/* $Id$ */

#include "stdafx.h"
#include "openttd.h"
#include "order.h"
#include "airport.h"
#include "depot.h"
#include "functions.h"
#include "table/strings.h"
#include "vehicle.h"
#include "waypoint.h"
#include "command.h"
#include "station.h"
#include "player.h"
#include "news.h"
#include "saveload.h"
#include "vehicle_gui.h"

/**
 * Called if a new block is added to the order-pool
 */
static void OrderPoolNewBlock(uint start_item)
{
	Order *order;

	/* We don't use FOR_ALL here, because FOR_ALL skips invalid items.
	 * TODO - This is just a temporary stage, this will be removed. */
	for (order = GetOrder(start_item); order != NULL; order = (order->index + 1U < GetOrderPoolSize()) ? GetOrder(order->index + 1U) : NULL) order->index = start_item++;
}

DEFINE_POOL(Order, Order, OrderPoolNewBlock, NULL)

/**
 *
 * Unpacks a order from savegames made with TTD(Patch)
 *
 */
Order UnpackOldOrder(uint16 packed)
{
	Order order;
	order.type    = GB(packed, 0, 4);
	order.flags   = GB(packed, 4, 4);
	order.dest    = GB(packed, 8, 8);
	order.next    = NULL;

	order.refit_cargo   = CT_NO_REFIT;
	order.refit_subtype = 0;
	order.index = 0; // avoid compiler warning

	// Sanity check
	// TTD stores invalid orders as OT_NOTHING with non-zero flags/station
	if (order.type == OT_NOTHING && (order.flags != 0 || order.dest != 0)) {
		order.type = OT_DUMMY;
		order.flags = 0;
	}

	return order;
}

/**
 *
 * Unpacks a order from savegames with version 4 and lower
 *
 */
static Order UnpackVersion4Order(uint16 packed)
{
	Order order;
	order.type  = GB(packed, 0, 4);
	order.flags = GB(packed, 4, 4);
	order.dest  = GB(packed, 8, 8);
	order.next  = NULL;
	order.index = 0; // avoid compiler warning
	order.refit_cargo   = CT_NO_REFIT;
	order.refit_subtype = 0;
	return order;
}

/**
 *
 * Updates the widgets of a vehicle which contains the order-data
 *
 */
void InvalidateVehicleOrder(const Vehicle *v)
{
	InvalidateWindow(WC_VEHICLE_VIEW,   v->index);
	InvalidateWindow(WC_VEHICLE_ORDERS, v->index);
}

/**
 *
 * Swap two orders
 *
 */
static void SwapOrders(Order *order1, Order *order2)
{
	Order temp_order;

	temp_order = *order1;
	AssignOrder(order1, *order2);
	order1->next = order2->next;
	AssignOrder(order2, temp_order);
	order2->next = temp_order.next;
}

/**
 *
 * Allocate a new order
 *
 * @return Order* if a free space is found, else NULL.
 *
 */
static Order *AllocateOrder(void)
{
	Order *order;

	/* We don't use FOR_ALL here, because FOR_ALL skips invalid items.
	 * TODO - This is just a temporary stage, this will be removed. */
	for (order = GetOrder(0); order != NULL; order = (order->index + 1U < GetOrderPoolSize()) ? GetOrder(order->index + 1U) : NULL) {
		if (!IsValidOrder(order)) {
			OrderID index = order->index;

			memset(order, 0, sizeof(*order));
			order->index = index;
			order->next = NULL;
			order->refit_cargo   = CT_NO_REFIT;
			order->refit_subtype = 0;

			return order;
		}
	}

	/* Check if we can add a block to the pool */
	if (AddBlockToPool(&_Order_pool)) return AllocateOrder();

	return NULL;
}

/**
 *
 * Assign data to an order (from an other order)
 *   This function makes sure that the index is maintained correctly
 *
 */
void AssignOrder(Order *order, Order data)
{
	order->type  = data.type;
	order->flags = data.flags;
	order->dest  = data.dest;

	order->refit_cargo   = data.refit_cargo;
	order->refit_subtype = data.refit_subtype;
}


/**
 * Delete all news items regarding defective orders about a vehicle
 * This could kill still valid warnings (for example about void order when just
 * another order gets added), but assume the player will notice the problems,
 * when (s)he's changing the orders.
 */
static void DeleteOrderWarnings(const Vehicle* v)
{
	DeleteVehicleNews(v->index, STR_TRAIN_HAS_TOO_FEW_ORDERS  + (v->type - VEH_Train) * 4);
	DeleteVehicleNews(v->index, STR_TRAIN_HAS_VOID_ORDER      + (v->type - VEH_Train) * 4);
	DeleteVehicleNews(v->index, STR_TRAIN_HAS_DUPLICATE_ENTRY + (v->type - VEH_Train) * 4);
	DeleteVehicleNews(v->index, STR_TRAIN_HAS_INVALID_ENTRY   + (v->type - VEH_Train) * 4);
}


