#!/bin/sh

#
## borg helper script for viewing and restoring backups
#

### trap
trap trapExit 1 2 3 6

### functions
cleanup () {
    # remove borg temp directory, if it exists
    if [ -d "${borgBaseDir}/tmp" ]; then
        if ! rm -rf "${borgBaseDir}/tmp" > /dev/null 2>&1; then
            consoleError 3 "Script completed successfully but could not remove temporary directory at $borgBaseDir/tmp. Sorry to be messy."
        fi
    fi
}

consoleError() {
    printf "%s\n%s\n" "$err" "$2"
    printf "Exiting.\n\n%s" "$norm"
    exit "$1"
}

scriptHelp() {
    printf "\n"
    textblock "${bold}Usage: borghelper.sh [parameters]${norm}"
    printf "\n"
    textblock "Simple script to read connection parameters from a flat text file and process borg 'info', 'list' and 'restore' commands without the very long command lines that are required when specifying repo names and passwords, etc."
    printf "\n"
    textblock "${magenta}The script has the following parameters:${norm}"
    printf "\n"
    textblock "${magenta}--- Required Parameters ---${norm}"
    printf "\n"
    ptextblock "-v|--vars"
    textblock "Path to the .borgvars file from which to read borg connection information. This is not required if run with '--makevars'."
    printf "\n"
    textblock "${magenta}--- Operation Modes ---${norm}"
    printf "\n"
    ptextblock "--makevars"
    textblock "Create a sample .borgvars file that you can fill in and use with this script."
    ptextblock "-i|--info"
    textblock "Get information about a specified borg repo archive. Requires you supply '--archive'."
    ptextblock "-l|--list"
    textblock "List contents of a specified borg repo archive. Requires you supply '--archive'."
    ptextblock "-la|--list-all"
    textblock "List all available archives within the repo specified in your .borgvars file."
    ptextblock "-r|--restore"
    textblock "Restore the specified borg repo archive/file(s). Requires you supply '--archive'."
    printf "\n"
    textblock "${magenta}--- Selector Parameters ---${norm}"
    printf "\n"
    ptextblock "-a|--archive"
    textblock "The archive within your borg repo you wish to work with."
    ptextblock "--exclude"
    textblock "Pattern (python/borg) of files to exclude from a restore operation."
    ptextblock "-f|--file"
    textblock "Specific file/pattern (python/borg) you want to restore from an archive. Requires that you supply '--archive'."
    ptextblock "-p|--path"
    textblock "Path to which you want your archive/files restored. This script will attempt to create the directory for you if it does not already exist."
    printf "\n"
    textblock "${magenta}--- Restore Options ---${norm}"
    printf "\n"
    ptextblock "--progress"
    textblock "Display progress indicator during restore operations. WARNING: This can drastically slow down operations on larger archives!"
    ptextblock "--verbose"
    textblock "List the individual files being processed during restore operations."
    printf "\n"
    textblock "${magenta}--- Other Parameters ---${norm}"
    printf "\n"
    ptextblock "-h|-?|--help"
    textblock "This help screen."
    printf "\n"
    exit 0
}

textblock() {
    printf "%s\n" "$1" | fold -w "$width" -s
}

ptextblock() {
    printf "%s%s%s\n" "$cyan" "$1" "$norm"
}

trapExit () {
    cleanup
    printf "%s\nScript execution terminated via signal.\n\n%s" "$err" "$norm"
    exit 99
}


### text formatting presets
if command -v tput > /dev/null; then
    bold=$(tput bold)
    cyan=$(tput setaf 6)
    err=$(tput bold)$(tput setaf 1)
    magenta=$(tput setaf 5)
    norm=$(tput sgr0)
    yellow=$(tput setaf 3)
    width=$(tput cols)
else
    bold=""
    cyan=""
    err="[ERROR] "
    magenta=""
    norm=""
    yellow=""
    width=80
fi


### pre-requisites

# is user root?
if [ ! "$( id -u )" -eq 0 ]; then
    consoleError 1 'You must be root to run this script.'
fi

# has a parameter been passed to this script?
if [ -z "$1" ]; then
    consoleError 1 "No operation requested. Please run this script with '--help' for valid parameters."
fi

