/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file vehiclelist.cpp Lists of vehicles. */

#include "stdafx.h"
#include "train.h"
#include "vehicle_func.h"
#include "vehiclelist.h"
#include "vehiclelist_func.h"
#include "group.h"
#include "tracerestrict.h"

#include "safeguards.h"

/**
 * Pack a VehicleListIdentifier in a single uint32.
 * @return The packed identifier.
 */
uint32_t VehicleListIdentifier::Pack() const
{
	byte c = this->company == OWNER_NONE ? 0xF : (byte)this->company;
	assert(c             < (1 <<  4));
	assert(this->vtype   < (1 <<  2));
	assert(this->index   < (1 << 20));
	assert(this->type    < VLT_END);
	static_assert(VLT_END <= (1 <<  3));

	return c << 28 | this->type << 23 | this->vtype << 26 | this->index;
}

/**
 * Unpack a VehicleListIdentifier from a single uint32.
 * @param data The data to unpack.
 * @return true iff the data was valid (enough).
 */
bool VehicleListIdentifier::UnpackIfValid(uint32_t data)
{
	byte c        = GB(data, 28, 4);
	this->company = c == 0xF ? OWNER_NONE : (CompanyID)c;
	this->type    = (VehicleListType)GB(data, 23, 3);
	this->vtype   = (VehicleType)GB(data, 26, 2);
	this->index   = GB(data, 0, 20);

	return this->type < VLT_END;
}

/**
 * Decode a packed vehicle list identifier into a new one.
 * @param data The data to unpack.
 */
/* static */ VehicleListIdentifier VehicleListIdentifier::UnPack(uint32_t data)
{
	VehicleListIdentifier result;
	[[maybe_unused]] bool ret = result.UnpackIfValid(data);
	assert(ret);
	return result;
}

/** Data for building a depot vehicle list. */
struct BuildDepotVehicleListData
{
	VehicleList *engines; ///< Pointer to list to add vehicles to.
	VehicleList *wagons; ///< Pointer to list to add wagons to (can be nullptr).
	bool individual_wagons; ///< If true add every wagon to \a wagons which is not attached to an engine. If false only add the first wagon of every row.
};

/**
 * Add vehicles to a depot vehicle list.
 * @param v The found vehicle.
 * @param data The depot vehicle list data.
 * @return Always nullptr.
 */
static Vehicle *BuildDepotVehicleListProc(Vehicle *v, void *data)
{
	auto bdvld = static_cast<BuildDepotVehicleListData *>(data);
	if (HasBit(v->subtype, GVSF_VIRTUAL) || !v->IsInDepot()) return nullptr;

	if (v->type == VEH_TRAIN) {
		const Train *t = Train::From(v);
		if (t->IsArticulatedPart() || t->IsRearDualheaded()) return nullptr;
		if (bdvld->wagons != nullptr && t->First()->IsFreeWagon()) {
			if (bdvld->individual_wagons || t->IsFreeWagon()) bdvld->wagons->push_back(t);
			return nullptr;
		}
	}

	if (v->IsPrimaryVehicle()) bdvld->engines->push_back(v);
	return nullptr;
};

/**
 * Generate a list of vehicles inside a depot.
 * @param type    Type of vehicle
 * @param tile    The tile the depot is located on
 * @param engines Pointer to list to add vehicles to
 * @param wagons  Pointer to list to add wagons to (can be nullptr)
 * @param individual_wagons If true add every wagon to \a wagons which is not attached to an engine. If false only add the first wagon of every row.
 */
void BuildDepotVehicleList(VehicleType type, TileIndex tile, VehicleList *engines, VehicleList *wagons, bool individual_wagons)
{
	engines->clear();
	if (wagons != nullptr && wagons != engines) wagons->clear();

	BuildDepotVehicleListData bdvld{engines, wagons, individual_wagons};
	FindVehicleOnPos(tile, type, &bdvld, BuildDepotVehicleListProc);

	/* Ensure the lists are not wasting too much space. If the lists are fresh
	 * (i.e. built within a command) then this will actually do nothing. */
	engines->shrink_to_fit();
	if (wagons != nullptr && wagons != engines) wagons->shrink_to_fit();
}