/** Add an order to the orderlist of a vehicle.
 * @param tile unused
 * @param p1 various bitstuffed elements
 * - p1 = (bit  0 - 15) - ID of the vehicle
 * - p1 = (bit 16 - 31) - the selected order (if any). If the last order is given,
 *                        the order will be inserted before that one
 *                        only the first 8 bits used currently (bit 16 - 23) (max 255)
 * @param p2 packed order to insert
 */
int32 CmdInsertOrder(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
{
	Vehicle *v;
	VehicleID veh   = GB(p1,  0, 16);
	VehicleOrderID sel_ord = GB(p1, 16, 16);
	Order new_order = UnpackOrder(p2);

	if (!IsValidVehicleID(veh)) return CMD_ERROR;

	v = GetVehicle(veh);

	if (!CheckOwnership(v->owner)) return CMD_ERROR;

	/* Check if the inserted order is to the correct destination (owner, type),
	 * and has the correct flags if any */
	switch (new_order.type) {
		case OT_GOTO_STATION: {
			const Station *st;

			if (!IsValidStationID(new_order.dest)) return CMD_ERROR;
			st = GetStation(new_order.dest);

			if (st->airport_type != AT_OILRIG && !IsBuoy(st) && !CheckOwnership(st->owner)) {
				return CMD_ERROR;
			}

			switch (v->type) {
				case VEH_Train:
					if (!(st->facilities & FACIL_TRAIN)) return CMD_ERROR;
					break;

				case VEH_Road:
					if (v->cargo_type == CT_PASSENGERS) {
						if (!(st->facilities & FACIL_BUS_STOP)) return CMD_ERROR;
					} else {
						if (!(st->facilities & FACIL_TRUCK_STOP)) return CMD_ERROR;
					}
					break;

				case VEH_Ship:
					if (!(st->facilities & FACIL_DOCK)) return CMD_ERROR;
					break;

				case VEH_Aircraft:
					if (!(st->facilities & FACIL_AIRPORT)) return CMD_ERROR;
					break;

				default: return CMD_ERROR;
			}

			/* Order flags can be any of the following for stations:
			 * [full-load | unload] [+ transfer] [+ non-stop]
			 * non-stop orders (if any) are only valid for trains */
			switch (new_order.flags) {
				case 0:
				case OF_FULL_LOAD:
				case OF_FULL_LOAD | OF_TRANSFER:
				case OF_UNLOAD:
				case OF_UNLOAD | OF_TRANSFER:
				case OF_TRANSFER:
					break;

				case OF_NON_STOP:
				case OF_NON_STOP | OF_FULL_LOAD:
				case OF_NON_STOP | OF_FULL_LOAD | OF_TRANSFER:
				case OF_NON_STOP | OF_UNLOAD:
				case OF_NON_STOP | OF_UNLOAD | OF_TRANSFER:
				case OF_NON_STOP | OF_TRANSFER:
					if (v->type != VEH_Train) return CMD_ERROR;
					break;

				default: return CMD_ERROR;
			}
			break;
		}

		case OT_GOTO_DEPOT: {
			if (v->type == VEH_Aircraft) {
				const Station* st;

				if (!IsValidStationID(new_order.dest)) return CMD_ERROR;
				st = GetStation(new_order.dest);

				if ((st->airport_type != AT_OILRIG && !CheckOwnership(st->owner)) ||
						!(st->facilities & FACIL_AIRPORT) ||
						GetAirport(st->airport_type)->nof_depots == 0) {
					return CMD_ERROR;
				}
			} else {
				const Depot* dp;

				if (!IsValidDepotID(new_order.dest)) return CMD_ERROR;
				dp = GetDepot(new_order.dest);

				if (!CheckOwnership(GetTileOwner(dp->xy))) return CMD_ERROR;

				switch (v->type) {
					case VEH_Train:
						if (!IsTileDepotType(dp->xy, TRANSPORT_RAIL)) return CMD_ERROR;
						break;

					case VEH_Road:
						if (!IsTileDepotType(dp->xy, TRANSPORT_ROAD)) return CMD_ERROR;
						break;

					case VEH_Ship:
						if (!IsTileDepotType(dp->xy, TRANSPORT_WATER)) return CMD_ERROR;
						break;

					default: return CMD_ERROR;
				}
			}

			/* Order flags can be any of the following for depots:
			 * order [+ halt] [+ non-stop]
			 * non-stop orders (if any) are only valid for trains */
			switch (new_order.flags) {
				case OF_PART_OF_ORDERS:
				case OF_PART_OF_ORDERS | OF_HALT_IN_DEPOT:
					break;

				case OF_NON_STOP | OF_PART_OF_ORDERS:
				case OF_NON_STOP | OF_PART_OF_ORDERS | OF_HALT_IN_DEPOT:
					if (v->type != VEH_Train) return CMD_ERROR;
					break;

				default: return CMD_ERROR;
			}
			break;
		}

		case OT_GOTO_WAYPOINT: {
			const Waypoint* wp;

			if (v->type != VEH_Train) return CMD_ERROR;

			if (!IsValidWaypointID(new_order.dest)) return CMD_ERROR;
			wp = GetWaypoint(new_order.dest);

			if (!CheckOwnership(GetTileOwner(wp->xy))) return CMD_ERROR;

