clocks.cpp

/* handle displaying local and UTC time
 */


#include "HamClock.h"

// format flags
uint8_t de_time_fmt;                            // one of DETIME_*
uint8_t desrss, dxsrss;                         // show actual de/dx sun rise/set else time to

// menu names for each AuxTimeFormat
AuxTimeFormat auxtime;
#define X(a,b)  b,                              // expands AUXTIME to each name plus comma
const char *auxtime_names[AUXT_N] = {
    AUXTIMES
};
#undef X

// time update interval, seconds
#define TIME_INTERVAL   (30*60)                 // normal resync interval when working ok, seconds
#define TIME_RETRY       15000                  // retry interval when not working ok, millis

// run flag and progression
static bool hide_clocks;                        // run but don't display
static int prev_yr, prev_mo, prev_dy, prev_hr, prev_mn, prev_sc, prev_wd;
static bool time_running_bw;                    // set if see time running backwards -- yes it can happen!
static bool time_is_stuck;                      // set if see time not changing -- yes it can happen!

// TimeLib's now() stays at real UTC, but user can adjust time offset
static int utc_offset;                          // nowWO() offset from UTC, secs

// display 
#define UTC_W           14                      // UTC button width in upper right corner of clock_b
#define UTC_H           (HMS_H-1)               // UTC button height in upper right corner of clock_b
#define QUESTION_W      28                      // Question mark width
#define HMS_H           (clock_b.h-6)           // main HMS character height
#define FFONT_W         6                       // fixed font width
#define FFONT_H         8                       // fixed font height
#define HMS_C           RA8875_WHITE            // HMS color
#define AUX_C           RA8875_WHITE            // auxtime color

/* draw the UTC "button" in clock_b depending on whether utc_offset is 0.
 * if offset is not 0 show red/black depending on even/odd second
 */
static void drawUTCButton()
{
    selectFontStyle (BOLD_FONT, FAST_FONT);
    char msg[4];

    if (utc_offset == 0 && !time_running_bw && !time_is_stuck) {
        // at UTC for sure
        tft.fillRect (clock_b.x+clock_b.w-UTC_W, clock_b.y, UTC_W, UTC_H, HMS_C);
        tft.setTextColor(RA8875_BLACK);
        strcpy (msg, "UTC");
    } else {
        // unknown or time is other than UTC
        bool toggle = (millis()%2000) > 1000;
        uint16_t fg = toggle ? RA8875_WHITE : RA8875_BLACK;
        uint16_t bg = RA8875_RED;
        tft.fillRect (clock_b.x+clock_b.w-UTC_W, clock_b.y, UTC_W, UTC_H, bg);
        tft.drawRect (clock_b.x+clock_b.w-UTC_W, clock_b.y, UTC_W, UTC_H, bg);
        tft.setTextColor(fg);
        strcpy (msg, "OFF");
    }

    uint16_t vgap = (UTC_H - 3*FFONT_H)/4;
    uint16_t x = clock_b.x+clock_b.w-UTC_W+(UTC_W-FFONT_W)/2;
    tft.setCursor(x, clock_b.y+vgap+1);             tft.print(msg[0]);
    tft.setCursor(x, clock_b.y+2*vgap+FFONT_H+1);   tft.print(msg[1]);
    tft.setCursor(x, clock_b.y+3*vgap+2*FFONT_H+1); tft.print(msg[2]);
}

/* function given to TimeLib's setSyncProvider() to resync its time base occasionally.
 * use whichever source has been configured.
 * return 0 if trouble so now() will unset status timeSet.
 */
static time_t getTime(void)
{
    // calling now() will recurse so we advance usr_datetime using millis
    static uint32_t usr_millis;

    // log string
    const char *time_src;

    // new value from configured source
    time_t t;

    if (usr_datetime > 0) {
        // just continue with invoked user time
        time_src = "-s user-time";
        uint32_t m = millis();
        t = (usr_datetime += (m - usr_millis)/1000);
        usr_millis = m;
    } else if (useOSTime()) {
        time_src = "OS";
        t = time(NULL);
    } else if (useGPSDTime()) {
        time_src = getGPSDHost();
        t = getGPSDUTC();
    } else if (useNMEATime()) {
        time_src = getNMEAFile();
        t = getNMEAUTC();
    } else {
        NTPServer *ntp = findBestNTP();         // include user's if set
        time_src = ntp->server;
        t = getNTPUTC(ntp);
    }

    if (t) {
        Serial.printf ("time: getTime from %s: %ld %04d-%02d-%02d %02d:%02d:%02dZ\n",
                time_src, (long)t, year(t), month(t), day(t), hour(t), minute(t), second(t));
    } else
        Serial.printf ("time: getTime from %s failed\n", time_src);

    return (t);
}

/* given number of seconds into a day, print HH:MM with optional leading 0 if needed
 */
static void prHM (const uint32_t t, bool leading_zero)
{
    uint16_t hh = t/SECS_PER_HOUR;
    uint16_t mm = (t - hh*SECS_PER_HOUR)/SECS_PER_MIN;

    char buf[20];
    if (leading_zero)
        snprintf (buf, sizeof(buf), "%02d:%02d", hh, mm);
    else
        snprintf (buf, sizeof(buf), "%d:%02d", hh, mm);
    tft.print(buf);
}

/* given unix seconds print 12 H:MM followed by AM/PM or A/P to always use exactly 6 chars
 */
static void prHM6 (const time_t t)
{
    uint16_t h = hour(t);
    uint16_t m = minute(t);

    int h12 = h%12;
    if (h12 == 0)
        h12 = 12;

    char buf[20];
    if (h12 < 10)
        snprintf (buf, sizeof(buf), "%d:%02d%s", h12, m, h < 12 ? "AM" : "PM");
    else
        snprintf (buf, sizeof(buf), "%d:%02d%c", h12, m, h < 12 ? 'A' : 'P');
    tft.print (buf);
}

/* common portion for drawing the rise set info in the given box.
 */
static void drawRiseSet(time_t t0, time_t trise, time_t tset, SBox &b, uint8_t srss, int tz_secs)
{
    fillSBox (b, RA8875_BLACK);
    //drawSBox (b.x, b.y, b.w, b.h, RA8875_WHITE);
    selectFontStyle (LIGHT_FONT, FAST_FONT);

    if (trise == 0) {
        tft.setCursor (b.x, b.y+8);
        tft.print ("No rise");
    } else if (tset == 0) {
        tft.setCursor (b.x, b.y+8);
        tft.print ("No set");
    } else {

        bool night_now;
        if (trise < tset)
            night_now = t0 < trise || t0 > tset;
        else
            night_now = t0 > tset && t0 < trise;

        if (srss) {

            // draw actual rise set times

            if (night_now) {
                tft.setCursor (b.x, b.y+8);
                tft.print ("R at ");
                prHM (3600*hour(trise+tz_secs) + 60*minute(trise+tz_secs), true);
                tft.setCursor (b.x, b.y+b.h/2+6);
                tft.print ("S at ");
                prHM (3600*hour(tset+tz_secs) + 60*minute(tset+tz_secs), true);
            } else {
                tft.setCursor (b.x, b.y+8);
                tft.print ("S at ");
                prHM (3600*hour(tset+tz_secs) + 60*minute(tset+tz_secs), true);
                tft.setCursor (b.x, b.y+b.h/2+6);
                tft.print ("R at ");
                prHM (3600*hour(trise+tz_secs) + 60*minute(trise+tz_secs), true);
            }

