#!/usr/bin/env python3

import sys
import time
from argparse import ArgumentParser


class Verbose:
    def __init__(self):
        self.progress_chars = " ▏▎▍▌▋▊▉█"
        self.progress_n = 0
        self.ts = 0
        self.loops = 0

    def next(self):
        if time.time() > self.ts + 0.1:
            s = (
                " "
                + self.loops * self.progress_chars[-1]
                + self.progress_chars[self.progress_n]
                + "\r"
            )
            print(s, file=sys.stderr, end="")
            self.progress_n = (1 + self.progress_n) % len(self.progress_chars)
            if self.progress_n == 0:
                self.loops += 1
            if self.loops >= 10:
                print(" " * 11 + "\r", file=sys.stderr, end="")
                self.loops = 0
            sys.stderr.flush()
            self.ts = time.time()


# Set up options
parser = ArgumentParser(
    description="Sponge file before writing output: grep foo file.txt | sponge file.txt",
    epilog="This tool is a modification from http://joeyh.name/code/moreutils/ with the same name.",
)
parser.add_argument(
    "-a",
    action="store_true",
    dest="append",
    default=False,
    help="Append to file instead of overwriting",
)
parser.add_argument(
    "-v", action="store_true", dest="verbose", default=False, help="Progress to stderr"
)
parser.add_argument(type=str, dest="file", help="File to write to")
options = parser.parse_args()


# choose mode
mode = "wb"
if options.append:
    mode = "ab"
if options.verbose:
    v = Verbose()
chunk_size = 1024 * 1024 * 1  # Mb

# Write the file
with open(options.file, mode) as writer:
    while True:
        chunk = sys.stdin.buffer.read(chunk_size)
        if not chunk:
            break
        if options.verbose:
            v.next()
        writer.write(chunk)