calendar.c: Rename to "ui-calendar.c"

This unit belongs to the presentation layer -- rename the file
accordingly.

Also, rename calendar_*() to ui_calendar_*().

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

1 files changed, 915 insertions, 0 deletions

diff --git a/src/ui-calendar.c b/src/ui-calendar.c
new file mode 100644
index 0000000..f9749c8
--- /dev/null
+++ b/src/ui-calendar.c
@@ -0,0 +1,915 @@
+/*
+ * Calcurse - text-based organizer
+ *
+ * Copyright (c) 2004-2013 calcurse Development Team <misc@calcurse.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the
+ *        following disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the
+ *        following disclaimer in the documentation and/or other
+ *        materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Send your feedback or comments to : misc@calcurse.org
+ * Calcurse home page : http://calcurse.org
+ *
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <time.h>
+#include <math.h>
+
+#include "calcurse.h"
+
+#ifndef M_PI
+#define	M_PI	  3.14159265358979323846
+#endif
+
+#define	EPOCH	  90
+#define	EPSILONg  279.403303    /* solar ecliptic long at EPOCH */
+#define	RHOg	  282.768422    /* solar ecliptic long of perigee at EPOCH */
+#define	ECCEN	  0.016713      /* solar orbit eccentricity */
+#define	lzero	  318.351648    /* lunar mean long at EPOCH */
+#define	Pzero	  36.340410     /* lunar mean long of perigee at EPOCH */
+#define	Nzero	  318.510107    /* lunar mean long of node at EPOCH */
+
+#define ISLEAP(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
+
+enum pom {
+  NO_POM,
+  FIRST_QUARTER,
+  FULL_MOON,
+  LAST_QUARTER,
+  NEW_MOON,
+  MOON_PHASES
+};
+
+static struct date today, slctd_day;
+static unsigned ui_calendar_view, week_begins_on_monday;
+static pthread_mutex_t date_thread_mutex = PTHREAD_MUTEX_INITIALIZER;
+static pthread_t ui_calendar_t_date;
+
+static void draw_monthly_view(struct window *, struct date *, unsigned);
+static void draw_weekly_view(struct window *, struct date *, unsigned);
+static void (*draw_calendar[CAL_VIEWS]) (struct window *, struct date *,
+                                         unsigned) = {
+draw_monthly_view, draw_weekly_view};
+
+static int monthly_view_cache[MAXDAYSPERMONTH];
+static int monthly_view_cache_valid = 0;
+static int monthly_view_cache_month = 0;
+
+/* Switch between calendar views (monthly view is selected by default). */
+void ui_calendar_view_next(void)
+{
+  ui_calendar_view++;
+  if (ui_calendar_view == CAL_VIEWS)
+    ui_calendar_view = 0;
+}
+
+void ui_calendar_view_prev(void)
+{
+  if (ui_calendar_view == 0)
+    ui_calendar_view = CAL_VIEWS;
+  ui_calendar_view--;
+}
+
+void ui_calendar_set_view(int view)
+{
+  ui_calendar_view = (view < 0 || view >= CAL_VIEWS) ? CAL_MONTH_VIEW : view;
+}
+
+int ui_calendar_get_view(void)
+{
+  return (int)ui_calendar_view;
+}
+
+/* Thread needed to update current date in calendar. */
+/* ARGSUSED0 */
+static void *ui_calendar_date_thread(void *arg)
+{
+  time_t actual, tomorrow;
+
+  for (;;) {
+    tomorrow = (time_t) (get_today() + DAYINSEC);
+