        } else {

            // draw until rise and set

            int rdt = t0 - trise;
            int sdt = t0 - tset;

            tft.setCursor (b.x, b.y+8);
            if (night_now) {
                tft.print ("R in ");
                prHM (rdt > 0 ? SECS_PER_DAY-rdt : -rdt, false);
                tft.setCursor (b.x, b.y+b.h/2+6);
                tft.print ("S ");
                prHM (sdt >= 0 ? sdt : SECS_PER_DAY+sdt, false);
                tft.print (" ago");
            } else {
                tft.print ("S in ");
                prHM (sdt > 0 ? SECS_PER_DAY-sdt : -sdt, false);
                tft.setCursor (b.x, b.y+b.h/2+6);
                tft.print ("R ");
                prHM (rdt >= 0 ? rdt : SECS_PER_DAY+rdt, false);
                tft.print (" ago");
            }
        }
    }
}

/* given DE time_t with user offset draw local analog time clock in de_info_b
 */
static void drawAnalogClock (time_t delocal_t)
{
    // find center of largest inscribed circle sitting at the bottom
    int x0, y0, r;
    if (de_info_b.w > de_info_b.h) {
        r = de_info_b.h/2 - 3;
        x0 = de_info_b.x + de_info_b.w/2;
        y0 = de_info_b.y + r;
    } else {
        r = de_info_b.w/2 - 3;
        x0 = de_info_b.x + r;
        y0 = de_info_b.y + de_info_b.h/2;
    }

    // break out time
    const int hr = hour(delocal_t);
    const int mn = minute(delocal_t);
    const int wd = weekday(delocal_t);
    const int dy = day(delocal_t);
    const int mo = month(delocal_t);

    // convert hours and minutes to degrees CCW from 3 oclock
    const float hr360 = 30.0F*(3-(((hr+24)%12) + mn/60.0F));    // + partial hour
    const float mn360 = 6.0F*(15-mn);

    const float pnr = 0.92F*r;                                  // points' near radius
    const float paw = 3;                                        // points' angular diam seen from center
    const float mfr = 0.82F*r;                                  // minute hand far radius
    const float hfr = 0.47F*r;                                  // hour hand far radius
    const float hbr = 0.06F*r;                                  // both hands near radius

    // start clock face
    tft.fillRect (de_info_b.x, de_info_b.y, de_info_b.w, de_info_b.h-1, RA8875_BLACK);
    tft.drawCircle (x0, y0, r, DE_COLOR);
    for (uint16_t a = 0; a < 360; a += 30) {
        uint16_t p0x = roundf (x0+r*cosf(deg2rad(a-paw/2)));
        uint16_t p0y = roundf (y0+r*sinf(deg2rad(a-paw/2)));
        uint16_t p1x = roundf (x0+r*cosf(deg2rad(a+paw/2)));
        uint16_t p1y = roundf (y0+r*sinf(deg2rad(a+paw/2)));
        uint16_t p2x = roundf (x0+pnr*cosf(deg2rad(a)));
        uint16_t p2y = roundf (y0+pnr*sinf(deg2rad(a)));
        tft.fillTriangle (p0x, p0y, p1x, p1y, p2x, p2y, DE_COLOR);
    }

    // draw full length minute hand
    float cosmn = cosf(deg2rad(mn360));
    float sinmn = sinf(deg2rad(mn360));
    uint16_t farmnx = roundf (x0+mfr*cosmn);
    uint16_t farmny = roundf (y0-mfr*sinmn);                    // -y up
    int16_t nearmnx0 = roundf (x0+hbr*sinmn);
    int16_t nearmny0 = roundf (y0+hbr*cosmn);
    int16_t nearmnx1 = roundf (x0-hbr*sinmn);
    int16_t nearmny1 = roundf (y0-hbr*cosmn);
    tft.fillTriangle (nearmnx0, nearmny0, farmnx, farmny, nearmnx1, nearmny1, DE_COLOR);
    tft.drawLine (x0, y0, farmnx, farmny, DE_COLOR);            // fill occasional bit turd at far tip

    // draw shorter hour hand
    float coshr = cosf(deg2rad(hr360));
    float sinhr = sinf(deg2rad(hr360));
    uint16_t farhrx = roundf (x0+hfr*coshr);
    uint16_t farhry = roundf (y0-hfr*sinhr);                    // -y up
    int16_t nearhrx0 = roundf (x0+hbr*sinhr);
    int16_t nearhry0 = roundf (y0+hbr*coshr);
    int16_t nearhrx1 = roundf (x0-hbr*sinhr);
    int16_t nearhry1 = roundf (y0-hbr*coshr);
    tft.fillTriangle (nearhrx0, nearhry0, farhrx, farhry, nearhrx1, nearhry1, DE_COLOR);
    tft.drawLine (x0, y0, farhrx, farhry, DE_COLOR);            // fill occasional bit turd at far tip

    // center post
    tft.fillCircle (x0, y0, roundf(hbr)+1, DE_COLOR);
    tft.drawCircle (x0, y0, roundf(hbr)+1, RA8875_BLACK);

    // draw time labels too if on
    if (de_time_fmt == DETIME_ANALOG_DTTM) {

        // dow
        const uint16_t indent = 5;
        const uint16_t rowh = 12;
        const uint16_t charw = 6;
        uint16_t tx = de_info_b.x+indent;
        selectFontStyle (LIGHT_FONT, FAST_FONT);
        tft.setTextColor (DE_COLOR);
        tft.setCursor (tx, y0-r+1);
        tft.print (dayShortStr(wd));

        // am/pm
        tft.setCursor (tx, y0-r+rowh+1);
        tft.print (hr < 12 ? "AM" : "PM");

        // mon
        tx = de_info_b.x+de_info_b.w-indent-3*charw;
        tft.setCursor (tx, y0-r+1);
        tft.print (monthShortStr(mo));

        // date
        tx = de_info_b.x+de_info_b.w-indent-charw;
        if (dy > 9)
            tx -= charw;
        tft.setCursor (tx, y0-r+rowh+1);
        tft.print (dy);

        // sunrise/set
        time_t trise, tset, t0 = nowWO();
        getSolarRS (t0, de_ll, &trise, &tset);

        // sunrise symbol
        // const uint16_t sx = de_info_b.x + 17;
        // const uint16_t sy = de_info_b.y + de_info_b.h - 15;
        // const uint16_t sr = 4;
        // tft.fillCircle (sx, sy, sr, RA8875_WHITE);
        // tft.fillRect (sx - sr, sy - 1, 2*sr+1, sr + 2, RA8875_BLACK);
        // tft.drawLine (sx - 2*sr, sy - 1, sx + 2*sr, sy - 1, DE_COLOR);

