#include <vector>
#include <iostream>
#include <string>
using namespace std;

class Mediator;

class Colleague{
    Mediator* pm=0;
protected:
	string name;
public:
	Colleague(Mediator& m, string name);
	virtual void Receive(string message, string from){
      cout<<name<<" received from "<<from<<": "<<message<<endl;
    }	
    void Send(string message);
};

class Mediator{
	vector<Colleague*> respond;
public:
	void SignOn(Colleague& colleague){ respond.push_back(&colleague);}

    void Block(Colleague& colleague){
	    for (auto item = respond.begin(); item != respond.end();item++){
        	if (*item==&colleague) {
            	respond.erase(item);
            	break;
        	}
        } 
        //throw "Not found!";
    } 

    void Unblock(Colleague& colleague){ respond.push_back(&colleague);}

    // Send is implemented as a broadcast
    void Send(string message, string from){
    	for (auto &c : respond) (*c).Receive(message, from);
      	cout<<endl;
    }
};

Colleague::Colleague(Mediator& m, string name)
	:name(name),pm(&m){
    m.SignOn(*this);
}
void Colleague::Send(string message){
	cout<<"Send (From "<<name<<"): "<<message<<endl;
    pm->Send(message, name);
}

class ColleagueB:public Colleague{
public:
	ColleagueB(Mediator& mediator,string name)
		:Colleague(mediator, name){ }

    // Does not get copies of own messages
    void Receive(string message, string from){
      if (from!=name) Colleague::Receive(message, from);
    }
};

int main(){
    Mediator m;
    
    // Two from head office and one from a branch office
    Colleague head1(m,"John");
    ColleagueB branch1(m,"David");
    Colleague head2(m,"Lucy");
      
    head1.Send("Meeting on Tuesday, please all ack");
    branch1.Send("Ack"); // by design does not get a copy
    m.Block(branch1); // temporarily gets no messages
    head1.Send("Still awaiting some Acks");
    head2.Send("Ack"); 
    m.Unblock(branch1); //open again
    head1.Send("Thanks all");
	return 0;
}

/* Output
Send (From John): Meeting on Tuesday, please all ack
John received from John: Meeting on Tuesday, please all ack
David received from John: Meeting on Tuesday, please all ack
Lucy received from John: Meeting on Tuesday, please all ack

Send (From David): Ack
John received from David: Ack
Lucy received from David: Ack

Send (From John): Still awaiting some Acks
John received from John: Still awaiting some Acks
Lucy received from John: Still awaiting some Acks

Send (From Lucy): Ack
John received from Lucy: Ack
Lucy received from Lucy: Ack

Send (From John): Thanks all
John received from John: Thanks all
Lucy received from John: Thanks all
David received from John: Thanks all
*/