/* $Id$ */

/** @file ai_order.cpp handles the functions of the AIOrder class */

#include "ai_order.hpp"
#include "ai_map.hpp"
#include "ai_vehicle.hpp"
#include "../../command.h"
#include "../../order.h"
#include "../../vehicle.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_STREET:  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;
	}
}

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

TileIndex AIOrder::GetOrderDestination(VehicleID vehicle_id, uint32 order_id)
{
	if (!AIOrder::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->type) {
		case OT_GOTO_DEPOT:    return ::GetDepot(order->dest)->xy;
		case OT_GOTO_STATION:  return ::GetStation(order->dest)->xy;
		case OT_GOTO_WAYPOINT: return ::GetWaypoint(order->dest)->xy;
		default:               return INVALID_TILE;
	}
}

AIOrder::AIOrderFlags AIOrder::GetOrderFlags(VehicleID vehicle_id, uint32 order_id)
{
	if (!AIOrder::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;

	return (AIOrder::AIOrderFlags)order->flags;
}

bool AIOrder::AppendOrder(VehicleID vehicle_id, TileIndex destination, AIOrderFlags order_flags)
{
	if (!AIVehicle::IsValidVehicle(vehicle_id)) return false;
	return this->InsertOrder(vehicle_id, GetVehicle(vehicle_id)->num_orders, destination, order_flags);
}

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. */
	if (!AIVehicle::IsValidVehicle(vehicle_id) || order_id > ::GetVehicle(vehicle_id)->num_orders ||
		!this->AreOrderFlagsValid(destination, order_flags)) return false;

	Order order;
	order.type  = ::GetOrderTypeByTile(destination);
	order.flags = order_flags;
	switch (order.type) {
		case OT_GOTO_DEPOT:    order.dest = ::GetDepotByTile(destination)->index; break;
		case OT_GOTO_STATION:  order.dest = ::GetStationIndex(destination);       break;
		case OT_GOTO_WAYPOINT: order.dest = ::GetWaypointIndex(destination);      break;
		default: NOT_REACHED(); return false;
	}

	return this->DoCommand(0, vehicle_id | (order_id << 16), PackOrder(&order), CMD_INSERT_ORDER);
}

bool AIOrder::RemoveOrder(VehicleID vehicle_id, uint32 order_id)
{
	if (!IsValidVehicleOrder(vehicle_id, order_id)) return false;

	return this->DoCommand(0, vehicle_id, order_id, CMD_DELETE_ORDER);
}

bool AIOrder::ChangeOrder(VehicleID vehicle_id, uint32 order_id, AIOrder::AIOrderFlags order_flags)
{
	if (!IsValidVehicleOrder(vehicle_id, order_id) ||
		!this->AreOrderFlagsValid(GetOrderDestination(vehicle_id, order_id), order_flags)) return false;

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

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

bool AIOrder::CopyOrders(VehicleID vehicle_id, VehicleID main_vehicle_id)
{
	if (!AIVehicle::IsValidVehicle(vehicle_id) || !AIVehicle::IsValidVehicle(main_vehicle_id)) return false;

	return this->DoCommand(0, vehicle_id | (main_vehicle_id << 16), CO_COPY, CMD_CLONE_ORDER);
}

bool AIOrder::ShareOrders(VehicleID vehicle_id, VehicleID main_vehicle_id)
{
	if (!AIVehicle::IsValidVehicle(vehicle_id) || !AIVehicle::IsValidVehicle(main_vehicle_id)) return false;

	return this->DoCommand(0, vehicle_id | (main_vehicle_id << 16), CO_SHARE, CMD_CLONE_ORDER);
}

bool AIOrder::UnshareOrders(VehicleID vehicle_id)
{
	if (!AIVehicle::IsValidVehicle(vehicle_id)) return false;

	return this->DoCommand(0, vehicle_id, CO_UNSHARE, CMD_CLONE_ORDER);
}