        // labels
        tft.setCursor (de_info_b.x + indent, de_info_b.y + de_info_b.h - 2*rowh);
        tft.print ("SR");
        tft.setCursor (de_info_b.x + de_info_b.w - (2*charw+indent), de_info_b.y + de_info_b.h - 2*rowh);
        tft.print ("SS");

        // rise
        tft.setCursor (de_info_b.x + indent, de_info_b.y + de_info_b.h - rowh);
        if (trise == 0 || tset == 0)
            tft.print ("NoRise");
        else
            prHM6 (trise + getTZ (de_tz));

        // set
        tft.setCursor (de_info_b.x + de_info_b.w - (6*charw+indent),  de_info_b.y + de_info_b.h - rowh);
        if (trise == 0 || tset == 0)
            tft.print (" NoSet");
        else
            prHM6 (tset + getTZ (de_tz));
    }
}

/* given DE time_t with user offset draw local digital time clock in de_info_b
 */
static void drawDigitalClock (time_t delocal_t)
{
    // break out
    int hr = hour(delocal_t);
    int mn = minute(delocal_t);
    int wd = weekday(delocal_t);
    int dy = day(delocal_t);
    int mo = month(delocal_t);
    int yr = year(delocal_t);

    // prep
    tft.fillRect (de_info_b.x, de_info_b.y, de_info_b.w, de_info_b.h-1, RA8875_BLACK);

    // format time
    char buf[50];
    if (de_time_fmt == DETIME_DIGITAL_12) {
        int hr12 = hr%12;
        if (hr12 == 0)
            hr12 = 12;
        snprintf (buf, sizeof(buf), "%d:%02d", hr12, mn);
    } else {
        snprintf (buf, sizeof(buf), "%02d:%02d", hr, mn);
    }

    // print time
    selectFontStyle (BOLD_FONT, LARGE_FONT);
    uint16_t bw = getTextWidth(buf);
    tft.setCursor (de_info_b.x+(de_info_b.w-bw)/2-4, de_info_b.y + de_info_b.h/2);
    tft.setTextColor (DE_COLOR);
    tft.print (buf);

    // other info
    // N.B. dayShortStr and monthShort return same static pointer
    size_t bl = 0;
    if (getDateFormat() == DF_DMY) {
        bl += snprintf (buf+bl, sizeof(buf)-bl, "%s, ", dayShortStr(wd));
        bl += snprintf (buf+bl, sizeof(buf)-bl, "%d %s %d", dy, monthShortStr(mo), yr);
    } else if (getDateFormat() == DF_MDY) {
        bl += snprintf (buf+bl, sizeof(buf)-bl, "%s ", dayShortStr(wd));
        bl += snprintf (buf+bl, sizeof(buf)-bl, "%s %d, %d", monthShortStr(mo), dy, yr);
    } else if (getDateFormat() == DF_YMD) {
        bl += snprintf (buf+bl, sizeof(buf)-bl, "%s, ", dayShortStr(wd));
        bl += snprintf (buf+bl, sizeof(buf)-bl, "%d %s %d", yr, monthShortStr(mo), dy);
    } else {
        fatalError ("bad date fmt: %d", (int)getDateFormat());
    }
    if (de_time_fmt == DETIME_DIGITAL_12)
        bl += snprintf (buf+bl, sizeof(buf)-bl, " %s", hr < 12 ? "AM" : "PM");
    else
        bl += snprintf (buf+bl, sizeof(buf)-bl, " 24h");
    selectFontStyle (LIGHT_FONT, FAST_FONT);
    bw = getTextWidth(buf);
    tft.setCursor (de_info_b.x + (de_info_b.w-bw)/2, de_info_b.y + 4*de_info_b.h/5);
    tft.print (buf);
}

/* offer a menu to change the aux time format
 * N.B. caller must restore original content
 */
static void runAuxTimeMenu()
{
    #define _AM_INDENT 4
    MenuItem mitems[AUXT_N] = {
        {MENU_1OFN, auxtime == AUXT_DATE, 1, _AM_INDENT, auxtime_names[AUXT_DATE], 0},
        {MENU_1OFN, auxtime == AUXT_DOY, 1, _AM_INDENT, auxtime_names[AUXT_DOY], 0},
        {MENU_1OFN, auxtime == AUXT_JD, 1, _AM_INDENT, auxtime_names[AUXT_JD], 0},
        {MENU_1OFN, auxtime == AUXT_MJD, 1, _AM_INDENT, auxtime_names[AUXT_MJD], 0},
        {MENU_1OFN, auxtime == AUXT_SIDEREAL, 1, _AM_INDENT, auxtime_names[AUXT_SIDEREAL], 0},
        {MENU_1OFN, auxtime == AUXT_SOLAR, 1, _AM_INDENT, auxtime_names[AUXT_SOLAR], 0},
        {MENU_1OFN, auxtime == AUXT_UNIX, 1, _AM_INDENT, auxtime_names[AUXT_UNIX], 0},
    };

    SBox menu_b = auxtime_b;
    menu_b.w = 0;   // shrink to fit
    menu_b.x += 20;
    SBox ok_b;
    MenuInfo menu = {menu_b, ok_b, UF_NOCLOCKS, M_CANCELOK, 1, AUXT_N, mitems};
    if (runMenu(menu)) {
        // update auxtime;
        for (int i = 0; i < AUXT_N; i++) {
            if (mitems[i].set) {
                auxtime = (AuxTimeFormat)i;
                NVWriteUInt8(NV_AUX_TIME, (uint8_t)auxtime);
                break;
            }
        }
    }
}

/* tell TimeLib where to get its time reference
 */
static void startSyncProvider(bool force)
{
    static uint32_t prev_start;
    if (timesUp(&prev_start, TIME_RETRY) || force) {
        Serial.print ("time: perform fresh sync\n");
        setSyncInterval (TIME_INTERVAL);
        setSyncProvider (getTime);
    }
}

/* given UTC including user offset draw auxtime_b depending on auxtime setting.
 * we are called every second so do the minimum required.
 */
static void drawAuxTime (bool all, const time_t &t_wo, const tmElements_t &tm_wo)
{
    // mostly common prep
    #define _UCHW       13                                              // approx char width
    #define _UCCD       8                                               // descent
    static int prev_day;                                                // note new day for many options
    int day = t_wo / (3600*24);
    int year = tm_wo.Year + 1970;
    selectFontStyle (LIGHT_FONT, SMALL_FONT);
    tft.setTextColor(AUX_C);
    uint16_t y = auxtime_b.y + auxtime_b.h - _UCCD;
    char buf[64];

    if (auxtime == AUXT_DATE) {

        if (all || day != prev_day) {

            fillSBox (auxtime_b, RA8875_BLACK);

