import pygame as pg

from math import copysign
from pygame import QUIT, KEYDOWN, K_ESCAPE
from pygame.math import Vector2
from pygame.time import Clock


UPDATE_RATE = 1 / 120

MAX_UPDATE_RATE = 1 / 20


class Follower:
    def __init__(self, surface, position, speed):
        self.surface = surface
        self.position = Vector2(position)
        self.speed = speed

        self.direction = Vector2(0, 1)
        self.angle_speed = 90 # Градусов в секунду
        self.color = (44, 44, 44)
        self.line_color = (244, 22, 22)
        self.radius = 20

    def update(self, delta_time):
        mouse_position = Vector2(pg.mouse.get_pos())


        direction_to_mouse = (mouse_position - self.position).normalize()
        if mouse_position.distance_to(self.position) > self.radius:
            angle = self.direction.angle_to(direction_to_mouse)
            if abs(angle) > 180:
                angle = -copysign((360 - abs(angle)), angle)
            self.direction = self.direction.rotate(copysign(min(abs(angle), self.angle_speed * delta_time), angle))
        else:
            self.direction = direction_to_mouse

        self.position += (self.direction * self.speed) * delta_time

    def render(self):
        pg.draw.circle(self.surface, self.color, self.position, self.radius)
        pg.draw.line(
            self.surface,
            self.line_color,
            self.position,
            self.position + self.direction * (self.radius + 10),
            5
        )


class Game:
    def __init__(self, surface):
        self.surface = surface
        self.bg_color = (220, 220, 220)
        self.follower = Follower(surface, (surface.get_width() / 2, 100), 200)
        self.clock = Clock()
        self.time_bucket = 0
        self.working = True

    def handle_events(self):
        for e in pg.event.get():
            if e.type == QUIT or (e.type == KEYDOWN and e.key == K_ESCAPE):
                self.working = False

    def update(self, delta_time):
        self.time_bucket += delta_time
        while self.time_bucket >= UPDATE_RATE:
            self.time_bucket -= UPDATE_RATE

            self.follower.update(UPDATE_RATE)

    def draw_direction(self):
        pg.draw.line(self.surface, (44, 200, 44), self.follower.position, pg.mouse.get_pos())

    def render(self):
        self.surface.fill(self.bg_color)

        self.follower.render()
        self.draw_direction()

        pg.display.update()

    def run(self):
        delta_time = 0
        self.clock.tick()
        while self.working:
            self.handle_events()
            self.update(min(delta_time, MAX_UPDATE_RATE))
            self.render()
            delta_time = self.clock.tick() / 1000

def main():
    pg.init()
    Game(pg.display.set_mode((1920, 1080), flags=pg.FULLSCREEN)).run()
    pg.quit()


if __name__ == "__main__":
    main()