+    while ((actual = time(NULL)) < tomorrow)
+      sleep(tomorrow - actual);
+
+    ui_calendar_set_current_date();
+    ui_calendar_update_panel(&win[CAL]);
+  }
+
+  return NULL;
+}
+
+/* Launch the calendar date thread. */
+void ui_calendar_start_date_thread(void)
+{
+  pthread_create(&ui_calendar_t_date, NULL, ui_calendar_date_thread, NULL);
+}
+
+/* Stop the calendar date thread. */
+void ui_calendar_stop_date_thread(void)
+{
+  if (ui_calendar_t_date) {
+    pthread_cancel(ui_calendar_t_date);
+    pthread_join(ui_calendar_t_date, NULL);
+  }
+}
+
+/* Set static variable today to current date */
+void ui_calendar_set_current_date(void)
+{
+  time_t timer;
+  struct tm tm;
+
+  timer = time(NULL);
+  localtime_r(&timer, &tm);
+
+  pthread_mutex_lock(&date_thread_mutex);
+  today.dd = tm.tm_mday;
+  today.mm = tm.tm_mon + 1;
+  today.yyyy = tm.tm_year + 1900;
+  pthread_mutex_unlock(&date_thread_mutex);
+}
+
+/* Needed to display sunday or monday as the first day of week in calendar. */
+void ui_calendar_set_first_day_of_week(enum wday first_day)
+{
+  switch (first_day) {
+  case SUNDAY:
+    week_begins_on_monday = 0;
+    break;
+  case MONDAY:
+    week_begins_on_monday = 1;
+    break;
+  default:
+    ERROR_MSG(_("ERROR setting first day of week"));
+    week_begins_on_monday = 0;
+    /* NOTREACHED */
+  }
+}
+
+/* Swap first day of week in calendar. */
+void ui_calendar_change_first_day_of_week(void)
+{
+  week_begins_on_monday = !week_begins_on_monday;
+}
+
+/* Return 1 if week begins on monday, 0 otherwise. */
+unsigned ui_calendar_week_begins_on_monday(void)
+{
+  return week_begins_on_monday;
+}
+
+/* Fill in the given variable with the current date. */
+void ui_calendar_store_current_date(struct date *date)
+{
+  pthread_mutex_lock(&date_thread_mutex);
+  *date = today;
+  pthread_mutex_unlock(&date_thread_mutex);
+}
+
+/* This is to start at the current date in calendar. */
+void ui_calendar_init_slctd_day(void)
+{
+  ui_calendar_store_current_date(&slctd_day);
+}
+
+/* Return the selected day in calendar */
+struct date *ui_calendar_get_slctd_day(void)
+{
+  return &slctd_day;
+}
+
+/* Returned value represents the selected day in calendar (in seconds) */
+long ui_calendar_get_slctd_day_sec(void)
+{
+  return date2sec(slctd_day, 0, 0);
+}
+
+static int ui_calendar_get_wday(struct date *date)
+{
+  struct tm t;
+
+  memset(&t, 0, sizeof(struct tm));
+  t.tm_mday = date->dd;
+  t.tm_mon = date->mm - 1;
+  t.tm_year = date->yyyy - 1900;
+
+  mktime(&t);
+
+  return t.tm_wday;
+}
+
+static unsigned months_to_days(unsigned month)
+{
+  return (month * 3057 - 3007) / 100;
+}
+
+static long years_to_days(unsigned year)
+{
+  return year * 365L + year / 4 - year / 100 + year / 400;
+}
+
+static long ymd_to_scalar(unsigned year, unsigned month, unsigned day)
+{
+  long scalar;
+
+  scalar = day + months_to_days(month);
+  if (month > 2)
+    scalar -= ISLEAP(year) ? 1 : 2;
+  year--;
+  scalar += years_to_days(year);
+
+  return scalar;
+}
+
+/*
+ * Used to change date by adding a certain amount of days or weeks.
+ * Returns 0 on success, 1 otherwise.
