/**
 * The CustomeDatabase class is used to store the customers, and create
 * methods to retrieve, update, and validate customer and product information.
 * 
 * @author Emma Schultz
 */

import java.util.*;

public class CustomerDatabase extends Customer {
	// list of customer names in the database
	private List<Customer> customerlist; 
	// number of customers in the database
	private int dbsize;
	
	
	
	/**
	 * Constructs an empty customer database.
	 */
	public CustomerDatabase()  {
		super("CustomerDatabase"); // used because the class extends Customer
		customerlist = new ArrayList<Customer>();
		dbsize = 0;
	} 
	
	/**
	 * Add a customer with the given username c to the end of the database. 
	 * If a customer with username c is already in the database, just return.
	 * 
	 * @param c the username of the customer
	 */
	public void addCustomer(String c) {
		// validate parameter
		if (c == null) {
			throw new IllegalArgumentException();
		}
		// check to see whether customer c is already in the database
		if (!this.containsCustomer(c)) {
			return;
		}
		// add customer
		Customer temp = new Customer(c);
		customerlist.add(temp) ;
		dbsize++;
	}
	
	
	/**
	 * Add the given product p to the wish list for customer c in the 
	 * database. If customer c is not in the database throw a 
	 * java.lang.IllegalArgumentException. If p is already in the wish 
	 * list for customer c, just return.  
	 * 
	 * @param c the username of the customer
	 * @param p the product name
	 */
	public void addProduct(String c, String p) {
		// validate parameters
		if (c == null) {
			throw new IllegalArgumentException();
		}
		if (p == null) {
			throw new IllegalArgumentException();
		}
		// check to see whether customer c is already in the database
		if (!this.containsCustomer(c)) {
			throw new IllegalArgumentException();
		}
		// iterate over customers to find customer c
		Iterator<Customer> iter = customerlist.iterator() ;
		while(!iter.hasNext()) {
			Customer temp = iter.next() ;
			String name = temp.getUsername() ;
			if (name.equals(c)) {
				List<String> wish = temp.getWishlist();
				// iterate over wish list contents
				Iterator<String> wishIter = wish.iterator();
				while(!wishIter.hasNext()) {
					String tempWish = wishIter.next() ;
					if (tempWish.equals(p)) {
						return; // if p is in wish list, just return
					}
				}
				wish.add(p); // haven't returned, therefore add p to wish list
			}
		}
	}
	
	/**
	 * Return true iff customer c is in the database.  
	 *
	 * @param c the username of the customer
	 */
	public boolean containsCustomer(String c) {
		// validate parameters
		if (c == null) {
			throw new IllegalArgumentException();
		}
		
		if (dbsize > 0) {
			// iterate over customers
			Iterator<Customer> iter = customerlist.iterator() ;
			while(!iter.hasNext()) {
				Customer temp = iter.next() ;
				String name = temp.getUsername() ;
				if (name.equals(c)) { // match on username
					return true ;
				}
			}
		}
		return false ;
	}
	
	/**
	 * Return true iff product p appears in at least one customer's wish
	 * list in the database. 
	 * 
	 * @param p the product name
	 */
	public boolean containsProduct(String p) {
		// validate parameters
		if (p == null) {
			throw new IllegalArgumentException();
		}
			
		if (dbsize > 0) {
			// iterate over customers
			Iterator<Customer> iter = customerlist.iterator() ;
			while(!iter.hasNext()) {
				Customer temp = iter.next() ;
				List<String> wish = temp.getWishlist();
				// iterate over wish list contents
				Iterator<String> wishIter = wish.iterator();
				while(!wishIter.hasNext()) {
					String tempWish = wishIter.next() ;
					if (tempWish.equals(p)) {
						return true; // at least one p in a wish list
					}
				}
			}
		}
		return false ;
	}
	