			/* Order flags can be any of the following for waypoints:
			 * [non-stop]
			 * non-stop orders (if any) are only valid for trains */
			switch (new_order.flags) {
				case 0: break;

				case OF_NON_STOP:
					if (v->type != VEH_Train) return CMD_ERROR;
					break;

				default: return CMD_ERROR;
			}
			break;
		}

		default: return CMD_ERROR;
	}

	if (sel_ord > v->num_orders) return CMD_ERROR;

	if (IsOrderPoolFull()) return_cmd_error(STR_8831_NO_MORE_SPACE_FOR_ORDERS);

	/* XXX - This limit is only here because the backuppedorders can't
	 * handle any more then this.. */
	if (v->num_orders >= MAX_BACKUP_ORDER_COUNT) return_cmd_error(STR_8832_TOO_MANY_ORDERS);

	/* For ships, make sure that the station is not too far away from the
	 * previous destination, for human players with new pathfinding disabled */
	if (v->type == VEH_Ship && IsHumanPlayer(v->owner) &&
		sel_ord != 0 && GetVehicleOrder(v, sel_ord - 1)->type == OT_GOTO_STATION
		&& !_patches.new_pathfinding_all) {

		int dist = DistanceManhattan(
			GetStation(GetVehicleOrder(v, sel_ord - 1)->dest)->xy,
			GetStation(new_order.dest)->xy // XXX type != OT_GOTO_STATION?
		);
		if (dist >= 130)
			return_cmd_error(STR_0210_TOO_FAR_FROM_PREVIOUS_DESTINATIO);
	}

	if (flags & DC_EXEC) {
		Vehicle *u;
		Order *new = AllocateOrder();
		AssignOrder(new, new_order);

		/* Create new order and link in list */
		if (v->orders == NULL) {
			v->orders = new;
		} else {
			/* Try to get the previous item (we are inserting above the
			    selected) */
			Order *order = GetVehicleOrder(v, sel_ord - 1);

			if (order == NULL && GetVehicleOrder(v, sel_ord) != NULL) {
				/* There is no previous item, so we are altering v->orders itself
				    But because the orders can be shared, we copy the info over
				    the v->orders, so we don't have to change the pointers of
				    all vehicles */
				SwapOrders(v->orders, new);
				/* Now update the next pointers */
				v->orders->next = new;
			} else if (order == NULL) {
				/* 'sel' is a non-existing order, add him to the end */
				order = GetLastVehicleOrder(v);
				order->next = new;
			} else {
				/* Put the new order in between */
				new->next = order->next;
				order->next = new;
			}
		}

		u = GetFirstVehicleFromSharedList(v);
		DeleteOrderWarnings(u);
		for (; u != NULL; u = u->next_shared) {
			/* Increase amount of orders */
			u->num_orders++;

			/* If the orderlist was empty, assign it */
			if (u->orders == NULL) u->orders = v->orders;

			assert(v->orders == u->orders);

			/* If there is added an order before the current one, we need
			to update the selected order */
			if (sel_ord <= u->cur_order_index) {
				uint cur = u->cur_order_index + 1;
				/* Check if we don't go out of bound */
				if (cur < u->num_orders)
					u->cur_order_index = cur;
			}
			/* Update any possible open window of the vehicle */
			InvalidateVehicleOrder(u);
		}

		/* Make sure to rebuild the whole list */
		RebuildVehicleLists();
	}

	return 0;
}

/** Declone an order-list
 * @param *dst delete the orders of this vehicle
 * @param flags execution flags
 */
static int32 DecloneOrder(Vehicle *dst, uint32 flags)
{
	if (flags & DC_EXEC) {
		DeleteVehicleOrders(dst);
		InvalidateVehicleOrder(dst);
		RebuildVehicleLists();
	}
	return 0;
}

/** Delete an order from the orderlist of a vehicle.
 * @param tile unused
 * @param p1 the ID of the vehicle
 * @param p2 the order to delete (max 255)
 */
int32 CmdDeleteOrder(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
{
	Vehicle *v, *u;
	VehicleID veh_id = p1;
	VehicleOrderID sel_ord = p2;
	Order *order;

	if (!IsValidVehicleID(veh_id)) return CMD_ERROR;

	v = GetVehicle(veh_id);

	if (!CheckOwnership(v->owner)) return CMD_ERROR;

	/* If we did not select an order, we maybe want to de-clone the orders */
	if (sel_ord >= v->num_orders)
		return DecloneOrder(v, flags);

	order = GetVehicleOrder(v, sel_ord);
	if (order == NULL) return CMD_ERROR;

	if (flags & DC_EXEC) {
		if (GetVehicleOrder(v, sel_ord - 1) == NULL) {
			if (GetVehicleOrder(v, sel_ord + 1) != NULL) {
				/* First item, but not the last, so we need to alter v->orders
				    Because we can have shared order, we copy the data
				    from the next item over the deleted */
				order = GetVehicleOrder(v, sel_ord + 1);
				SwapOrders(v->orders, order);
			} else {
				/* Last item, so clean the list */
				v->orders = NULL;
			}
		} else {
			GetVehicleOrder(v, sel_ord - 1)->next = order->next;
		}

		/* Give the item free */
		order->type = OT_NOTHING;
		order->next = NULL;

		u = GetFirstVehicleFromSharedList(v);
		DeleteOrderWarnings(u);
		for (; u != NULL; u = u->next_shared) {
			u->num_orders--;

			if (sel_ord < u->cur_order_index)
				u->cur_order_index--;

