/* libiso8601/src/tests/calconv.c
 *
 *  (c)2006, Laurence Withers, <l@lwithers.me.uk>.
 *  Released under the GNU GPLv2. See file COPYING or
 *  http://www.gnu.org/copyleft/gpl.html for details.
*/

#include "iso8601.h"

#include <errno.h>
#include <stdio.h>
#include <string.h>



const int _days_in_month_common[] = {
    31,
    28,
    31,
    30,
    31,
    30,
    31,
    31,
    30,
    31,
    30,
    31
};

const int _days_in_month_leap[] = {
    31,
    29,
    31,
    30,
    31,
    30,
    31,
    31,
    30,
    31,
    30,
    31
};


int try_year(int year)
{
    static int daycount = 0;
    const int* mc;
    int m, d, y2, m2, d2, ret = 0;
    struct iso8601_date dt;

    mc = iso8601_isleap(year) ? _days_in_month_leap : _days_in_month_common;

    for(m = 0; m < 12; ++m) {
        for(d = 0; d < mc[m]; ++d) {
            if(iso8601_from_cal(&dt, year, m + 1, d + 1)) {
                ++ret;
                printf("[cal2date     ] %04d-%02d-%02d: %s (%d)\n",
                    year, m + 1, d + 1, strerror(errno), errno);

            } else if(dt.day != daycount) {
                ++ret;
                printf("[discontinuity] %04d-%02d-%02d: got day=%d, expected day=%d\n",
                    year, m + 1, d + 1, dt.day, daycount);

            } else if(iso8601_to_cal(&y2, &m2, &d2, &dt), year != y2 || m + 1 != m2 || d + 1 != d2) {
                ++ret;
                printf("[date2cal     ] %04d-%02d-%02d ==> %04d-%02d-%02d (%d)\n",
                    year, m + 1, d + 1, y2, m2, d2, daycount);

            }

            ++daycount;
        }
    }

    return ret;
}



int try_neg_year(int year)
{
    static int daycount = 365;
    const int* mc;
    int m, d, y2, m2, d2, ret = 0;
    struct iso8601_date dt;

    mc = iso8601_isleap(year) ? _days_in_month_leap : _days_in_month_common;

    for(m = 11; m >= 0; --m) {
        for(d = mc[m]; d; --d) {
            if(iso8601_from_cal(&dt, year, m + 1, d)) {
                ++ret;
                printf("[cal2date     ] %04d-%02d-%02d: %s (%d)\n",
                    year, m + 1, d, strerror(errno), errno);

            } else if(dt.day != daycount) {
                ++ret;
                printf("[discontinuity] %04d-%02d-%02d: got day=%d, expected day=%d\n",
                    year, m + 1, d, dt.day, daycount);

            } else if(iso8601_to_cal(&y2, &m2, &d2, &dt), year != y2 || m + 1 != m2 || d != d2) {
                ++ret;
                printf("[date2cal     ] %04d-%02d-%02d ==> %04d-%02d-%02d (%d)\n",
                    year, m + 1, d, y2, m2, d2, daycount);

            }

            --daycount;
        }
    }

    return ret;
}



// stuff repeats on a 400-year cycle, so we really shouldn't need to worry too much about this
#define MAX_YEAR_COUNT 2400



int try_weeks(void)
{
    // starting position
    int weekcount = 52, weekday = 5, isoyear = -1;
    int y, wk, wd, ret = 0;
    struct iso8601_date dt, dt2;
    
    for(dt.day = 0; dt.day < MAX_YEAR_COUNT * 366; ++dt.day) {
        iso8601_to_week(&y, &wk, &wd, &dt);
        if(wd == 1) {
            if(weekday != 7) goto discont;
            ++weekcount;
            if(wk == 1) {
                if(weekcount != 53 && weekcount != 54) goto discont;
                weekcount = 1;
                ++isoyear;
            }
        }

        if(wk != weekcount || y != isoyear) goto discont;
        weekday = wd;

        iso8601_from_week(&dt2, isoyear, weekcount, weekday);
        if(dt2.day != dt.day) {
            printf("[weekmismatch    ] %04d-W%02d-%d: should be %d, got %d\n", 
                isoyear, weekcount, weekday, dt.day, dt2.day);
            if(++ret > 20) return ret;
        }

        continue;

    discont:
        printf("[weekdiscont     ] %04d-W%02d-%d ==> %04d-W%02d-%d (%d)\n",
            isoyear, weekcount, weekday, y, wk, wd, dt.day);
        isoyear = y;
        weekcount = wk;
        weekday = wd;
        if(++ret > 20) return ret;
    }

    return ret;
}



int main(int argc, char* argv[])
{
    int ret = 0, year;

    if(argc == 2 && !strcmp(argv[1], "--print-summary")) {
        printf("Calendar date / day number conversion test.\n");
        return 0;
    }

    for(year = 0; year <= MAX_YEAR_COUNT; ++year) {
        ret += try_year(year);
        if(ret > 20) return ret;
    }

    for(year = 0; year >= -MAX_YEAR_COUNT; --year) {
        ret += try_neg_year(year);
        if(ret > 20) return ret;
    }

    ret += try_weeks();
    if(ret > 20) return ret;

    return ret;
}

/* options for text editors
kate: replace-trailing-space-save true; space-indent true; tab-width 4;
vim: expandtab:ts=4:sw=4
*/