Downloading every video for a TikTok account

#!/usr/bin/env python3

import sys
import time
import subprocess

def main():
    if len(sys.argv) < 3:
        print(f"Usage: {sys.argv[0]} <total> <shell_command>")
        sys.exit(1)
    
    total = int(sys.argv[1])
    # If your command may include spaces, you might need to do this:
    # shell_command = ' '.join(sys.argv[2:])
    # but for the simple example provided:
    shell_command = sys.argv[2]

    # -- Step 1: Get initial progress and record the time --
    try:
        initial_output = subprocess.check_output(shell_command, shell=True)
        done_initial = int(initial_output.strip())
    except Exception as e:
        print(f"Error running initial command: {shell_command}\n{e}")
        sys.exit(1)

    # Clamp in case the command returns something above the total or below zero
    if done_initial < 0:
        done_initial = 0
    if done_initial > total:
        done_initial = total

    time_initial = time.time()

    # Print one quick update before we start the loop
    print_progress(done_initial, total, 0, 0)

    # If we already reached (or exceeded) the total, exit immediately
    if done_initial >= total:
        print("\nDone!")
        sys.exit(0)

    # -- Step 2: Repeatedly poll the command to update progress --
    polling_interval = 1.0  # seconds between checks

    while True:
        time.sleep(polling_interval)

        # Fetch current progress
        try:
            output = subprocess.check_output(shell_command, shell=True)
            done = int(output.strip())
        except Exception as e:
            print(f"\nError running command: {shell_command}\n{e}")
            sys.exit(1)
        
        # Clamp done to never exceed total or go below 0
        if done < 0:
            done = 0
        if done > total:
            done = total

        # How much progress has been made since we started measuring?
        delta_done = done - done_initial
        delta_time = time.time() - time_initial

        # Print the progress bar
        print_progress(done, total, delta_done, delta_time)

        if done >= total:
            break

    print("\nDone!")


def print_progress(done, total, delta_done, delta_time):
    """
    Print a single-line progress bar with percentage and ETA (if possible).
    Overwrites the previous line via carriage return.
    """

    # Fraction complete
    fraction = done / total if total else 1.0

    # Build the bar
    bar_length = 50
    filled_length = int(bar_length * fraction)
    bar = "#" * filled_length + "-" * (bar_length - filled_length)

    # Compute ETA based only on new progress (delta_done)
    if delta_done > 0:
        time_per_item = delta_time / delta_done
        remaining = total - done
        eta_seconds = int(time_per_item * remaining)
        eta_string = format_eta(eta_seconds)
    else:
        # If no new items have completed since the script started, can't guess yet
        eta_string = "calculating..."

    progress_line = (
        f"\r[{bar}] {done}/{total} ({fraction*100:.1f}%) - ETA: {eta_string}"
    )
    print(progress_line, end='', flush=True)


def format_eta(seconds):
    """Convert number of seconds into a H:MM:SS or M:SS format string."""
    h = seconds // 3600
    m = (seconds % 3600) // 60
    s = seconds % 60

    if h > 0:
        return f"{h:d}:{m:02d}:{s:02d}"
    else:
        return f"{m:02d}:{s:02d}"


if __name__ == "__main__":
    main()