/*
 * Copyright (C) 2004-2020 by the Widelands Development Team
 *
 * This program 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; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 */

#include "economy/ware_instance.h"

#include <memory>

#include "base/macros.h"
#include "base/wexception.h"
#include "economy/economy.h"
#include "economy/flag.h"
#include "economy/portdock.h"
#include "economy/request.h"
#include "economy/ship_fleet.h"
#include "economy/transfer.h"
#include "io/fileread.h"
#include "io/filewrite.h"
#include "logic/game.h"
#include "logic/map_objects/tribes/ship.h"
#include "logic/map_objects/tribes/tribe_descr.h"
#include "logic/map_objects/tribes/warehouse.h"
#include "logic/map_objects/tribes/worker.h"
#include "map_io/map_object_loader.h"
#include "map_io/map_object_saver.h"

namespace Widelands {

/**
 * Whenever a WareInstance is idle, it issues an IdleWareSupply.
 */
// TODO(unknown): This maybe shouldn't be here.
struct IdleWareSupply : public Supply {
	explicit IdleWareSupply(WareInstance&);
	~IdleWareSupply() override;

	void set_economy(Economy*);

	//  implementation of Supply
	PlayerImmovable* get_position(Game&) override;
	bool is_active() const override;
	SupplyProviders provider_type(Game*) const override;
	bool has_storage() const override;
	void get_ware_type(WareWorker& type, DescriptionIndex& ware) const override;
	void send_to_storage(Game&, Warehouse* wh) override;

	uint32_t nr_supplies(const Game&, const Request&) const override;
	WareInstance& launch_ware(Game&, const Request&) override;
	Worker& launch_worker(Game&, const Request&) override;

private:
	WareInstance& ware_;
	Economy* economy_;
};

/**
 * Initialize the Supply and update the economy.
 */
IdleWareSupply::IdleWareSupply(WareInstance& ware) : ware_(ware), economy_(nullptr) {
	set_economy(ware.get_economy());
}

/**
 * Cleanup.
 */
IdleWareSupply::~IdleWareSupply() {
	set_economy(nullptr);
}

/**
 * Add/remove self from economies as necessary.
 */
void IdleWareSupply::set_economy(Economy* const e) {
	if (economy_ != e) {
		if (economy_)
			economy_->remove_supply(*this);
		if ((economy_ = e))
			economy_->add_supply(*this);
	}
}

/**
 * Figure out the player immovable that this ware belongs to.
 */
PlayerImmovable* IdleWareSupply::get_position(Game& game) {
	MapObject* const loc = ware_.get_location(game);

	if (upcast(PlayerImmovable, playerimmovable, loc))
		return playerimmovable;

	if (upcast(Worker, worker, loc))
		return worker->get_location(game);

	if (upcast(Ship, ship, loc)) {
		if (PortDock* pd = ship->get_destination()) {
			return pd;
		}
		return ship->get_fleet()->get_arbitrary_dock();
	}

	return nullptr;
}

bool IdleWareSupply::is_active() const {
	return true;
}

SupplyProviders IdleWareSupply::provider_type(Game* game) const {
	MapObject* const loc = ware_.get_location(*game);
	if (is_a(Ship, loc)) {
		return SupplyProviders::kShip;
	}
	if (upcast(Worker, worker, loc)) {
		if (worker->is_shipping()) {
			return SupplyProviders::kShip;
		}
	}
	return SupplyProviders::kFlagOrRoad;
}

bool IdleWareSupply::has_storage() const {
	return ware_.is_moving();
}

void IdleWareSupply::get_ware_type(WareWorker& type, DescriptionIndex& ware) const {
	type = wwWARE;
	ware = ware_.descr_index();
}

uint32_t IdleWareSupply::nr_supplies(const Game&, const Request& req) const {
	if (req.get_type() == wwWARE && req.get_index() == ware_.descr_index())
		return 1;

	return 0;
}

/**
 * The ware is already "launched", so we only need to return it.
 */
WareInstance& IdleWareSupply::launch_ware(Game&, const Request& req) {
	if (req.get_type() != wwWARE)
		throw wexception("IdleWareSupply::launch_ware : called for non-ware request");
	if (req.get_index() != ware_.descr_index())
		throw wexception("IdleWareSupply: ware(%u) (type = %i) requested for %i", ware_.serial(),
		                 ware_.descr_index(), req.get_index());

	return ware_;
}

Worker& IdleWareSupply::launch_worker(Game&, const Request&) {
	throw wexception("IdleWareSupply::launch_worker makes no sense");
}

void IdleWareSupply::send_to_storage(Game& game, Warehouse* wh) {
	assert(!has_storage());