+ */
+static int date_change(struct tm *date, int delta_month, int delta_day)
+{
+  struct tm t;
+
+  t = *date;
+  t.tm_mon += delta_month;
+  t.tm_mday += delta_day;
+
+  if (mktime(&t) == -1)
+    return 1;
+  else {
+    *date = t;
+    return 0;
+  }
+}
+
+void ui_calendar_monthly_view_cache_set_invalid(void)
+{
+  monthly_view_cache_valid = 0;
+}
+
+/* Draw the monthly view inside calendar panel. */
+static void
+draw_monthly_view(struct window *cwin, struct date *current_day,
+                  unsigned sunday_first)
+{
+  const int OFFY = CALHEIGHT / 2 - (conf.compact_panels ? 3 : 1);
+  struct date check_day;
+  int c_day, c_day_1, day_1_sav, numdays, j;
+  unsigned yr, mo;
+  int OFFX, SBAR_WIDTH, ofs_x, ofs_y;
+  int item_this_day = 0;
+
+  mo = slctd_day.mm;
+  yr = slctd_day.yyyy;
+
+  /* offset for centering calendar in window */
+  SBAR_WIDTH = wins_sbar_width();
+  OFFX = (SBAR_WIDTH - 27) / 2;
+  ofs_y = OFFY;
+  ofs_x = OFFX;
+
+  /* checking the number of days in february */
+  numdays = days[mo - 1];
+  if (2 == mo && ISLEAP(yr))
+    ++numdays;
+
+  /*
+   * the first calendar day will be monday or sunday, depending on
+   * 'week_begins_on_monday' value
+   */
+  c_day_1 = (int)((ymd_to_scalar(yr, mo, 1 + sunday_first) - (long)1) % 7L);
+
+  /* Write the current month and year on top of the calendar */
+  WINS_CALENDAR_LOCK;
+  custom_apply_attr(cwin->p, ATTR_HIGHEST);
+  mvwprintw(cwin->p, ofs_y,
+            (SBAR_WIDTH - (strlen(_(monthnames[mo - 1])) + 5)) / 2,
+            "%s %d", _(monthnames[mo - 1]), slctd_day.yyyy);
+  custom_remove_attr(cwin->p, ATTR_HIGHEST);
+  ++ofs_y;
+
+  /* print the days, with regards to the first day of the week */
+  custom_apply_attr(cwin->p, ATTR_HIGHEST);
+  for (j = 0; j < WEEKINDAYS; j++) {
+    mvwaddstr(cwin->p, ofs_y, ofs_x + 4 * j, _(daynames[1 + j - sunday_first]));
+  }
+  custom_remove_attr(cwin->p, ATTR_HIGHEST);
+  WINS_CALENDAR_UNLOCK;
+
+  day_1_sav = (c_day_1 + 1) * 3 + c_day_1 - 7;
+
+  /* invalidate cache if a new month is selected */
+  if (yr * YEARINMONTHS + mo != monthly_view_cache_month) {
+    monthly_view_cache_month = yr * YEARINMONTHS + mo;
+    monthly_view_cache_valid = 0;
+  }
+
+  for (c_day = 1; c_day <= numdays; ++c_day, ++c_day_1, c_day_1 %= 7) {
+    check_day.dd = c_day;
+    check_day.mm = slctd_day.mm;
+    check_day.yyyy = slctd_day.yyyy;
+
+    /* check if the day contains an event or an appointment */
+    if (monthly_view_cache_valid) {
+      item_this_day = monthly_view_cache[c_day - 1];
+    }
+    else {
+      item_this_day = monthly_view_cache[c_day - 1] =
+        day_check_if_item(check_day);
+    }
+
+    /* Go to next line, the week is over. */
+    if (!c_day_1 && 1 != c_day) {
+      ofs_y++;
+      ofs_x = OFFX - day_1_sav - 4 * c_day;
+    }
+
+    WINS_CALENDAR_LOCK;
+    if (c_day == current_day->dd
+        && current_day->mm == slctd_day.mm
+        && current_day->yyyy == slctd_day.yyyy
+        && current_day->dd != slctd_day.dd) {
+      /* This is today, so print it in yellow. */
+      custom_apply_attr(cwin->p, ATTR_LOWEST);
+      mvwprintw(cwin->p, ofs_y + 1,
+                ofs_x + day_1_sav + 4 * c_day + 1, "%2d", c_day);
+      custom_remove_attr(cwin->p, ATTR_LOWEST);
+    } else if (c_day == slctd_day.dd) {
