#!/bin/bash
set -eou pipefail

# usage: auto-restart.sh python program.py

trap 'exit 1' SIGINT

count=$(ps -eo args | grep ^/bin/bash | grep "auto-restart $*"$ | grep -v grep | wc -l)
if (($count > 2)); then
    echo already running: auto-restart $@ >&2
    exit 1
fi

reset_count_after_seconds=${reset_count_after_seconds:-10}
max_retries=${max_retries:-5}
now() { date +%s; }

last=$(now)
retry_count=0
while true; do
    if eval "$@"; then
        echo exited 0: "$@" >&2
    else
        echo exited $?: "$@" >&2
    fi
    seconds_since_last_bounce=$(($(now) - $last))
    if (($seconds_since_last_bounce > $reset_count_after_seconds)); then
        echo resetting bounce count since $seconds_since_last_bounce seconds have passed since the last bounce >&2
        retry_count=0
    fi
    retry_count=$(($retry_count + 1))
    if (($retry_count > $max_retries)); then
        echo exceeded max max_retries $max_retries
        exit 1
    fi
    last=$(now)
    echo sleep for retry_count=$retry_count seconds >&2
    sleep $retry_count
done