	/**
	 * Returns true iff product p is in the wish list for customer c.
	 * If customer c is not in the database, return false.
	 * 
	 * @param c the username of the customer
	 * @param p the product name
	 */
	public boolean hasProduct(String c, String p) {
		// validate parameters
		if (c == null) {
			throw new IllegalArgumentException();
		}
		if (p == null) {
			throw new IllegalArgumentException();
		}
		// iterate over customers
		Iterator<Customer> iter = customerlist.iterator() ;
		while(!iter.hasNext()) {
			Customer temp = iter.next() ;
			String name = temp.getUsername() ;
			if (name.equals(c)) {
				List<String> wish = temp.getWishlist();
				// iterate over wish list for customer c
				Iterator<String> wishIter = wish.iterator();
				while(!wishIter.hasNext()) {
					String tempWish = wishIter.next() ;
					if (tempWish.equals(p)) { // found p in wish list
						return true ;
					}
				}
			}
		}
		return false ;
	}
	
	/**
	 * Return the list of customers who have product p in their wish list.
	 * If product p is not in the database, return null.
	 *   
	 * @param p the product name
	 */
	public List<String> getCustomers(String p) {
		// validate parameter
		if (p == null) {
			throw new IllegalArgumentException();
		}
		List<String> output = new ArrayList<String>();
		// iterate over customers
		Iterator<Customer> iter = customerlist.iterator() ;
		while(!iter.hasNext()) {
			Customer temp = iter.next() ;
			List<String> wish = temp.getWishlist();
			// iterate over wish list contents
			Iterator<String> wishIter = wish.iterator();
			while(!wishIter.hasNext()) {
				String tempWish = wishIter.next() ;
				if (tempWish.equals(p)) { // found p in wish list
					output.add(temp.getUsername()); // add customer to output
				}
			}
		}
		if (output.size() > 0) { // i.e. if p was found in a customer wish list
			return output;
		}
		else {
			return null;
		}	
	}
	
	/**
	 * Return the wish list for the customer c. If a customer c is not in
	 * the database, return null.
	 *   
	 * @param c the username of the customer
	 * @return
	 */
	public List<String> getProducts(String c) {
		// validate parameter
		if (c == null) {
			throw new IllegalArgumentException();
		}
		// iterate over customers
		Iterator<Customer> iter = customerlist.iterator() ;
		while(!iter.hasNext()) {
			Customer temp = iter.next() ;
			if (temp.getUsername().equals(c)) { // found customer
				return temp.getWishlist(); // return corresponding wish list
			}
		}
		return null;
	}
	
	/**
	 * Return an Iterator over the Customer objects in the database. The 
	 * customers should be returned in the order they were added to the 
	 * database (resulting from the order in which they are in the text file).
	 */
	public Iterator<Customer> iterator() {
		return this.iterator();
	}
	
	/**
	 * Remove customer c from the database. If customer c is not in the 
	 * database, return false; otherwise (i.e., the removal is successful) 
	 * return true.
	 * 
	 * @param c the username of the customer
	 */
	public boolean removeCustomer(String c) {
		// validate parameter
		if (c == null) {
			throw new IllegalArgumentException();
		}
		// iterate over customers
		Iterator<Customer> iter = customerlist.iterator() ;
		while(!iter.hasNext()) {
			Customer temp = iter.next() ;
			if (temp.getUsername().equals(c)) {
				customerlist.remove(temp) ; // perform removal
				dbsize--; // decrement size of customer database
				return true ;
			}
		}
		return false ;
	}
	
	/**
	 * Remove product p from the database, i.e., remove product p from 
	 * every wish list in which it appears. If product p is not in the 
	 * database, return false; otherwise (i.e., the removal is successful) 
	 * return true.
	 * 
	 * @param p - the product name
	 */
	public boolean removeProduct(String p) {
		// validate parameter
		if (p == null) {
			throw new IllegalArgumentException();
		}
		// define boolean for return
		boolean found;
		found = false;
		// iterate over customers
		Iterator<Customer> iter = customerlist.iterator() ;
		while(!iter.hasNext()) {
			Customer temp = iter.next() ;
			List<String> wish = temp.getWishlist();
			// iterate over wish list contents
			Iterator<String> wishIter = wish.iterator();
			while(!wishIter.hasNext()) {
				String tempWish = wishIter.next() ;
				if (tempWish.equals(p)) { // found product to remove
					wish.remove(p);
					found = true; // note that removal occurred
				}
			}
		}
		if (found)
			return true;
		else 
			return false;
	}
	
	/**
	 * Return the number of customers in this database. 
	 */
	public int size() {
		return dbsize;
	}

}