	Transfer* t = new Transfer(game, ware_);
	t->set_destination(*wh);
	ware_.set_transfer(game, *t);
}

/*************************************************************************/
/*                     Ware Instance Implementation                      */
/*************************************************************************/
WareInstance::WareInstance(DescriptionIndex const i, const WareDescr* const ware_descr)
   : MapObject(ware_descr),
     economy_(nullptr),
     descr_index_(i),
     supply_(nullptr),
     transfer_(nullptr) {
}

WareInstance::~WareInstance() {
	if (supply_) {
		FORMAT_WARNINGS_OFF
		molog("Ware %u still has supply %p\n", descr_index_, supply_);
		FORMAT_WARNINGS_ON
		delete supply_;
	}
}

bool WareInstance::init(EditorGameBase& egbase) {
	return MapObject::init(egbase);
}

void WareInstance::cleanup(EditorGameBase& egbase) {
	// Unlink from our current location, if necessary
	if (upcast(Flag, flag, location_.get(egbase)))
		flag->remove_ware(egbase, this);

	delete supply_;
	supply_ = nullptr;

	cancel_moving();
	set_location(egbase, nullptr);

	MapObject::cleanup(egbase);
}

/**
 * Ware accounting
 */
void WareInstance::set_economy(Economy* const e) {
	assert(!e || e->type() == wwWARE);
	if (descr_index_ == INVALID_INDEX || economy_ == e)
		return;

	if (economy_)
		economy_->remove_wares_or_workers(descr_index_, 1);

	economy_ = e;
	if (supply_)
		supply_->set_economy(e);

	if (economy_)
		economy_->add_wares_or_workers(descr_index_, 1);
}

/**
 * Change the current location.
 * Once you've assigned a ware to its new location, you usually have to call
 * \ref update() as well.
 */
void WareInstance::set_location(EditorGameBase& egbase, MapObject* const location) {
	MapObject* const oldlocation = location_.get(egbase);

	if (oldlocation == location)
		return;

	location_ = location;

	if (location) {
		Economy* eco = nullptr;

		if (upcast(Flag const, flag, location))
			eco = flag->get_economy(wwWARE);
		else if (upcast(Worker const, worker, location))
			eco = worker->get_economy(wwWARE);
		else if (upcast(PortDock const, portdock, location))
			eco = portdock->get_economy(wwWARE);
		else if (upcast(Ship const, ship, location))
			eco = ship->get_economy(wwWARE);
		else
			throw wexception("WareInstance delivered to bad location %u", location->serial());

		if (oldlocation && get_economy()) {
			if (get_economy() != eco)
				throw wexception("WareInstance::set_location() implies change of economy");
		} else {
			set_economy(eco);
		}
	} else {
		set_economy(nullptr);
	}
}

/**
 * Handle delayed updates.
 */
void WareInstance::act(Game& game, uint32_t) {
	update(game);
}

/**
 * Performs the state updates necessary for the current location:
 * - if it's a building, acknowledge the Request or incorporate into warehouse
 * - if it's a flag and we have no request, start the return to warehouse timer
 * and issue a Supply
 *
 * \note \ref update() may result in the deletion of this object.
 * \note It is important that this function is idempotent, i.e. calling
 *       \ref update() twice in a row should have the same effect as calling
 *       it only once, \em unless the instance is deleted as a side-effect of
 *       \ref update().
 */
void WareInstance::update(Game& game) {
	if (!descr_)  // Upsy, we're not even initialized. Happens on load
		return;

	MapObject* const loc = location_.get(game);

	// Reset our state if we're not on location or outside an economy
	if (!get_economy()) {
		cancel_moving();
		return;
	}

	if (!loc) {
		// Before dying, output as much information as we can.
		log_general_info(game);

		// If our location gets lost, our owner is supposed to destroy us
		throw wexception("WARE(%u): WareInstance::update has no location\n", serial());
	}

