from typing import List, Tuple
from random import randint

import thumby

import images

from map import ObstacleSlice

class Entity:
    """
    An entity exists within the game world. It has coordinates, bounds, and optionally collision and sprite
    """
    def __init__(self, x: int = 0, y: int = 0, width: int = 8, height: int = 8, collision: bytearray = None, sprite: thumby.Sprite = None):
        self.x = x
        self.y = y
        self.sprite = sprite
        self.collision = collision
        self.width = width
        self.height = height

    def intersects_pixel(self, loc_x: int, loc_y: int) -> bool:
        """
        Checks to see if this entity intersects a location in the game world.

        :param loc_x:
            An global x location within the game world.
        :param loc_y:
            A global y position within the game world.
        :return:
            True if the collision shape of this entity intersects a point in the world,
            False otherwise.
        """
        if not self.collision:
            return False
        if loc_x < self.x or loc_x >= self.x + self.width or loc_y < self.y or loc_y >= self.y + self.height:
            return False
        rel_x = loc_x - self.x
        rel_y = loc_y - self.y
        return bool((self.collision[rel_x] >> (self.height - rel_y)) & 1)

    def can_render(self, current_depth: int) -> bool:
        """
        Checks to see if this sprite is within the game screen.

        :param current_depth:
            The current depth, as measured from the top of the screen. We can display anything
            up to the screen height down from this number.

        :return:
            True if the sprite shows up on screen in any capacity, false otherwise.
        """
        if self.x < -self.width or self.x >= thumby.display.width:
            return False
        max = current_depth
        min = current_depth - thumby.display.height
        if self.y < (min - self.height) or self.y >= max:
            return False
        return True

    def update(self, tpf: float, current_depth: int, prev_depth: int) -> bool:
        """
        Updates the state of the entity based on the game state.

        :param tpf:
            The number of seconds since the last tick.
        :param current_depth:
            The current depth the game is on.
        :param prev_depth:
            The depth the game was on last tick.

        :return:
            True if the game should keep this entity, false if the game should drop
            this entity from memory.
        """
        return False

    def render(self, tpf: float, current_depth: int, prev_depth: int) -> bool:
        """
        Sets the position of the sprite and draws it.
        
        :param tpf:
            The number of seconds since the last tick.
        :param current_depth:
            The current depth the game is on.
        :param prev_depth:
            The depth the game was on last tick.

        :return:
            True if the game should actually draw the sprite, false the sprite
            should be hidden.
        """
        if self.sprite:
            self.sprite.y = self.y - self.current_depth
            self.sprite.x = self.x
            if self.can_render(current_depth):
                thumby.display.drawSprite(self.sprite)
                return True
        return False

class Obstacle(Entity):    
    def update(self, tpf: float, current_depth: int, prev_depth: int) -> bool:
        return self.can_render(current_depth)


def update_entities(current_slice: ObstacleSlice, current_depth: int, prev_depth: int) -> List[Entity]:
    """
    Checks the current game state and generates new sprites based on said state.

    :param current_slice:
        The current obstacle slice we are using. Once the bottom of the slice displays, we switch
        to a new slice.
    :param current_depth:
        The global world depth we are at. This is modulused by the slice height to determine how
        far through the slice we are.
    :param prev_depth:
        The depth we were at during the last tick. This helps make sure we don't miss spawning
        entities

    :return:
        A list of entities to generate this tick.
    """
    if current_depth == prev_depth:
        # If we haven't moved, we don't need to spawn anything
        return []
    min_height = min(current_depth, prev_depth)
    max_height = max(current_depth, prev_depth)
    spawned = []
    for entity in current_slice.obstacle_map:
        if y >= min_height and y < max_height:
            sprite_image = OBSTACLES[entity[2]]
            sprite = thumby.Sprite(sprite_image.width, sprite_image.height, sprite_image.sprite, entity[0], entity[1], -1, entity[3] - current_depth, entity[4])
            spawned = Obstacle(entity[0], entity[1], sprite_image.width, sprite_image.height, sprite_image.collision, sprite)