/* $Id$ */

/** @file ai_bridge.cpp Implementation of AIBridge. */

#include "ai_bridge.hpp"
#include "../../openttd.h"
#include "../../bridge_map.h"
#include "../../strings_func.h"
#include "../../core/alloc_func.hpp"
#include "../../economy_func.h"
#include "../../settings_type.h"
#include "../../road_map.h"
#include "table/strings.h"

/* static */ bool AIBridge::IsValidBridge(BridgeID bridge_id)
{
	return bridge_id < MAX_BRIDGES;
}

/* static */ bool AIBridge::IsBridgeTile(TileIndex tile)
{
	return ::IsBridgeTile(tile);
}

/* static */ bool AIBridge::BuildBridge(AIVehicle::VehicleType vehicle_type, BridgeID bridge_id, TileIndex start, TileIndex end)
{
	EnforcePrecondition(false, start != end);
	EnforcePrecondition(false, ::IsValidTile(start) && ::IsValidTile(end));
	EnforcePrecondition(false, TileX(start) == TileX(end) || TileY(start) == TileY(end));
	EnforcePrecondition(false, vehicle_type == AIVehicle::VEHICLE_ROAD || vehicle_type == AIVehicle::VEHICLE_RAIL);

	uint type = 0;
	if (vehicle_type == AIVehicle::VEHICLE_ROAD) {
		type |= (TRANSPORT_ROAD << 15);
		type |= (RoadTypeToRoadTypes((::RoadType)AIObject::GetRoadType()) << 8);
	} else {
		type |= (TRANSPORT_RAIL << 15);
		type |= (RAILTYPES_RAIL << 8);
	}

	if (!AIObject::DoCommand(end, start, type | bridge_id, CMD_BUILD_BRIDGE)) return false;
	if (vehicle_type == AIVehicle::VEHICLE_RAIL) return true;

	/* Build 2 road-pieces at both ends of the bridge */
	DiagDirection dir_1 = (DiagDirection)((::TileX(start) == ::TileX(end)) ? (::TileY(start) < ::TileY(end) ? DIAGDIR_NW : DIAGDIR_SE) : (::TileX(start) < ::TileX(end) ? DIAGDIR_NE : DIAGDIR_SW));
	DiagDirection dir_2 = ::ReverseDiagDir(dir_1);

	AIObject::DoCommand(start + ::TileOffsByDiagDir(dir_1), ::DiagDirToRoadBits(dir_2) | (AIObject::GetRoadType() << 4), 0, CMD_BUILD_ROAD);
	AIObject::DoCommand(end + ::TileOffsByDiagDir(dir_2), ::DiagDirToRoadBits(dir_1) | (AIObject::GetRoadType() << 4), 0, CMD_BUILD_ROAD);

	return true;
}

/* static */ bool AIBridge::RemoveBridge(TileIndex tile)
{
	EnforcePrecondition(false, IsBridgeTile(tile));
	return AIObject::DoCommand(tile, 0, 0, CMD_LANDSCAPE_CLEAR);
}

/* static */ char *AIBridge::GetName(BridgeID bridge_id)
{
	if (!IsValidBridge(bridge_id)) return NULL;

	static const int len = 64;
	char *bridge_name = MallocT<char>(len);

	::GetString(bridge_name, ::GetBridgeSpec(bridge_id)->transport_name[0], &bridge_name[len - 1]);
	return bridge_name;
}

/* static */ int32 AIBridge::GetMaxSpeed(BridgeID bridge_id)
{
	if (!IsValidBridge(bridge_id)) return -1;

	return ::GetBridgeSpec(bridge_id)->speed;
}

/* static */ Money AIBridge::GetPrice(BridgeID bridge_id, uint length)
{
	if (!IsValidBridge(bridge_id)) return -1;

	return length * _price.build_bridge * ::GetBridgeSpec(bridge_id)->price >> 8;
}

/* static */ int32 AIBridge::GetMaxLength(BridgeID bridge_id)
{
	if (!IsValidBridge(bridge_id)) return -1;

	uint max = ::GetBridgeSpec(bridge_id)->max_length;
	if (max >= 16 && _settings_game.construction.longbridges) max = 100;
	return max + 2;
}

/* static */ int32 AIBridge::GetMinLength(BridgeID bridge_id)
{
	if (!IsValidBridge(bridge_id)) return -1;

	return ::GetBridgeSpec(bridge_id)->min_length + 2;
}

/* static */ int32 AIBridge::GetYearAvailable(BridgeID bridge_id)
{
	if (!IsValidBridge(bridge_id)) return -1;

	return ::GetBridgeSpec(bridge_id)->avail_year;
}

/* static */ TileIndex AIBridge::GetOtherBridgeEnd(TileIndex tile)
{
	if (!::IsValidTile(tile)) return INVALID_TILE;
	if (!IsBridgeTile(tile)) return INVALID_TILE;

	return ::GetOtherBridgeEnd(tile);
}