#!/bin/bash

# name: restic_backup.sh
# version: 0.1
# author: david@socialnerds.org
# license: MIT
# description: a simple script to automate the restic backup utility.
#              i created this for my personal use, though you are very
#              welcome reuse and improve.


#  ****  CONFIG  ****
PASSWORD="/root/.restic-password"
REPO="sftp:remote-server.tld:/path/to/repository"
KEEP=30
BIN="/usr/bin/restic" 
OPTIONS="-q"


#  ****  START  ****
CMD="$BIN -p $PASSWORD -r $REPO $OPTIONS"

#TODO: check for elevated privileges

# Generate a new password file if it is missing or empty
if [ ! -s $PASSWORD ]; then
    #echo "error: Password file is empty or does not exist. [$PASSWORD]"
    #exit 1
    tr -cd '[:alnum:]' < /dev/urandom | fold -w32 | head -n1 > $PASSWORD
    chmod 600 $PASSWORD
    echo "warning: New password file generated since it does not exist or is empty. [$PASSWORD]"
fi

# Initialize a new repo if the repo url has no config file
$CMD snapshots >/dev/null 2>&1
if [ $? -ne 0 ]; then
    $CMD init >/dev/null 2>&1
    if [ $? -ne 0 ]; then
	echo "error: A problem occured while creating a new repository. [$REPO]"
        exit 1
    fi
    echo "warning: New repository initialized. [$REPO]"
fi

# Run the restic repository check
$CMD check > /dev/null
if [ $? -ne 0 ]; then
    echo "error: Repository check failed. [$REPO]"
    exit 1
fi

# First option must be a readable folder/file
if [ $1 ]; then
    if [ -r $1 ]; then
        LOCAL=$1
    else
        echo "error: The path given does not seem to be readable. [$1]"
	exit 1
    fi
else
    echo "error: Local path must be given as an option."
    exit 1
fi

# Run the actual backup
$CMD backup ${@:2} $LOCAL > /dev/null
if [ $? -ne 0 ]; then
    echo "error: Something went wrong while running backup. [$LOCAL]"
    exit 1
fi

# Delete old snapshots
$CMD forget --keep-last $KEEP --path $LOCAL --prune > /dev/null
if [ $? -ne 0 ]; then
    echo "error: Something went wrong while deleting old snapshots. [$LOCAL]"
    exit 1
fi


#  ****  END  ****
exit 0