text: /**
   * @file lv_calendar.c
   *
   */
  
  /*********************
   *      INCLUDES
   *********************/
  #include "lv_calendar.h"
  #if USE_LV_CALENDAR != 0
  
  #include "../lv_draw/lv_draw.h"
  #include "../lv_hal/lv_hal_indev.h"
  #include "../lv_misc/lv_math.h"
  #include "../lv_core/lv_indev.h"
  #include "../lv_themes/lv_theme.h"
  #include <string.h>
  
  /*********************
   *      DEFINES
   *********************/
  
  /**********************
   *      TYPEDEFS
   **********************/
  enum {
      DAY_DRAW_PREV_MONTH,
      DAY_DRAW_ACT_MONTH,
      DAY_DRAW_NEXT_MONTH,
  };
  typedef uint8_t day_draw_state_t;
  
  /**********************
   *  STATIC PROTOTYPES
   **********************/
  static bool lv_calendar_design(lv_obj_t * calendar, const lv_area_t * mask, lv_design_mode_t mode);
  static lv_res_t lv_calendar_signal(lv_obj_t * calendar, lv_signal_t sign, void * param);
  static bool calculate_touched_day(lv_obj_t * calendar, const lv_point_t * touched_point);
  static lv_coord_t get_header_height(lv_obj_t * calendar);
  static lv_coord_t get_day_names_height(lv_obj_t * calendar);
  static void draw_header(lv_obj_t * calendar, const lv_area_t * mask);
  static void draw_day_names(lv_obj_t * calendar, const lv_area_t * mask);
  static void draw_days(lv_obj_t * calendar, const lv_area_t * mask);
  static uint8_t get_day_of_week(uint32_t year, uint32_t month, uint32_t day);
  static bool is_highlighted(lv_obj_t * calendar, int32_t year, int32_t month, int32_t day);
  static const char * get_day_name(lv_obj_t * calendar, uint8_t day);
  static const char * get_month_name(lv_obj_t * calendar, int32_t month);
  static uint8_t get_month_length(int32_t year, int32_t month);
  static uint8_t is_leap_year(uint32_t year);
  
  
  /**********************
   *  STATIC VARIABLES
   **********************/
  static lv_signal_func_t ancestor_signal;
  static lv_design_func_t ancestor_design;
  static const char * day_name[7] = {"Su", "Mo", "Tu", "We", "Th", "Fr", "Sa"};
  static const char * month_name[12] = {"January",   "February",   "March",    "April",
          "May",       "June",       "July",     "August",
          "September", "October",    "November", "December"
  };
  
  /**********************
   *      MACROS
   **********************/
  
  /**********************
   *   GLOBAL FUNCTIONS
   **********************/
  
  /**
   * Create a calendar object
   * @param par pointer to an object, it will be the parent of the new calendar
   * @param copy pointer to a calendar object, if not NULL then the new object will be copied from it
   * @return pointer to the created calendar
   */
  lv_obj_t * lv_calendar_create(lv_obj_t * par, const lv_obj_t * copy)
  {
      LV_LOG_TRACE("calendar create started");
  
      /*Create the ancestor of calendar*/
      lv_obj_t * new_calendar = lv_obj_create(par, copy);
      lv_mem_assert(new_calendar);
      if(new_calendar == NULL) return NULL;
  
      /*Allocate the calendar type specific extended data*/
      lv_calendar_ext_t * ext = lv_obj_allocate_ext_attr(new_calendar, sizeof(lv_calendar_ext_t));
      lv_mem_assert(ext);
      if(ext == NULL) return NULL;
      if(ancestor_signal == NULL) ancestor_signal = lv_obj_get_signal_func(new_calendar);
      if(ancestor_design == NULL) ancestor_design = lv_obj_get_design_func(new_calendar);
  
      /*Initialize the allocated 'ext' */
      ext->today.year = 2018;
      ext->today.month = 1;
      ext->today.day = 1;
  
      ext->showed_date.year = 2018;
      ext->showed_date.month = 1;
      ext->showed_date.day = 1;
  
      ext->pressed_date.year = 0;
      ext->pressed_date.month = 0;
      ext->pressed_date.day = 0;
  
      ext->highlighted_dates  = NULL;
      ext->highlighted_dates_num = 0;
      ext->day_names = NULL;
      ext->month_names = NULL;
      ext->actions[LV_CALENDAR_ACTION_PR] = NULL;
      ext->actions[LV_CALENDAR_ACTION_CLICK] = NULL;
      ext->actions[LV_CALENDAR_ACTION_LONG_PR] = NULL;
      ext->actions[LV_CALENDAR_ACTION_LONG_PR_REPEAT] = NULL;
      ext->style_header = &lv_style_plain_color;
      ext->style_header_pr = &lv_style_pretty_color;
      ext->style_highlighted_days = &lv_style_plain_color;
      ext->style_inactive_days = &lv_style_btn_ina;
      ext->style_week_box = &lv_style_plain_color;
      ext->style_today_box = &lv_style_pretty_color;
      ext->style_day_names = &lv_style_pretty;
  
