# ferry.py - tct - 5/19,20,21,24/15

import pygame, sys
pygame.init()

# slow ferry
def sf(t):
    sp = t
    if sp >= 1760:
        srp = 3520-sp
    else:
        srp = sp
    return srp

# fast ferry
def ff(t):
    fp = 13./9.*t
    if fp <= 1760:
        frp = 1760-fp
    else:
        frp = fp-1760
    return frp

screen = pygame.display.set_mode([900,300])

# draw the ferries
for t in range(2161):
    screen.fill([255, 255, 255])

    inst1_font = pygame.font.Font(None, 24)

    str = "slow ferry : %.1f" % sf(t)
    inst1_surf = inst1_font.render(str, 1, (255, 0, 0))
    screen.blit(inst1_surf, [100, 50])
    str = "fast ferry : %.1f" % ff(t)
    inst1_surf = inst1_font.render(str, 1, (0, 0, 255))
    screen.blit(inst1_surf, [660, 50])
    str = "http://primepuzzle.com/tunxis/ferry.htm"
    inst1_surf = inst1_font.render(str, 1, (0, 0, 0))
    screen.blit(inst1_surf, [330, 250])

    pygame.draw.rect(screen, (255,0,0), (sf(t)/2,100,20,10), 2)
    pygame.draw.rect(screen, (0,0,255), (ff(t)/2,150,20,10), 2)
    pygame.display.flip()

    pygame.time.delay(10)

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()