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diff --git a/src/ai/api/ai_subsidy.hpp b/src/ai/api/ai_subsidy.hpp
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+++ b/src/ai/api/ai_subsidy.hpp
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+/* $Id$ */
+
+/** @file ai_subsidy.hpp Everything to query subsidies. */
+
+#ifndef AI_SUBSIDY_HPP
+#define AI_SUBSIDY_HPP
+
+#include "ai_object.hpp"
+#include "ai_company.hpp"
+
+/**
+ * Class that handles all subsidy related functions.
+ */
+class AISubsidy : public AIObject {
+public:
+	static const char *GetClassName() { return "AISubsidy"; }
+
+	/**
+	 * Check whether this is a valid SubsidyID.
+	 * @param subsidy_id The SubsidyID to check.
+	 * @return True if and only if this subsidy is still valid.
+	 */
+	static bool IsValidSubsidy(SubsidyID subsidy_id);
+
+	/**
+	 * Checks whether this subsidy is already awarded to some company.
+	 * @param subsidy_id The SubsidyID to check.
+	 * @pre IsValidSubsidy(subsidy).
+	 * @return True if and only if this subsidy is already awarded.
+	 */
+	static bool IsAwarded(SubsidyID subsidy_id);
+
+	/**
+	 * Get the company index of the company this subsidy is awarded to.
+	 * @param subsidy_id The SubsidyID to check.
+	 * @pre IsAwarded(subsidy_id).
+	 * @return The companyindex of the company this subsidy is awarded to.
+	 */
+	static AICompany::CompanyID GetAwardedTo(SubsidyID subsidy_id);
+
+	/**
+	 * Get the date this subsidy expires. In case the subsidy is already
+	 *  awarded, return the date the subsidy expires, else, return the date the
+	 *  offer expires.
+	 * @param subsidy_id The SubsidyID to check.
+	 * @pre IsValidSubsidy(subsidy_id).
+	 * @return The last valid date of this subsidy.
+	 * @note The return value of this function will change if the subsidy is
+	 *  awarded.
+	 */
+	static int32 GetExpireDate(SubsidyID subsidy_id);
+
+	/**
+	 * Get the cargo type that has to be transported in order to be awarded this
+	 *  subsidy.
+	 * @param subsidy_id The SubsidyID to check.
+	 * @pre IsValidSubsidy(subsidy_id).
+	 * @return The cargo type to transport.
+	 */
+	static CargoID GetCargoType(SubsidyID subsidy_id);
+
+	/**
+	 * Is the source of the subsidy a town or an industry.
+	 * @param subsidy_id The SubsidyID to check.
+	 * @pre IsValidSubsidy(subsidy_id) && !IsAwarded(subsidy_id).
+	 * @return True if the source is a town, false if it is an industry.
+	 */
+	static bool SourceIsTown(SubsidyID subsidy_id);
+
+	/**
+	 * Return the source TownID/IndustryID/StationID the subsidy is for.
+	 * 1) IsAwarded(subsidy_id) -> return the StationID the subsidy is awarded to.
+	 * 2) !IsAwarded(subsidy_id) && SourceIsTown(subsidy_id) -> return the TownID.
+	 * 3) !IsAwarded(subsidy_id) && !SourceIsTown(subsidy_id) -> return the IndustryID.
+	 * @param subsidy_id The SubsidyID to check.
+	 * @pre IsValidSubsidy(subsidy_id).
+	 * @return One of TownID/IndustryID/StationID.
+	 */
+	static int32 GetSource(SubsidyID subsidy_id);
+
+	/**
+	 * Is the destination of the subsidy a town or an industry.
+	 * @param subsidy_id The SubsidyID to check.
+	 * @pre IsValidSubsidy(subsidy_id) && !IsAwarded(subsidy_id).
+	 * @return True if the destination is a town, false if it is an industry.
+	 */
+	static bool DestinationIsTown(SubsidyID subsidy_id);
+
+	/**
+	 * Return the destination TownID/IndustryID/StationID the subsidy is for.
+	 * 1) IsAwarded(subsidy_id) -> return the StationID the subsidy is awarded to.
+	 * 2) !IsAwarded(subsidy_id) && SourceIsTown(subsidy_id) -> return the TownID.
+	 * 3) !IsAwarded(subsidy_id) && !SourceIsTown(subsidy_id) -> return the IndustryID.
+	 * @param subsidy_id the SubsidyID to check.
+	 * @pre IsValidSubsidy(subsidy_id).
+	 * @return One of TownID/IndustryID/StationID.
+	 */
+	static int32 GetDestination(SubsidyID subsidy_id);
+};
+
+#endif /* AI_SUBSIDY_HPP */