// This may look like C code, but it's really -*- C++ -*-

/*

 * Copyright (C) 2008 Emweb bv, Herent, Belgium.

 *

 * See the LICENSE file for terms of use.

 */

#ifndef WCALENDAR_H_

#define WCALENDAR_H_

#include <Wt/WCompositeWidget.h>

#include <Wt/WDate.h>

#include <set>

namespace Wt {

/*! \brief The calendar header format.

 */

enum class CalendarHeaderFormat {

  SingleLetterDayNames,  //!< First letter of a day (e.g. 'M' for Monday)

  ShortDayNames,         //!< First 3 letters of a day (e.g. 'Mon' for Monday)

  LongDayNames           //!< Full day name

    // NoHorizontalHeader  //No horizontal header (not yet implemented)

};

class WComboBox;

class WInPlaceEdit;

class WTemplate;

/*! \class WCalendar Wt/WCalendar.h Wt/WCalendar.h

 *  \brief A calendar.

 *

 * The calendar provides navigation by month and year, and indicates the

 * current day.

 *

 * You can listen for single click or double click events on a

 * calendar cell using the clicked() and activated() methods.

 *

 * The calendar may be configured to allow selection of single or

 * multiple days using setSelectionMode(), and you may listen for

 * changes in the selection using the selectionChanged()

 * signals. Selection can also be entirely disabled in which case you

 * can implement your own selection handling by listening for cell

 * click events.

 *

 * Cell rendering may be customized by reimplementing renderCell().

 *

 * Internationalization is provided by the internationalization

 * features of the Wt::WDate class.

 *

 * \if cpp

 * Usage example:

 * \code

 * Wt::WDate today = Wt::WDate::currentDate();

 *

 * Wt::WCalendar *calendar = addWidget(std::make_unique<Wt::WCalendar>());

 * calendar->browseTo(today.addMonths(1));

 * calendar->select(today.addMonths(1).addDays(3));

 * calendar->selected().connect(this, &MyWidget::daySelected);

 * \endcode

 * \endif

 *

 * Here is a snapshot, taken on 19/01/2010 (shown as

 * today), and 14/01/2010 currently selected.

 * <TABLE border="0" align="center"> <TR> <TD>

 * \image html WCalendar-default-1.png "WCalendar with default look"

 * </TD> <TD>

 * \image html WCalendar-polished-1.png "WCalendar with polished look"

 * </TD> </TR> </TABLE>

 *

 */

class WT_API WCalendar : public WCompositeWidget

{

public:

  /*! \brief Typedef for enum Wt::CalendarHeaderFormat */

  typedef CalendarHeaderFormat HeaderFormat;

  /*! \brief Creates a new calendar.

   *

   * Constructs a new calendar with English day/month names.  The

   * calendar shows the current day, and has an empty selection.

   */

  WCalendar();

  /*! \brief Sets the selection mode.

   *

   * The default selection mode is

   * \link Wt::SingleSelection SingleSelection\endlink.

   */

  void setSelectionMode(SelectionMode mode);

  /*! \brief Browses to the same month in the previous year.

   *

   * Displays the same month in the previous year. This does not

   * affect the selection.

   *

   * This will emit the currentPageChanged() singal.

   */

  void browseToPreviousYear();

  /*! \brief Browses to the previous month.

   *

   * Displays the previous month. This does not affect the selection.

   *

   * This will emit the currentPageChanged() singal.

   */

  void browseToPreviousMonth();

  /*! \brief Browses to the same month in the next year.

   *

   * Displays the same month in the next year. This does not change

   * the current selection.

   *

   * This will emit the currentPageChanged() singal.

   */

  void browseToNextYear();

  /*! \brief Browses to the next month.

   *

   * Displays the next month. This does not change the current selection.

   *

   * This will emit the currentPageChanged() singal.

   */

  void browseToNextMonth();

  /*! \brief Browses to a date.

   *

   * Displays the month which contains the given date. This does not change

   * the current selection.

   *

   * This will emit the currentPageChanged() signal if another month

   * is displayed.

   */

  void browseTo(const WDate& date);

  /*! \brief Returns the current month displayed

   *

   * Returns the month (1-12) that is currently displayed.

   */

  int currentMonth() const { return currentMonth_; }

  /*! \brief Returns the current year displayed

   *

   * Returns the year that is currently displayed.

   */

  int currentYear() const { return currentYear_; }

  /*! \brief Clears the current selection.

   *

   * Clears the current selection. Will result in a selection() that is

   * empty().

   */

  void clearSelection();

  /*! \brief Selects a date.

   *

   * Select one date. Both in single or multiple selection mode, this results

   * in a selection() that contains exactly one date.

   */

  void select(const WDate& date);

  /*! \brief Selects multiple dates.

   *

   * Select multiple dates. In multiple selection mode, this results

   * in a selection() that contains exactly the given dates. In single

   * selection mode, at most one date is set.

   */

  void select(const std::set<WDate>& dates);

  /*! \brief Sets the horizontal header format.

