import sys

class ProgressBar:
    def __init__(self, num_elements):
        self.num_elements = num_elements
        self.current_element = 0

    def show(self, msg=''):
        total_blocks = 10
        blocks_done = ((self.current_element * total_blocks)
                       // self.num_elements)
        blocks_to_go = total_blocks - blocks_done

        print('\r'        # Go to the start of the line
              '\x1b[K'    # Clear line
              '\x1b[0m'   # Restart the "style"
              '\x1b[?7l'  # Disable line wrapping
              '|'         # Put the first "|"
              + blocks_done * '█'  # Completed blocks
              + blocks_to_go * ' '  # Uncompleted blocks
              + '\x1b[7m|\x1b[0m'   # End the bar
              + ' '
              + msg         # Add message
              + '\x1b[?7h'  # Enable line wrapping
              + '\r',       # Go back to the start
              end='')

    def next_iter(self, msg=''):
        self.current_element += 1
        self.show(msg)