/* $Id$ */

/** @file ai_order.cpp Implementation of AIOrder. */

#include "ai_order.hpp"
#include "ai_map.hpp"
#include "ai_vehicle.hpp"
#include "../../command_type.h"
#include "../../vehicle_base.h"
#include "../../depot.h"
#include "../../landscape.h"
#include "../../rail_map.h"
#include "../../road_map.h"
#include "../../station_map.h"
#include "../../water_map.h"
#include "../../waypoint.h"

/**
 * Gets the order type given a tile
 * @param t the tile to get the order from
 * @return the order type, or OT_END when there is no order
 */
static OrderType GetOrderTypeByTile(TileIndex t)
{
	if (!::IsValidTile(t)) return OT_END;

	switch (::GetTileType(t)) {
		default: break;
		case MP_STATION: return OT_GOTO_STATION; break;
		case MP_WATER:   if (::IsShipDepot(t)) return OT_GOTO_DEPOT; break;
		case MP_ROAD:    if (::GetRoadTileType(t) == ROAD_TILE_DEPOT) return OT_GOTO_DEPOT; break;
		case MP_RAILWAY:
			switch (::GetRailTileType(t)) {
				case RAIL_TILE_DEPOT:    return OT_GOTO_DEPOT;
				case RAIL_TILE_WAYPOINT: return OT_GOTO_WAYPOINT;
				default: break;
			}
			break;
	}

	return OT_END;
}

/* static */ bool AIOrder::IsValidVehicleOrder(VehicleID vehicle_id, uint32 order_id)
{
	return AIVehicle::IsValidVehicle(vehicle_id) && order_id < ::GetVehicle(vehicle_id)->num_orders;
}

/* static */ bool AIOrder::AreOrderFlagsValid(TileIndex destination, AIOrderFlags order_flags)
{
	switch (::GetOrderTypeByTile(destination)) {
		case OT_GOTO_DEPOT:    return (order_flags & ~(AIOF_NON_STOP | AIOF_SERVICE_IF_NEEDED)) == 0;
		case OT_GOTO_STATION:  return (order_flags & ~(AIOF_NON_STOP | AIOF_TRANSFER | AIOF_UNLOAD | AIOF_FULL_LOAD)) == 0 && ((order_flags & AIOF_UNLOAD) == 0 || (order_flags & AIOF_FULL_LOAD) == 0);
		case OT_GOTO_WAYPOINT: return (order_flags & ~(AIOF_NON_STOP)) == 0;
		default:               return false;
	}
}

/* static */ int32 AIOrder::GetNumberOfOrders(VehicleID vehicle_id)
{
	return AIVehicle::IsValidVehicle(vehicle_id) ? ::GetVehicle(vehicle_id)->num_orders : -1;
}

/* static */ TileIndex AIOrder::GetOrderDestination(VehicleID vehicle_id, uint32 order_id)
{
	if (!IsValidVehicleOrder(vehicle_id, order_id)) return INVALID_TILE;

	Order *order = ::GetVehicle(vehicle_id)->orders;
	for (uint i = 0; i < order_id; i++) order = order->next;

	switch (order->GetType()) {
		case OT_GOTO_DEPOT:    return ::GetDepot(order->GetDestination())->xy;
		case OT_GOTO_STATION:  return ::GetStation(order->GetDestination())->xy;
		case OT_GOTO_WAYPOINT: return ::GetWaypoint(order->GetDestination())->xy;
		default:               return INVALID_TILE;
	}
}

/* static */ AIOrder::AIOrderFlags AIOrder::GetOrderFlags(VehicleID vehicle_id, uint32 order_id)
{
	if (!IsValidVehicleOrder(vehicle_id, order_id)) return AIOF_INVALID;

	Order *order = ::GetVehicle(vehicle_id)->orders;
	for (uint i = 0; i < order_id; i++) order = order->next;

	AIOrderFlags order_flags= AIOF_NONE;
	if (order->GetNonStopType() != OFB_NO_NON_STOP) order_flags |= AIOF_NON_STOP;
	switch (order->GetType()) {
		case OT_GOTO_DEPOT:
			if (order->GetDepotOrderType() & OFB_SERVICE_IF_NEEDED) order_flags |= AIOF_SERVICE_IF_NEEDED;
			break;

		case OT_GOTO_STATION:
			if (order->GetLoadType()   & OFB_FULL_LOAD) order_flags |= AIOF_FULL_LOAD;
			if (order->GetUnloadType() & OFB_UNLOAD)    order_flags |= AIOF_UNLOAD;
			if (order->GetUnloadType() & OFB_TRANSFER)  order_flags |= AIOF_TRANSFER;
			break;

		default: break;
	}

	return order_flags;
}

/* static */ bool AIOrder::AppendOrder(VehicleID vehicle_id, TileIndex destination, AIOrderFlags order_flags)
{
	EnforcePrecondition(false, AIVehicle::IsValidVehicle(vehicle_id));
	return InsertOrder(vehicle_id, ::GetVehicle(vehicle_id)->num_orders, destination, order_flags);
}