      /*The signal and design functions are not copied so set them here*/
      lv_obj_set_signal_func(new_calendar, lv_calendar_signal);
      lv_obj_set_design_func(new_calendar, lv_calendar_design);
  
      /*Init the new calendar calendar*/
      if(copy == NULL) {
          lv_obj_set_size(new_calendar, LV_DPI * 2, LV_DPI * 2);
          lv_obj_set_style(new_calendar, &lv_style_pretty);
  
          lv_theme_t * th = lv_theme_get_current();
          if(th) {
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_BG, th->calendar.bg);
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_HEADER, th->calendar.header);
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_HEADER_PR, th->calendar.header_pr);
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_DAY_NAMES, th->calendar.day_names);
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_WEEK_BOX, th->calendar.week_box);
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_TODAY_BOX, th->calendar.today_box);
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_HIGHLIGHTED_DAYS, th->calendar.highlighted_days);
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_INACTIVE_DAYS, th->calendar.inactive_days);
          } else {
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_BG, &lv_style_pretty);
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_HEADER, ext->style_header);
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_HEADER_PR, ext->style_header_pr);
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_DAY_NAMES, ext->style_day_names);
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_WEEK_BOX, ext->style_week_box);
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_TODAY_BOX, ext->style_today_box);
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_HIGHLIGHTED_DAYS, ext->style_highlighted_days);
              lv_calendar_set_style(new_calendar, LV_CALENDAR_STYLE_INACTIVE_DAYS, ext->style_inactive_days);
  
          }
  
      }
      /*Copy an existing calendar*/
      else {
          lv_calendar_ext_t * copy_ext = lv_obj_get_ext_attr(copy);
          ext->today.year = copy_ext->today.year;
          ext->today.month = copy_ext->today.month;
          ext->today.day = copy_ext->today.day;
  
          ext->showed_date.year = copy_ext->showed_date.year;
          ext->showed_date.month = copy_ext->showed_date.month;
          ext->showed_date.day = copy_ext->showed_date.day;
  
          ext->highlighted_dates  = copy_ext->highlighted_dates;
          ext->highlighted_dates_num = copy_ext->highlighted_dates_num;
          ext->day_names = copy_ext->day_names;
  
          memcpy(ext->actions, copy_ext->actions, sizeof(ext->actions));
  
          ext->month_names = copy_ext->month_names;
          ext->style_header = copy_ext->style_header;
          ext->style_header_pr = copy_ext->style_header_pr;
          ext->style_highlighted_days = copy_ext->style_highlighted_days;
          ext->style_inactive_days = copy_ext->style_inactive_days;
          ext->style_week_box = copy_ext->style_week_box;
          ext->style_today_box = copy_ext->style_today_box;
          ext->style_day_names = copy_ext->style_day_names;
          /*Refresh the style with new signal function*/
          lv_obj_refresh_style(new_calendar);
      }
  
      LV_LOG_INFO("calendar created");
  
      return new_calendar;
  }
  
  /*======================
   * Add/remove functions
   *=====================*/
  
  /*
   * New object specific "add" or "remove" functions come here
   */
  
  
  /*=====================
   * Setter functions
   *====================*/
  
  /**
   * Set a function to call when a calendar event happens
   * @param calendar pointer to a calendar object
   * @param action type of event form 'lv_action_t' (press, release, long press, long press repeat)
   */
  void lv_calendar_set_action(lv_obj_t * calendar, lv_calendar_action_t type, lv_action_t action)
  {
      if(type >= LV_CALENDAR_ACTION_NUM) return;
  
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      ext->actions[type] = action;
  }
  
  /**
   * Set the today's date
   * @param calendar pointer to a calendar object
   * @param today pointer to an `lv_calendar_date_t` variable containing the date of today. The value will be saved it can be local variable too.
   */
  void lv_calendar_set_today_date(lv_obj_t * calendar, lv_calendar_date_t * today)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      ext->today.year = today->year;
      ext->today.month = today->month;
      ext->today.day = today->day;
  
      lv_obj_invalidate(calendar);
  }
  
  /**
   * Set the currently showed
   * @param calendar pointer to a calendar object
   * @param showed pointer to an `lv_calendar_date_t` variable containing the date to show. The value will be saved it can be local variable too.
   */
  void lv_calendar_set_showed_date(lv_obj_t * calendar, lv_calendar_date_t * showed)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      ext->showed_date.year = showed->year;
      ext->showed_date.month = showed->month;
      ext->showed_date.day = showed->day;
  
      lv_obj_invalidate(calendar);
  }
  
  /**
   * Set the the highlighted dates
   * @param calendar pointer to a calendar object
   * @param highlighted pointer to an `lv_calendar_date_t` array containing the dates. ONLY A POINTER WILL BE SAVED! CAN'T BE LOCAL ARRAY.
   * @param date_num number of dates in the array
   */
  void lv_calendar_set_highlighted_dates(lv_obj_t * calendar, lv_calendar_date_t * highlighted, uint16_t date_num)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      ext->highlighted_dates = highlighted;
      ext->highlighted_dates_num = date_num;
  
      lv_obj_invalidate(calendar);
  }
  
  
  /**
   * Set the name of the days
   * @param calendar pointer to a calendar object
   * @param day_names pointer to an array with the names. E.g. `const char * days[7] = {"Sun", "Mon", ...}`
   *                  Only the pointer will be saved so this variable can't be local which will be destroyed later.
   */
  void lv_calendar_set_day_names(lv_obj_t * calendar, const char ** day_names)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      ext->day_names = day_names;
      lv_obj_invalidate(calendar);
  }
  
