#!/usr/bin/env python3

import os
import sys

def pp_size(size):
    suffixes = ["", "KiB", "MiB", "GiB"]
    for i, suffix in enumerate(suffixes):
        if size < 1024:
            break
        size /= 1024
    return "%.2f %s" % (size, suffix)


def check_path(path):
    stat = os.statvfs(path)
    total = stat.f_bsize * stat.f_blocks
    free = stat.f_bsize * stat.f_bavail
    warn = False

    if total < 5*1024*1024*1024:
        if free < total * 0.05:
            warn = True
    elif free < 2*1024*1024*1024:
        warn = True

    if warn:
        print("WARNING! %s has only %s remaining" % (path, pp_size(free)))
        return False

    return True

def read_fstab():
    for line in open("/etc/fstab"):
        if line.startswith("#") or not line.strip():
            continue
        _, path, _ = line.split(maxsplit=2)
        if path.startswith("/"):
            yield path

def main():
    paths = set(["/"])
    paths.update(read_fstab())
    ok = True
    for path in paths:
        ok = ok and check_path(path)

    if not ok:
        sys.exit(1)

if __name__ == "__main__":
    main()