src/script/api/script_date.hpp

   1 /*
   2  * This file is part of OpenTTD.
   3  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   4  * OpenTTD 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.
   5  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   6  */
   7
   8 /** @file script_date.hpp Everything to query and manipulate date related information. */
   9
  10 #ifndef SCRIPT_DATE_HPP
  11 #define SCRIPT_DATE_HPP
  12
  13 #include "script_object.hpp"
  14 #include "../../timer/timer_game_economy.h"
  15
  16 /**
  17  * Class that handles all date related (calculation) functions.
  18  * @api ai game
  19  *
  20  * @note Months and days of month are 1-based; the first month of the
  21  *       year is 1 and the first day of the month is also 1.
  22  * @note Years are zero based; they start with the year 0.
  23  * @note Dates can be used to determine the number of days between
  24  *       two different moments in time because they count the number
  25  *       of days since the year 0.
  26  *
  27  * \anchor ScriptCalendarTime
  28  * \b Calendar-Time
  29  *
  30  * Calendar time measures the technological progression in the game.
  31  * \li The calendar date is shown in the status bar.
  32  * \li The calendar date affects engine model introduction and expiration.
  33  * \li Progression of calendar time can be slowed or even halted via game settings.
  34  *
  35  * Calendar time uses the Gregorian calendar with 365 or 366 days per year.
  36  *
  37  * \anchor ScriptEconomyTime
  38  * \b Economy-Time
  39  *
  40  * Economy time measures the in-game time progression, while the game is not paused.
  41  * \li Cargo production and consumption follows economy time.
  42  * \li Recurring income and expenses follow economy time.
  43  * \li Production and income statistics and balances are created per economy month/quarter/year.
  44  *
  45  * Depending on game settings economy time is represented differently:
  46  * \li Calendar-based timekeeping: Economy- and calendar-time use the identical Gregorian calendar.
  47  * \li Wallclock-based timekeeping: Economy- and calendar-time are separate.
  48  *     Economy-time will use a 360 day calendar (12 months with 30 days each), which runs at a constant speed of one economy-month per realtime-minute.
  49  *     Calendar-time will use a Gregorian calendar, which can be slowed to stopped via game settings.
  50  */
  51 class ScriptDate : public ScriptObject {
  52 public:
  53         /**
  54          * Date data type is an integer value. Use ScriptDate::GetDate to
  55          * compose valid date values for a known year, month and day.
  56          */
  57         enum Date {
  58                 DATE_INVALID = ::EconomyTime::INVALID_DATE.base(), ///< A value representing an invalid date.
  59         };
  60
  61         /**
  62          * Validates if a date value represent a valid date.
  63          * @param date The date to validate.
  64          * @return True if the date is valid, otherwise false
  65          */
  66         static bool IsValidDate(Date date);
  67
  68         /**
  69          * Get the current date.
  70          * This is the number of days since epoch under the assumption that
  71          *  there is a leap year every 4 years, except when dividable by
  72          *  100 but not by 400.
  73          * @return The current date.
  74          */
  75         static Date GetCurrentDate();
  76
  77         /**
  78          * Get the year of the given date.
  79          * @param date The date to get the year of.
  80          * @return The year.
  81          */
  82         static SQInteger GetYear(Date date);
  83
  84         /**
  85          * Get the month of the given date.
  86          * @param date The date to get the month of.
  87          * @return The month.
  88          */
  89         static SQInteger GetMonth(Date date);
  90
  91         /**
  92          * Get the day (of the month) of the given date.
  93          * @param date The date to get the day of.
  94          * @return The day.
  95          */
  96         static SQInteger GetDayOfMonth(Date date);
  97
  98         /**
  99          * Get the date given a year, month and day of month.
 100          * @param year The year of the to-be determined date.
 101          * @param month The month of the to-be determined date.
 102          * @param day_of_month The day of month of the to-be determined date.
 103          * @return The date.
 104          */
 105         static Date GetDate(SQInteger year, SQInteger month, SQInteger day_of_month);
 106
 107         /**
 108          * Get the time of the host system.
 109          * @return The amount of seconds passed since 1 Jan 1970.
 110          * @api -ai
 111          * @note This uses the clock of the host system, which can skew or be set back. Use with caution.
 112          */
 113         static SQInteger GetSystemTime();
 114 };
 115
 116 #endif /* SCRIPT_DATE_HPP */