  /**
   * Set the name of the month
   * @param calendar pointer to a calendar object
   * @param day_names pointer to an array with the names. E.g. `const char * days[12] = {"Jan", "Feb", ...}`
   *                  Only the pointer will be saved so this variable can't be local which will be destroyed later.
   */
  void lv_calendar_set_month_names(lv_obj_t * calendar, const char ** day_names)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      ext->month_names = day_names;
      lv_obj_invalidate(calendar);
  }
  
  /**
   * Set a style of a calendar.
   * @param calendar pointer to calendar object
   * @param type which style should be set
   * @param style pointer to a style
   *  */
  void lv_calendar_set_style(lv_obj_t * calendar, lv_calendar_style_t type, lv_style_t * style)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
  
      switch(type) {
      case LV_CALENDAR_STYLE_BG:
          lv_obj_set_style(calendar, style);
          break;
      case LV_CALENDAR_STYLE_DAY_NAMES:
          ext->style_day_names = style;
          break;
      case LV_CALENDAR_STYLE_HEADER:
          ext->style_header = style;
          break;
      case LV_CALENDAR_STYLE_HEADER_PR:
          ext->style_header_pr = style;
          break;
      case LV_CALENDAR_STYLE_HIGHLIGHTED_DAYS:
          ext->style_highlighted_days = style;
          break;
      case LV_CALENDAR_STYLE_INACTIVE_DAYS:
          ext->style_inactive_days = style;
          break;
      case LV_CALENDAR_STYLE_TODAY_BOX:
          ext->style_today_box = style;
          break;
      case LV_CALENDAR_STYLE_WEEK_BOX:
          ext->style_week_box = style;
          break;
      }
  
      lv_obj_invalidate(calendar);
  }
  
  /*=====================
   * Getter functions
   *====================*/
  
  /**
   * Get the action of a calendar
   * @param calendar pointer to a calendar object
   * @return pointer to the action function
   */
  lv_action_t lv_calendar_get_action(const lv_obj_t * calendar, lv_calendar_action_t type)
  {
      if(type >= LV_CALENDAR_ACTION_NUM) return NULL;
  
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      return ext->actions[type];
  }
  
  /**
   * Get the today's date
   * @param calendar pointer to a calendar object
   * @return return pointer to an `lv_calendar_date_t` variable containing the date of today.
   */
  lv_calendar_date_t * lv_calendar_get_today_date(const lv_obj_t * calendar)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      return &ext->today;
  }
  
  /**
   * Get the currently showed
   * @param calendar pointer to a calendar object
   * @return pointer to an `lv_calendar_date_t` variable containing the date is being shown.
   */
  lv_calendar_date_t * lv_calendar_get_showed_date(const lv_obj_t * calendar)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      return &ext->showed_date;
  }
  
  /**
   * Get the the pressed date.
   * @param calendar pointer to a calendar object
   * @return pointer to an `lv_calendar_date_t` variable containing the pressed date.
   */
  lv_calendar_date_t * lv_calendar_get_pressed_date(const lv_obj_t * calendar)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      return &ext->pressed_date;
  }
  
  /**
   * Get the the highlighted dates
   * @param calendar pointer to a calendar object
   * @return pointer to an `lv_calendar_date_t` array containing the dates.
   */
  lv_calendar_date_t * lv_calendar_get_highlighted_dates(const lv_obj_t * calendar)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      return ext->highlighted_dates;
  }
  
  /**
   * Get the number of the highlighted dates
   * @param calendar pointer to a calendar object
   * @return number of highlighted days
   */
  uint16_t lv_calendar_get_highlighted_dates_num(const lv_obj_t * calendar)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      return ext->highlighted_dates_num;
  }
  
  /**
   * Get the name of the days
   * @param calendar pointer to a calendar object
   * @return pointer to the array of day names
   */
  const char ** lv_calendar_get_day_names(const lv_obj_t * calendar)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      return ext->day_names;
  }
  
  /**
   * Get the name of the month
   * @param calendar pointer to a calendar object
   * @return pointer to the array of month names
   */
  const char ** lv_calendar_get_month_names(const lv_obj_t * calendar)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      return ext->month_names;
  }
  