+      /* This is the selected day, print it according to user's theme. */
+      custom_apply_attr(cwin->p, ATTR_HIGHEST);
+      mvwprintw(cwin->p, ofs_y + 1,
+                ofs_x + day_1_sav + 4 * c_day + 1, "%2d", c_day);
+      custom_remove_attr(cwin->p, ATTR_HIGHEST);
+    } else if (item_this_day) {
+      custom_apply_attr(cwin->p, ATTR_LOW);
+      mvwprintw(cwin->p, ofs_y + 1,
+                ofs_x + day_1_sav + 4 * c_day + 1, "%2d", c_day);
+      custom_remove_attr(cwin->p, ATTR_LOW);
+    } else {
+      /* otherwise, print normal days in black */
+      mvwprintw(cwin->p, ofs_y + 1,
+                ofs_x + day_1_sav + 4 * c_day + 1, "%2d", c_day);
+    }
+    WINS_CALENDAR_UNLOCK;
+  }
+
+  monthly_view_cache_valid = 1;
+}
+
+static int weeknum(const struct tm *t, int firstweekday)
+{
+  int wday, wnum;
+
+  wday = t->tm_wday;
+  if (firstweekday == MONDAY) {
+    if (wday == SUNDAY)
+      wday = 6;
+    else
+      wday--;
+  }
+  wnum = ((t->tm_yday + WEEKINDAYS - wday) / WEEKINDAYS);
+  if (wnum < 0)
+    wnum = 0;
+
+  return wnum;
+}
+
+/*
+ * Compute the week number according to ISO 8601.
+ */
+static int ISO8601weeknum(const struct tm *t)
+{
+  int wnum, jan1day;
+
+  wnum = weeknum(t, MONDAY);
+
+  jan1day = t->tm_wday - (t->tm_yday % WEEKINDAYS);
+  if (jan1day < 0)
+    jan1day += WEEKINDAYS;
+
+  switch (jan1day) {
+  case MONDAY:
+    break;
+  case TUESDAY:
+  case WEDNESDAY:
+  case THURSDAY:
+    wnum++;
+    break;
+  case FRIDAY:
+  case SATURDAY:
+  case SUNDAY:
+    if (wnum == 0) {
+      /* Get week number of last week of last year. */
+      struct tm dec31ly;        /* 12/31 last year */
+
+      dec31ly = *t;
+      dec31ly.tm_year--;
+      dec31ly.tm_mon = 11;
+      dec31ly.tm_mday = 31;
+      dec31ly.tm_wday = (jan1day == SUNDAY) ? 6 : jan1day - 1;
+      dec31ly.tm_yday = 364 + ISLEAP(dec31ly.tm_year + 1900);
+      wnum = ISO8601weeknum(&dec31ly);
+    }
+    break;
+  }
+
+  if (t->tm_mon == 11) {
+    int wday, mday;
+
+    wday = t->tm_wday;
+    mday = t->tm_mday;
+    if ((wday == MONDAY && (mday >= 29 && mday <= 31))
+        || (wday == TUESDAY && (mday == 30 || mday == 31))
+        || (wday == WEDNESDAY && mday == 31))
+      wnum = 1;
+  }
+
+  return wnum;
+}
+
+/* Draw the weekly view inside calendar panel. */
+static void
+draw_weekly_view(struct window *cwin, struct date *current_day,
+                 unsigned sunday_first)
+{
+#define DAYSLICESNO  6
+  const int WCALWIDTH = 30;
+  const int OFFY = CALHEIGHT / 2 - (conf.compact_panels ? 3 : 1);
+  struct tm t;
+  int OFFX, j, c_wday, days_to_remove, weeknum;
+
+  OFFX = (wins_sbar_width() - WCALWIDTH) / 2 + 1;
+
+  /* Fill in a tm structure with the first day of the selected week. */
+  c_wday = ui_calendar_get_wday(&slctd_day);
+  if (sunday_first)
+    days_to_remove = c_wday;
+  else
+    days_to_remove = c_wday == 0 ? WEEKINDAYS - 1 : c_wday - 1;
+
+  memset(&t, 0, sizeof(struct tm));
+  t.tm_mday = slctd_day.dd;
+  t.tm_mon = slctd_day.mm - 1;
+  t.tm_year = slctd_day.yyyy - 1900;
+  mktime(&t);
+  date_change(&t, 0, -days_to_remove);
+
+  /* Print the week number. */
+  weeknum = ISO8601weeknum(&t);
+  WINS_CALENDAR_LOCK;
+  custom_apply_attr(cwin->p, ATTR_HIGHEST);
+  mvwprintw(cwin->p, conf.compact_panels ? 0 : 2, cwin->w - 9, "(# %02d)",
+            weeknum);
