progress-bar.py

import math
import sys
import time


# Colours
BOLD = '\033[1m'
RED = '\033[91m'
GREEN = '\033[92m'
YELLOW = '\033[93m'
BLUE = '\033[94m'
ENDC = '\033[0m'

# Other Escape Sequences
MOVE_UP_TWO = '\033[2A'
CLEAR_LINE = '\033[0K'
HIDE_CURSOR = '\033[?25l'
SHOW_CURSOR = '\033[?25h'


def print_overlap(text, first=False, file=sys.stdout):
    """
    Prints a block of overlapping text ensuring that previous output is cleared.

    :param text: The text to display as a multiline string or list (where each item is one line).
    :param first: Whether or not this is the first run of the function.
    :param file: The stream to display the output to.
    """
    # Obtain the lines that we will print
    lines = text.split('\n') if isinstance(text, str) else text

    # Determine how many times we need to move up two lines
    num_moves_up_two = math.ceil(len(lines) / 2)

    if not first:
        print(MOVE_UP_TWO * num_moves_up_two, end='', file=file, flush=True)

        # If an odd number of lines is found, we need to move the cursor down one line with a \n
        if len(lines) % 2 == 1:
            print(file=file, flush=True)

    for line in lines:
        print(f'{CLEAR_LINE}{line}', file=file, flush=True)


def progress_bar(
    percent, width=40, boundary_symbol_left='|', boundary_symbol_right='|',
    progress_symbols=['▏', '▎', '▍', '▌', '▋', '▊', '▉', '█']
):
    """
    Builds a progress bar based on the required appearance.

    :param percent: The current percentage to display (as a number between 0 and 100).
    :param width: The total width of the progress bar (includes the boundaries).
    :param boundary_symbol_left: The left boundary symbol to display.
    :param boundary_symbol_right: The right boundary symbol to display.
    :param progress_symbols: A list containing gradual progress indicators.

    :return: a unicode string which may be printed to display the progress bar
    """
    # Remove the two boundary items to determine the width of the progress bar
    progress_width = width - 2

    # Calculate how far we've progressed based on the width requested
    complete_width = progress_width * percent / 100

    # Calculate how many full blocks we will display for completeed progress
    complete_blocks = int(complete_width)

    # Determine which progress symbol to use for the last block
    partial_block_width = complete_width - complete_blocks
    partial_block_symbol_index = int(partial_block_width * len(progress_symbols))

    # If progress is less than 100%, we need to show the partial block
    partial_block_show = complete_blocks < progress_width

    # Calculate how many full blocks we will display for incomplete progress
    incomplete_blocks = progress_width - complete_blocks - (1 if partial_block_show else 1)

    return (
        # left boundary
        f'{boundary_symbol_left}'
        # completed blocks
        f'{progress_symbols[-1] * (complete_blocks)}'
        # partial block
        f'{progress_symbols[partial_block_symbol_index] if partial_block_show else ""}'
        # incomplete blocks
        f'{" " * incomplete_blocks}'
        # right boundary
        f'{boundary_symbol_right}'
    )


def main():
    # Progress bar example
    try:
        print(HIDE_CURSOR, end='', flush=True)

        progress = 0
        while progress <= 100:
            print_overlap([
                '',
                f'{BOLD}Installing Something Awesome{ENDC}',
                '',
                f'{BLUE}Extracting the_awesome_thing.zip...{ENDC}',
                '',
                f'{progress:8.1f} % {progress_bar(progress, width=50)} file_{int(progress)}.txt',
            ], first=True if progress == 0 else False)

            progress += 0.01
            time.sleep(0.001)

    finally:
        print()
        print(SHOW_CURSOR, end='', flush=True)


if __name__ == '__main__':
    main()