Shoot sprite more then once and not reset it?

Question

I have looked over a lot of sites but I have only found stuff that was either much over my head or not aplicable to my situation. I want to be able to shoot a sprite out of my tank, I've got that working, but it fires and then I have to wait till it hits something and resets before I can shoot again without messing up my shot.

I've seen stuff with list and things but I couldn't undestand it or how they 'fixed' their problems.

My code is alittle messy but I'll try and make it understandable

Oh, and I'm new here:>

import pgzrun
import pygame
import random
"""setting up sprites"""
ptank = Actor('tank_a', anchor=('center', 'middle'))
ptmissile = Actor('shot_c', anchor=('center', 'middle'))
etank = Actor('tank_bbb', anchor=('center', 'top'))
ptshot = Actor('shot_cc', anchor=('center', 'middle'))
ptank.topright = 550, 800
etank.topright = 550, 200
ptmissile.topright = ptank.x, ptank.y
ptshot.topright = ptank.x, ptank.y

WIDTH = 1000
HEIGHT = 1000

"""global variables for gamplay"""

global pscore
pscore = 0

global escore
escore = 0

global ehealth
ehealth = 10

global phealth
phealth = 10

global shotdirect
shotdirect = 1

global shoot
shoot = 0

global missile
missile = 0

global gcheck
gcheck = 1

global graphics
graphics = 2

"""functions for gameplay"""
def follow():
    if ptmissile.y < etank.y:
        ptmissile.y += 1
    elif ptmissile.y > etank.y:
        ptmissile.y -= 1
    if ptmissile.x < etank.x:
        ptmissile.x += 1
    elif ptmissile.x > etank.x:
        ptmissile.x -= 1

def missile_reset():
    global missile
    missile = 0
    ptmissile.topright = ptank.x, ptank.y

def shot_reset():
    global shoot
    shoot = 0
    ptshot.topright = ptank.x, ptank.y

def shot_right():
    ptshot.x += 10

def shot_left():
    ptshot.x -= 10

def shot_up():
    ptshot.y -= 10

def shot_down():
    ptshot.y += 10

def missile_to():
    i = 0
    while i < 20:
        follow()
        i += 1

def on_mouse_down(pos):
    global graphics
    if ptank.collidepoint(pos) or etank.collidepoint(pos):
        gcheck = 0

    if ptank.collidepoint(pos):
        graphics = 0
        gcheck = 0
    elif etank.collidepoint(pos):
        graphics = 1
        gcheck = 0

"""drawing sprites"""

def draw():
    global missile
    global gcheck
    global graphics
    global shoot
    screen.clear()
    if gcheck == 1:
        screen.draw.text("Graphics level: click on low: you, or high: enemy", [500, 500])
    if graphics == 1:
        screen.blit('background_a', (0, 0))
    if graphics == 0:
        gcheck = 0
    ptank.draw()
    etank.draw()
    if missile == 1:
        ptmissile.draw()
    if shoot == 1:
        ptshot.draw()

"""main code"""

def update():
    global missile
    global shoot
    global graphics
    global gcheck
    global shotdirect

    if shoot == 1:
        if shotdirect == 1:
            shot_up()
        if shotdirect == 2:
            shot_right()
        if shotdirect == 3:
            shot_down()
        if shotdirect == 4:
            shot_left()

    if ptshot.x < 0:
        shot_reset()
        shoot = 0

    if ptshot.x > WIDTH:
        shot_reset()
        shoot = 0

    if ptshot.y < 0:
        shot_reset()
        shoot = 0

    if ptshot.y > HEIGHT:
        shot_reset()
        shoot = 0

    if ptmissile.collidepoint(etank.x, etank.y):
        missile_reset()
        missile = 0

        sounds.explosion_b.play()
    if missile == 1:
        missile_to()

    if keyboard.tab:
        missile_reset()
        missile = 1
        print(str(missile))

    if ptshot.collidepoint(etank.x, etank.y):
        shot_reset()
        shoot = 0
        sounds.explosion_b.play()

    if keyboard.space:
        shoot = 0
        shot_reset()
        shoot = 1
        print(str(shoot))

    if keyboard.left:
        ptank.angle = 90
        ptank.x -=10
        if shoot == 0:
            shotdirect = 4
    if keyboard.right:
        ptank.angle = 270
        ptank.x +=10
        if shoot == 0:
            shotdirect = 2

    if keyboard.up:
        ptank.angle = 360
        ptank.y -=10
        if shoot == 0:
            shotdirect = 1

    if keyboard.down:
        ptank.angle = 180
        ptank.y +=10
        if shoot == 0:
            shotdirect = 3

"""this isn't the best way to do it but I've started fixing it (see: above; using angle)"""

    if keyboard.a:
        etank.image = 'tank_bbbb'
        etank.x -=10

    if keyboard.d:
        etank.image = 'tank_bb'
        etank.x +=10

    if keyboard.w:
        etank.image = 'tank_b'
        etank.y -=10

    if keyboard.s:
        etank.image = 'tank_bbb'
        etank.y +=10
pgzrun.go()