			/* If we removed the last order, make sure the shared vehicles
			 * also set their orders to NULL */
			if (v->orders == NULL) u->orders = NULL;

			assert(v->orders == u->orders);

			/* NON-stop flag is misused to see if a train is in a station that is
			 * on his order list or not */
			if (sel_ord == u->cur_order_index && u->current_order.type == OT_LOADING &&
					HASBIT(u->current_order.flags, OFB_NON_STOP)) {
				u->current_order.flags = 0;
			}

			/* Update any possible open window of the vehicle */
			InvalidateVehicleOrder(u);
		}

		RebuildVehicleLists();
	}

	return 0;
}

/** Goto next order of order-list.
 * @param tile unused
 * @param p1 The ID of the vehicle which order is skipped
 * @param p2 unused
 */
int32 CmdSkipOrder(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
{
	Vehicle *v;
	VehicleID veh_id = p1;

	if (!IsValidVehicleID(veh_id)) return CMD_ERROR;

	v = GetVehicle(veh_id);

	if (!CheckOwnership(v->owner)) return CMD_ERROR;

	if (flags & DC_EXEC) {
		/* Goto next order */
		VehicleOrderID b = v->cur_order_index + 1;
		if (b >= v->num_orders) b = 0;

		v->cur_order_index = b;

		if (v->type == VEH_Train) v->u.rail.days_since_order_progr = 0;

		if (v->type == VEH_Road) ClearSlot(v);

		/* NON-stop flag is misused to see if a train is in a station that is
		 * on his order list or not */
		if (v->current_order.type == OT_LOADING && HASBIT(v->current_order.flags, OFB_NON_STOP))
			v->current_order.flags = 0;

		InvalidateVehicleOrder(v);
	}

	/* We have an aircraft/ship, they have a mini-schedule, so update them all */
	if (v->type == VEH_Aircraft) InvalidateWindowClasses(WC_AIRCRAFT_LIST);
	if (v->type == VEH_Ship) InvalidateWindowClasses(WC_SHIPS_LIST);

	return 0;
}


/** Modify an order in the orderlist of a vehicle.
 * @param tile unused
 * @param p1 various bitstuffed elements
 * - p1 = (bit  0 - 15) - ID of the vehicle
 * - p1 = (bit 16 - 31) - the selected order (if any). If the last order is given,
 *                        the order will be inserted before that one
 *                        only the first 8 bits used currently (bit 16 - 23) (max 255)
 * @param p2 mode to change the order to (always set)
 */
int32 CmdModifyOrder(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
{
	Vehicle *v;
	Order *order;
	VehicleOrderID sel_ord = GB(p1, 16, 16); // XXX - automatically truncated to 8 bits.
	VehicleID veh   = GB(p1,  0, 16);

	if (!IsValidVehicleID(veh)) return CMD_ERROR;
	if (p2 != OFB_FULL_LOAD && p2 != OFB_UNLOAD && p2 != OFB_NON_STOP && p2 != OFB_TRANSFER) return CMD_ERROR;

	v = GetVehicle(veh);

	if (!CheckOwnership(v->owner)) return CMD_ERROR;

	/* Is it a valid order? */
	if (sel_ord >= v->num_orders) return CMD_ERROR;

	order = GetVehicleOrder(v, sel_ord);
	if (order->type != OT_GOTO_STATION &&
			(order->type != OT_GOTO_DEPOT    || p2 == OFB_UNLOAD) &&
			(order->type != OT_GOTO_WAYPOINT || p2 != OFB_NON_STOP)) {
		return CMD_ERROR;
	}

	if (flags & DC_EXEC) {
		switch (p2) {
		case OFB_FULL_LOAD:
			TOGGLEBIT(order->flags, OFB_FULL_LOAD);
			if (order->type != OT_GOTO_DEPOT) CLRBIT(order->flags, OFB_UNLOAD);
			break;
		case OFB_UNLOAD:
			TOGGLEBIT(order->flags, OFB_UNLOAD);
			CLRBIT(order->flags, OFB_FULL_LOAD);
			break;
		case OFB_NON_STOP:
			TOGGLEBIT(order->flags, OFB_NON_STOP);
			break;
		case OFB_TRANSFER:
			TOGGLEBIT(order->flags, OFB_TRANSFER);
			break;
		default: NOT_REACHED();
		}