# process startup parameters
while [ $# -gt 0 ]; do
    case "$1" in
        -a|--archive)
            # name of backup archive
            if [ -z "$2" ]; then
                consoleError 1 "Please provide the name of the backup archive you want to work with or use '--list-all' to get a full list."
            fi
            archiveName="$2"
            shift
            ;;
        --exclude)
            # exclude files from restore
            if [ -z "$2" ]; then
                consoleError 1 "Please provide a list of exclusions in the proper borg format."
            fi
            exclusions="$2"
            shift
            ;;
        -f|--file)
            # specific file to restore
            if [ -z "$2" ]; then
                consoleError 1 'Please provide the name of the specific file you want to restore.'
            fi
            fileName="$2"
            shift
            ;;
        -h|-\?|--help)
            # display help
            scriptHelp
            exit 0
            ;;
        -i|--info)
            # show archive information
            operation='info'
            ;;
        -l|--list)
            # list contents of specific backup
            operation='viewarchive'
            ;;
            
        -la|--list-all)
            # list all backup archives
            operation='listall'
            ;;
        --makevars)
            # make a borgvars template file
            operation='makevars'
            ;;
        -p|--path)
            # path to restore files
            if [ -z "$2" ]; then
                consoleError 1 'Please specify a path where you want files restored.'
            fi
            restorePath="${2%/}"
            shift
            ;;
        --progress)
            # show progress
            commonOptions="$commonOptions --progress"
            ;;
        -r|--restore)
            # restore archive/file
            operation='restore'
            ;;
        -v|--vars)
            # location of borgvars file
            if [ -z "$2" ]; then
                consoleError 1 'Please provide the path to the file with your borg connection information.'
            elif [ ! -f "$2" ]; then
                consoleError 1 'The specified borg connection information file does not exist.'
                exit 1
            fi
            varsFile="$2"
            shift
            ;;
        --verbose)
            # display each file being processed
            restoreOptions="$restoreOptions --list"
            ;;
        *)
            # invalid option
            printf "%s\nUnknown option: %s\n" "$err" "$1"
            printf "Use '--help' for valid options.\n\n%s" "$norm"
            exit 1
            ;;
    esac
    shift
done


### process 'makevars' operation
if [ "$operation" = 'makevars' ]; then
    if ! printf "sshKeyFile=\nborgBaseDir=\nborgRepo=\nborgRepoPassword=\nborgRemote=\n" > ./sample.borgvars; then
        consoleError 4 'Could not write sample borgvars file.'
    else
        exit 0
    fi
fi

### check parameter validity

# no operation
if [ -z "$operation" ]; then
    consoleError 1 'Nothing to do!'
fi

# no borg information file
if [ -z "$varsFile" ]; then
    consoleError 1 'You must provide a valid .borgvars file with information about your borg repo.'
fi

# info without archive
if [ "$operation" = 'info' ] && [ -z "$archiveName" ]; then
    consoleError 1 "Info operation requested but no archive name provided. Please use '--list-all' for a list of all available archives."
fi

# list without archive
if [ "$operation" = 'viewarchive' ] && [ -z "$archiveName" ]; then
    consoleError 1 "List operation requested but no archive name provided. Please use '--list-all' for a list of all available archives."
fi

# restore with no path
if [ "$operation" = 'restore' ] && [ -z "$restorePath" ]; then
    consoleError 1 "Restore operation requested but no restore path provided."
# restore with no archive
elif [ "$operation" = 'restore' ] && [ -z "$archiveName" ]; then
    consoleError 1 "Restore operation requested but no archive name provided."
fi

# file provided but no archive
if [ "$fileName" ] && [ -z "$archiveName" ]; then
    consoleError 1 "Filename specified without an associated archive name."
fi

# clean-up leading spaces in option strings
if [ "$commonOptions" ]; then commonOptions=${commonOptions##[[:space:]]}; fi
if [ "$restoreOptions" ]; then restoreOptions=${restoreOptions##[[:space:]]}; fi


