package tsp.hashmap;

public class HashMap<K, V> implements Map<K, V> {
	private Map<K, V>[] table;
	private int size = 0;

	private final double loadFactor = 0.75;
	
	public HashMap() {
		table = new Map[5]; /* the only type unsafe operation of the application */
		for(int i=0; i<table.length; i++)
			table[i] = new ListMap<>(null, null);
	}
	
	private Map<K, V> getList(K key) {
		int code = key.hashCode() % table.length;
		if(code < 0)
			code += table.length;
		return table[code];
	}
	
	public V get(K key) {
		return getList(key).get(key);
	}
	
	public boolean put(K key, V value) {
		boolean wasInMap = getList(key).put(key, value);
		if (wasInMap) size++;
		if (size > this.table.length * loadFactor) resize();
		return wasInMap;
	}
	
	public boolean remove(K key) {
		boolean wasInMap = getList(key).remove(key);
		if (wasInMap) size--;
		return wasInMap;
	}
	
	public void display() {
		for(int i=0; i<table.length; i++)
			table[i].display();
	}

	@Override
	public void addAllTo(HashMap<K, V> map) {
		for (int i = 0; i < map.table.length; i++){
			map.table[i].addAllTo(this);
		}
	}

	@Override
	public int getSize() {
		return this.size;
	}

	public HashMap(int capacity) {
		table = new Map[capacity]; /* the only type unsafe operation of the application */
		for(int i=0; i<table.length; i++)
			table[i] = new ListMap<>(null, null);
	}

	public void resize() {
		int newCapacity = this.table.length * 2;
		HashMap<K, V> newHashMap = new HashMap<>(newCapacity);
		for (int i = 0; i < this.table.length; i++){
			this.table[i].addAllTo(newHashMap);
		}
		this.table = newHashMap.table;
	}
}