }

    else if (isdigit((int) *str)) {

        if (strchr(str, 'T')) { /* ISO (limited format) date string */

            DBG(cerr << "Format...... YYYY.MM.DDThh:mmStzWkd" << endl);

            s = (char *) str;

            while (*s && *s == ' ') s++;

            if ((int)strlen(s) < 21) {

                DBG(cerr << "ERROR....... Not a valid time format \""

                    << s << "\"" << endl);

                return 0;

            }

            tm.tm_year = strtol(s, &s, 10) - 1900;

            ++s;

            tm.tm_mon  = strtol(s, &s, 10);

            ++s;

            tm.tm_mday = strtol(s, &s, 10);

            ++s;

            tm.tm_hour = strtol(s, &s, 10);

            ++s;

            tm.tm_min  = strtol(s, &s, 10);

            ++s;

            tm.tm_sec  = strtol(s, &s, 10);

        }

        else {         /* delta seconds */

            t = expand ? time(NULL) + atol(str) : atol(str);

            return t;

        }

    }

    else {       /* Try the other format:  Wed Jun  9 01:29:59 1993 GMT */

        DBG(cerr << "Format...... Wkd Mon 00 00:00:00 0000 GMT" << endl);

        s = (char *) str;

        while (*s && *s == ' ') s++;

        DBG(cerr << "Trying...... The Wrong time format: " << s << endl);

        if ((int)strlen(s) < 24) {

            DBG(cerr << "ERROR....... Not a valid time format \""

                << s << "\"" << endl);

            return 0;

        }

        tm.tm_mon = make_month(s, &s);

        tm.tm_mday = strtol(s, &s, 10);

        tm.tm_hour = strtol(s, &s, 10);

        ++s;

        tm.tm_min = strtol(s, &s, 10);

        ++s;

        tm.tm_sec = strtol(s, &s, 10);

        tm.tm_year = strtol(s, &s, 10) - 1900;

    }

    if (tm.tm_sec  < 0  ||  tm.tm_sec  > 59  ||

        tm.tm_min  < 0  ||  tm.tm_min  > 59  ||

        tm.tm_hour < 0  ||  tm.tm_hour > 23  ||

        tm.tm_mday < 1  ||  tm.tm_mday > 31  ||

        tm.tm_mon  < 0  ||  tm.tm_mon  > 11  ||

        tm.tm_year < 70  ||  tm.tm_year > 120) {

        DBG(cerr << "ERROR....... Parsed illegal time" << endl);

        return 0;

    }

    /* Let mktime decide whether we have DST or not */

    tm.tm_isdst = -1;

#ifdef HAVE_TIMEGM

    t = timegm(&tm;;

#else

#ifdef HAVE_MKTIME

    // Compute offset between localtime and GMT.

    time_t offset;

    time_t now = time(0);

#ifdef _REENTRANT

    struct tm gmt, local;

    offset = mktime(gmtime_r(&now, &gmt)) - mktime(localtime_r(&now, &local));

#else

    offset = mktime(gmtime(&now)) - mktime(localtime(&now));

#endif

    t = mktime(&tm) + offset;

#else

#error "Neither mktime nor timegm defined"

#endif /* HAVE_TIMEGM */

#endif /* HAVE_MKTIME */

    DBG(cerr << "Time string. " << str << " parsed to " << t

        << " calendar time or \"" << ctime(&t) << "\" in local time" << endl);

    return t;

}

/** Given a time in seconds since midnight 1 Jan 1970, return the RFC 1123

    date string. Example result string: Sun, 06 Nov 1994 08:49:37 GMT

    @param calendar Time in seconds

    @param local If true, return the local time, if false return GMT. The

    default value is false.

    @return A RFC 1123 date string. */

string date_time_str(time_t *calendar, bool local)

{

    char buf[40];

#ifdef HAVE_STRFTIME

    if (local) {

        /*

        ** Solaris 2.3 has a bug so we _must_ use reentrant version

        ** Thomas Maslen <tmaslen@verity.com>

        */

#if defined(_REENTRANT) || defined(SOLARIS)

        struct tm loctime;

        localtime_r(calendar, &loctime);

        strftime(buf, 40, "%a, %d %b %Y %H:%M:%S", &loctime);

#else

        struct tm *loctime = localtime(calendar);

        strftime(buf, 40, "%a, %d %b %Y %H:%M:%S", loctime);

#endif /* SOLARIS || _REENTRANT */

    }

    else {

#if defined(_REENTRANT) || defined(SOLARIS)

        struct tm gmt;

        gmtime_r(calendar, &gmt);

        strftime(buf, 40, "%a, %d %b %Y %H:%M:%S GMT", &gmt);

#else

        struct tm *gmt = gmtime(calendar);

        strftime(buf, 40, "%a, %d %b %Y %H:%M:%S GMT", gmt);

#endif /* SOLARIS || _REENTRANT */

    }

#else  /* !HAVE_STRFTIME */

    if (local) {

#if defined(_REENTRANT)

        struct tm loctime;

        localtime_r(calendar, &loctime);

        snprintf(buf, 40, "%s, %02d %s %04d %02d:%02d:%02d",

                wkdays[loctime.tm_wday],

                loctime.tm_mday,

                months[loctime.tm_mon],

                loctime.tm_year + 1900,

                loctime.tm_hour,

                loctime.tm_min,

                loctime.tm_sec);

#else

    struct tm *loctime = localtime(calendar);

    if (!loctime)

    	return "";

    snprintf(buf, 40, "%s, %02d %s %04d %02d:%02d:%02d",

            wkdays[loctime->tm_wday],

            loctime->tm_mday,

            months[loctime->tm_mon],

            loctime->tm_year + 1900,

            loctime->tm_hour,

            loctime->tm_min,

            loctime->tm_sec);

#endif /* _REENTRANT */

    }

    else {

#if defined(_REENTRANT) || defined(SOLARIS)

        struct tm gmt;

        gmtime_r(calendar, &gmt);

        snprintf(buf, 40, "%s, %02d %s %04d %02d:%02d:%02d GMT",

                wkdays[gmt.tm_wday],

                gmt.tm_mday,

                months[gmt.tm_mon],

                gmt.tm_year + 1900,

                gmt.tm_hour,

                gmt.tm_min,

                gmt.tm_sec);

#else

    struct tm *gmt = gmtime(calendar);

    if (!gmt)

    	return "";

    snprintf(buf, 40, "%s, %02d %s %04d %02d:%02d:%02d GMT",

            wkdays[gmt->tm_wday],

            gmt->tm_mday,

            months[gmt->tm_mon],

            gmt->tm_year + 1900,

            gmt->tm_hour,

            gmt->tm_min,

            gmt->tm_sec);

#endif

    }

#endif

    return string(buf);

}

} // namespace libdap