package jrummikub.model;

import static jrummikub.model.StoneTray.Direction.LEFT;
import static jrummikub.model.StoneTray.Direction.RIGHT;

import java.util.Arrays;
import java.util.Comparator;
import java.util.TreeMap;

import jrummikub.util.Pair;

/** Class managing a {@link Player}'s {@link Stone}s */
public class Hand extends StoneTray<Stone> implements IHand {
	/**
	 * The width of the hand
	 */
	public final static int WIDTH = 14;

	private GameSettings settings;

	/**
	 * Create a new empty hand with given game settings
	 * 
	 * @param settings
	 *            the game settings
	 */
	public Hand(GameSettings settings) {
		this.settings = settings;
	}

	@Override
	public int getFreeRowSpace(int row) {
		int count = 0;
		for (Pair<Stone, Position> entry : this) {
			if (entry.getSecond().getY() == row) {
				count++;
			}
		}
		return WIDTH - count;
	}

	@Override
	public int getRowCount() {
		int rows = 0;

		for (Pair<Stone, Position> entry : this) {
			if (entry.getSecond().getY() > rows) {
				rows = (int) entry.getSecond().getY();
			}
		}

		return rows + 1;
	}

	@Override
	protected Pair<Position, Direction> fixInvalidDrop(Stone stone,
			Position pos, Direction dir) {
		float x = pos.getX();
		float y = pos.getY();

		if (x >= 0 && x <= WIDTH - 1) {
			return null;
		}
		if (x < 0) {
			return new Pair<Position, Direction>(new Position(0, y), RIGHT);
		} else {
			if (getFreeRowSpace((int) y) == 0) {
				return new Pair<Position, Direction>(new Position(0, y + 1),
						RIGHT);
			} else {
				return new Pair<Position, Direction>(
						new Position(WIDTH - 1, y), LEFT);
			}
		}
	}

	public int getStonePoints() {
		int points = 0;

		for (Pair<Stone, Position> entry : this) {
			if (entry.getFirst().isJoker()) {
				points += settings.getJokerPoints();
			} else {
				points += entry.getFirst().getValue();
			}
		}

		return points;
	}

	private final static Comparator<Pair<Integer, StoneColor>> comparator = new Comparator<Pair<Integer, StoneColor>>() {

		@Override
		public int compare(Pair<Integer, StoneColor> o1,
				Pair<Integer, StoneColor> o2) {
			int firstComparison = o1.getFirst().compareTo(o2.getFirst());
			if (firstComparison != 0) {
				return -firstComparison;
			} else {
				return o1.getSecond().compareTo(o2.getSecond());
			}
		}
	};

	@Override
	public boolean isInitialMeldPossible() {
		Pair<TreeMap<Pair<Integer, StoneColor>, Integer>, Integer> stoneCounts = countStones();
		
		return findSetsWithTotalPoints(settings.getInitialMeldThreshold(),
				stoneCounts.getFirst(), stoneCounts.getSecond());
	}

	private Pair<TreeMap<Pair<Integer, StoneColor>, Integer>, Integer> countStones() {
		int jokerCount = 0;
		TreeMap<Pair<Integer, StoneColor>, Integer> stoneCounts = new TreeMap<Pair<Integer, StoneColor>, Integer>(
				comparator);
		
		
		for (Pair<Stone, Position> entry : this) {
			if (entry.getFirst().isJoker()) {
				jokerCount++;
			} else {
				Pair<Integer, StoneColor> key = new Pair<Integer, StoneColor>(
						entry.getFirst().getValue(), entry.getFirst()
								.getColor());

				incrementStoneCount(stoneCounts, key);
			}
		}
		return new Pair<TreeMap<Pair<Integer, StoneColor>, Integer>, Integer>(stoneCounts, jokerCount);
	}

	private void incrementStoneCount(
			TreeMap<Pair<Integer, StoneColor>, Integer> stones,
			Pair<Integer, StoneColor> stone) {
		if (stones.containsKey(stone)) {
			stones.put(stone, stones.get(stone) + 1);
		} else {
			stones.put(stone, 1);
		}
	}

	private void decrementStoneCount(
			TreeMap<Pair<Integer, StoneColor>, Integer> stones,
			Pair<Integer, StoneColor> stone) {
		int count = stones.get(stone);
		count--;

		if (count == 0) {
			stones.remove(stone);
		} else {
			stones.put(stone, count);
		}
	}

