// Purpose.  Facade design pattern demo.
// 
// Discussion.  Structuring a system into subsystems helps reduce
// complexity.  A common design goal is to minimize the communication and
// dependencies between subsystems.  One way to achieve this goal is to
// introduce a "facade" object that provides a single, simplified
// interface to the many, potentially complex, individual interfaces
// within the subsystem.  In this example, the "subsystem" for responding
// to a networking service request has been modeled, and a facade
// (FacilitiesFacade) interposed.  The facade "hides" the twisted and
// bizarre choreography necessary to satisfy even the most basic of
// requests.  All the user of the facade object has to do is make one or
// two phone calls a week for 5 months, and a completed service request
// results.

#include <iostream.h>

class MisDepartment {
public:
	void submitNetworkRequest() { _state = 0; }
	bool checkOnStatus() {
		_state++;
		if (_state == Complete)
			return 1;
		return 0; }
private:
	enum States {Received, DenyAllKnowledge, ReferClientToFacilities,
		FacilitiesHasNotSentPaperwork, ElectricianIsNotDone,
		ElectricianDidItWrong, DispatchTechnician, SignedOff, DoesNotWork,
		FixElectriciansWiring, Complete};
	int _state;
};

class ElectricianUnion {
public:
	void submitNetworkRequest() { _state = 0; }
	bool checkOnStatus() {
		_state++;
		if (_state == Complete)
			return 1;
		return 0; }
private:
	enum States {Received, RejectTheForm, SizeTheJob, SmokeAndJokeBreak,
		WaitForAuthorization, DoTheWrongJob, BlameTheEngineer, WaitToPunchOut,
		DoHalfAJob, ComplainToEngineer, GetClarification, CompleteTheJob,
		TurnInThePaperwork, Complete};
	int _state;
};

class FacilitiesDepartment {
public:
	void submitNetworkRequest() { _state = 0; }
	bool checkOnStatus() {
		_state++;
		if (_state == Complete)
			return 1;
		return 0; }
private:
	enum States {Received, AssignToEngineer, EngineerResearches,
		RequestIsNotPossible, EngineerLeavesCompany, AssignToNewEngineer,
		NewEngineerResearches, ReassignEngineer, EngineerReturns,
		EngineerResearchesAgain, EngineerFillsOutPaperWork, Complete};
	int _state;
};

class FacilitiesFacade {
public:
	FacilitiesFacade()          { _count = 0; }
	void submitNetworkRequest() { _state = 0; }
	bool checkOnStatus() {
		_count++;
		/* Job request has just been received */
		if (_state == Received) {
			_state++;
			/* Forward the job request to the engineer */
			_engineer.submitNetworkRequest();
			cout << "submitted to Facilities - " << _count
				<< " phone calls so far" << endl; }
		else if (_state == SubmitToEngineer) {
			/* If engineer is complete, forward to electrician */
			if (_engineer.checkOnStatus()) {
				_state++;
				_electrician.submitNetworkRequest();
				cout << "submitted to Electrician - " << _count
					<< " phone calls so far" << endl; } }
		else if (_state == SubmitToElectrician) {
			/* If electrician is complete, forward to technician */
			if (_electrician.checkOnStatus()) {
				_state++;
				_technician.submitNetworkRequest();
				cout << "submitted to MIS - " << _count
					<< " phone calls so far" << endl; } }
		else if (_state == SubmitToTechnician) {
			/* If technician is complete, job is done */
			if (_technician.checkOnStatus())
				return 1; }
		/* The job is not entirely complete */
		return 0; }
	int getNumberOfCalls() { return _count; }
private:
	enum States {Received, SubmitToEngineer, SubmitToElectrician,
		SubmitToTechnician};
	int                   _state;
	int                   _count;
	FacilitiesDepartment  _engineer;
	ElectricianUnion      _electrician;
	MisDepartment         _technician;
};

main()
{
	FacilitiesFacade  facilities;

	facilities.submitNetworkRequest();
	/* Keep checking until job is complete */
	while ( ! facilities.checkOnStatus())
		;
	cout << "job completed after only " << facilities.getNumberOfCalls()
		<< " phone calls" << endl;
}

// submitted to Facilities - 1 phone calls so far
// submitted to Electrician - 12 phone calls so far
// submitted to MIS - 25 phone calls so far
// job completed after only 35 phone calls