+  custom_remove_attr(cwin->p, ATTR_HIGHEST);
+  WINS_CALENDAR_UNLOCK;
+
+  /* Now draw calendar view. */
+  for (j = 0; j < WEEKINDAYS; j++) {
+    struct date date;
+    unsigned attr, item_this_day;
+    int i, slices[DAYSLICESNO];
+
+    /* print the day names, with regards to the first day of the week */
+    custom_apply_attr(cwin->p, ATTR_HIGHEST);
+    mvwaddstr(cwin->p, OFFY, OFFX + 4 * j, _(daynames[1 + j - sunday_first]));
+    custom_remove_attr(cwin->p, ATTR_HIGHEST);
+
+    /* Check if the day to be printed has an item or not. */
+    date.dd = t.tm_mday;
+    date.mm = t.tm_mon + 1;
+    date.yyyy = t.tm_year + 1900;
+    item_this_day = day_check_if_item(date);
+
+    /* Print the day numbers with appropriate decoration. */
+    if (t.tm_mday == current_day->dd
+        && current_day->mm == slctd_day.mm
+        && current_day->yyyy == slctd_day.yyyy
+        && current_day->dd != slctd_day.dd)
+      attr = ATTR_LOWEST;       /* today, but not selected */
+    else if (t.tm_mday == slctd_day.dd)
+      attr = ATTR_HIGHEST;      /* selected day */
+    else if (item_this_day)
+      attr = ATTR_LOW;
+    else
+      attr = 0;
+
+    WINS_CALENDAR_LOCK;
+    if (attr)
+      custom_apply_attr(cwin->p, attr);
+    mvwprintw(cwin->p, OFFY + 1, OFFX + 1 + 4 * j, "%02d", t.tm_mday);
+    if (attr)
+      custom_remove_attr(cwin->p, attr);
+    WINS_CALENDAR_UNLOCK;
+
+    /* Draw slices indicating appointment times. */
+    memset(slices, 0, DAYSLICESNO * sizeof *slices);
+    if (day_chk_busy_slices(date, DAYSLICESNO, slices)) {
+      for (i = 0; i < DAYSLICESNO; i++) {
+        if (j != WEEKINDAYS - 1 && i != DAYSLICESNO - 1) {
+          WINS_CALENDAR_LOCK;
+          mvwhline(cwin->p, OFFY + 2 + i, OFFX + 3 + 4 * j, ACS_S9, 2);
+          WINS_CALENDAR_UNLOCK;
+        }
+        if (slices[i]) {
+          int highlight;
+
+          highlight = (t.tm_mday == slctd_day.dd) ? 1 : 0;
+          WINS_CALENDAR_LOCK;
+          if (highlight)
+            custom_apply_attr(cwin->p, attr);
+          wattron(cwin->p, A_REVERSE);
+          mvwaddstr(cwin->p, OFFY + 2 + i, OFFX + 1 + 4 * j, " ");
+          mvwaddstr(cwin->p, OFFY + 2 + i, OFFX + 2 + 4 * j, " ");
+          wattroff(cwin->p, A_REVERSE);
+          if (highlight)
+            custom_remove_attr(cwin->p, attr);
+          WINS_CALENDAR_UNLOCK;
+        }
+      }
+    }
+
+    /* get next day */
+    date_change(&t, 0, 1);
+  }
+
+  /* Draw marks to indicate midday on the sides of the calendar. */
+  WINS_CALENDAR_LOCK;
+  custom_apply_attr(cwin->p, ATTR_HIGHEST);
+  mvwhline(cwin->p, OFFY + 1 + DAYSLICESNO / 2, OFFX, ACS_S9, 1);
+  mvwhline(cwin->p, OFFY + 1 + DAYSLICESNO / 2,
+           OFFX + WCALWIDTH - 3, ACS_S9, 1);
+  custom_remove_attr(cwin->p, ATTR_HIGHEST);
+  WINS_CALENDAR_UNLOCK;
+
+#undef DAYSLICESNO
+}
+
+/* Function used to display the calendar panel. */
+void ui_calendar_update_panel(struct window *cwin)
+{
+  struct date current_day;
+  unsigned sunday_first;
+
+  ui_calendar_store_current_date(&current_day);
+
+  WINS_CALENDAR_LOCK;
+  erase_window_part(cwin->p, 1, conf.compact_panels ? 1 : 3, cwin->w - 2,
+                    cwin->h - 2);
+  if (!conf.compact_panels)
+    mvwhline(cwin->p, 2, 1, ACS_HLINE, cwin->w - 2);
+  WINS_CALENDAR_UNLOCK;
+