		/* Update the windows and full load flags, also for vehicles that share the same order list */
		{
			Vehicle* u;

			u = GetFirstVehicleFromSharedList(v);
			DeleteOrderWarnings(u);
			for (; u != NULL; u = u->next_shared) {
				/* toggle u->current_order "Full load" flag if it changed */
				if (sel_ord == u->cur_order_index &&
						HASBIT(u->current_order.flags, OFB_FULL_LOAD) != HASBIT(order->flags, OFB_FULL_LOAD)) {
					TOGGLEBIT(u->current_order.flags, OFB_FULL_LOAD);
				}
				InvalidateVehicleOrder(u);
			}
		}
	}

	return 0;
}

/** Clone/share/copy an order-list of an other vehicle.
 * @param p1 various bitstuffed elements
 * - p1 = (bit  0-15) - destination vehicle to clone orders to (p1 & 0xFFFF)
 * - p1 = (bit 16-31) - source vehicle to clone orders from, if any (none for CO_UNSHARE)
 * @param p2 mode of cloning: CO_SHARE, CO_COPY, or CO_UNSHARE
 */
int32 CmdCloneOrder(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
{
	Vehicle *dst;
	VehicleID veh_src = GB(p1, 16, 16);
	VehicleID veh_dst = GB(p1,  0, 16);

	if (!IsValidVehicleID(veh_dst)) return CMD_ERROR;

	dst = GetVehicle(veh_dst);

	if (!CheckOwnership(dst->owner)) return CMD_ERROR;

	switch (p2) {
		case CO_SHARE: {
			Vehicle *src;

			if (!IsValidVehicleID(veh_src)) return CMD_ERROR;

			src = GetVehicle(veh_src);

			/* Sanity checks */
			if (!CheckOwnership(src->owner) || dst->type != src->type || dst == src)
				return CMD_ERROR;

			/* Trucks can't share orders with busses (and visa versa) */
			if (src->type == VEH_Road) {
				if (src->cargo_type != dst->cargo_type && (src->cargo_type == CT_PASSENGERS || dst->cargo_type == CT_PASSENGERS))
					return CMD_ERROR;
			}

			/* Is the vehicle already in the shared list? */
			{
				const Vehicle* u;

				for (u = GetFirstVehicleFromSharedList(src); u != NULL; u = u->next_shared) {
					if (u == dst) return CMD_ERROR;
				}
			}

			if (flags & DC_EXEC) {
				/* If the destination vehicle had a OrderList, destroy it */
				DeleteVehicleOrders(dst);

				dst->orders = src->orders;
				dst->num_orders = src->num_orders;

				/* Link this vehicle in the shared-list */
				dst->next_shared = src->next_shared;
				dst->prev_shared = src;
				if (src->next_shared != NULL) src->next_shared->prev_shared = dst;
				src->next_shared = dst;

				InvalidateVehicleOrder(dst);
				InvalidateVehicleOrder(src);

				RebuildVehicleLists();
			}
		} break;

		case CO_COPY: {
			Vehicle *src;
			int delta;

			if (!IsValidVehicleID(veh_src)) return CMD_ERROR;

			src = GetVehicle(veh_src);

			/* Sanity checks */
			if (!CheckOwnership(src->owner) || dst->type != src->type || dst == src)
				return CMD_ERROR;

			/* Trucks can't copy all the orders from busses (and visa versa) */
			if (src->type == VEH_Road) {
				const Order *order;
				TileIndex required_dst = INVALID_TILE;

				FOR_VEHICLE_ORDERS(src, order) {
					if (order->type == OT_GOTO_STATION) {
						const Station *st = GetStation(order->dest);
						if (dst->cargo_type == CT_PASSENGERS) {
							if (st->bus_stops != NULL) required_dst = st->bus_stops->xy;
						} else {
							if (st->truck_stops != NULL) required_dst = st->truck_stops->xy;
						}
						/* This station has not the correct road-bay, so we can't copy! */
						if (required_dst == INVALID_TILE)
							return CMD_ERROR;
					}
				}
			}

			/* make sure there are orders available */
			delta = IsOrderListShared(dst) ? src->num_orders + 1 : src->num_orders - dst->num_orders;
			if (!HasOrderPoolFree(delta))
				return_cmd_error(STR_8831_NO_MORE_SPACE_FOR_ORDERS);

			if (flags & DC_EXEC) {
				const Order *order;
				Order **order_dst;

				/* If the destination vehicle had a OrderList, destroy it */
				DeleteVehicleOrders(dst);

				order_dst = &dst->orders;
				FOR_VEHICLE_ORDERS(src, order) {
					*order_dst = AllocateOrder();
					AssignOrder(*order_dst, *order);
					order_dst = &(*order_dst)->next;
				}

				dst->num_orders = src->num_orders;

				InvalidateVehicleOrder(dst);

				RebuildVehicleLists();
			}
		} break;

		case CO_UNSHARE: return DecloneOrder(dst, flags);
		default: return CMD_ERROR;
	}

	return 0;
}

/** Add/remove refit orders from an order
 * @param tile Not used
 * @param p1 VehicleIndex of the vehicle having the order
 * @param p2 bitmask
 *   - bit 0-7 CargoID
 *   - bit 8-15 Cargo subtype
 *   - bit 16-23 number of order to modify
 */
int32 CmdOrderRefit(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
{
	const Vehicle *v;
	Order *order;
	VehicleID veh = GB(p1, 0, 16);
	VehicleOrderID order_number  = GB(p2, 16, 8);
	CargoID cargo = GB(p2, 0, 8);
	byte subtype  = GB(p2, 8, 8);

	if (!IsValidVehicleID(veh)) return CMD_ERROR;

	v = GetVehicle(veh);

	if (!CheckOwnership(v->owner)) return CMD_ERROR;

	order = GetVehicleOrder(v, order_number);
	if (order == NULL) return CMD_ERROR;

	if (flags & DC_EXEC) {
		Vehicle *u;

		order->refit_cargo = cargo;
		order->refit_subtype = subtype;

		u = GetFirstVehicleFromSharedList(v);
		for (; u != NULL; u = u->next_shared) {
			/* Update any possible open window of the vehicle */
			InvalidateVehicleOrder(u);