            // N.B. dayShortStr() and monthShortStr() share the same static pointer

            if (getDateFormat() == DF_DMY) {

                // Weekday, date month year

                int buf_l = snprintf (buf, sizeof(buf), "%s, ", dayShortStr(tm_wo.Wday));
                snprintf (buf+buf_l, sizeof(buf)-buf_l, "%2d %s %d",
                                                                tm_wo.Day, monthShortStr(tm_wo.Month), year);
                uint16_t bw = getTextWidth (buf);
                int16_t x = auxtime_b.x + (auxtime_b.w-bw)/2;
                if (x < 0)
                    x = 0;
                tft.setCursor(x, y);
                tft.print(buf);

            } else if (getDateFormat() == DF_MDY) {

                // Weekday month date, year

                int buf_l = snprintf (buf, sizeof(buf), "%s  ", dayShortStr(tm_wo.Wday));
                snprintf (buf+buf_l, sizeof(buf)-buf_l, "%s %2d, %d",
                                                                monthShortStr(tm_wo.Month), tm_wo.Day, year);
                uint16_t bw = getTextWidth (buf);
                int16_t x = auxtime_b.x + (auxtime_b.w-bw)/2;
                if (x < 0)
                    x = 0;
                tft.setCursor(x, y);
                tft.print(buf);

            } else if (getDateFormat() == DF_YMD) {

                // Weekday, year month date

                int buf_l = snprintf (buf, sizeof(buf), "%s,  ", dayShortStr(tm_wo.Wday));
                snprintf (buf+buf_l, sizeof(buf)-buf_l, "%d %s %2d",
                                                                year, monthShortStr(tm_wo.Month), tm_wo.Day);
                uint16_t bw = getTextWidth (buf);
                int16_t x = auxtime_b.x + (auxtime_b.w-bw)/2;
                if (x < 0)
                    x = 0;
                tft.setCursor(x, y);
                tft.print(buf);

            } else {

                fatalError ("bad format: %d", (int)getDateFormat());

            }

            prev_day = day;
        }


    } else if (auxtime == AUXT_DOY) {


        if (all || day != prev_day) {

            fillSBox (auxtime_b, RA8875_BLACK);

            // Weekday DOY <doy> year

            // find day of year
            tmElements_t tm_doy = tm_wo;
            tm_doy.Second = tm_doy.Minute = tm_doy.Hour = 0;
            tm_doy.Month = tm_doy.Day = 1;
            time_t year0 = makeTime (tm_doy);
            int doy = (t_wo - year0) / (24*3600) + 1;

            snprintf (buf, sizeof(buf), "%s DoY %d  %d", dayShortStr(tm_wo.Wday), doy, year);
            uint16_t bw = getTextWidth (buf);
            int16_t x = auxtime_b.x + (auxtime_b.w-bw)/2;
            if (x < 0)
                x = 0;
            tft.setCursor(x, y);
            tft.print(buf);

            prev_day = day;
        }

    } else if (auxtime == AUXT_JD || auxtime == AUXT_MJD) {

        static long prev_whole;                                         // previous whole value
        static uint16_t prev_xdp;                                       // x coord of decimal point
        #define _JDNFRAC   5                                            // n fractional digits

        // find value
        double d = t_wo / 86400.0 + 2440587.5;                          // JD
        if (auxtime == AUXT_MJD)
            d -= 2400000.5;                                             // MJD

        // draw
        const long whole = floor(d);
        if (all || whole != prev_whole || prev_xdp == 0) {
            // draw complete value up to decimal point
            fillSBox (auxtime_b, RA8875_BLACK);
            long val = whole;
            int millions = val / 1000000L;
            val -= millions * 1000000L;                                 // now thousands
            int thousands = val / 1000;
            val -= thousands * 1000;                                    // now units
            int units = val;
            if (millions)
                snprintf (buf, sizeof(buf), "JD %d,%03d,%03d", millions, thousands, units);
            else
                snprintf (buf, sizeof(buf), "MJD %d,%03d", thousands, units);
            uint16_t bw = getTextWidth (buf);
            int16_t x = auxtime_b.x + (auxtime_b.w-bw-(_JDNFRAC+1)*_UCHW)/2;
            tft.setCursor(x, y);
            tft.print(buf);
            prev_xdp = tft.getCursorX();
        } else {
            // just draw the fraction
            tft.fillRect (prev_xdp, auxtime_b.y, (_JDNFRAC+1)*_UCHW, auxtime_b.h, RA8875_BLACK);
            tft.setCursor(prev_xdp, y);
        }
        snprintf (buf, sizeof(buf), "%.*f", _JDNFRAC, d - whole);
        tft.print (buf+1);                                              // skip the leading 0

        // persist
        prev_whole = whole;

    } else if (auxtime == AUXT_SIDEREAL) {

        static int prev_wholemn;                                        // previous whole minutes
        static uint16_t prev_xcolon;                                    // x coord of 2nd colon

        // find lst at DE
        double lst;                                                     // hours
        double astro_mjd = t_wo/86400.0 + 2440587.5 - 2415020.0;        // just for now_lst()
        now_lst (astro_mjd, de_ll.lng, &lst);
        int wholemn = floor(lst*60);

        // break out
        int lst_hr = lst;
        lst = (lst - lst_hr)*60;                                        // now mins
        int lst_mn = lst;
        lst = (lst - lst_mn)*60;                                        // now secs
        int lst_sc = lst;

        if (all || wholemn != prev_wholemn || prev_xcolon == 0) {
            // draw complete value but note location of 2nd colon
            snprintf (buf, sizeof(buf), "LST  %02d:%02d:", lst_hr, lst_mn);
            uint16_t bw = getTextWidth (buf);
            int16_t x = auxtime_b.x + (auxtime_b.w-bw-2*_UCHW)/2;       // center including secs
            tft.setCursor(x, y);
            fillSBox (auxtime_b, RA8875_BLACK);
            tft.print(buf);
            prev_xcolon = tft.getCursorX();
        } else {
            // just redraw seconds
            tft.fillRect (prev_xcolon, auxtime_b.y, 2*_UCHW, auxtime_b.h, RA8875_BLACK);
            tft.setCursor(prev_xcolon, y);
        }
        snprintf (buf, sizeof(buf), "%02d", lst_sc);
        tft.print (buf);

        // persist
        prev_wholemn = wholemn;

    } else if (auxtime == AUXT_SOLAR) {

        static int prev_wholemn;                                        // previous whole minutes
        static uint16_t prev_xcolon;                                    // x coord of 2nd colon

        // find solar time at DE in hours -- requires fresh solar gha each second
        AstroCir cir;
        getSolarCir (t_wo, de_ll, cir);
        float solar = fmodf (12 + (de_ll.lng_d + rad2deg(cir.gha))/15 + 48, 24);
        int wholemn = floorf(solar*60);

        // break out
        int solar_hr = solar;
        solar = (solar - solar_hr)*60;                                  // now mins
        int solar_mn = solar;
        solar = (solar - solar_mn)*60;                                  // now secs
        int solar_sc = solar;