	// Update whether we have a Supply or not
	if (!transfer_ || !transfer_->get_request()) {
		if (!supply_) {
			supply_ = new IdleWareSupply(*this);
		}
	} else {
		delete supply_;
		supply_ = nullptr;
	}

	// Deal with transfers
	if (transfer_) {
		upcast(PlayerImmovable, location, loc);

		if (!location) {
			return;  // wait
		}

		bool success;
		PlayerImmovable* const nextstep = transfer_->get_next_step(location, success);
		transfer_nextstep_ = nextstep;

		if (!nextstep) {
			if (upcast(Flag, flag, location))
				flag->call_carrier(game, *this, nullptr);

			Transfer* const t = transfer_;

			transfer_ = nullptr;
			transfer_nextstep_ = nullptr;

			if (success) {
				t->has_finished();
				return;
			} else {
				t->has_failed();

				cancel_moving();
				update(game);
				return;
			}
		}

		if (upcast(Flag, flag, location)) {
			flag->call_carrier(game, *this, dynamic_cast<Building const*>(nextstep) &&
			                                      &nextstep->base_flag() != location ?
			                                   &nextstep->base_flag() :
			                                   nextstep);
		} else if (upcast(PortDock, pd, location)) {
			pd->update_shippingitem(game, *this);
		} else {
			throw wexception(
			   "Ware_Instance::update in bad type of PlayerImmovable %u", location->serial());
		}
	}
}

/**
 * Called by a worker when it carries the ware into the given building.
 */
void WareInstance::enter_building(Game& game, Building& building) {
	if (transfer_) {
		if (transfer_->get_destination(game) == &building) {
			Transfer* t = transfer_;

			transfer_ = nullptr;
			transfer_nextstep_ = nullptr;

			t->has_finished();
			return;
		}

		bool success;
		PlayerImmovable* const nextstep = transfer_->get_next_step(&building, success);
		transfer_nextstep_ = nextstep;

		if (success) {
			assert(nextstep);

			if (upcast(PortDock, pd, nextstep)) {
				pd->add_shippingitem(game, *this);
				return;
			}

			// There are some situations where we might end up in a warehouse
			// as part of a requested route, and we need to move out of it
			// again, e.g.:
			//  - we were requested just when we were being carried into the
			//    warehouse
			//  - we were carried into a harbour/warehouse to be
			//    shipped across the sea, but a better, land-based route has been
			//    found
			if (upcast(Warehouse, warehouse, &building)) {
				warehouse->do_launch_ware(game, *this);
				return;
			}

			throw wexception(
			   "MO(%u): ware(%s): do not know how to move from building %u (%s at (%u,%u)) "
			   "to %u (%s) -> not a warehouse!",
			   serial(), descr_->name().c_str(), building.serial(), building.descr().name().c_str(),
			   building.get_position().x, building.get_position().y, nextstep->serial(),
			   nextstep->descr().name().c_str());
		} else {
			Transfer* t = transfer_;

			transfer_ = nullptr;
			transfer_nextstep_ = nullptr;

			t->has_failed();
			cancel_moving();

			if (is_a(Warehouse, &building)) {
				building.receive_ware(game, descr_index_);
				remove(game);
			} else {
				update(game);
			}
			return;
		}
	} else {
		// We don't have a transfer, so just enter the building
		building.receive_ware(game, descr_index_);
		remove(game);
	}
}

/**
 * Set ware state so that it follows the given transfer.
 *
 * \param t the new transfer (non-zero; use \ref cancel_transfer to stop a
 *          transfer).
 */
void WareInstance::set_transfer(Game& game, Transfer& t) {
	transfer_nextstep_ = nullptr;

	// Reset current transfer
	if (transfer_) {
		transfer_->has_failed();
		transfer_ = nullptr;
	}

	// Set transfer state
	transfer_ = &t;

	delete supply_;
	supply_ = nullptr;

	// Schedule an update.
	// Do not update immediately, because update() could try to reference
	// the Transfer object in a way that is not valid yet (note that this
	// function is called in the Transfer constructor before the Transfer
	// is linked to the corresponding Request).
	schedule_act(game, 1, 0);
}

/**
 * The transfer has been cancelled, just stop moving.
 */
void WareInstance::cancel_transfer(Game& game) {
	transfer_ = nullptr;
	transfer_nextstep_ = nullptr;

	update(game);
}

/**
 * We are moving when there's a transfer, it's that simple.
 */
bool WareInstance::is_moving() const {
	return transfer_;
}