  /**
   * Get style of a calendar.
   * @param calendar pointer to calendar object
   * @param type which style should be get
   * @return style pointer to the style
   *  */
  lv_style_t * lv_calendar_get_style(const lv_obj_t * calendar, lv_calendar_style_t type)
  {
      lv_style_t * style = NULL;
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
  
      switch(type) {
          case LV_CALENDAR_STYLE_BG:
              style = lv_obj_get_style(calendar);
              break;
          case LV_CALENDAR_STYLE_HEADER:
              style = ext->style_header;
              break;
          case LV_CALENDAR_STYLE_HEADER_PR:
              style = ext->style_header_pr;
              break;
          case LV_CALENDAR_STYLE_DAY_NAMES:
              style = ext->style_day_names;
              break;
          case LV_CALENDAR_STYLE_HIGHLIGHTED_DAYS:
              style = ext->style_highlighted_days;
              break;
          case LV_CALENDAR_STYLE_INACTIVE_DAYS:
              style = ext->style_inactive_days;
              break;
          case LV_CALENDAR_STYLE_WEEK_BOX:
              style = ext->style_week_box;
              break;
          case LV_CALENDAR_STYLE_TODAY_BOX:
              style = ext->style_today_box;
              break;
          default:
              style = NULL;
              break;
      }
  
      return style;
  }
  
  /*=====================
   * Other functions
   *====================*/
  
  /*
   * New object specific "other" functions come here
   */
  
  /**********************
   *   STATIC FUNCTIONS
   **********************/
  
  /**
   * Handle the drawing related tasks of the calendars
   * @param calendar pointer to an object
   * @param mask the object will be drawn only in this area
   * @param mode LV_DESIGN_COVER_CHK: only check if the object fully covers the 'mask_p' area
   *                                  (return 'true' if yes)
   *             LV_DESIGN_DRAW: draw the object (always return 'true')
   *             LV_DESIGN_DRAW_POST: drawing after every children are drawn
   * @param return true/false, depends on 'mode'
   */
  static bool lv_calendar_design(lv_obj_t * calendar, const lv_area_t * mask, lv_design_mode_t mode)
  {
      /*Return false if the object is not covers the mask_p area*/
      if(mode == LV_DESIGN_COVER_CHK) {
          return false;
      }
      /*Draw the object*/
      else if(mode == LV_DESIGN_DRAW_MAIN) {
          lv_opa_t opa_scale = lv_obj_get_opa_scale(calendar);
          lv_draw_rect(&calendar->coords, mask, lv_calendar_get_style(calendar, LV_CALENDAR_STYLE_BG), opa_scale);
  
          draw_header(calendar, mask);
          draw_day_names(calendar, mask);
          draw_days(calendar, mask);
  
      }
      /*Post draw when the children are drawn*/
      else if(mode == LV_DESIGN_DRAW_POST) {
  
      }
  
      return true;
  }
  
  /**
   * Signal function of the calendar
   * @param calendar pointer to a calendar object
   * @param sign a signal type from lv_signal_t enum
   * @param param pointer to a signal specific variable
   * @return LV_RES_OK: the object is not deleted in the function; LV_RES_INV: the object is deleted
   */
  static lv_res_t lv_calendar_signal(lv_obj_t * calendar, lv_signal_t sign, void * param)
  {
      lv_res_t res;
  
      /* Include the ancient signal function */
      res = ancestor_signal(calendar, sign, param);
      if(res != LV_RES_OK) return res;
  
  
      if(sign == LV_SIGNAL_CLEANUP) {
          /*Nothing to cleanup. (No dynamically allocated memory in 'ext')*/
      } else if(sign == LV_SIGNAL_PRESSED) {
          lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
          /*Call the press action, 'param' is the caller indev_proc*/
          if(ext->actions[LV_CALENDAR_ACTION_PR]) {
              lv_indev_t * indev = lv_indev_get_act();
              lv_point_t p;
              lv_indev_get_point(indev, &p);
  
              if(calculate_touched_day(calendar, &p)){
                  if(ext->btn_pressing != 0) lv_obj_invalidate(calendar);
                  ext->btn_pressing = 0;
                  res = ext->actions[LV_CALENDAR_ACTION_PR](calendar);
              }
          }
      } else if(sign == LV_SIGNAL_PRESSING) {
          lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
          lv_area_t header_area;
          lv_area_copy(&header_area, &calendar->coords);
          header_area.y2 = header_area.y1 + get_header_height(calendar);
  
          lv_indev_t * indev = lv_indev_get_act();
          lv_point_t p;
          lv_indev_get_point(indev, &p);
  
          if(lv_area_is_point_on(&header_area, &p)) {
              if(p.x < header_area.x1 + lv_area_get_width(&header_area) / 2) {
                  if(ext->btn_pressing != -1) lv_obj_invalidate(calendar);
                  ext->btn_pressing = -1;
              } else {
                  if(ext->btn_pressing != 1) lv_obj_invalidate(calendar);
                  ext->btn_pressing = 1;
              }
  
              ext->pressed_date.year = 0;
          } else if(calculate_touched_day(calendar, &p)) {
              if(ext->btn_pressing != 0) lv_obj_invalidate(calendar);
              ext->btn_pressing = 0;
          } else {
              if(ext->btn_pressing != 0) lv_obj_invalidate(calendar);
              ext->btn_pressing = 0;
              ext->pressed_date.year = 0;
          }
      } else if(sign == LV_SIGNAL_PRESS_LOST) {
          lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
          ext->pressed_date.year = 0;
          ext->btn_pressing = 0;
          lv_obj_invalidate(calendar);
  