			/* If the vehicle already got the current depot set as current order, then update current order as well */
			if (u->cur_order_index == order_number && HASBIT(u->current_order.flags, OFB_PART_OF_ORDERS)) {
				u->current_order.refit_cargo = cargo;
				u->current_order.refit_subtype = subtype;
			}
		}
	}

	return 0;
}

/**
 *
 * Backup a vehicle order-list, so you can replace a vehicle
 *  without loosing the order-list
 *
 */
void BackupVehicleOrders(const Vehicle *v, BackuppedOrders *bak)
{
	/* Save general info */
	bak->orderindex       = v->cur_order_index;
	bak->service_interval = v->service_interval;

	/* Safe custom string, if any */
	if (!IsCustomName(v->string_id)) {
		bak->name[0] = '\0';
	} else {
		GetName(bak->name, v->string_id & 0x7FF, lastof(bak->name));
	}

	/* If we have shared orders, store it on a special way */
	if (IsOrderListShared(v)) {
		const Vehicle *u = (v->next_shared) ? v->next_shared : v->prev_shared;

		bak->clone = u->index;
	} else {
		/* Else copy the orders */
		Order *order, *dest;

		dest = bak->order;

		/* We do not have shared orders */
		bak->clone = INVALID_VEHICLE;

		/* Copy the orders */
		FOR_VEHICLE_ORDERS(v, order) {
			*dest = *order;
			dest++;
		}
		/* End the list with an OT_NOTHING */
		dest->type = OT_NOTHING;
		dest->next = NULL;
	}
}

/**
 *
 * Restore vehicle orders that are backupped via BackupVehicleOrders
 *
 */
void RestoreVehicleOrders(const Vehicle* v, const BackuppedOrders* bak)
{
	uint i;

	/* If we have a custom name, process that */
	if (bak->name[0] != 0) {
		_cmd_text = bak->name;
		DoCommandP(0, v->index, 0, NULL, CMD_NAME_VEHICLE);
	}

	/* If we had shared orders, recover that */
	if (bak->clone != INVALID_VEHICLE) {
		DoCommandP(0, v->index | (bak->clone << 16), 0, NULL, CMD_CLONE_ORDER);
		return;
	}

	/* CMD_NO_TEST_IF_IN_NETWORK is used here, because CMD_INSERT_ORDER checks if the
	 *  order number is one more than the current amount of orders, and because
	 *  in network the commands are queued before send, the second insert always
	 *  fails in test mode. By bypassing the test-mode, that no longer is a problem. */
	for (i = 0; bak->order[i].type != OT_NOTHING; i++) {
		if (!DoCommandP(0, v->index + (i << 16), PackOrder(&bak->order[i]), NULL, CMD_INSERT_ORDER | CMD_NO_TEST_IF_IN_NETWORK))
			break;
	}

	/* Restore vehicle order-index and service interval */
	DoCommandP(0, v->index, bak->orderindex | (bak->service_interval << 16) , NULL, CMD_RESTORE_ORDER_INDEX);
}

/** Restore the current order-index of a vehicle and sets service-interval.
 * @param tile unused
 * @param p1 the ID of the vehicle
 * @param p2 various bistuffed elements
 * - p2 = (bit  0-15) - current order-index (p2 & 0xFFFF)
 * - p2 = (bit 16-31) - service interval (p2 >> 16)
 * @todo Unfortunately you cannot safely restore the unitnumber or the old vehicle
 * as far as I can see. We can store it in BackuppedOrders, and restore it, but
 * but we have no way of seeing it has been tampered with or not, as we have no
 * legit way of knowing what that ID was.@n
 * If we do want to backup/restore it, just add UnitID uid to BackuppedOrders, and
 * restore it as parameter 'y' (ugly hack I know) for example. "v->unitnumber = y;"
 */
int32 CmdRestoreOrderIndex(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
{
	Vehicle *v;
	VehicleOrderID cur_ord = GB(p2,  0, 16);
	uint16 serv_int = GB(p2, 16, 16);

	if (!IsValidVehicleID(p1)) return CMD_ERROR;

	v = GetVehicle(p1);

	/* Check the vehicle type and ownership, and if the service interval and order are in range */
	if (!CheckOwnership(v->owner)) return CMD_ERROR;
	if (serv_int != GetServiceIntervalClamped(serv_int) || cur_ord >= v->num_orders) return CMD_ERROR;

	if (flags & DC_EXEC) {
		v->cur_order_index = cur_ord;
		v->service_interval = serv_int;
	}

	return 0;
}


static TileIndex GetStationTileForVehicle(const Vehicle* v, const Station* st)
{
	switch (v->type) {
		default: NOT_REACHED();
		case VEH_Train:     return st->train_tile;
		case VEH_Aircraft:  return st->airport_tile;
		case VEH_Ship:      return st->dock_tile;
		case VEH_Road:
			if (v->cargo_type == CT_PASSENGERS) {
				return (st->bus_stops != NULL) ? st->bus_stops->xy : 0;
			} else {
				return (st->truck_stops != NULL) ? st->truck_stops->xy : 0;
			}
	}
}