### read borg information file

# check if file was provided as a relative or absolute path
case "${varsFile}" in
    /*)
        # absolute path, no need to rewrite variable
        . "${varsFile}"
        ;;
    *)
        # relative path, prepend './' to create absolute path
        . "./${varsFile}"
        ;;
esac

# verify borg base directory
if [ -z "${borgBaseDir}" ]; then
    consoleError 2 "$varsFile: 'borgBaseDir' is not specified."
elif [ ! -d "${borgBaseDir}" ]; then
    consoleError 2 "$varsFile: 'borgBaseDir' does not exist."
fi
export BORG_BASE_DIR="${borgBaseDir%/}"

## check path to SSH keyfile
if [ -z "${sshKeyFile}" ]; then
    consoleError 2 "$varsFile: 'sshKeyFile' is not specified."
elif [ ! -f "${sshKeyFile}" ]; then
    consoleError 2 "$varsFile: 'sshKeyFile' does not exist."
fi
export BORG_RSH="ssh -i ${sshKeyFile}"

# check borg repo connect string
if [ -z "${borgRepo}" ]; then
    consoleError 2 "$varsFile: 'borgRepo' is not specified."
fi
export BORG_REPO="${borgRepo}"

# check borg repo password
if [ -n "${borgRepoPassword}" ]; then
    export BORG_PASSPHRASE="${borgRepoPassword}"
elif [ "${borgRepoPassword}" = 'none' ]; then
    export BORG_PASSPHRASE=""
else
    consoleError 2 "$varsFile: 'borgRepoPassword' must be specified or must be 'none' if no password has been set (VERY INSECURE!)."
fi

# export borg remote path, if specified
if [ -n "${borgRemote}" ]; then export BORG_REMOTE_PATH="${borgRemote}"; fi


### create borg temp dir:
## python requires a writable temporary directory when unpacking borg and
## executing commands.  This defaults to /tmp but many systems mount /tmp with
## the 'noexec' option for security.  Thus, we will use/create a 'tmp' folder
## within the BORG_BASE_DIR and instruct python to use that instead of /tmp

# check if BORG_BASE_DIR/tmp exists, if not, create it
if [ ! -d "${borgBaseDir}/tmp" ]; then
    if ! mkdir "${borgBaseDir}/tmp"; then
        consoleError 3 'Unable to create temp working directory for borg.'
    fi
fi
export TMPDIR="${borgBaseDir}/tmp"


### execute borg operations

# info operations
if [ "$operation" = 'info' ]; then
    borg info ::"${archiveName}"
# list operations
elif [ "$operation" = 'listall' ]; then
    borg list
elif [ "$operation" = 'viewarchive' ]; then
    borg list ::"${archiveName}"
# restore operations
elif [ "$operation" = 'restore' ]; then
    cd "$restorePath" || consoleError 4 'Could not change to restore directory.'
    if [ -z "$fileName" ]; then
        # restore entire archive
        if [ "$exclusions" ]; then
            borg --show-rc ${commonOptions} extract ${restoreOptions} ::"${archiveName}" --exclude "${exclusions}"
        else
            borg --show-rc ${commonOptions} extract ${restoreOptions} ::"${archiveName}"
        fi
    elif [ "$fileName" ]; then
        # restore file/pattern
        if [ "$exclusions" ]; then
            borg --show-rc ${commonOptions} extract ${restoreOptions} ::"${archiveName}" "${fileName}" --exclude "${exclusions}"
        else
            borg --show-rc ${commonOptions} extract ${restoreOptions} ::"${archiveName}" "${fileName}"
        fi
    fi
fi


### exit gracefully
cleanup
exit 0


### exit codes
# 0:    no errors, script completed successfully
# 1:    parameter error (missing, non-existant or invalid input)
# 2:    parameter missing/invalid in .borgvars file
# 3:    could not create/remove borg tmp directory

#EOF# 4:    could not write sample borgvars file (permissions?)
# 5:    cannot create/write to restore path