+  sunday_first = ui_calendar_week_begins_on_monday()? 0 : 1;
+
+  draw_calendar[ui_calendar_view] (cwin, &current_day, sunday_first);
+
+  wnoutrefresh(cwin->p);
+}
+
+/* Set the selected day in calendar to current day. */
+void ui_calendar_goto_today(void)
+{
+  struct date today;
+
+  ui_calendar_store_current_date(&today);
+  slctd_day.dd = today.dd;
+  slctd_day.mm = today.mm;
+  slctd_day.yyyy = today.yyyy;
+}
+
+/*
+ * Ask for a date to jump to, then check the correctness of that date
+ * and jump to it.
+ * If the entered date is empty, automatically jump to the current date.
+ * slctd_day is updated with the newly selected date.
+ */
+void ui_calendar_change_day(int datefmt)
+{
+#define LDAY 11
+  char selected_day[LDAY] = "";
+  char outstr[BUFSIZ];
+  int dday, dmonth, dyear;
+  int wrong_day = 1;
+  const char *mesg_line1 =
+      _("The day you entered is not valid "
+        "(should be between 01/01/1902 and 12/31/2037)");
+  const char *mesg_line2 = _("Press [ENTER] to continue");
+  const char *request_date = _("Enter the day to go to [ENTER for today] : %s");
+
+  while (wrong_day) {
+    snprintf(outstr, BUFSIZ, request_date, DATEFMT_DESC(datefmt));
+    status_mesg(outstr, "");
+    if (getstring(win[STA].p, selected_day, LDAY, 0, 1) == GETSTRING_ESC)
+      return;
+    else {
+      if (strlen(selected_day) == 0) {
+        wrong_day = 0;
+        ui_calendar_goto_today();
+      } else if (parse_date(selected_day, datefmt, &dyear, &dmonth, &dday,
+                            ui_calendar_get_slctd_day())) {
+        wrong_day = 0;
+        /* go to chosen day */
+        slctd_day.dd = dday;
+        slctd_day.mm = dmonth;
+        slctd_day.yyyy = dyear;
+      }
+      if (wrong_day) {
+        status_mesg(mesg_line1, mesg_line2);
+        wgetch(win[KEY].p);
+      }
+    }
+  }
+
+  return;
+}
+
+void ui_calendar_move(enum move move, int count)
+{
+  int ret, days_to_remove, days_to_add;
+  struct tm t;
+
+  memset(&t, 0, sizeof(struct tm));
+  t.tm_mday = slctd_day.dd;
+  t.tm_mon = slctd_day.mm - 1;
+  t.tm_year = slctd_day.yyyy - 1900;
+
+  switch (move) {
+  case DAY_PREV:
+    ret = date_change(&t, 0, -count);
+    break;
+  case DAY_NEXT:
+    ret = date_change(&t, 0, count);
+    break;
+  case WEEK_PREV:
+    ret = date_change(&t, 0, -count * WEEKINDAYS);
+    break;
+  case WEEK_NEXT:
+    ret = date_change(&t, 0, count * WEEKINDAYS);
+    break;
+  case MONTH_PREV:
+    ret = date_change(&t, -count, 0);
+    break;
+  case MONTH_NEXT:
+    ret = date_change(&t, count, 0);
+    break;
+  case YEAR_PREV:
+    ret = date_change(&t, -count * YEARINMONTHS, 0);
+    break;
+  case YEAR_NEXT:
+    ret = date_change(&t, count * YEARINMONTHS, 0);
+    break;
+  case WEEK_START:
+    /* Normalize struct tm to get week day number. */
+    mktime(&t);
+    if (ui_calendar_week_begins_on_monday())
+      days_to_remove = ((t.tm_wday == 0) ? WEEKINDAYS - 1 : t.tm_wday - 1);
+    else
+      days_to_remove = ((t.tm_wday == 0) ? 0 : t.tm_wday);
+    days_to_remove += (count - 1) * WEEKINDAYS;
+    ret = date_change(&t, 0, -days_to_remove);
+    break;
+  case WEEK_END:
+    mktime(&t);
+    if (ui_calendar_week_begins_on_monday())
+      days_to_add = ((t.tm_wday == 0) ? 0 : WEEKINDAYS - t.tm_wday);
+    else
+      days_to_add = ((t.tm_wday == 0) ?