	@SuppressWarnings("unchecked")
	private boolean findSetsWithTotalPoints(int pointsMissing,
			TreeMap<Pair<Integer, StoneColor>, Integer> stoneCounts,
			int jokerCount) {

		if (pointsMissing <= 0) {
			return true;
		}

		stoneCounts = (TreeMap<Pair<Integer, StoneColor>, Integer>) stoneCounts
				.clone();

		for (int value = 13; value >= 1; value--) {
			for (StoneColor color : StoneColor.values()) {
				Pair<Integer, StoneColor> stone = new Pair<Integer, StoneColor>(
						value, color);

				if (stoneCounts.containsKey(stone)) {
					decrementStoneCount(stoneCounts, stone);

					if (findRunsWithTotalPoints(pointsMissing - value,
							stoneCounts, jokerCount, stone, 1))
						return true;
					if (findGroupsWithTotalPoints(pointsMissing - value,
							stoneCounts, jokerCount, stone, 1))
						return true;
				}

				if (jokerCount > 0) {
					if (findRunsWithTotalPoints(pointsMissing - value,
							stoneCounts, jokerCount - 1, stone, 1))
						return true;
					if (findGroupsWithTotalPoints(pointsMissing - value,
							stoneCounts, jokerCount - 1, stone, 1))
						return true;
				}
			}
		}

		return false;
	}

	private StoneColor getNextColor(StoneColor color) {
		int index = Arrays.binarySearch(StoneColor.values(), color) + 1;
		if (index >= StoneColor.values().length) {
			return null;
		}
		return StoneColor.values()[index];
	}

	private boolean findGroupsWithTotalPoints(int pointsMissing,
			TreeMap<Pair<Integer, StoneColor>, Integer> stoneCounts,
			int jokerCount, Pair<Integer, StoneColor> stone, int groupSize) {

		StoneColor nextColor = getNextColor(stone.getSecond());
		Pair<Integer, StoneColor> nextStone = new Pair<Integer, StoneColor>(
				stone.getFirst(), nextColor);

		if (nextColor != null) {
			if (stoneCounts.containsKey(nextStone)) {
				decrementStoneCount(stoneCounts, nextStone);
				if (findGroupsWithTotalPoints(pointsMissing - stone.getFirst(),
						stoneCounts, jokerCount, nextStone, groupSize + 1))
					return true;
				incrementStoneCount(stoneCounts, nextStone);
			}
			if (jokerCount > 0) {
				if (findGroupsWithTotalPoints(pointsMissing - stone.getFirst(),
						stoneCounts, jokerCount - 1, nextStone, groupSize + 1))
					return true;
			}
			if (findGroupsWithTotalPoints(pointsMissing, stoneCounts,
					jokerCount, nextStone, groupSize))
				return true;
		}

		if (groupSize >= 3) {
			if (findSetsWithTotalPoints(pointsMissing, stoneCounts, jokerCount))
				return true;
		}
		return false;
	}

	private boolean findRunsWithTotalPoints(int pointsMissing,
			TreeMap<Pair<Integer, StoneColor>, Integer> stoneCounts,
			int jokerCount, Pair<Integer, StoneColor> stone, int runLength) {

		Pair<Integer, StoneColor> nextStone = null;
		if (stone.getFirst() > 1) {
			int nextValue = stone.getFirst() - 1;
			nextStone = new Pair<Integer, StoneColor>(nextValue,
					stone.getSecond());

			if (stoneCounts.containsKey(nextStone)) {
				decrementStoneCount(stoneCounts, nextStone);
				if (findRunsWithTotalPoints(pointsMissing - nextValue,
						stoneCounts, jokerCount, nextStone, runLength + 1))
					return true;
				incrementStoneCount(stoneCounts, nextStone);

			}
			if (jokerCount > 0) {
				if (findRunsWithTotalPoints(pointsMissing - nextValue,
						stoneCounts, jokerCount - 1, nextStone, runLength + 1))
					return true;
			}
		}

		if (runLength >= 3) {
			if (findSetsWithTotalPoints(pointsMissing, stoneCounts, jokerCount))
				return true;
		}
		return false;
	}

	@Override
	public int getIdenticalStoneCount() {
		Pair<TreeMap<Pair<Integer, StoneColor>, Integer>, Integer> stoneCounts = countStones();
		int pairCount = 0;
		
		for(int count : stoneCounts.getFirst().values()) {
			pairCount += count / 2;
		}
		
		return pairCount;
	}
}