   *

   * The default horizontal header format is CalendarHeaderFormat::ShortDayNames.

   */

  void setHorizontalHeaderFormat(CalendarHeaderFormat format);

  /*! \brief Returns the horizontal header format.

   *

   * \sa setHorizontalHeaderFormat()

   */

  CalendarHeaderFormat horizontalHeaderFormat() {

    return horizontalHeaderFormat_;

  }

  /*! \brief Sets the first day of the week.

   *

   * Possible values are 1 to 7. The default value is 1 ("Monday").

   */

  void setFirstDayOfWeek(int dayOfWeek);

  /*! \brief Returns the current selection.

   *

   * Returns the set of dates currently selected. In single selection mode,

   * this set contains 0 or 1 dates.

   */

  const std::set<WDate>& selection() const { return selection_; }

  /*! \brief %Signal emitted when the user changes the selection.

   *

   * Emitted after the user has changed the current selection.

   */

  Signal<>& selectionChanged() { return selectionChanged_; }

  /*! \brief %Signal emitted when the user double-clicks a date.

   *

   * You may want to connect to this signal to treat a double click

   * as the selection of a date.

   */

  Signal<WDate>& activated() { return activated_; }

  /*! \brief %Signal emitted when the user clicks a date.

   *

   * You may want to connect to this signal if you want to provide a

   * custom selection handling.

   */

  Signal<WDate>& clicked() { return clicked_; }

  /*! \brief %Signal emitted when the current month is changed.

   *

   * The method is emitted both when the change is done through the

   * user interface or via the public API. The two parameters are

   * respectively the new year and month.

   */

  Signal<int, int>& currentPageChanged() { return currentPageChanged_; }

  /*! \brief Configures the calendar to use single click for activation

   *

   * By default, double click will trigger activate(). Use this method

   * if you want a single click to trigger activate() (and the now

   * deprecated selected() method). This only applies to a

   * single-selection calendar.

   *

   * If selectionMode() is set to \link Wt::SingleSelection SingleSelection\endlink,

   * this will cause the selection to change on a single click instead of a double click.

   *

   * Instead of enabling single click, you can also listen to the clicked()

   * signal to process a single click.

   *

   * \sa setSelectionMode()

   */

  void setSingleClickSelect(bool single);

  /*! \brief Sets the bottom of the valid date range.

   *

   * \if cpp

   * The default is a null date constructed using WDate().

   * \elseif java

   * The default bottom is null.

   * \endif

   */

  void setBottom(const WDate& bottom);

  /*! \brief Returns the bottom date of the valid range.

   */

  const WDate& bottom() const { return bottom_; }

  /*! \brief Sets the top of the valid date range.

   *

   * \if cpp

   * The default is a null date constructed using WDate().

   * \elseif java

   * The default top is null.

   * \endif

   */

  void setTop(const WDate& top);

  /*! \brief Returns the top date of the valid range.

   */

  const WDate& top() const { return top_; }

  virtual void load() override;

protected:

  virtual void render(WFlags<RenderFlag> renderFlags) override;

  /*! \brief Creates or updates a widget that renders a cell.

   *

   * The default implementation creates a WText

   *

   * You may want to reimplement this method if you wish to customize

   * how a cell is rendered. When \p widget is \c 0, a new widget

   * should be created and returned. Otherwise, you may either modify

   * the passed \p widget, or return a new widget. If you return a new

   * widget, the prevoius widget will be deleted.

   */

  virtual WWidget* renderCell(WWidget* widget, const WDate& date);

  /*! \brief Returns whether a date is selected.

   *

   * This is a convenience method that can be used when reimplementing

   * renderCell().

   */

  bool isSelected(const WDate& date) const;

  virtual void enableAjax() override;

private:

  SelectionMode     selectionMode_;

  bool              singleClickSelect_;

  int               currentYear_;

  int               currentMonth_;

  CalendarHeaderFormat horizontalHeaderFormat_;

  int               firstDayOfWeek_;

  std::set<WDate>   selection_;

  bool              needRenderMonth_;

  Signal<>          selectionChanged_;

  Signal<WDate>     activated_;

  Signal<WDate>     clicked_;

  Signal<int, int>  currentPageChanged_;

  WDate             bottom_, top_;

  struct Coordinate {

    int i, j;

    Coordinate() : i(0), j(0) { }

    Coordinate(int x, int y) { i = x; j = y; }

  };

  WTemplate *impl_;

  WComboBox *monthEdit_;

  WInPlaceEdit *yearEdit_;

  void create();

  void renderMonth();

  void emitCurrentPageChanged();

  void monthChanged(int newMonth);

  void yearChanged(WString newYear);

  WDate dateForCell(int week, int dayOfWeek);

  void selectInCurrentMonth(const WDate& d);

  bool isInvalid(const WDate& d);

  void cellClicked(Coordinate c);

  void cellDblClicked(Coordinate c);

};

}

#endif // WCALENDAR_H_