        // draw time
        if (all || wholemn != prev_wholemn || prev_xcolon == 0) {
            // draw complete value but note location of 2nd colon
            snprintf (buf, sizeof(buf), "Solar  %02d:%02d:", solar_hr, solar_mn);
            uint16_t bw = getTextWidth (buf);
            int16_t x = auxtime_b.x + (auxtime_b.w-bw-2*_UCHW)/2;       // center including secs
            tft.setCursor(x, y);
            fillSBox (auxtime_b, RA8875_BLACK);
            tft.print(buf);
            prev_xcolon = tft.getCursorX();
        } else {
            // just redraw seconds
            tft.fillRect (prev_xcolon, auxtime_b.y, 2*_UCHW, auxtime_b.h, RA8875_BLACK);
            tft.setCursor(prev_xcolon, y);
        }
        snprintf (buf, sizeof(buf), "%02d", solar_sc);
        tft.print (buf);

        // persist
        prev_wholemn = wholemn;

    } else if (auxtime == AUXT_UNIX) {

        static time_t prev_t;                                           // previous time drawn
        static uint16_t prev_xend;                                      // x coord of last digit

        // draw time
        if (all || t_wo/10 != prev_t/10 || prev_xend == 0) {
            // draw complete time but note location of last digit
            fillSBox (auxtime_b, RA8875_BLACK);
            time_t t0 = t_wo;
            int billions = t_wo/1000000000UL;
            t0 -= billions * 1000000000UL;                              // now millions
            int millions = t0/1000000UL;
            t0 -= millions * 1000000UL;                                 // now thousands
            int thousands = t0/1000;
            t0 -= thousands*1000;                                       // now units
            int tens = t0/10;
            snprintf (buf, sizeof(buf), "Unix %d,%03d,%03d,%02d", billions, millions, thousands, tens);
            uint16_t bw = getTextWidth (buf);
            int16_t x = auxtime_b.x + (auxtime_b.w-bw-_UCHW)/2;         // center including units
            tft.setCursor(x, y);
            tft.print(buf);
            prev_xend = tft.getCursorX();
        } else {
            // just draw last digit
            tft.fillRect (prev_xend, auxtime_b.y, _UCHW, auxtime_b.h, RA8875_BLACK);
            tft.setCursor(prev_xend, y);
        }
        tft.print ((int)(t_wo % 10));

        // persist
        prev_t = t_wo;
    }
}

/* draw a calendar in de_info_b below time
 */
void drawCalendar(bool force)
{

    // looks a little better to me if we put a small border around the edges
    #define CAL_BW 4

    // find local time
    tmElements_t tm;
    time_t tnow = nowWO() + getTZ (de_tz);
    breakTime (tnow, tm);                       // break into components
    // Serial.printf ("cal force= %d YMD %d %d %d\n", force, tm.Year, tm.Month, tm.Day);

    // avoid redraws unless force
    static uint8_t prev_Year, prev_Month, prev_Day;
    if (!force && prev_Year == tm.Year && prev_Month == tm.Month && prev_Day == tm.Day)
        return;
    prev_Year = tm.Year;
    prev_Month = tm.Month;
    prev_Day = tm.Day;

    // cal in box below time
    uint16_t vspace = de_info_b.h/DE_INFO_ROWS;
    uint16_t cal_y = de_info_b.y + vspace;
    uint16_t cal_h = de_info_b.y + de_info_b.h - cal_y;

    // erase all
    tft.fillRect (de_info_b.x, cal_y, de_info_b.w, cal_h, RA8875_BLACK);

    // find column for 1st of this month
    int week_mon = weekStartsOnMonday() ? 1 : 0;
    uint8_t today = tm.Day;                     // save today's date, 1 based
    tm.Day = 1;                                 // set 1st
    uint32_t t1st = makeTime(tm);               // synth new time
    uint8_t col1 = (weekday (t1st) - 1 - week_mon + 7)%7;          // 0-based column of 1st day of month

    // find number of days in this month
    if (++tm.Month == 13) {                     // advance to next month, which is 1-based
        tm.Month = 1;                           // roll to next year 
        tm.Year++;
    }
    uint32_t t1stmo = makeTime (tm);            // first of next month
    uint8_t dtm = (t1stmo - t1st)/SECSPERDAY;   // n days this month

    // find required number of rows
    int8_t dom = 1-col1;                        // 1-based day of month in first cell, <=0 if prev mon
    const uint8_t n_cols = 7;                   // always 7 cols
    uint8_t n_rows = (dtm - dom + 7)/n_cols;    // n rows required
    // Serial.printf ("col1= %d dtm= %d dom= %d n_cols= %d n_rows= %d\n", col1, dtm, dom, n_cols, n_rows);

    // draw grid
    for (uint8_t i = 0; i <= n_rows; i++) {
        uint16_t y = cal_y + i*(de_info_b.h-vspace-1)/n_rows;
        tft.drawLine (de_info_b.x+CAL_BW, y, de_info_b.x + de_info_b.w - CAL_BW, y, DE_COLOR);
    }
    for (uint8_t i = 0; i <= n_cols; i++) {
        uint16_t x = de_info_b.x + CAL_BW + i*(de_info_b.w-2*CAL_BW)/n_cols;
        tft.drawLine (x, cal_y, x, de_info_b.y+de_info_b.h-1, DE_COLOR);
    }

    // prep font
    selectFontStyle (LIGHT_FONT, FAST_FONT);

    // fill dates or day names
    for (uint8_t r = 0; r < n_rows; r++) {
        for (uint8_t c = 0; c < n_cols; c++) {
            uint16_t x0 = CAL_BW + de_info_b.x + c*(de_info_b.w-2*CAL_BW)/n_cols + 4;
            uint16_t y0 = cal_y + r*cal_h/n_rows + 3;
            if (dom >= 1 && dom <= dtm) {
                // date
                tft.setTextColor (utc_offset == 0 && dom == today ? RA8875_WHITE : DE_COLOR);
                if (dom < 10)
                    x0 += 2;
                tft.setCursor (x0, y0);
                tft.print (dom);
            } else {
                // name of day
                static char dnames[7*2+1] PROGMEM = "SuMoTuWeThFrSa";
                char dname[3];
                strncpy_P (dname, &dnames[2*((c+week_mon)%7)], 2);
                dname[2] = '\0';
                tft.setTextColor (GRAY);
                tft.setCursor (x0, y0);
                tft.print(dname);
            }

            dom++;
        }
    }
}

/* start the clock running
 */
void initTime()
{
    // get last UTC offset from ENVROM
    if (!NVReadInt32 (NV_UTC_OFFSET, &utc_offset)) {
        utc_offset = 0;
        NVWriteInt32 (NV_UTC_OFFSET, utc_offset);
    }

    // get desired aux time format
    uint8_t at;
    if (!NVReadUInt8(NV_AUX_TIME, &at)) {
        at = AUXT_DATE;
        NVWriteUInt8(NV_AUX_TIME, at);
    }
    auxtime = (AuxTimeFormat)at;
    Serial.printf ("time: auxtime format %s\n", auxtime_names[auxtime]);

