/* $Id$ */

/** @file ai_bridge.hpp Everything to query and build bridges. */

#ifndef AI_BRIDGE_HPP
#define AI_BRIDGE_HPP

#include "ai_object.hpp"
#include "ai_vehicle.hpp"
#include "../../bridge.h"

/** In OpenTTD Core 'BridgeID' is called 'BridgeType', so map it to make this API more logic. */
typedef BridgeType BridgeID;

/**
 * Class that handles all bridge related functions.
 */
class AIBridge : public AIObject {
public:
	static const char *GetClassName() { return "AIBridge"; }

	/**
	 * Checks whether the given bridge type is valid.
	 * @param bridge_id The bridge to check.
	 * @return True if and only if the bridge type is valid.
	 */
	static bool IsValidBridge(BridgeID bridge_id);

	/**
	 * Checks whether the given tile is actually a bridge start or end tile.
	 * @param tile The tile to check.
	 * @pre AIMap::IsValidTile(tile).
	 * @return True if and only if the tile is the beginning or end of a bridge.
	 */
	static bool IsBridgeTile(TileIndex tile);

	/**
	 * Get the name of a bridge.
	 * @param bridge_id The bridge to get the name of.
	 * @pre IsValidBridge(bridge_id).
	 * @return The name the bridge has.
	 */
	static char *GetName(BridgeID bridge_id);

	/**
	 * Get the maximum speed of a bridge (in km/h).
	 * @param bridge_id The bridge to get the maximum speed of.
	 * @pre IsValidBridge(bridge_id).
	 * @return The maximum speed the bridge has.
	 */
	static uint32 GetMaxSpeed(BridgeID bridge_id);

	/**
	 * Get the new cost of a bridge.
	 * @param bridge_id The bridge to get the new cost of.
	 * @param length The length of the bridge.
	 * @pre IsValidBridge(bridge_id).
	 * @return The new cost the bridge has.
	 */
	static uint32 GetPrice(BridgeID bridge_id, uint length);

	/**
	 * Get the maximum length of a bridge.
	 * @param bridge_id The bridge to get the maximum length of.
	 * @pre IsValidBridge(bridge_id).
	 * @returns The maximum length the bridge has.
	 */
	static uint32 GetMaxLength(BridgeID bridge_id);

	/**
	 * Get the minimum length of a bridge.
	 * @param bridge_id The bridge to get the minimum length of.
	 * @pre IsValidBridge(bridge_id).
	 * @returns The minimum length the bridge has.
	 */
	static uint32 GetMinLength(BridgeID bridge_id);

	/**
	 * Get the year in which a bridge becomes available.
	 * @param bridge_id The bridge to get the year of availability of.
	 * @pre IsValidBridge(bridge_id).
	 * @returns The year of availability the bridge has.
	 * @note Years are like 2010, -10 (10 B.C.), 1950, ..
	 */
	static int32 GetYearAvailable(BridgeID bridge_id);

	/**
	 * Build a bridge from one tile to the other.
	 * @param vehicle_type The vehicle-type of bridge to build.
	 * @param bridge_id The bridge-type to build.
	 * @param start Where to start the bridge.
	 * @param end Where to end the bridge.
	 * @pre AIMap::IsValidTile(start).
	 * @pre AIMap::IsValidTile(end).
	 * @pre 'start' and 'end' are in a straight line, i.e.
	 *  AIMap::GetTileX(start) == AIMap::GetTileX(end) or
	 *  AIMap::GetTileY(start) == AIMap::GetTileY(end).
	 * @pre 'vehicle_type' is either AIVehicle::VEHICLE_RAIL or AIVEHICLE::VEHICLE_ROAD.
	 * @return Whether the bridge has been/can be build or not.
	 */
	static bool BuildBridge(AIVehicle::VehicleType vehicle_type, BridgeID bridge_id, TileIndex start, TileIndex end);

	/**
	 * Removes a bridge, by executing it on either the start or end tile.
	 * @param tile An end or start tile of the bridge.
	 * @pre AIMap::IsValidTile(tile).
	 * @return Whether the bridge has been/can be removed or not.
	 */
	static bool RemoveBridge(TileIndex tile);
};

#endif /* AI_BRIDGE_HPP */