//
//	test of inventory system
//
//	Described in Chapter 9 of
//	Data Structures in C++ using the STL
//	Published by Addison-Wesley, 1997
//	Written by Tim Budd, budd@cs.orst.edu
//	Oregon State University
//

# include <iostream.h>
# include <list.h>
# include <algo.h>

class  Widget {
public:
		// constructors
	Widget () : id_number (0) { }
	Widget (int a) : id_number (a) { }

		// operations
	int id () { return id_number; }
	void operator =  (Widget & rhs) 
		{ id_number = rhs.id_number; }
	bool operator == (Widget & rhs) 
		{ return id_number == rhs.id_number; }
	bool operator <  (Widget & rhs) 
		{ return id_number < rhs.id_number; }

protected:
	int id_number;	// widget identification number
};

ostream & operator << (ostream & out, Widget & w)
	// output printable representation of widget
{
	return out << "Widget " << w.id();
}

class WidgetTester {
public:
	WidgetTester (int id) { test_id = id; }
	int test_id;

		// define the function call operator
	bool operator () (Widget & wid)
		{ return wid.id() == test_id; }
};

//
//	class inventory
//		manage inventory control

class inventory {
public:
	void order (int wid);	// process order for widget type wid
	void receive (Widget wid);	// receive widget of type wid in shipment

protected:
	list <Widget> on_hand;
	list <int> on_order;
};

void inventory::receive (Widget wid)
	// process a widget received in shipment
{
	cout << "Received shipment of widget " << wid << endl;
	list<int>::iterator we_need = 
			find (on_order.begin(), on_order.end(), wid.id()); 
	if (we_need != on_order.end()) {
		cout << "Ship " << wid << " to fill back order" << endl;
		on_order.erase(we_need);
		}
	else
		on_hand.push_front(wid);
}

void inventory::order (int wid)
	// process an order for a widget with given id number
{
	cout << "Received order for widget type " << wid << endl;
	WidgetTester wtest(wid); // create the tester object
	list<Widget>::iterator we_have = 
		find_if(on_hand.begin(), on_hand.end(), wtest);
	if (we_have != on_hand.end()) {
		cout << "Ship " << *we_have << endl;
		on_hand.erase(we_have);
		}
	else {
		cout << "Back order widget of type "  << wid  << endl;
		on_order.push_front(wid);
		}
}

//
//	driver program
//

void main() {
	inventory wworks;

	wworks.receive (Widget(1));
	wworks.receive (Widget(2));
	wworks.receive (Widget(3));
	wworks.order (2);
	wworks.order (2);
	wworks.receive (Widget(3));
	wworks.receive (Widget(2));
	wworks.order (1);
}