      } else if(sign == LV_SIGNAL_RELEASED) {
          lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
          if(ext->btn_pressing < 0) {
              if(ext->showed_date.month <= 1) {
                  ext->showed_date.month = 12;
                  ext->showed_date.year --;
              } else {
                  ext->showed_date.month --;
              }
          } else if(ext->btn_pressing >  0) {
              if(ext->showed_date.month >= 12) {
                  ext->showed_date.month = 1;
                  ext->showed_date.year ++;
              } else {
                  ext->showed_date.month ++;
              }
          }
          else if(ext->pressed_date.year != 0)
          {
              if(ext->actions[LV_CALENDAR_ACTION_CLICK]) {
                  res = ext->actions[LV_CALENDAR_ACTION_CLICK](calendar);
              }
          }
  
          ext->pressed_date.year = 0;
          ext->btn_pressing = 0;
          lv_obj_invalidate(calendar);
  
  
      } else if(sign == LV_SIGNAL_LONG_PRESS) {
          lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
          if(ext->actions[LV_CALENDAR_ACTION_LONG_PR] && (ext->pressed_date.year != 0)) {
              res = ext->actions[LV_CALENDAR_ACTION_LONG_PR](calendar);
          }
      } else if(sign == LV_SIGNAL_LONG_PRESS_REP) {
          lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
          if(ext->actions[LV_CALENDAR_ACTION_LONG_PR_REPEAT] && (ext->pressed_date.year != 0)) {
              res = ext->actions[LV_CALENDAR_ACTION_LONG_PR_REPEAT](calendar);
          }
      } else if(sign == LV_SIGNAL_CONTROLL) {
          uint8_t c = *((uint8_t *) param);
          lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
          if(c == LV_GROUP_KEY_RIGHT || c == LV_GROUP_KEY_UP) {
              if(ext->showed_date.month >= 12) {
                  ext->showed_date.month = 1;
                  ext->showed_date.year ++;
              } else {
                  ext->showed_date.month ++;
              }
              lv_obj_invalidate(calendar);
          } else if(c == LV_GROUP_KEY_LEFT || c == LV_GROUP_KEY_DOWN) {
              if(ext->showed_date.month <= 1) {
                  ext->showed_date.month = 12;
                  ext->showed_date.year --;
              } else {
                  ext->showed_date.month --;
              }
              lv_obj_invalidate(calendar);
          }
      } else if(sign == LV_SIGNAL_GET_TYPE) {
          lv_obj_type_t * buf = param;
          uint8_t i;
          for(i = 0; i < LV_MAX_ANCESTOR_NUM - 1; i++) {  /*Find the last set date*/
              if(buf->type[i] == NULL) break;
          }
          buf->type[i] = "lv_calendar";
      }
  
      return res;
  }
  
  /**
   * It will check if the days part of calendar is touched
   * and if it is, it will calculate the day and put it in pressed_date of calendar object.
   * @param calendar pointer to a calendar object
   * @param pointer to a point
   * @return true: days part of calendar is touched and its related date is put in pressed date
   * false: the point is out of days part area.
   */
  static bool calculate_touched_day(lv_obj_t * calendar, const lv_point_t * touched_point)
  {
      lv_area_t days_area;
      lv_area_copy(&days_area, &calendar->coords);
      lv_style_t * style_bg = lv_calendar_get_style(calendar, LV_CALENDAR_STYLE_BG);
      days_area.x1 += style_bg->body.padding.hor;
      days_area.x2 -= style_bg->body.padding.hor;
      days_area.y1 = calendar->coords.y1 + get_header_height(calendar) + get_day_names_height(calendar) - style_bg->body.padding.ver;
  
      if(lv_area_is_point_on(&days_area, touched_point)) {
          lv_coord_t w = (days_area.x2 - days_area.x1 + 1) / 7;
          lv_coord_t h = (days_area.y2 - days_area.y1 + 1) / 6;
          uint8_t x_pos = 0;
          x_pos = (touched_point->x - days_area.x1) / w;
          if(x_pos > 6) x_pos = 6;
          uint8_t y_pos = 0;
          y_pos = (touched_point->y - days_area.y1) / h;
          if(y_pos > 5) y_pos = 5;
  