    // start using time source
    startSyncProvider(true);
}

/* do not display clocks
 */
void hideClocks()
{
    hide_clocks = true;
}


/* resume displaying clocks and insure everything gets drawn first time
 */
void showClocks()
{
    hide_clocks = false;

    prev_yr = 99;
    prev_mo = 99;
    prev_dy = 99;
    prev_hr = 99;
    prev_mn = 99;
    prev_sc = 99;
    prev_wd = 99;

    drawUTCButton();
}

/* like now() but with current user offset
 */
time_t nowWO()
{
    return (myNow() + utc_offset);
}


/* now() can return small values until time sync or even run backwards if NTP packets get reordered.
 * that raises havoc so this wrapper hides that and makes note.
 */
time_t myNow()
{
    // state to detect odd behaviors
    static uint32_t m_ok;
    static time_t prev_t;

    // beware recursion, eg vis nextRetry if now decides to ask for an update
    static bool reentry;
    if (reentry) {
        // Serial.printf ("myNow() detected recursion\n");
        return (prev_t);
    }
    reentry = true;

    // ok, let's see what we get
    uint32_t m = millis();
    time_t t = now();

    // now just counts up from 0 until first sync
    if (t < 1000000000L)
        t = 0;

    // check progress
    if (t < prev_t) {

        // backwards ?!?!
        if (!time_running_bw)
            Serial.printf ("time: running backwards: %ld -> %ld\n", (long)prev_t, (long)t);
        time_running_bw = true;

    } else if (t == prev_t) {

        // beware same t for longer than a few seconds
        if (m_ok && m > m_ok + 5000) {
            if (!time_is_stuck) {
                Serial.printf ("time: stuck at %ld for %u ms (%u - %u)\n", (long)t, m - m_ok, m, m_ok);
                time_is_stuck = true;
            }
        }

    } else {

        // normal advance
        if (time_is_stuck)
            Serial.printf ("time: unstuck at %ld after %d ms\n", (long)t, m - m_ok);
        time_is_stuck = false;
        m_ok = m;
        if (time_running_bw)
            Serial.printf ("time: running forwards now: %ld -> %ld\n", (long)prev_t, (long)t);
        time_running_bw = false;
    }

    // history
    prev_t = t;

    // reset recursion detector
    reentry = false;

    return (t);
}


/* return whether time is working for the clock.
 * if not goose occasionally.
 */
bool clockTimeOk()
{
    bool time_ok = useOSTime() || (timeStatus() == timeSet && !time_running_bw && !time_is_stuck);
    if (!time_ok)
        startSyncProvider(false);
    return (time_ok);
}

/* return current user offset from UTC 
 */
int utcOffset()
{
    return (utc_offset);
}

/* draw all clocks if time system has been initialized.
 * N.B. this is called a lot so make it very fast when nothing to do
 */
void updateClocks(bool all)
{
    // ignore if disabled
    if (hide_clocks)
        return;

    // get user's UTC time now, get out fast if still same second
    time_t t_wo = nowWO();
    if ((t_wo%60) == prev_sc && !all)
        return;

    // preserve caller's font
    FontWeight fw;
    FontSize fs;
    getFontStyle (&fw, &fs);

    // misc
    char buf[32];

    // break into components
    tmElements_t tm_wo;
    breakTime (t_wo, tm_wo);

    // set to update other times as well
    bool draw_other_times = false;

    // always draw seconds because we know it has changed
    if (all || (tm_wo.Second/10) != (prev_sc/10)) {

        // Change in tens digit of seconds process normally W2ROW
        uint16_t sx = clock_b.x+2*clock_b.w/3;          // right 1/3 for seconds
        selectFontStyle (BOLD_FONT, SMALL_FONT);
        snprintf (buf, sizeof(buf), "%02d", tm_wo.Second);      // includes ones digit
        tft.fillRect(sx, clock_b.y, 30, HMS_H/2+4, RA8875_BLACK);  // dont erase ? if present
        tft.setCursor(sx, clock_b.y+HMS_H-19);
        tft.setTextColor(HMS_C);
        tft.print(buf);

    } else {

        // Change only in units digit of seconds - process only that digit  W2ROW
        uint16_t sx = clock_b.x+2*clock_b.w/3+15;       // right 1/3 for seconds (15 by experiment) W2ROW
        selectFontStyle (BOLD_FONT, SMALL_FONT);        // W2ROW
        snprintf (buf, sizeof(buf), "%01d", tm_wo.Second%10);   // W2ROW
        tft.fillRect(sx, clock_b.y, 15, HMS_H/2+4, RA8875_BLACK);  // dont erase ? W2ROW
        tft.setCursor(sx, clock_b.y+HMS_H-19);          // W2ROW
        tft.setTextColor(HMS_C);                        // W2ROW
        tft.print(buf);                                 // W2ROW
      
    }

    // check time
    static bool time_was_bad;
    if (clockTimeOk()) {
        if (time_was_bad) {

            // just came back on, show and update state
            Serial.printf ("time: back ok\n");
            drawUTCButton();
            tft.fillRect(clock_b.x+2*clock_b.w/3+34, clock_b.y, 25, HMS_H+4, RA8875_BLACK); // erase ?

            time_was_bad = false;
        }
    } else {
        if (!time_was_bad) {

            // just went bad, show and update state
            Serial.printf ("time: error\n");
            drawUTCButton();
            selectFontStyle (BOLD_FONT, LARGE_FONT);
            tft.setTextColor(HMS_C);
            tft.setCursor(clock_b.x+clock_b.w-UTC_W-QUESTION_W, clock_b.y+HMS_H);
            tft.print('?');

            time_was_bad = true;
        }
    }

    // persist
    prev_sc = tm_wo.Second;

    // draw H:M if either changes
    if (all || tm_wo.Minute != prev_mn || tm_wo.Hour != prev_hr) {

        // draw H:M roughly right-justified in left 2/3
        selectFontStyle (BOLD_FONT, LARGE_FONT);
        snprintf (buf, sizeof(buf), "%02d:%02d", tm_wo.Hour, tm_wo.Minute);
        uint16_t w = 135;
        int16_t x = clock_b.x+2*clock_b.w/3-w;
        tft.fillRect (x, clock_b.y, w, HMS_H+2, RA8875_BLACK);
        tft.setCursor(x, clock_b.y+HMS_H);
        tft.setTextColor(HMS_C);
        tft.print(buf);

        // update BC time marker if new hour and up
        if (prev_hr != tm_wo.Hour) {
            PlotPane bc_pane = findPaneChoiceNow(PLOT_CH_BC);
            if (bc_pane != PANE_NONE && bc_matrix.ok)
                plotBandConditions (plot_b[bc_pane], 0, NULL, NULL);
        }

        // update other info
        draw_other_times = true;

        // persist
        prev_mn = tm_wo.Minute;
        prev_hr = tm_wo.Hour;
    }

    // draw date if new day
    if (all || tm_wo.Day != prev_dy || tm_wo.Wday != prev_wd || tm_wo.Month != prev_mo || tm_wo.Year != prev_yr) {

