/* Monolith calendar widget.
 * - by Richard W.M. Jones <rich@annexia.org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id: ml_calendar_month.c,v 1.9 2003/02/22 15:34:26 rich Exp $
 */

#include "config.h"

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

#ifdef HAVE_TIME_H
#include <time.h>
#endif

#ifdef HAVE_STRING_H
#include <string.h>
#endif

#include <pool.h>
#include <vector.h>
#include <pstring.h>

#include <pthr_dbi.h>

#include <monolith.h>
#include <ml_widget.h>
#include <ml_button.h>
#include <ml_text_label.h>
#include <ml_table_layout.h>

#include "ml_calendar_lib.h"
#include "ml_calendar_month.h"

static void repaint (void *, ml_session, const char *, io_handle);

struct ml_widget_operations calendar_month_ops =
  {
    repaint: repaint
  };

struct ml_calendar_month
{
  struct ml_widget_operations *ops;
  pool pool;			/* Pool for allocations. */
  ml_session session;		/* Current session. */
  const char *conninfo;		/* Database connection. */
  ml_calendar calendar;		/* Parent calendar. */
  int yyyy, mm, dd;		/* Current date. */

  ml_table_layout tbl;		/* Top-level table layout. */
  ml_text_label days[7];	/* Days of the week labels. */
  ml_button b[32];		/* Buttons (we reuse these). */
};

/* This structure is passed to the button callbacks. */
struct button_data
{
  int dd;			/* Day (1 - 31). */
  ml_calendar_month w;		/* Widget pointer. */
};

static void button_press (ml_session, void *);
static void update_buttons (ml_calendar_month w);

ml_calendar_month
new_ml_calendar_month (pool pool, ml_session session, const char *conninfo,
		       ml_calendar calendar)
{
  ml_calendar_month w = pmalloc (pool, sizeof *w);
  int i, j;
  struct button_data *data;

  w->ops = &calendar_month_ops;
  w->pool = pool;
  w->session = session;
  w->conninfo = conninfo;
  w->calendar = calendar;

  /* The parent calendar must call ml_calendar_month_set_date to set these
   * before using this widget.
   */
  w->yyyy = w->mm = w->dd = -1;

  /* Create the days of the week labels and buttons. */
  /* XXX Waiting for ml_text_label and ml_button to give us more control
   * over the rendering of labels and buttons.
   */
  w->days[0] = new_ml_text_label (pool, "Su");
  ml_widget_set_property (w->days[0], "font.weight", "bold");
  w->days[1] = new_ml_text_label (pool, "Mo");
  ml_widget_set_property (w->days[1], "font.weight", "bold");
  w->days[2] = new_ml_text_label (pool, "Tu");
  ml_widget_set_property (w->days[2], "font.weight", "bold");
  w->days[3] = new_ml_text_label (pool, "We");
  ml_widget_set_property (w->days[3], "font.weight", "bold");
  w->days[4] = new_ml_text_label (pool, "Th");
  ml_widget_set_property (w->days[4], "font.weight", "bold");
  w->days[5] = new_ml_text_label (pool, "Fr");
  ml_widget_set_property (w->days[5], "font.weight", "bold");
  w->days[6] = new_ml_text_label (pool, "Sa");
  ml_widget_set_property (w->days[6], "font.weight", "bold");

  w->b[0] = 0;			/* This is a dummy entry. */

  for (i = 1; i <= 31; ++i)
    {
      data = pmalloc (pool, sizeof *data);
      w->b[i] = new_ml_button (pool, pitoa (pool, i));
      data->dd = i;
      data->w = w;
      ml_button_set_callback (w->b[i], button_press, session, data);
    }

  /* Create the top-level table widget, also reused. */
  w->tbl = new_ml_table_layout (pool, 7, 7);
  for (i = 0; i < 7; ++i)
    {
      ml_table_layout_pack (w->tbl, w->days[i], 0, i);
      ml_table_layout_set_align (w->tbl, 0, i, "center");
    }
  for (j = 1; j < 7; ++j)
    for (i = 0; i < 7; ++i)
      ml_table_layout_set_align (w->tbl, j, i, "right");

  return w;
}

/* Update the date, then update the widget. */
void
ml_calendar_month_set_date (ml_calendar_month w, int yyyy, int mm, int dd)
{
  int j, i, d, n;

  /* Update the date. */
  w->yyyy = yyyy;
  w->mm = mm;
  w->dd = dd;

  /* Clear the existing table of widgets. */
  for (j = 1; j < 7; ++j)
    for (i = 0; i < 7; ++i)
      ml_table_layout_pack (w->tbl, 0, j, i);

  /* Redraw the month. */
  j = 1;
  i = _ml_calendar_first_wday_of_month (mm, yyyy);
  n = _ml_calendar_days_in_month (mm, yyyy);

  for (d = 1; d <= n; ++d)
    {
      ml_table_layout_pack (w->tbl, w->b[d], j, i);
      i++;
      if (i == 7)
	{
	  i = 0;
	  j++;
	}
    }

  /* Update buttons from the database. */
  update_buttons (w);
}

/* This function is called when a button is pressed. */
static void
button_press (ml_session session, void *vdata)
{
  struct button_data *data = (struct button_data *) vdata;

  /* This function, in the parent calendar, will eventually call our
   * ml_calendar_month_set_date.
   */
  ml_calendar_set_date (data->w->calendar,
			data->w->yyyy, data->w->mm, data->dd);
}

/* This function updates the state of the buttons from the database,
 * and also highlights the currently selected day.
 */
static void
update_buttons (ml_calendar_month w)
{
  db_handle dbh;
  st_handle sth;
  unsigned char flags[32];
  int dd;
  const vector resids = _ml_calendar_get_calendars (w->calendar);

  dbh = get_db_handle (w->conninfo, DBI_THROW_ERRORS);

  /* Find out which days contain data. Note how with PostgreSQL we
   * can leave the database to take the strain of date munging. This
   * is one of the great reasons to use and recommend PostgreSQL.
   */
  sth = st_prepare_cached
    (dbh,
     "select date_part ('day', start_time) from ml_calendar_events "
     " where resid in (@) "
     "   and start_time >= date (? || '/' || ? || '/01') "
     "   and start_time <  (date (? || '/' || ? || '/01') + "
     "                      interval '1 month')",
     DBI_VECTOR_INT, DBI_INT, DBI_INT, DBI_INT, DBI_INT);
  st_execute (sth, resids, w->yyyy, w->mm, w->yyyy, w->mm);

  st_bind (sth, 0, dd, DBI_INT);

  memset (flags, 0, sizeof flags);

  while (st_fetch (sth))
    {
      assert (0 < dd && dd < 32);
      flags[dd] |= 1;
    }

  flags[w->dd] |= 2;

  /* Depending on the flags, we now set the class of each button. */
  for (dd = 1; dd <= 31; ++dd)
    {
      switch (flags[dd]) {
      case 0:
	ml_widget_set_property (w->b[dd], "class", "ml_calendar_day");
	break;
      case 1:
	ml_widget_set_property (w->b[dd], "class", "ml_calendar_day_events");
	break;
      case 2:
	ml_widget_set_property (w->b[dd], "class", "ml_calendar_day_selected");
	break;
      case 3:
	ml_widget_set_property (w->b[dd], "class",
				"ml_calendar_day_events_selected");
	break;
      }
    }

  put_db_handle (dbh);
}

static void
repaint (void *vw, ml_session session, const char *windowid, io_handle io)
{
  ml_calendar_month w = (ml_calendar_month) vw;

  ml_widget_repaint (w->tbl, session, windowid, io);
}