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_subsidy.hpp Everything to query subsidies. */ 9 10 #ifndef SCRIPT_SUBSIDY_HPP 11 #define SCRIPT_SUBSIDY_HPP 12 13 #include "script_company.hpp" 14 #include "script_date.hpp" 15 16 /** 17 * Class that handles all subsidy related functions. 18 * @api ai game 19 */ 20 class ScriptSubsidy : public ScriptObject { 21 public: 22 /** 23 * Enumeration for source and destination of a subsidy. 24 * @note The list of values may grow in future. 25 */ 26 enum SubsidyParticipantType { 27 /* Values are important, as they represent the internal state of the game. 28 * It is originally named SourceType. ST_HEADQUARTERS is intentionally 29 * left out, as it cannot be used for Subsidies. */ 30 SPT_INDUSTRY = 0, ///< Subsidy participant is an industry 31 SPT_TOWN = 1, ///< Subsidy participant is a town 32 SPT_INVALID = 0xFF, ///< Invalid/unknown participant type 33 }; 34 35 /** 36 * Check whether this is a valid SubsidyID. 37 * @param subsidy_id The SubsidyID to check. 38 * @return True if and only if this subsidy is still valid. 39 */ 40 static bool IsValidSubsidy(SubsidyID subsidy_id); 41 42 /** 43 * Checks whether this subsidy is already awarded to some company. 44 * @param subsidy_id The SubsidyID to check. 45 * @pre IsValidSubsidy(subsidy). 46 * @return True if and only if this subsidy is already awarded. 47 */ 48 static bool IsAwarded(SubsidyID subsidy_id); 49 50 /** 51 * Create a new subsidy. 52 * @param cargo_type The type of cargo to cary for the subsidy. 53 * @param from_type The type of the subsidy on the 'from' side. 54 * @param from_id The ID of the 'from' side. 55 * @param to_type The type of the subsidy on the 'to' side. 56 * @param to_id The ID of the 'to' side. 57 * @return True if the action succeeded. 58 * @pre ScriptCargo::IsValidCargo(cargo_type) 59 * @pre from_type == SPT_INDUSTRY || from_type == SPT_TOWN. 60 * @pre to_type == SPT_INDUSTRY || to_type == SPT_TOWN. 61 * @pre (from_type == SPT_INDUSTRY && ScriptIndustry::IsValidIndustry(from_id)) || (from_type == SPT_TOWN && ScriptTown::IsValidTown(from_id)) 62 * @pre (to_type == SPT_INDUSTRY && ScriptIndustry::IsValidIndustry(to_id)) || (to_type == SPT_TOWN && ScriptTown::IsValidTown(to_id)) 63 * @api -ai 64 */ 65 static bool Create(CargoID cargo_type, SubsidyParticipantType from_type, uint16 from_id, SubsidyParticipantType to_type, uint16 to_id); 66 67 /** 68 * Get the company index of the company this subsidy is awarded to. 69 * @param subsidy_id The SubsidyID to check. 70 * @pre IsAwarded(subsidy_id). 71 * @return The companyindex of the company this subsidy is awarded to. 72 */ 73 static ScriptCompany::CompanyID GetAwardedTo(SubsidyID subsidy_id); 74 75 /** 76 * Get the date this subsidy expires. In case the subsidy is already 77 * awarded, return the date the subsidy expires, else, return the date the 78 * offer expires. 79 * @param subsidy_id The SubsidyID to check. 80 * @pre IsValidSubsidy(subsidy_id). 81 * @return The last valid date of this subsidy. 82 * @note The return value of this function will change if the subsidy is 83 * awarded. 84 */ 85 static ScriptDate::Date GetExpireDate(SubsidyID subsidy_id); 86 87 /** 88 * Get the cargo type that has to be transported in order to be awarded this 89 * subsidy. 90 * @param subsidy_id The SubsidyID to check. 91 * @pre IsValidSubsidy(subsidy_id). 92 * @return The cargo type to transport. 93 */ 94 static CargoID GetCargoType(SubsidyID subsidy_id); 95 96 /** 97 * Returns the type of source of subsidy. 98 * @param subsidy_id The SubsidyID to check. 99 * @pre IsValidSubsidy(subsidy_id). 100 * @return Type of source of subsidy. 101 */ 102 static SubsidyParticipantType GetSourceType(SubsidyID subsidy_id); 103 104 /** 105 * Return the source IndustryID/TownID the subsidy is for. 106 * \li GetSourceType(subsidy_id) == SPT_INDUSTRY -> return the IndustryID. 107 * \li GetSourceType(subsidy_id) == SPT_TOWN -> return the TownID. 108 * @param subsidy_id The SubsidyID to check. 109 * @pre IsValidSubsidy(subsidy_id). 110 * @return One of TownID/IndustryID. 111 */ 112 static int32 GetSourceIndex(SubsidyID subsidy_id); 113 114 /** 115 * Returns the type of destination of subsidy. 116 * @param subsidy_id The SubsidyID to check. 117 * @pre IsValidSubsidy(subsidy_id). 118 * @return Type of destination of subsidy. 119 */ 120 static SubsidyParticipantType GetDestinationType(SubsidyID subsidy_id); 121 122 /** 123 * Return the destination IndustryID/TownID the subsidy is for. 124 * \li GetDestinationType(subsidy_id) == SPT_INDUSTRY -> return the IndustryID. 125 * \li GetDestinationType(subsidy_id) == SPT_TOWN -> return the TownID. 126 * @param subsidy_id the SubsidyID to check. 127 * @pre IsValidSubsidy(subsidy_id). 128 * @return One of TownID/IndustryID. 129 */ 130 static int32 GetDestinationIndex(SubsidyID subsidy_id); 131 }; 132 133 #endif /* SCRIPT_SUBSIDY_HPP */ 134