        // update other info
        draw_other_times = true;

        // persist
        prev_yr = tm_wo.Year;
        prev_mo = tm_wo.Month;
        prev_dy = tm_wo.Day;
        prev_wd = tm_wo.Wday;
    }

    drawAuxTime (all, t_wo, tm_wo);

    // draw other misc time items unless showing pane 0
    if (draw_other_times && !SHOWING_PANE_0()) {

        // DE pane
        switch (de_time_fmt) {
        case DETIME_CAL:
            drawDECalTime(true);
            drawCalendar(false);
            break;
        case DETIME_ANALOG:     // fallthru
        case DETIME_ANALOG_DTTM:
            drawAnalogClock (t_wo + getTZ (de_tz));
            break;
        case DETIME_INFO:
            drawDECalTime(false);
            drawDESunRiseSetInfo();
            break;
        case DETIME_DIGITAL_12: // fallthru
        case DETIME_DIGITAL_24: // fallthru
            drawDigitalClock (t_wo + getTZ (de_tz));
            break;
        default:
            fatalError ("unknown de fmt %d", de_time_fmt);
            break;
        }

        // DX pane
        if (!dx_info_for_sat) {
            drawDXTime();
            drawDXSunRiseSetInfo();
        }
    }

    // flash panes or NCDXF if rotating
    showRotatingBorder();

    // flash UTC if not current
    if (utc_offset != 0 || !clockTimeOk())
        drawUTCButton();

    // restore caller's font
    selectFontStyle (fw, fs);
}

/* draw DE sun rise and set info
 */
void drawDESunRiseSetInfo()
{
    time_t trise, tset, t0 = nowWO();
    getSolarRS (t0, de_ll, &trise, &tset);

    tft.setTextColor(DE_COLOR);
    drawRiseSet (t0, trise, tset, desrss_b, desrss, getTZ (de_tz));
}

/* draw DX sun rise and set info.
 * skip if showing dx prefix there.
 */
void drawDXSunRiseSetInfo()
{
    if (dxsrss == DXSRSS_PREFIX)
        return;

    time_t trise, tset, t0 = nowWO();
    getSolarRS (t0, dx_ll, &trise, &tset);

    tft.setTextColor(DX_COLOR);
    drawRiseSet (t0, trise, tset, dxsrss_b, dxsrss, getTZ(dx_tz));

}

/* return whether touch event at s is in clock_b (OTHER THAN lkscrn_b and stopwatch_b which have already
 *   been checked) or auxtime_b.
 * if so, offer menus to change time or aux format.
 * N.B. we expect caller to call updateClocks if we return true.
 */
bool checkClockTouch (SCoord &s)
{
    bool ours = false;

    if (inBox (s, auxtime_b)) {

        runAuxTimeMenu();

        // we never change the time but still need to claim the touch
        ours = true;

    } else if (inBox (s, clock_b) && !inBox (s, lkscrn_b) && !inBox (s, stopwatch_b)) {

        // tapped here
        ours = true;

        // find touch position within clock_b
        uint16_t dx = s.x - clock_b.x;
        uint16_t dy = s.y - clock_b.y;

        // get time state now
        time_t real_utc = myNow();
        time_t user_utc = real_utc + utc_offset;                // don't use nowWO
        int off0 = utc_offset;

        // check a few special cases but mostly we put up a menu to allow editing time

        if (dx >= clock_b.w-UTC_W && dy <= UTC_H) {

            // tapped UTC "button": return to UTC if not already

            if (utc_offset != 0 || !clockTimeOk()) {
                utc_offset = 0;
                startSyncProvider(true);
            }

        } else if (dx < 7*clock_b.w/8) {

            // show and engage menu of time change choices

            // list of menu choices. N.B. must be in same order as mitems[]
            enum {     
                _CT_TITLE,
                _CT_DIRLBL,
                    _CT_DIR_FRW,
                    _CT_DIR_BKW,
                _CT_MODLBL,
                    _CT_MOD_1MIN,
                    _CT_MOD_10MINS,
                    _CT_MOD_1HOUR,
                    _CT_MOD_2HOURS,
                    _CT_MOD_1DAY,
                    _CT_MOD_1WEEK,
                    _CT_MOD_1MON,
                    _CT_MOD_1YEAR,
                _CT_MOD_0SECS,
                _CT_N
            };
            #define _CT_INDENT1 5
            #define _CT_INDENT2 10

            // preset to previous settings
            static uint8_t prev_dir = _CT_DIR_FRW;
            static uint8_t prev_mod = _CT_MOD_1HOUR;

            // menu
            MenuItem mitems[_CT_N] = {
                { MENU_LABEL, false, 0, _CT_INDENT1, " Change Time", 0},
                { MENU_LABEL, false, 0, _CT_INDENT1, "Direction:", 0},
                    { MENU_1OFN, prev_dir == _CT_DIR_FRW, 1, _CT_INDENT2, "Forward", 0},
                    { MENU_1OFN, prev_dir == _CT_DIR_BKW, 1, _CT_INDENT2, "Backward", 0},
                { MENU_LABEL, false, 2, _CT_INDENT1, "Amount:", 0},
                    { MENU_01OFN, prev_mod == _CT_MOD_1MIN, 3, _CT_INDENT2, "1 minute", 0},
                    { MENU_01OFN, prev_mod == _CT_MOD_10MINS, 3, _CT_INDENT2, "10 minutes", 0},
                    { MENU_01OFN, prev_mod == _CT_MOD_1HOUR, 3, _CT_INDENT2, "1 hour", 0},
                    { MENU_01OFN, prev_mod == _CT_MOD_2HOURS, 3, _CT_INDENT2, "2 hours", 0},
                    { MENU_01OFN, prev_mod == _CT_MOD_1DAY, 3, _CT_INDENT2, "1 day", 0},
                    { MENU_01OFN, prev_mod == _CT_MOD_1WEEK, 3, _CT_INDENT2, "1 week", 0},
                    { MENU_01OFN, prev_mod == _CT_MOD_1MON, 3, _CT_INDENT2, "1 month", 0},
                    { MENU_01OFN, prev_mod == _CT_MOD_1YEAR, 3, _CT_INDENT2, "1 year", 0},
                { MENU_TOGGLE, false, 4, _CT_INDENT1, "Zero seconds", 0},
            };

            // run, do nothing if cancelled
            SBox menu_b = clock_b;
            menu_b.w = 0;   // shrink to fit
            menu_b.x += 20;
            SBox ok_b;
            MenuInfo menu = {menu_b, ok_b, UF_NOCLOCKS, M_CANCELOK, 1, _CT_N, mitems};
            if (runMenu(menu) && askPasswd ("changeUTC", true)) {

                // find change direction
                int sign = mitems[_CT_DIR_FRW].set ? 1 : -1;
                prev_dir = sign > 0 ? _CT_DIR_FRW : _CT_DIR_BKW;