          uint8_t i_pos = 0;
          i_pos = (y_pos * 7) + x_pos;
          lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
          if(i_pos < get_day_of_week(ext->showed_date.year, ext->showed_date.month, 1) ) {
              ext->pressed_date.year = ext->showed_date.year - (ext->showed_date.month == 1 ? 1 : 0);
              ext->pressed_date.month = ext->showed_date.month == 1 ? 12 : (ext->showed_date.month - 1);
              ext->pressed_date.day = get_month_length(ext->pressed_date.year, ext->pressed_date.month) -
                      get_day_of_week(ext->showed_date.year, ext->showed_date.month, 1) + 1 + i_pos;
          }
          else if(i_pos < (get_day_of_week(ext->showed_date.year, ext->showed_date.month, 1) +
                  get_month_length(ext->showed_date.year, ext->showed_date.month))) {
              ext->pressed_date.year = ext->showed_date.year;
              ext->pressed_date.month = ext->showed_date.month;
              ext->pressed_date.day = i_pos + 1 - get_day_of_week(ext->showed_date.year, ext->showed_date.month, 1);
          }
          else if(i_pos < 42) {
              ext->pressed_date.year = ext->showed_date.year + (ext->showed_date.month == 12 ? 1 : 0);
              ext->pressed_date.month = ext->showed_date.month == 12 ? 1 : (ext->showed_date.month + 1);
              ext->pressed_date.day = i_pos + 1 - get_day_of_week(ext->showed_date.year, ext->showed_date.month, 1)
                                                                                                                                                                                                                                                                                             - get_month_length(ext->showed_date.year, ext->showed_date.month);
          }
          return true;
      }else {
          return false;
      }
  }
  
  /**
   * Get the height of a calendar's header based on it's style
   * @param calendar point to a calendar
   * @return the header's height
   */
  static lv_coord_t get_header_height(lv_obj_t * calendar)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
  
      return lv_font_get_height(ext->style_header->text.font) + ext->style_header->body.padding.ver * 2;
  }
  
  /**
   * Get the height of a calendar's day_names based on it's style
   * @param calendar point to a calendar
   * @return the day_names's height
   */
  static lv_coord_t get_day_names_height(lv_obj_t * calendar)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
  
      return lv_font_get_height(ext->style_day_names->text.font) + ext->style_day_names->body.padding.ver;// * 2;
  }
  
  /**
   * Draw the calendar header with month name and arrows
   * @param calendar point to a calendar
   * @param mask a mask for drawing
   */
  static void draw_header(lv_obj_t * calendar, const lv_area_t * mask)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      lv_opa_t opa_scale = lv_obj_get_opa_scale(calendar);
  
      lv_area_t header_area;
      header_area.x1 = calendar->coords.x1;
      header_area.x2 = calendar->coords.x2;
      header_area.y1 = calendar->coords.y1;
      header_area.y2 = calendar->coords.y1 + get_header_height(calendar);
  
      lv_draw_rect(&header_area, mask, ext->style_header, opa_scale);
  
      /*Add the year + month name*/
      char txt_buf[64];
      lv_math_num_to_str(ext->showed_date.year, txt_buf);
      txt_buf[4] =  ' ';
      txt_buf[5] =  '\0';
      strcpy(&txt_buf[5], get_month_name(calendar, ext->showed_date.month));
      header_area.y1 += ext->style_header->body.padding.ver;
      lv_draw_label(&header_area, mask, ext->style_header, opa_scale, txt_buf, LV_TXT_FLAG_CENTER, NULL);
  
      /*Add the left arrow*/
      lv_style_t * arrow_style = ext->btn_pressing < 0 ? ext->style_header_pr : ext->style_header;
      header_area.x1 += ext->style_header->body.padding.hor;
      lv_draw_label(&header_area, mask, arrow_style, opa_scale, SYMBOL_LEFT, LV_TXT_FLAG_NONE, NULL);
  
      /*Add the right arrow*/
      arrow_style = ext->btn_pressing > 0 ? ext->style_header_pr : ext->style_header;
      header_area.x1 = header_area.x2 - ext->style_header->body.padding.hor -
              lv_txt_get_width(SYMBOL_RIGHT, strlen(SYMBOL_RIGHT), arrow_style->text.font,
                      arrow_style->text.line_space, LV_TXT_FLAG_NONE);
      lv_draw_label(&header_area, mask, arrow_style, opa_scale, SYMBOL_RIGHT, LV_TXT_FLAG_NONE, NULL);
  
  }
  
  /**
   * Draw the day's name below the header
   * @param calendar point to a calendar
   * @param mask a mask for drawing
   */
  static void draw_day_names(lv_obj_t * calendar, const lv_area_t * mask)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      lv_opa_t opa_scale = lv_obj_get_opa_scale(calendar);
  
      lv_coord_t hpad = ext->style_day_names->body.padding.hor;
      lv_coord_t w = lv_obj_get_width(calendar) - 2 * hpad;
      lv_coord_t box_w = w / 7;
      lv_area_t label_area;
      label_area.y1 = calendar->coords.y1 + get_header_height(calendar);// + ext->style_day_names->body.padding.ver;
      label_area.y2 = label_area.y1 + lv_font_get_height(ext->style_day_names->text.font);
      uint32_t i;
      for(i = 0; i < 7; i++) {
          label_area.x1 = calendar->coords.x1 + (w * i) / 7 + hpad;
          label_area.x2 = label_area.x1 + box_w;
          lv_draw_label(&label_area, mask, ext->style_day_names, opa_scale, get_day_name(calendar, i), LV_TXT_FLAG_CENTER, NULL);
      }
  