/* static */ bool AIOrder::InsertOrder(VehicleID vehicle_id, uint32 order_id, TileIndex destination, AIOrder::AIOrderFlags order_flags)
{
	/* IsValidVehicleOrder is not good enough because it does not allow appending. */
	EnforcePrecondition(false, AIVehicle::IsValidVehicle(vehicle_id));
	EnforcePrecondition(false, order_id <= ::GetVehicle(vehicle_id)->num_orders);
	EnforcePrecondition(false, AreOrderFlagsValid(destination, order_flags));

	Order order;
	switch (::GetOrderTypeByTile(destination)) {
		case OT_GOTO_DEPOT:
			order.MakeGoToDepot(::GetDepotByTile(destination)->index, true);
			if (order_flags & AIOF_SERVICE_IF_NEEDED) order.SetDepotOrderType(OFB_SERVICE_IF_NEEDED);
			break;

		case OT_GOTO_STATION:
			order.MakeGoToStation(::GetStationIndex(destination));
			if (order_flags & AIOF_FULL_LOAD) order.SetLoadType(OFB_FULL_LOAD);
			order.SetUnloadType(((order_flags & AIOF_TRANSFER) ? OFB_TRANSFER : 0) | ((order_flags & AIOF_UNLOAD) ? OFB_UNLOAD : 0));
			break;

		case OT_GOTO_WAYPOINT:
			order.MakeGoToWaypoint(::GetWaypointIndex(destination));
			break;

		default:
			return false;
	}

	if (order_flags & AIOF_NON_STOP) order.SetNonStopType(OFB_NON_STOP);

	return AIObject::DoCommand(0, vehicle_id | (order_id << 16), order.Pack(), CMD_INSERT_ORDER);
}

/* static */ bool AIOrder::RemoveOrder(VehicleID vehicle_id, uint32 order_id)
{
	EnforcePrecondition(false, IsValidVehicleOrder(vehicle_id, order_id));

	return AIObject::DoCommand(0, vehicle_id, order_id, CMD_DELETE_ORDER);
}

/* static */ bool AIOrder::ChangeOrder(VehicleID vehicle_id, uint32 order_id, AIOrder::AIOrderFlags order_flags)
{
	EnforcePrecondition(false, IsValidVehicleOrder(vehicle_id, order_id));
	EnforcePrecondition(false, AreOrderFlagsValid(GetOrderDestination(vehicle_id, order_id), order_flags));

	for (;;) {
		/* Loop as long as there is a difference between the requested and
		 * the current orders of the vehicle. */
		AIOrderFlags current = GetOrderFlags(vehicle_id, order_id);
		AIOrderFlags diff = current ^ order_flags;
		if (diff == 0) return true;

		bool res = AIObject::DoCommand(0, vehicle_id | (order_id << 16), FIND_FIRST_BIT(diff), CMD_MODIFY_ORDER);
		if (!res) return false;
	}
}

/* static */ bool AIOrder::MoveOrder(VehicleID vehicle_id, uint32 order_id_move, uint32 order_id_target)
{
	EnforcePrecondition(false, IsValidVehicleOrder(vehicle_id, order_id_move));
	EnforcePrecondition(false, IsValidVehicleOrder(vehicle_id, order_id_target));

	return AIObject::DoCommand(0, vehicle_id, order_id_move | (order_id_target << 16), CMD_MOVE_ORDER);
}

/* static */ bool AIOrder::CopyOrders(VehicleID vehicle_id, VehicleID main_vehicle_id)
{
	EnforcePrecondition(false, AIVehicle::IsValidVehicle(vehicle_id));
	EnforcePrecondition(false, AIVehicle::IsValidVehicle(main_vehicle_id));

	return AIObject::DoCommand(0, vehicle_id | (main_vehicle_id << 16), CO_COPY, CMD_CLONE_ORDER);
}

/* static */ bool AIOrder::ShareOrders(VehicleID vehicle_id, VehicleID main_vehicle_id)
{
	EnforcePrecondition(false, AIVehicle::IsValidVehicle(vehicle_id));
	EnforcePrecondition(false, AIVehicle::IsValidVehicle(main_vehicle_id));

	return AIObject::DoCommand(0, vehicle_id | (main_vehicle_id << 16), CO_SHARE, CMD_CLONE_ORDER);
}

/* static */ bool AIOrder::UnshareOrders(VehicleID vehicle_id)
{
	EnforcePrecondition(false, AIVehicle::IsValidVehicle(vehicle_id));

	return AIObject::DoCommand(0, vehicle_id, CO_UNSHARE, CMD_CLONE_ORDER);
}