from dataclasses import dataclass, replace

from directions import Direction


@dataclass
class Block:
    x: int
    y: int

    def move(self, direction: Direction) -> None:
        """
        Moves the block in the given direction.
        """
        if direction is Direction.NORTH:
            self.y -= 1
        elif direction is Direction.EAST:
            self.x += 1
        elif direction is Direction.SOUTH:
            self.y += 1
        elif direction is Direction.WEST:
            self.x -= 1

    def to_tuple(self) -> tuple:
        """
        Returns the block in tuple representation (x,y).
        """
        return (self.x, self.y)

    def __repr__(self) -> str:
        return f"Block({self.x}, {self.y})"


class Snake:
    def __init__(self, x: int, y: int):
        self.body = [Block(x, y)]

    def preview(self, direction: Direction) -> Block:
        """
        Previews the head of the snake after a move in the given direction is made.
        """
        head = replace(self.body[0])
        head.move(direction)
        return head

    def move(self, direction: Direction, extend: bool = False) -> None:
        """
        Moves the snake in the given direction. Extends the snake by one block if extend
        is true.
        """
        head = replace(self.body[0])
        head.move(direction)
        self.body.insert(0, head)

        if not extend:
            self.body.pop()

    def __len__(self) -> int:
        return len(self.body)

    def __contains__(self, item: Block) -> bool:
        return item in self.body