/**
 * Call this function if movement + potential request need to be cancelled for
 * whatever reason.
 */
void WareInstance::cancel_moving() {
	molog("cancel_moving\n");

	if (transfer_) {
		transfer_->has_failed();
		transfer_ = nullptr;
		transfer_nextstep_ = nullptr;
	}
}

/**
 * Return the next flag we should be moving to, or the final target if the route
 * has been completed successfully.
 */
PlayerImmovable* WareInstance::get_next_move_step(Game& game) {
	return transfer_ ? dynamic_cast<PlayerImmovable*>(transfer_nextstep_.get(game)) : nullptr;
}

void WareInstance::log_general_info(const EditorGameBase& egbase) const {
	MapObject::log_general_info(egbase);

	molog("Ware: %s\n", descr().name().c_str());
	molog("Location: %u\n", location_.serial());
}

/*
==============================

Load/save support

==============================
*/

constexpr uint8_t kCurrentPacketVersion = 2;

void WareInstance::Loader::load(FileRead& fr) {
	MapObject::Loader::load(fr);

	WareInstance& ware = get<WareInstance>();
	location_ = fr.unsigned_32();
	transfer_nextstep_ = fr.unsigned_32();
	if (fr.unsigned_8()) {
		ware.transfer_ = new Transfer(dynamic_cast<Game&>(egbase()), ware);
		ware.transfer_->read(fr, transfer_);
	}
}

void WareInstance::Loader::load_pointers() {
	MapObject::Loader::load_pointers();

	WareInstance& ware = get<WareInstance>();

	// There is a race condition where a ware may lose its location and be scheduled
	// for removal via the update callback, but the game is saved just before the
	// removal. This is why we allow a null location on load.
	if (location_)
		ware.set_location(egbase(), &mol().get<MapObject>(location_));
	if (transfer_nextstep_)
		ware.transfer_nextstep_ = &mol().get<MapObject>(transfer_nextstep_);
	if (ware.transfer_)
		ware.transfer_->read_pointers(mol(), transfer_);
}

void WareInstance::Loader::load_finish() {
	MapObject::Loader::load_finish();

	WareInstance& ware = get<WareInstance>();
	if (!ware.transfer_ || !ware.transfer_->get_request()) {
		if (!ware.supply_)
			ware.supply_ = new IdleWareSupply(ware);
	}
}

void WareInstance::save(EditorGameBase& egbase, MapObjectSaver& mos, FileWrite& fw) {
	fw.unsigned_8(HeaderWareInstance);
	fw.unsigned_8(kCurrentPacketVersion);
	fw.c_string(descr().name());

	MapObject::save(egbase, mos, fw);

	fw.unsigned_32(mos.get_object_file_index_or_zero(location_.get(egbase)));
	fw.unsigned_32(mos.get_object_file_index_or_zero(transfer_nextstep_.get(egbase)));
	if (transfer_) {
		fw.unsigned_8(1);
		transfer_->write(mos, fw);
	} else {
		fw.unsigned_8(0);
	}
}

MapObject::Loader* WareInstance::load(EditorGameBase& egbase,
                                      MapObjectLoader& mol,
                                      FileRead& fr,
                                      const TribesLegacyLookupTable& lookup_table) {
	try {
		uint8_t packet_version = fr.unsigned_8();

		// Some maps may contain ware info, so we need compatibility here.
		if (1 <= packet_version && packet_version <= kCurrentPacketVersion) {
			if (packet_version == 1) {
				fr.c_string();  // Consume tribe name
			}
			const std::string warename = lookup_table.lookup_ware(fr.c_string());

			DescriptionIndex wareindex = egbase.tribes().ware_index(warename);
			const WareDescr* descr = egbase.tribes().get_ware_descr(wareindex);

			std::unique_ptr<Loader> loader(new Loader);
			loader->init(egbase, mol, *new WareInstance(wareindex, descr));
			loader->load(fr);

			return loader.release();
		} else {
			throw UnhandledVersionError("WareInstance", packet_version, kCurrentPacketVersion);
		}
	} catch (const std::exception& e) {
		throw wexception("WareInstance: %s", e.what());
	}
	NEVER_HERE();
}
}  // namespace Widelands