  }
  
  /**
   * Draw the date numbers in a matrix
   * @param calendar point to a calendar
   * @param mask a mask for drawing
   */
  static void draw_days(lv_obj_t * calendar, const lv_area_t * mask)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      lv_style_t * style_bg = lv_calendar_get_style(calendar, LV_CALENDAR_STYLE_BG);
      lv_coord_t hpad = style_bg->body.padding.hor;
      lv_area_t label_area;
      lv_opa_t opa_scale = lv_obj_get_opa_scale(calendar);
      label_area.y1 = calendar->coords.y1 + get_header_height(calendar) 
      				+ lv_font_get_height(ext->style_day_names->text.font);// + ext->style_day_names->body.padding.ver * 2;            
      label_area.y2 = label_area.y1 + lv_font_get_height(style_bg->text.font);
  
      lv_coord_t w = lv_obj_get_width(calendar) - 2 * hpad;
      lv_coord_t h = calendar->coords.y2 - label_area.y1 - style_bg->body.padding.ver;
      lv_coord_t box_w = w / 7;
      lv_coord_t vert_space = (h - (6 * lv_font_get_height(style_bg->text.font))) / 5;
  
      uint32_t week;
      uint8_t day_cnt;
      uint8_t month_start_day = get_day_of_week(ext->showed_date.year, ext->showed_date.month, 1);
      day_draw_state_t draw_state;    /*true: Not the prev. or next month is drawn*/
      lv_style_t * act_style;
  
      /*If starting with the first day of the week then the previous month is not visible*/
      if(month_start_day == 0) {
          day_cnt = 1;
          draw_state = DAY_DRAW_ACT_MONTH;
          act_style = style_bg;
      } else {
          draw_state = DAY_DRAW_PREV_MONTH;
          day_cnt = get_month_length(ext->showed_date.year, ext->showed_date.month - 1); /*Length of the previous month*/
          day_cnt -= month_start_day - 1;             /*First visible number of the previous month*/
          act_style = ext->style_inactive_days;
      }
  
  
      bool month_of_today_shown = false;
      if(ext->showed_date.year ==  ext->today.year &&
              ext->showed_date.month ==  ext->today.month) {
          month_of_today_shown = true;
      }
  
      char buf[3];
      bool in_week_box = false;
  
      /*Draw 6 weeks*/
      for(week = 0; week < 6; week++) {
  
          /*Draw the "week box"*/
          if(month_of_today_shown &&
                  ((draw_state == DAY_DRAW_ACT_MONTH  && ext->today.day >= day_cnt && ext->today.day < day_cnt + 7) ||
                          (draw_state == DAY_DRAW_PREV_MONTH && ext->today.day <= 7 - month_start_day && week == 0))) {
              lv_area_t week_box_area;
              lv_area_copy(&week_box_area, &label_area);      /*'label_area' is already set for this row*/
              week_box_area.x1 = calendar->coords.x1 + style_bg->body.padding.hor - ext->style_week_box->body.padding.hor;
              week_box_area.x2 = calendar->coords.x2 - style_bg->body.padding.hor + ext->style_week_box->body.padding.hor;
  
              week_box_area.y1 -= ext->style_week_box->body.padding.ver;
              week_box_area.y2 += ext->style_week_box->body.padding.ver;
              lv_draw_rect(&week_box_area, mask, ext->style_week_box, opa_scale);
  
              in_week_box = true;
          } else {
              in_week_box = false;
          }
  
          /*Draw the 7 days of a week*/
          uint32_t day;
          for(day = 0; day < 7; day++) {
              /*The previous month is over*/
              if(draw_state == DAY_DRAW_PREV_MONTH && day == month_start_day) {
                  draw_state = DAY_DRAW_ACT_MONTH;
                  day_cnt = 1;
                  act_style = style_bg;
              }
              /*The current month is over*/
              if(draw_state == DAY_DRAW_ACT_MONTH &&
                      day_cnt > get_month_length(ext->showed_date.year, ext->showed_date.month)) {
                  draw_state = DAY_DRAW_NEXT_MONTH;
                  day_cnt = 1;
                  act_style = ext->style_inactive_days;
              }
  
              label_area.x1 = calendar->coords.x1 + (w * day) / 7 + hpad;
              label_area.x2 = label_area.x1 + box_w;
  
              /*Draw the "today box"*/
              if(draw_state == DAY_DRAW_ACT_MONTH && month_of_today_shown && ext->today.day == day_cnt) {
                  lv_area_t today_box_area;
                  lv_area_copy(&today_box_area, &label_area);
                  today_box_area.x1 = label_area.x1;
                  today_box_area.x2 = label_area.x2;
  
                  today_box_area.y1 = label_area.y1 - ext->style_today_box->body.padding.ver;
                  today_box_area.y2 = label_area.y2 + ext->style_today_box->body.padding.ver;
                  lv_draw_rect(&today_box_area, mask, ext->style_today_box, opa_scale);
              }
  
