package ch.epfl.maze.physical.zoo;

import ch.epfl.maze.physical.Animal;
import ch.epfl.maze.util.Direction;
import ch.epfl.maze.util.Vector2D;

import java.util.Set;

/**
 * Monkey A.I. that puts its hand on the left wall and follows it.
 *
 * @author EPFL
 * @author Pacien TRAN-GIRARD
 */
public class Monkey extends Animal {

    private Direction currentDirection;

    /**
     * Constructs a monkey with a starting position.
     *
     * @param position Starting position of the monkey in the labyrinth
     */
    public Monkey(Vector2D position) {
        super(position);
        this.currentDirection = Direction.NONE;
    }

    /**
     * Finds a currentDirection following the "left paw rule".
     *
     * @param choices A set of possible directions
     * @return The currentDirection to take according to the "left paw rule"
     */
    private Direction followLeft(Set<Direction> choices) {
        Direction dir = this.currentDirection.rotateLeft();
        while (!choices.contains(dir)) dir = dir.rotateRight();

        return dir;
    }

    /**
     * Determines the strategy to follow depending on special cases.
     *
     * @param choices A set of possible directions
     * @return The Direction to take
     */
    private Direction findDirection(Set<Direction> choices) {
        if (choices.isEmpty()) return Direction.NONE;
        if (this.currentDirection == Direction.NONE) return choices.stream().findAny().get();
        if (choices.size() == 1) return choices.stream().findAny().get();
        return this.followLeft(choices);
    }

    /**
     * Moves according to the relative left wall that the monkey has to follow.
     */
    @Override
    public Direction move(Set<Direction> choices) {
        this.currentDirection = this.findDirection(choices);
        return this.currentDirection;
    }

    @Override
    public Animal copy() {
        return new Monkey(this.getPosition());
    }

}