/**
 *
 * Check the orders of a vehicle, to see if there are invalid orders and stuff
 *
 */
void CheckOrders(const Vehicle* v)
{
	/* Does the user wants us to check things? */
	if (_patches.order_review_system == 0) return;

	/* Do nothing for crashed vehicles */
	if (v->vehstatus & VS_CRASHED) return;

	/* Do nothing for stopped vehicles if setting is '1' */
	if (_patches.order_review_system == 1 && v->vehstatus & VS_STOPPED)
		return;

	/* do nothing we we're not the first vehicle in a share-chain */
	if (v->next_shared != NULL) return;

	/* Only check every 20 days, so that we don't flood the message log */
	if (v->owner == _local_player && v->day_counter % 20 == 0) {
		int n_st, problem_type = -1;
		const Order *order;
		int message = 0;

		/* Check the order list */
		n_st = 0;

		FOR_VEHICLE_ORDERS(v, order) {
			/* Dummy order? */
			if (order->type == OT_DUMMY) {
				problem_type = 1;
				break;
			}
			/* Does station have a load-bay for this vehicle? */
			if (order->type == OT_GOTO_STATION) {
				const Station* st = GetStation(order->dest);
				TileIndex required_tile = GetStationTileForVehicle(v, st);

				n_st++;
				if (required_tile == 0) problem_type = 3;
			}
		}

		/* Check if the last and the first order are the same */
		if (v->num_orders > 1) {
			const Order* last = GetLastVehicleOrder(v);

			if (v->orders->type  == last->type &&
					v->orders->flags == last->flags &&
					v->orders->dest  == last->dest) {
				problem_type = 2;
			}
		}

		/* Do we only have 1 station in our order list? */
		if (n_st < 2 && problem_type == -1) problem_type = 0;

		/* We don't have a problem */
		if (problem_type < 0) return;

		message = STR_TRAIN_HAS_TOO_FEW_ORDERS + ((v->type - VEH_Train) << 2) + problem_type;
		//DEBUG(misc, 3) ("Triggered News Item for %d", v->index);

		SetDParam(0, v->unitnumber);
		AddNewsItem(
			message,
			NEWS_FLAGS(NM_SMALL, NF_VIEWPORT | NF_VEHICLE, NT_ADVICE, 0),
			v->index,
			0
		);
	}
}

/**
 * Removes an order from all vehicles. Triggers when, say, a station is removed.
 * @param type The type of the order (OT_GOTO_[STATION|DEPOT|WAYPOINT]).
 * @param destination The destination. Can be a StationID, DepotID or WaypointID.
 */
void RemoveOrderFromAllVehicles(OrderType type, DestinationID destination)
{
	Vehicle *v;

	/* Aircraft have StationIDs for depot orders and never use DepotIDs
	 * This fact is handled specially below
	 */

	/* Go through all vehicles */
	FOR_ALL_VEHICLES(v) {
		Order *order;
		bool invalidate;

		/* Forget about this station if this station is removed */
		if (v->last_station_visited == destination && type == OT_GOTO_STATION) {
			v->last_station_visited = INVALID_STATION;
		}

		order = &v->current_order;
		if ((v->type == VEH_Aircraft && order->type == OT_GOTO_DEPOT ? OT_GOTO_STATION : order->type) == type &&
				v->current_order.dest == destination) {
			order->type = OT_DUMMY;
			order->flags = 0;
			InvalidateWindow(WC_VEHICLE_VIEW, v->index);
		}

		/* Clear the order from the order-list */
		invalidate = false;
		FOR_VEHICLE_ORDERS(v, order) {
			if ((v->type == VEH_Aircraft && order->type == OT_GOTO_DEPOT ? OT_GOTO_STATION : order->type) == type &&
					order->dest == destination) {
				order->type = OT_DUMMY;
				order->flags = 0;
				invalidate = true;
			}
		}

		/* Only invalidate once, and if needed */
		if (invalidate) InvalidateWindow(WC_VEHICLE_ORDERS, v->index);
	}
}

/**
 *
 * Checks if a vehicle has a GOTO_DEPOT in his order list
 *
 * @return True if this is true (lol ;))
 *
 */
bool VehicleHasDepotOrders(const Vehicle *v)
{
	const Order *order;

	FOR_VEHICLE_ORDERS(v, order) {
		if (order->type == OT_GOTO_DEPOT)
			return true;
	}

	return false;
}

/**
 *
 * Delete all orders from a vehicle
 *
 */
void DeleteVehicleOrders(Vehicle *v)
{
	Order *cur, *next;

	DeleteOrderWarnings(v);

	/* If we have a shared order-list, don't delete the list, but just
	    remove our pointer */
	if (IsOrderListShared(v)) {
		const Vehicle *u = v;

		v->orders = NULL;
		v->num_orders = 0;

		/* Unlink ourself */
		if (v->prev_shared != NULL) {
			v->prev_shared->next_shared = v->next_shared;
			u = v->prev_shared;
		}
		if (v->next_shared != NULL) {
			v->next_shared->prev_shared = v->prev_shared;
			u = v->next_shared;
		}
		v->prev_shared = NULL;
		v->next_shared = NULL;

