/* $Id$ */

/** @file ai_tunnel.cpp Implementation of AITunnel. */

#include "ai_tunnel.hpp"

#include "ai_map.hpp"

#include "ai_rail.hpp"

#include "../ai_instance.hpp"

#include "../../openttd.h"

#include "../../landscape.h"

#include "../../tunnel_map.h"

#include "../../road_type.h"

#include "../../command_func.h"

#include "../../tunnelbridge.h"

#include "../../road_func.h"

/* static */ bool AITunnel::IsTunnelTile(TileIndex tile)

{

	if (!::IsValidTile(tile)) return false;

	return ::IsTunnelTile(tile);

}

/* static */ TileIndex AITunnel::GetOtherTunnelEnd(TileIndex tile)

{

	if (!::IsValidTile(tile)) return INVALID_TILE;

	/* If it's a tunnel alread, take the easy way out! */

	if (IsTunnelTile(tile)) return ::GetOtherTunnelEnd(tile);

	::DoCommand(tile, 0, 0, DC_AUTO, CMD_BUILD_TUNNEL);

	return _build_tunnel_endtile == 0 ? INVALID_TILE : _build_tunnel_endtile;

}

static void _DoCommandReturnBuildTunnel2(class AIInstance *instance)

{

	if (!AITunnel::_BuildTunnelRoad2()) {

		AIObject::SetLastCommandRes(false);

		AIInstance::DoCommandReturn(instance);

		return;

	}

	/* This can never happen, as in test-mode this callback is never executed,

	 *  and in execute-mode, the other callback is called. */

	NOT_REACHED();

}

static void _DoCommandReturnBuildTunnel1(class AIInstance *instance)

{

	if (!AITunnel::_BuildTunnelRoad1()) {

		AIObject::SetLastCommandRes(false);

		AIInstance::DoCommandReturn(instance);

		return;

	}

	/* This can never happen, as in test-mode this callback is never executed,

	 *  and in execute-mode, the other callback is called. */

	NOT_REACHED();

}

/* static */ bool AITunnel::BuildTunnel(AIVehicle::VehicleType vehicle_type, TileIndex start)

{

	EnforcePrecondition(false, ::IsValidTile(start));

	EnforcePrecondition(false, vehicle_type == AIVehicle::VEHICLE_RAIL || vehicle_type == AIVehicle::VEHICLE_ROAD);

	EnforcePrecondition(false, vehicle_type != AIVehicle::VEHICLE_RAIL || AIRail::IsRailTypeAvailable(AIRail::GetCurrentRailType()));

	uint type = 0;

	if (vehicle_type == AIVehicle::VEHICLE_ROAD) {

		type |= (TRANSPORT_ROAD << 9);

		type |= RoadTypeToRoadTypes((::RoadType)AIObject::GetRoadType());

	} else {

		type |= (TRANSPORT_RAIL << 9);

		type |= AIRail::GetCurrentRailType();

	}

	/* For rail we do nothing special */

	if (vehicle_type == AIVehicle::VEHICLE_RAIL) {

		return AIObject::DoCommand(start, type, 0, CMD_BUILD_TUNNEL);

	}

	AIObject::SetCallbackVariable(0, start);

	if (!AIObject::DoCommand(start, type, 0, CMD_BUILD_TUNNEL, NULL, &_DoCommandReturnBuildTunnel1)) return false;

	/* In case of test-mode, test if we can build both road pieces */

	return _BuildTunnelRoad1();

}

/* static */ bool AITunnel::_BuildTunnelRoad1()

{

	/* Build the piece of road on the 'start' side of the tunnel */

	TileIndex end = AIObject::GetCallbackVariable(0);

	TileIndex start = AITunnel::GetOtherTunnelEnd(end);

	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);

	if (!AIObject::DoCommand(start + ::TileOffsByDiagDir(dir_1), ::DiagDirToRoadBits(dir_2) | (AIObject::GetRoadType() << 4), 0, CMD_BUILD_ROAD, NULL, &_DoCommandReturnBuildTunnel2)) return false;

	/* In case of test-mode, test the other road piece too */

	return _BuildTunnelRoad2();

}

/* static */ bool AITunnel::_BuildTunnelRoad2()

{

	/* Build the piece of road on the 'end' side of the tunnel */

	TileIndex end = AIObject::GetCallbackVariable(0);

	TileIndex start = AITunnel::GetOtherTunnelEnd(end);

	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);

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

}

/* static */ bool AITunnel::RemoveTunnel(TileIndex tile)

{

	EnforcePrecondition(false, IsTunnelTile(tile));

	return AIObject::DoCommand(tile, 0, 0, CMD_LANDSCAPE_CLEAR);

}