/** Cargo filter functions */
bool VehicleCargoFilter(const Vehicle *v, const CargoID cid)
{
	if (cid == CargoFilterCriteria::CF_ANY) {
		return true;
	} else if (cid == CargoFilterCriteria::CF_NONE) {
		for (const Vehicle *w = v; w != nullptr; w = w->Next()) {
			if (w->cargo_cap > 0) {
				return false;
			}
		}
		return true;
	} else if (cid == CargoFilterCriteria::CF_FREIGHT) {
		bool have_capacity = false;
		for (const Vehicle *w = v; w != nullptr; w = w->Next()) {
			if (w->cargo_cap) {
				if (IsCargoInClass(w->cargo_type, CC_PASSENGERS)) {
					return false;
				} else {
					have_capacity = true;
				}
			}
		}
		return have_capacity;
	} else {
		for (const Vehicle *w = v; w != nullptr; w = w->Next()) {
			if (w->cargo_cap > 0 && w->cargo_type == cid) {
				return true;
			}
		}
		return false;
	}
}

/**
 * Generate a list of vehicles based on window type.
 * @param list Pointer to list to add vehicles to
 * @param vli  The identifier of this vehicle list.
 * @return false if invalid list is requested
 */
bool GenerateVehicleSortList(VehicleList *list, const VehicleListIdentifier &vli, const CargoID cid)
{
	list->clear();

	auto add_veh = [&](const Vehicle *v) {
		if (cid == CargoFilterCriteria::CF_ANY || VehicleCargoFilter(v, cid)) list->push_back(v);
	};

	auto fill_all_vehicles = [&]() {
		for (const Vehicle *v : Vehicle::IterateTypeFrontOnly(vli.vtype)) {
			if (!HasBit(v->subtype, GVSF_VIRTUAL) && v->owner == vli.company && v->IsPrimaryVehicle()) {
				add_veh(v);
			}
		}
	};

	switch (vli.type) {
		case VL_STATION_LIST:
			FindVehiclesWithOrder(
				[&vli](const Vehicle *v) { return v->type == vli.vtype; },
				[&vli](const Order *order) { return (order->IsType(OT_GOTO_STATION) || order->IsType(OT_GOTO_WAYPOINT) || order->IsType(OT_IMPLICIT)) && order->GetDestination() == vli.index; },
				[&add_veh](const Vehicle *v) { add_veh(v); }
			);
			break;

		case VL_SHARED_ORDERS: {
			/* Add all vehicles from this vehicle's shared order list */
			const Vehicle *v = Vehicle::GetIfValid(vli.index);
			if (v == nullptr || v->type != vli.vtype || !v->IsPrimaryVehicle()) return false;

			for (; v != nullptr; v = v->NextShared()) {
				add_veh(v);
			}
			break;
		}

		case VL_GROUP_LIST:
			if (vli.index != ALL_GROUP) {
				for (const Vehicle *v : Vehicle::IterateTypeFrontOnly(vli.vtype)) {
					if (!HasBit(v->subtype, GVSF_VIRTUAL) && v->IsPrimaryVehicle() &&
							v->owner == vli.company && GroupIsInGroup(v->group_id, vli.index)) {
						add_veh(v);
					}
				}
				break;
			}
			fill_all_vehicles();
			break;

		case VL_STANDARD:
			fill_all_vehicles();
			break;

		case VL_DEPOT_LIST:
			FindVehiclesWithOrder(
				[&vli](const Vehicle *v) { return v->type == vli.vtype; },
				[&vli](const Order *order) { return order->IsType(OT_GOTO_DEPOT) && !(order->GetDepotActionType() & ODATFB_NEAREST_DEPOT) && order->GetDestination() == vli.index; },
				[&add_veh](const Vehicle *v) { add_veh(v); }
			);
			break;

		case VL_SLOT_LIST: {
			if (vli.index == ALL_TRAINS_TRACE_RESTRICT_SLOT_ID) {
				fill_all_vehicles();
			} else {
				const TraceRestrictSlot *slot = TraceRestrictSlot::GetIfValid(vli.index);
				if (slot == nullptr) return false;
				for (VehicleID id : slot->occupants) {
					add_veh(Vehicle::Get(id));
				}
			}
			break;
		}

		case VL_SINGLE_VEH: {
			const Vehicle *v = Vehicle::GetIfValid(vli.index);
			if (v != nullptr) add_veh(v);
			break;
		}

		default: return false;
	}

	list->shrink_to_fit();
	return true;
}