import pygame
import random

# Pygame setup
pygame.display.init()
pygame.font.init()
screen = pygame.display.set_mode((800, 600))
font = pygame.font.SysFont("Courier New", 16)
done = False
clock = pygame.time.Clock()

# Create Variables
player_pos = [400, 300]
player_speed = 100      # Pixels / s
player_rad = 20
dt = 0.0
bullets = []            # Each element of bullets will
                        # be a sub-list [x, y, xspeed, yspeed]

# Game Loop
while not done:
    # INPUT
    evt = pygame.event.poll()
    # ... event-handling

    # ... device-polling
    key_pressed = pygame.key.get_pressed()
    if key_pressed[pygame.K_ESCAPE]:
        done = True
    if key_pressed[pygame.K_a]:
        player_pos[0] -= dt * player_speed
    if key_pressed[pygame.K_d]:
        player_pos[0] += dt * player_speed
    if key_pressed[pygame.K_w]:
        player_pos[1] -= dt * player_speed
    if key_pressed[pygame.K_s]:
        player_pos[1] += dt * player_speed

    # UPDATES
    dt = clock.tick() / 1000.0

    # (temporary) Spawn a new bullet with a random speed
    new_xspeed = random.randint(-200, 200)
    new_yspeed = random.randint(-200, 200)
    new_x = player_pos[0]    # Bullets spawn at player-pos
    new_y = player_pos[1]
    new_bullet = [new_x, new_y, new_xspeed, new_yspeed]
    bullets.append(new_bullet)

    # Update all bullets (using a for loop)
    for b in bullets:
        # b is the "current" sub-list
        b[0] += b[2] * dt
        b[1] += b[3] * dt

    # DRAWING
    screen.fill((0,0,0))
    pygame.draw.rect(screen, (255,0,0),
                     (player_pos[0] - player_rad,
                      player_pos[1] - player_rad,
                      player_rad * 2, player_rad * 2))
    pygame.draw.circle(screen, (0,255,0),
                       (int(player_pos[0]),
                        int(player_pos[1])), 3)
    # Draw all bullets (using a while loop)
    i = 0
    while i < len(bullets):
        x = int(bullets[i][0])
        y = int(bullets[i][1])
        pygame.draw.circle(screen, (255,255,0), (x,y), 3)
        i += 1
    pygame.display.flip()