import pygame
from game_object import GameObject
from snake_segment import SnakeSegment
from snake_state_machine import SnakeStateMachine
from wall import Wall
from prey import Prey


class Snake(GameObject):
    def __init__(self, start_position: tuple|list, length: int, radius: float|int, color: tuple) -> None:
        self.__segments = [SnakeSegment(center=(start_position[0]+2*radius*idx, start_position[1]),
                                        radius=radius,
                                        color=color) 
                           for idx in range(length)]
        
        self.__state_machine = SnakeStateMachine()
        self.__is_dead = False
        self.__shall_grow = False

    
    def __collides_with_wall(self, obj: GameObject):
        return isinstance(obj, Wall) and self.get_bounding_boxes()[0].collidelist(obj.get_bounding_boxes()) > -1


    def __collides_with_self(self, obj: GameObject):
        return isinstance(obj, Snake) and self.get_bounding_boxes()[0].collidelist(obj.get_bounding_boxes()[1:]) > -1


    def __collides_with_prey(self, obj: GameObject):
        return isinstance(obj, Prey) and self.get_bounding_boxes()[0].colliderect(obj.get_bounding_boxes()[0])


    def __update_on_collision(self, game_objs: list[GameObject]) -> None:
        for obj in game_objs:
            if self.__collides_with_wall(obj) or self.__collides_with_self(obj):
                self.__is_dead = True
            elif self.__collides_with_prey(obj):
                self.__shall_grow = True


    def draw(self, surface: pygame.Surface) -> None:
        for segment in self.__segments:
            segment.draw(surface)

    def update(self, user_input: int, game_objs: list[GameObject]) -> None:
        self.__shall_grow = False

        if not self.__is_dead:
            self.__update_on_collision(game_objs)

            if not self.__is_dead:
                self.__state_machine.update(user_input)
                new_head = self.__state_machine.get_state().get_next_head(self.__segments[0])
                
                self.__segments.insert(0, new_head)
                
                if not self.__shall_grow:
                    self.__segments.pop()
    

    def get_bounding_boxes(self) -> list[pygame.rect.Rect]:
        return [seg.get_bounding_boxes()[0] for seg in self.__segments]
    
    
    def is_dead(self):
        return self.__is_dead