              /*Get the final style : highlighted/week box/today box/normal*/
              lv_style_t * final_style;
              if(draw_state == DAY_DRAW_PREV_MONTH &&
                      is_highlighted(calendar, ext->showed_date.year - (ext->showed_date.month == 1 ? 1 : 0),
                              ext->showed_date.month == 1 ? 12 : ext->showed_date.month - 1,
                                      day_cnt)) {
                  final_style = ext->style_highlighted_days;
              } else if(draw_state == DAY_DRAW_ACT_MONTH &&
                      is_highlighted(calendar, ext->showed_date.year,
                              ext->showed_date.month,
                              day_cnt)) {
                  final_style = ext->style_highlighted_days;
              } else if(draw_state == DAY_DRAW_NEXT_MONTH &&
                      is_highlighted(calendar, ext->showed_date.year + (ext->showed_date.month == 12 ? 1 : 0),
                              ext->showed_date.month == 12 ? 1 : ext->showed_date.month + 1,
                                      day_cnt)) {
                  final_style = ext->style_highlighted_days;
              } else if(month_of_today_shown && day_cnt == ext->today.day && draw_state == DAY_DRAW_ACT_MONTH) final_style = ext->style_today_box;
              else if(in_week_box && draw_state == DAY_DRAW_ACT_MONTH) final_style = ext->style_week_box;
              else final_style = act_style;
  
              /*Write the day's number*/
              lv_math_num_to_str(day_cnt, buf);
              lv_draw_label(&label_area, mask, final_style, opa_scale, buf, LV_TXT_FLAG_CENTER, NULL);
  
              /*Go to the next day*/
              day_cnt ++;
  
          }
  
          /*Got to the next weeks row*/
          label_area.y1 += vert_space + lv_font_get_height(style_bg->text.font);
          label_area.y2 += vert_space + lv_font_get_height(style_bg->text.font);
      }
  }
  
  /**
   * Check weather a date is highlighted or not
   * @param calendar pointer to a calendar object
   * @param year a year
   * @param month a  month [1..12]
   * @param day a day [1..31]
   * @return true: highlighted
   */
  static bool is_highlighted(lv_obj_t * calendar, int32_t year, int32_t month, int32_t day)
  {
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
  
      if(ext->highlighted_dates == NULL || ext->highlighted_dates_num == 0) return false;
  
      uint32_t i;
      for(i = 0; i < ext->highlighted_dates_num; i++) {
          if(ext->highlighted_dates[i].year == year &&
                  ext->highlighted_dates[i].month == month &&
                  ext->highlighted_dates[i].day == day) {
              return true;
          }
      }
  
      return false;
  }
  
  /**
   * Get the day name
   * @param calendar pointer to a calendar object
   * @param day a day in [0..6]
   * @return
   */
  static const char * get_day_name(lv_obj_t * calendar, uint8_t day)
  {
  
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      if(ext->day_names) return ext->day_names[day];
      else return day_name[day];
  }
  
  /**
   * Get the month name
   * @param calendar pointer to a calendar object
   * @param month a month. The range is basically [1..12] but [-11..1] is also supported to handle previous year
   * @return
   */
  static const char * get_month_name(lv_obj_t * calendar, int32_t month)
  {
      month --;   /*Range of months id [1..12] but range of indexes is [0..11]*/
      if(month < 0) month = 12 + month;
  
      lv_calendar_ext_t * ext = lv_obj_get_ext_attr(calendar);
      if(ext->month_names) return ext->month_names[month];
      else return month_name[month];
  }
  
  /**
   * Get the number of days in a month
   * @param year a year
   * @param month a month. The range is basically [1..12] but [-11..1] is also supported to handle previous year
   * @return [28..31]
   */
  static uint8_t get_month_length(int32_t year, int32_t month)
  {
      month --;   /*Range of months id [1..12] but range of indexes is [0..11]*/
      if(month < 0) {
          year--;   /*Already in the previous year (won't be less then -12 to skip a whole year)*/
          month = 12 + month; /*`month` is negative, the result will be < 12*/
      }
      if(month >= 12) {
          year ++;
          month -= 12;
      }
  
      /*month == 1 is february*/
      return (month == 1) ? (28 + is_leap_year(year)) : 31 - month % 7 % 2;
  
  
  }
  
  /**
   * Tells whether a year is leap year or not
   * @param year a year
   * @return 0: not leap year; 1: leap year
   */
  static uint8_t is_leap_year(uint32_t year)
  {
      return (year % 4) || ((year % 100 == 0) && (year % 400)) ? 0 : 1;
  }
  
  /**
   * Get the day of the week
   * @param year a year
   * @param month a  month
   * @param day a day
   * @return [0..6] which means [Sun..Sat]
   */
  static uint8_t get_day_of_week(uint32_t year, uint32_t month, uint32_t day)
  {
      uint32_t a = month < 3 ? 1 : 0;
      uint32_t b = year - a;
  
      uint32_t day_of_week = (day + (31 * (month - 2 + 12 * a) / 12) +
              b + (b / 4) - (b / 100) + (b / 400)) % 7;
  
      return day_of_week;
  }
  
  #endif
  