#!/usr/bin/python3
from gpiozero import Motor, Button
from time import sleep

# GPIO numbers for motor
MOTOR_PIN_FWD = 17
MOTOR_PIN_REV = 18
# GPIO pin for reed switch
REED_PIN = 4

# max speed to reduce top speed
# maximum value is 1
MAX_SPEED = 1.0
# How long to wait between speed increases
ACC_DELAY = 0.5
# How long to wait at the station
STATION_DELAY = 10

m1 = Motor (MOTOR_PIN_FWD, MOTOR_PIN_REV)
reed_switch = Button (REED_PIN)

# Go from stop to max speed
def train_speed_up (max_speed):
    speed = 0
    while speed < max_speed:
        speed += 0.1
        if speed >= 1:
            speed = 1
        m1.forward(speed)
        sleep(ACC_DELAY)

def train_slow_down (current_speed):
    speed = current_speed
    while speed > 0:
        speed -= 0.1
        if speed <= 0 :
            m1.stop()
        else:
            m1.forward(speed)
        sleep(ACC_DELAY)

# Go immediately to set speed
def train_set_speed (speed):
    m1.forward(speed)

def main():
    while True:
        print ("Leaving the station")
        # Accelerate up to full speed
        train_speed_up(MAX_SPEED)
        # wait until it triggers reed switch
        print ("Going to station")
        reed_switch.wait_for_press()
        print ("Stopping at station")
        train_slow_down(MAX_SPEED)
        sleep(STATION_DELAY)

#Run the main function when this program is run
if __name__ == "__main__":
    main()