import pygame
from .demos import aabb, vec_proj, sat
from . import HEIGHT
from .colors import *
from .draw import text_screen

class Screen:

    def __init__(self):
        self.demos = [
            vec_proj.VecProj(),
            aabb.AABBDistance(),
            aabb.PointAABBDistance(),
            sat.SeparatingAxisTheorem(),
        ]
        self.demo = 0

    def handle_input(self):
        for event in pygame.event.get(pygame.KEYDOWN):
            if event.key == pygame.K_DOWN:
                self.demo += 1
                if self.demo >= len(self.demos):
                    self.demo = 0
            elif event.key == pygame.K_UP:
                self.demo -= 1
                if self.demo < 0:
                    self.demo = len(self.demos) - 1

    def draw_demo_list(self, surface):
        y_offset = 10
        for i in range(len(self.demos)):
            text_screen(surface,
                      CYAN if self.demo == i else WHITE,
                      (10, y_offset + i * 20),
                      self.demos[i].title)

    def render(self, surface):
        self.handle_input()

        self.demos[self.demo].render(surface)

        self.draw_demo_list(surface)