#!/usr/bin/python3
#
# do-until - run a command until it succeeds
# Copyright (C) 2008, 2011  Lars Wirzenius
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


"""Run a command until it succeeds."""


import cliapp
import subprocess
import sys
import time


class DoUntil(cliapp.Application):
    def add_settings(self):
        self.settings.boolean(
            ["no-act", "n"],
            "Do not run command, just pretend to do it, "
            "and pretend that it succeeds.",
        )
        self.settings.boolean(["verbose", "v"], "Print command before executing it.")
        self.settings.integer(
            ["sleep"],
            "Wait SECS seconds before re-trying a command. " "(Default is %default.)",
            default=1,
        )
        self.settings.integer(
            ["max-tries"],
            "Try at most COUNT times, with 0 meaning forever. "
            "(Default is %default.)",
            default=0,
        )

    def process_args(self, argv):
        tries = 0
        max_tries = self.settings["max-tries"]
        while max_tries == 0 or tries < max_tries:
            tries += 1
            if self.settings["verbose"]:
                sys.stderr.write(
                    "do-until: attempt #%d: %s\n" % (tries, " ".join(argv))
                )
            if self.settings["no-act"]:
                sys.stderr.write(
                    "do-until: not running command, " "pretending it works anyway\n"
                )
                break
            else:
                p = subprocess.Popen(argv)
                p.communicate()
                if p.returncode == 0:
                    break
            sys.stderr.write(
                "do-until: attempt %d failed, "
                "trying again in %d second(s)\n" % (tries, self.settings["sleep"])
            )
            time.sleep(self.settings["sleep"])


if __name__ == "__main__":
    DoUntil().run()