		/* We only need to update this-one, because if there is a third
		 *  vehicle which shares the same order-list, nothing will change. If
		 *  this is the last vehicle, the last line of the order-window
		 *  will change from Shared order list, to Order list, so it needs
		 *  an update */
		InvalidateVehicleOrder(u);
		return;
	}

	/* Remove the orders */
	cur = v->orders;
	v->orders = NULL;
	v->num_orders = 0;

	if (cur != NULL) {
		/* Delete the vehicle list of shared orders, if any */
		int window_type = 0;

		switch (v->type) {
			case VEH_Train:    window_type = WC_TRAINS_LIST;   break;
			case VEH_Road:     window_type = WC_ROADVEH_LIST;  break;
			case VEH_Ship:     window_type = WC_SHIPS_LIST;    break;
			case VEH_Aircraft: window_type = WC_AIRCRAFT_LIST; break;
			default: NOT_REACHED();
		}
		DeleteWindowById(window_type, (cur->index << 16) | (v->type << 11) | VLW_SHARED_ORDERS | v->owner);
	}

	while (cur != NULL) {
		next = cur->next;
		DeleteOrder(cur);
		cur = next;
	}
}

/**
 *
 * Check if we share our orders with an other vehicle
 *
 * @return Returns the vehicle who has the same order
 *
 */
bool IsOrderListShared(const Vehicle *v)
{
	return v->next_shared != NULL || v->prev_shared != NULL;
}

/**
 *
 * Check if a vehicle has any valid orders
 *
 * @return false if there are no valid orders
 *
 */
bool CheckForValidOrders(const Vehicle* v)
{
	const Order *order;

	FOR_VEHICLE_ORDERS(v, order) if (order->type != OT_DUMMY) return true;

	return false;
}

void InitializeOrders(void)
{
	CleanPool(&_Order_pool);
	AddBlockToPool(&_Order_pool);

	_backup_orders_tile = 0;
}

static const SaveLoad _order_desc[] = {
	SLE_VAR(Order, type,  SLE_UINT8),
	SLE_VAR(Order, flags, SLE_UINT8),
	SLE_VAR(Order, dest,  SLE_UINT16),
	SLE_REF(Order, next,  REF_ORDER),
	SLE_CONDVAR(Order, refit_cargo,    SLE_UINT8, 36, SL_MAX_VERSION),
	SLE_CONDVAR(Order, refit_subtype,  SLE_UINT8, 36, SL_MAX_VERSION),

	/* Leftover from the minor savegame version stuff
	 * We will never use those free bytes, but we have to keep this line to allow loading of old savegames */
	SLE_CONDNULL(10, 5, 35),
	SLE_END()
};

static void Save_ORDR(void)
{
	Order *order;

	FOR_ALL_ORDERS(order) {
		SlSetArrayIndex(order->index);
		SlObject(order, _order_desc);
	}
}

static void Load_ORDR(void)
{
	if (CheckSavegameVersionOldStyle(5, 2)) {
		/* Version older than 5.2 did not have a ->next pointer. Convert them
		    (in the old days, the orderlist was 5000 items big) */
		uint len = SlGetFieldLength();
		uint i;

		if (CheckSavegameVersion(5)) {
			/* Pre-version 5 had an other layout for orders
			    (uint16 instead of uint32) */
			uint16 orders[5000];

			len /= sizeof(uint16);
			assert (len <= lengthof(orders));

			SlArray(orders, len, SLE_UINT16);

			for (i = 0; i < len; ++i) {
				if (!AddBlockIfNeeded(&_Order_pool, i))
					error("Orders: failed loading savegame: too many orders");

				AssignOrder(GetOrder(i), UnpackVersion4Order(orders[i]));
			}
		} else if (CheckSavegameVersionOldStyle(5, 2)) {
			uint32 orders[5000];

			len /= sizeof(uint32);
			assert (len <= lengthof(orders));

			SlArray(orders, len, SLE_UINT32);

			for (i = 0; i < len; ++i) {
				if (!AddBlockIfNeeded(&_Order_pool, i))
					error("Orders: failed loading savegame: too many orders");

				AssignOrder(GetOrder(i), UnpackOrder(orders[i]));
			}
		}

		/* Update all the next pointer */
		for (i = 1; i < len; ++i) {
			/* The orders were built like this:
			 *   Vehicle one had order[0], and as long as order++.type was not
			 *   OT_NOTHING, it was part of the order-list of that vehicle */
			if (GetOrder(i)->type != OT_NOTHING)
				GetOrder(i - 1)->next = GetOrder(i);
		}
	} else {
		int index;

		while ((index = SlIterateArray()) != -1) {
			Order *order;

			if (!AddBlockIfNeeded(&_Order_pool, index))
				error("Orders: failed loading savegame: too many orders");

			order = GetOrder(index);
			SlObject(order, _order_desc);
		}
	}
}

const ChunkHandler _order_chunk_handlers[] = {
	{ 'ORDR', Save_ORDR, Load_ORDR, CH_ARRAY | CH_LAST},
};