#include <iostream>
using namespace std;

/* ContactList.cpp
 *  purp: maintain a contact list, as used in a cellphone
 *  does: adds entries, lists entries, searches, partial matches
 *  todo: split into functions
 *  todo: lookup by number (used to display name of incoming call)
 *  more: add other attributes
 */

const int MAX_ITEMS = 10000;
const int NOT_FOUND = -1;

void menu(string[], string[]);
void show_choices();
int lookup(string[], string[], int);
void print(string[], string[], int);
void modify(string[], string[], int);
int add(string[], string[], int);
int del(string[], string[], int);
int find(string[], string[], int, string);

int main()
{
	// define arrays here for storage
	
	string	nm[MAX_ITEMS];
	string	pn[MAX_ITEMS];

	menu(nm, pn);
	return 0;
}
// run the main menu -- show choices, get selection, do action, repeat
void menu(string nm[], string pn[])
{
	int	n;		// keeps count of number of entries in list
	char	choice;		// user menu choice

	n = 0;
	do {
		show_choices();
		cout << "\nChoice: ";
		cin  >> choice;
		switch(choice){
			case 'p':	print(nm, pn, n);
					break;
			case 'a':	n = add(nm, pn, n);
					break;
			case 'd':	n = del(nm, pn, n);
					break;
			case 'l':	lookup(nm, pn, n);
					break;
			case 'm':	modify(nm, pn, n);
					break;
			case 'c':	break;
			case 'x':	break;
			default:	cout << "Unknown command\n";
		}
		cout << endl;
	}
	while( choice != 'x' );
}
//
// display list of choices
//
void show_choices()
{
	cout << "\nContactList 1.0\n\n";
	cout << "  p: print list\n";
	cout << "  a: add entry\n";
	cout << "  d: delete entry\n";
	cout << "  l: lookup person\n";
	cout << "  c: clear all entries\n";
	cout << "  m: modify entry\n";
	cout << "  x: exit\n";
}

//  print the list, one line per entry
void print(string nm[MAX_ITEMS], string pn[MAX_ITEMS], int n)
{
	int	i;

	for(i=0; i<n; i++){
		cout << nm[i] << " " << pn[i] << endl;
	}
}
//
// add a new entry, return the new number of items
//
int add(string nm[MAX_ITEMS], string pn[MAX_ITEMS], int n)
{
	string	name, num;
	cout << "Name? ";
	cin  >> name;
	cout << "phone number? ";
	cin  >> num;

	nm[n] = name;
	pn[n] = num;
	n++;
	return n;
}
//
// del an entry, return the new number of items
//
int del(string nm[MAX_ITEMS], string pn[MAX_ITEMS], int n)
{
	int	who_to_rem;
	int	i;
	string	ans;

	who_to_rem = lookup(nm, pn, n);

	if ( who_to_rem == NOT_FOUND ){
		return n;
	}
	cout << "Are you SURE (y/n)? ";
	cin  >> ans;
	if ( ans != "y" ){
		return n;
	}
	n--;
	
	for(i=who_to_rem; i<n; i++){
		nm[i] = nm[i+1];
		pn[i] = pn[i+1];
	}
	return n;
}
//
// look for a string in nm or pn and return the index
// OR -1 if not found
// HOW: does a sequential search
//
int find(string nm[MAX_ITEMS], string pn[MAX_ITEMS], int n, string sv)
{
	int	i;

	for(i=0; i<n; i++){
		if ( sv == nm[i] || sv == pn[i] ){
			return i;
		}
	}
	// no luck, so we return -1 to indicate not found
	return NOT_FOUND;
}
//
// lookup then allow a change
//
void modify(string nm[MAX_ITEMS], string pn[MAX_ITEMS], int n)
{
	int	item_to_change;
	string	newnum;

	item_to_change = lookup(nm, pn, n);
	if ( item_to_change != NOT_FOUND )
	{
		cout << "New number: " ;
		cin  >> newnum;
		pn[item_to_change] = newnum;
	}
}

//
// lookup person by name
//
int lookup(string nm[MAX_ITEMS], string pn[MAX_ITEMS], int n)
{
	int	where_it_is;

	string	name;
	cout << "Name? ";
	cin  >> name;

	where_it_is = find(nm, pn, n, name);		// find it
	if ( where_it_is == NOT_FOUND ){
		cout << "Cannot find " << name << endl;
	}
	else
	{
		cout << nm[where_it_is] << " " << pn[where_it_is] << endl;
	}
	return where_it_is;
}