+                     WEEKINDAYS - 1 : WEEKINDAYS - 1 - t.tm_wday);
+    days_to_add += (count - 1) * WEEKINDAYS;
+    ret = date_change(&t, 0, days_to_add);
+    break;
+  default:
+    ret = 1;
+    /* NOTREACHED */
+  }
+
+  if (ret == 0) {
+    if (t.tm_year < 2) {
+      t.tm_mday = 1;
+      t.tm_mon = 0;
+      t.tm_year = 2;
+    } else if (t.tm_year > 137) {
+      t.tm_mday = 31;
+      t.tm_mon = 11;
+      t.tm_year = 137;
+    }
+
+    slctd_day.dd = t.tm_mday;
+    slctd_day.mm = t.tm_mon + 1;
+    slctd_day.yyyy = t.tm_year + 1900;
+  }
+}
+
+/* Returns the beginning of current year as a long. */
+long ui_calendar_start_of_year(void)
+{
+  time_t timer;
+  struct tm tm;
+
+  timer = time(NULL);
+  localtime_r(&timer, &tm);
+  tm.tm_mon = 0;
+  tm.tm_mday = 1;
+  tm.tm_hour = 0;
+  tm.tm_min = 0;
+  tm.tm_sec = 0;
+  timer = mktime(&tm);
+
+  return (long)timer;
+}
+
+long ui_calendar_end_of_year(void)
+{
+  time_t timer;
+  struct tm tm;
+
+  timer = time(NULL);
+  localtime_r(&timer, &tm);
+  tm.tm_mon = 0;
+  tm.tm_mday = 1;
+  tm.tm_hour = 0;
+  tm.tm_min = 0;
+  tm.tm_sec = 0;
+  tm.tm_year++;
+  timer = mktime(&tm);
+
+  return (long)(timer - 1);
+}
+
+/*
+ * The pom, potm, dotr, adj360 are used to compute the current
+ * phase of the moon.
+ * The code is based on the OpenBSD version of pom(6).
+ * Below is reported the copyright notice.