                // update utc_offset according to desired change
                if (mitems[_CT_MOD_1MIN].set) {
                    utc_offset += 60 * sign;
                    prev_mod = _CT_MOD_1MIN;
                } else if (mitems[_CT_MOD_10MINS].set) {
                    utc_offset += 600 * sign;
                    prev_mod = _CT_MOD_10MINS;
                } else if (mitems[_CT_MOD_1HOUR].set) {
                    utc_offset += 3600 * sign;
                    prev_mod = _CT_MOD_1HOUR;
                } else if (mitems[_CT_MOD_2HOURS].set) {
                    utc_offset += 2*3600 * sign;
                    prev_mod = _CT_MOD_2HOURS;
                } else if (mitems[_CT_MOD_1DAY].set) {
                    utc_offset += SECSPERDAY * sign;
                    prev_mod = _CT_MOD_1DAY;
                } else if (mitems[_CT_MOD_1WEEK].set) {
                    utc_offset += 7*SECSPERDAY * sign;
                    prev_mod = _CT_MOD_1WEEK;
                } else if (mitems[_CT_MOD_1MON].set) {
                    tmElements_t tm;
                    breakTime (user_utc, tm);
                    if (sign > 0) {
                        if (++tm.Month > 12) {
                            tm.Month = 1;
                            tm.Year += 1;
                        }
                    } else {
                        if (--tm.Month == 0) {
                            tm.Month = 12;
                            tm.Year -= 1;
                        }
                    }
                    utc_offset = makeTime(tm) - real_utc;
                    prev_mod = _CT_MOD_1MON;
                } else if (mitems[_CT_MOD_1YEAR].set) {
                    tmElements_t tm;
                    breakTime (user_utc, tm);
                    tm.Year += sign;
                    utc_offset = makeTime(tm) - real_utc;
                    prev_mod = _CT_MOD_1YEAR;
                } else {
                    prev_mod = _CT_TITLE;               // any otherwise unused value
                }

                // then zero seconds too if desired
                if (mitems[_CT_MOD_0SECS].set) {
                    time_t ut = myNow();                // need fresh time because of time spent in menu
                    utc_offset = 60*((ut + utc_offset)/60) - ut;
                }
            }
        }

        // save new offset
        NVWriteInt32 (NV_UTC_OFFSET, utc_offset);

        // show whether UTC now
        drawUTCButton();

        // restart systems if likely effected by time change
        int dt = abs (utc_offset - off0);
        if (dt > 60)
            initWiFiRetry();
        if (dt >= 30) {
            if (setNewSatCircumstance ())
                drawSatPass();
        }

    }

    return (ours);
}

/* return DE today's weekday 1..7 == Sun..Sat
 */
int DEWeekday(void)
{
    time_t de_local = nowWO() + getTZ (de_tz);
    return (weekday (de_local));
}

/* set time to UNIX t, maintaining user's offset, or to UTC if t == 0.
 */
void changeTime (time_t t)
{
    // update offset
    if (t == 0)
        utc_offset = 0;
    else
        utc_offset += t - nowWO();

    // save
    NVWriteInt32 (NV_UTC_OFFSET, utc_offset);

    // UTC button, normal loop will update clocks
    drawUTCButton();

    // update map and panes that rely on time.
    if (setNewSatCircumstance ())
        drawSatPass();
    initEarthMap();
    scheduleNewPlot(PLOT_CH_MOON);
    scheduleNewPlot(PLOT_CH_SDO);
    scheduleNewPlot(PLOT_CH_BC);
}

/* show menu of timezone offsets +- a few hours from nominal plus option for auto.
 * if user taps ok update tzi and return true, else false.
 */
bool TZMenu (TZInfo &tzi, const LatLong &ll)
{
    // get TZ for this location and likely step sizes for neighboring zones
    int tz0_secs = getTZ (tzi);
    int step_secs = getFastTZStep(ll);

    // config
    #define N_NEW_TZ    5                       // number of discrete TZ choices
    #define N_TZMENU    (N_NEW_TZ+1)            // total number of menu items: choices + Auto last
    #define CURRENT_I   (N_NEW_TZ/2)            // index to show current offset
    #define TZAUTO_I    N_NEW_TZ                // index of the Auto choice, ie, last
    #define MAX_NEW_TZ  20                      // max choice strlen

    // create menu -- first N_NEW_TZ followed by Auto
    MenuItem mitems[N_TZMENU];                  // menu items
    char tz_label[N_TZMENU][MAX_NEW_TZ];        // labels good for lifetime of runMenu()
    for (int i = 0; i < N_TZMENU; i++) {
        if (i == TZAUTO_I)
            snprintf (tz_label[i], MAX_NEW_TZ, "Auto");
        else
            snprintf (tz_label[i], MAX_NEW_TZ, "UTC%+g", (tz0_secs + step_secs*(i-CURRENT_I))/3600.0F);
        MenuItem &mi = mitems[i];
        mi.type = MENU_1OFN;
        mi.group = 1;
        mi.set = tzi.auto_tz ? (i == TZAUTO_I) : (i == CURRENT_I);
        mi.indent = 4;
        mi.label = tz_label[i];
    }

    // boxes
    SBox menu_b;
    menu_b.x = tzi.box.x - 5;
    menu_b.y = tzi.box.y + tzi.box.h+2;
    menu_b.w = 0;       // shrink to fit

    // run
    SBox ok_b;
    MenuInfo menu = {menu_b, ok_b, UF_NOCLOCKS, M_NOCANCEL, 1, N_TZMENU, mitems};
    bool menu_ok = runMenu (menu);

    // engage if ok
    if (menu_ok) {

        // update tzi from set item
        for (int i = 0; i < N_TZMENU; i++) {
            if (mitems[i].set) {
                if (i == TZAUTO_I)
                    setTZAuto (tzi);
                else
                    setTZSecs (tzi, tz0_secs + step_secs*(i-CURRENT_I));
                break;
            }
        }
    }

    return (menu_ok);
}

/* draw a TZ control box with current state
 */
void drawTZ (TZInfo &tzi)
{
    // format as UTC + hours
    char buf[32];
    uint16_t w, h;
    snprintf (buf, sizeof(buf), "UTC%+g", getTZ (tzi)/3600.0F);
    selectFontStyle (BOLD_FONT, FAST_FONT);
    getTextBounds (buf, &w, &h);

    // box
    fillSBox (tzi.box, RA8875_BLACK);
    drawSBox (tzi.box, tzi.color);
    tft.setTextColor (tzi.color);
    tft.setCursor (tzi.box.x+(tzi.box.w-w)/2, tzi.box.y+(tzi.box.h-h)/2);
    tft.print (buf);
}

/* given a standard 3-char abbreviation for month, set *monp to 1-12 and return true, else false
 * if nothing matches
 */
bool crackMonth (const char *name, int *monp)
{
    for (int m = 1; m <= 12; m++) {
        if (strcmp (name, monthShortStr(m)) == 0) {
            *monp = m;
            return (true);
        }
    }

    return (false);
}