"""Deep Cave, by Al Sweigart al@inventwithpython.com
An animation of a deep cave that goes forever into the earth.
This code is available at https://nostarch.com/big-book-small-python-programming
Tags: tiny, beginner, scrolling, artistic"""


import random, sys, time

# Set up the constants:
WIDTH = 70  # (!) Try changing this to 10 or 30.
PAUSE_AMOUNT = 0.05  # (!) Try changing this to 0 or 1.0.

print('Deep Cave, by Al Sweigart al@inventwithpython.com')
print('Press Ctrl-C to stop.')
time.sleep(2)

leftWidth = 20
gapWidth = 10

while True:
    # Display the tunnel segment:
    rightWidth = WIDTH - gapWidth - leftWidth
    print(('#' * leftWidth) + (' ' * gapWidth) + ('#' * rightWidth))

    # Check for Ctrl-C press during the brief pause:
    try:
        time.sleep(PAUSE_AMOUNT)
    except KeyboardInterrupt:
        sys.exit()  # When Ctrl-C is pressed, end the program.

    # Adjust the left side width:
    diceRoll = random.randint(1, 6)
    if diceRoll == 1 and leftWidth > 1:
        leftWidth = leftWidth - 1  # Decrease left side width.
    elif diceRoll == 2 and leftWidth + gapWidth < WIDTH - 1:
        leftWidth = leftWidth + 1  # Increase left side width.
    else:
        pass  # Do nothing; no change in left side width.

    # Adjust the gap width:
    # (!) Try uncommenting out all of the following code:
    #diceRoll = random.randint(1, 6)
    #if diceRoll == 1 and gapWidth > 1:
    #    gapWidth = gapWidth - 1  # Decrease gap width.
    #elif diceRoll == 2 and leftWidth + gapWidth < WIDTH - 1:
    #    gapWidth = gapWidth + 1  # Increase gap width.
    #else:
    #    pass  # Do nothing; no change in gap width.