+ */
+/*
+ * Copyright (c) 1989, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software posted to USENET.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * dtor --
+ *	convert degrees to radians
+ */
+static double dtor(double deg)
+{
+  return deg * M_PI / 180;
+}
+
+/*
+ * adj360 --
+ *	adjust value so 0 <= deg <= 360
+ */
+static void adj360(double *deg)
+{
+  for (;;)
+    if (*deg < 0.0)
+      *deg += 360.0;
+    else if (*deg > 360.0)
+      *deg -= 360.0;
+    else
+      break;
+}
+
+/*
+ * potm --
+ *	return phase of the moon
+ */
+static double potm(double days)
+{
+  double N, Msol, Ec, LambdaSol, l, Mm, Ev, Ac, A3, Mmprime;
+  double A4, lprime, V, ldprime, D, Nm;
+
+  N = 360.0 * days / 365.242191;        /* sec 46 #3 */
+  adj360(&N);
+  Msol = N + EPSILONg - RHOg;   /* sec 46 #4 */
+  adj360(&Msol);
+  Ec = 360 / M_PI * ECCEN * sin(dtor(Msol));    /* sec 46 #5 */
+  LambdaSol = N + Ec + EPSILONg;        /* sec 46 #6 */
+  adj360(&LambdaSol);
+  l = 13.1763966 * days + lzero;        /* sec 65 #4 */
+  adj360(&l);
+  Mm = l - (0.1114041 * days) - Pzero;  /* sec 65 #5 */
+  adj360(&Mm);
+  Nm = Nzero - (0.0529539 * days);      /* sec 65 #6 */
+  adj360(&Nm);
+  Ev = 1.2739 * sin(dtor(2 * (l - LambdaSol) - Mm));    /* sec 65 #7 */
+  Ac = 0.1858 * sin(dtor(Msol));        /* sec 65 #8 */
+  A3 = 0.37 * sin(dtor(Msol));
+  Mmprime = Mm + Ev - Ac - A3;  /* sec 65 #9 */
+  Ec = 6.2886 * sin(dtor(Mmprime));     /* sec 65 #10 */
+  A4 = 0.214 * sin(dtor(2 * Mmprime));  /* sec 65 #11 */
+  lprime = l + Ev + Ec - Ac + A4;       /* sec 65 #12 */
+  V = 0.6583 * sin(dtor(2 * (lprime - LambdaSol)));     /* sec 65 #13 */
+  ldprime = lprime + V;         /* sec 65 #14 */
+  D = ldprime - LambdaSol;      /* sec 67 #2 */
+  return 50.0 * (1 - cos(dtor(D)));     /* sec 67 #3 */
+}
+
+/*
+ * Phase of the Moon.  Calculates the current phase of the moon.
+ * Based on routines from `Practical Astronomy with Your Calculator',
+ * by Duffett-Smith.  Comments give the section from the book that
+ * particular piece of code was adapted from.
+ *
+ * -- Keith E. Brandt  VIII 1984
+ *
+ * Updated to the Third Edition of Duffett-Smith's book, IX 1998
+ *
+ */
+static double pom(time_t tmpt)
+{
+  struct tm *GMT;
+  double days;
+  int cnt;
+
+  GMT = gmtime(&tmpt);
+  days = (GMT->tm_yday + 1) + ((GMT->tm_hour + (GMT->tm_min / 60.0) +
+                                (GMT->tm_sec / 3600.0)) / 24.0);
+  for (cnt = EPOCH; cnt < GMT->tm_year; ++cnt)
+    days += ISLEAP(cnt + TM_YEAR_BASE) ? 366 : 365;
+  /* Selected time could be before EPOCH */
+  for (cnt = GMT->tm_year; cnt < EPOCH; ++cnt)
+    days -= ISLEAP(cnt + TM_YEAR_BASE) ? 366 : 365;
+
+  return potm(days);
+}
+
+/*
+ * Return a pictogram representing the current phase of the moon.
+ * Careful: date is the selected day in calendar at 00:00, so it represents
+ * the phase of the moon for previous day.
+ */
+const char *ui_calendar_get_pom(time_t date)
+{
+  const char *pom_pict[MOON_PHASES] = { "   ", "|) ", "(|)", "(| ", " | " };
+  enum pom phase = NO_POM;
+  double pom_today, relative_pom, pom_yesterday, pom_tomorrow;
+  const double half = 50.0;
+
+  pom_yesterday = pom(date);
+  pom_today = pom(date + DAYINSEC);
+  relative_pom = abs(pom_today - half);
+  pom_tomorrow = pom(date + 2 * DAYINSEC);
+  if (pom_today > pom_yesterday && pom_today > pom_tomorrow)
+    phase = FULL_MOON;
+  else if (pom_today < pom_yesterday && pom_today < pom_tomorrow)
+    phase = NEW_MOON;
+  else if (relative_pom < abs(pom_yesterday - half)
+           && relative_pom < abs(pom_tomorrow - half))
+    phase = (pom_tomorrow > pom_today) ? FIRST_QUARTER : LAST_QUARTER;
+
+  return pom_pict[phase];
+}