// Purpose: messages travel both up and down the layers,
// message interface per layer per direction,
// one concrete Facade per layer (implements 1 or 2 interfaces)
// Singleton access to Facade objects

#include <iostream>
using namespace std;

class ChildOf3 { public: virtual void downMessage() = 0; };
class ParentOf2 { public: virtual void upMessage() = 0; };
class ChildOf2 { public: virtual void downMessage() = 0; };
class ParentOf1 { public: virtual void upMessage() = 0; };

class C : public ParentOf2 { public:
void execute();
void upMessage();
};
class B : public ParentOf1, public ChildOf3 { public:
void upMessage();
void downMessage();
};
class A : public ChildOf2 { public:
void downMessage();
void execute();
};

class SC { // Singleton Collection
public:
static C& layer3() { return cObject; }
static B& layer2() { return bObject; }
static A& layer1() { return aObject; }
private:
static C cObject; static B bObject; static A aObject;
};
C SC::cObject; B SC::bObject; A SC::aObject;

void thirdParty( ChildOf2& obj1, ChildOf3& obj2, ParentOf2& obj3 ) {
obj1.downMessage();
obj2.downMessage();
obj3.upMessage();
}

void main( void ) {
SC::layer3().execute();
SC::layer1().execute();
thirdParty( SC::layer1(), SC::layer2(), SC::layer3() );
}

// C::execute // A::execute // A::downMessage
// B::downMessage // B::upMessage // B::downMessage
// A::downMessage // C::upMessage // A::downMessage
// C::upMessage

void C::execute() { cout << "C::execute" << endl;
SC::layer2().downMessage(); }
void C::upMessage() { cout << "C::upMessage" << endl; }

void B::upMessage() { cout << "B::upMessage" << endl;
SC::layer3().upMessage(); }
void B::downMessage() { cout << "B::downMessage" << endl;
SC::layer1().downMessage(); }

void A::execute() { cout << "A::execute" << endl;
SC::layer2().upMessage(); }
void A::downMessage() { cout << "A::downMessage" << endl; }