#!/bin/bash

# Accept the following
    # 1 - source directory
         # Default to $HOME
    # 2 - destination directory
        # Mandatory
        # Exclude destination directory from backup
    # 2 - Backup_name
        # Default to $USER
    # 3 - Unique Identifier
        # Default to $HOST
    # 4 - Log Directory
        # Default to /var/log/borg
        # Create if does not exist
    # BORG_PASSPHRASE
        # Default to blank
# Display usage on -h and on wrong params

##############################################################
# Usage
##############################################################

function usage() {
    if [ -n "$1" ]; then
        echo ""
        echo -e "${CRED}$1${CEND}\n"
    fi

    echo "Usage: bash $0  -dstdir path [-srcdir path] [-name name] [-uname uname] [-logdir path] [-pass passphrase]"
    echo "      -dstdir         Directory where borg will create backup files"
    echo "                      Will be created if it does not exist"
    echo "      -srcdir         Directory that you want to backup (Default is \$HOME)"
    echo "      -name           Name for the backup. Useful when you use borg to create multiple backups on a system"
    echo "      -uname          Unique name to identify backup from this system from other systems"
    echo "                      Default is \$HOST"
    echo "      -logdir         Directory where log files will be created. Default /var/log/borg"
    echo "                      Will be created if it does not exist"
    echo "      -pass           borg will encrypt the backup with this passphrase"
    echo "      -h|--help       Displays this help text"

    echo ""
    echo "Example: bash ./$0 -dstdir ${HOME}/backups -name home -logdir ${HOME}/backups/logs"
    printf "\\nBelow restrictions apply to passphrase - \\n"
    printf "%2s - [a-zA-Z0-9] [-] [_] are allowed\\n%2s - NO special characters.\\n%2s - NO spaces.\\n" " " " " " "

    if [ -n "$1" ]; then
        exit 2
    fi
}

##############################################################
# Parse and validate arguments
##############################################################

while [[ "${#}" -gt 0 ]]; do
    case $1 in
        -dstdir)

            # If it exists > Check if you have write access
            if [[ (-d "$2") && (-r "$2") && (-w "$2") && (-x "$2")]]; then
                backup_dir="$2"
            else
                echo
                echo "Can't access the backup directory ${2}"
                echo "You need to have write access to backup destination directory."
                exit 5
            fi

            # Create if it does not exist
            if [[ ! -d "$2" ]]; then
                mkdir -p "$2"
                return_code=$?

                if [[ $return_code != 0 ]]; then
                    echo "Error creating backup directory ${2}"
                    exit 6
                fi
            fi

            backup_dir="$2"

            echo "$backup_dir"

            shift 2
            ;;
        -srcdir)
            # Check if it exists
            if [[ -d "$2" ]]; then
                source_dir="$2"
            else
                echo "No directory to backup. ${2} not found."
                exit 7
            fi

            shift 2
            ;;
        -name)
            backup_name="$2"
            shift 2
            ;;
        -uname)
            unique_identifier="$2"
            shift 2
            ;;
        -logdir)
            # If it exists > Check if you have write access
            if [[ (-d "$2") && (-r "$2") && (-w "$2") && (-x "$2")]]; then
                log_dir="$2"
            else
                echo "Can't access the log directory ${2}"
                exit 8
            fi

            # Create if it does not exist
            if [[ ! -d "$2" ]]; then
                mkdir -p "$2"
                return_code=$?

                if [[ $return_code != 0 ]]; then
                    echo "Error creating log directory ${2}"
                    exit 9
                fi
            fi

            log_dir="$2"

            shift 2
            ;;
        -pass)
            BORG_PASSPHRASE="$2"
            shift 2
            ;;
        -h|--help)
            echo
            usage
            echo
            exit 0
            ;;
        *)
            usage "Unknown parameter passed: $1" "h"
            exit 3
            ;;

    esac
done

# TODO - Display usage() error when dstdir is NOT provided by user


##############################################################
# Default values
##############################################################

# If nothing provided by user assign defaults
backup_name=$USER
unique_identifier="$HOST"
log_dir=/var/logs/borg/
source_dir="$HOME"



exit


#########################################################################


# Setting this, so you won't be asked for your repository passphrase:
export BORG_PASSPHRASE

# Setting this, so the repo does not need to be given on the commandline:
export BORG_REPO=$backup_dir$backup_name

# some helpers and error handling:
log_file=$log_dir$backup_name-$(date +%d%m%Y-%H%M%S)
readonly log_file

# if borg is currently running - stop sync
if [[ "$(pidof borg -s | wc -w)" -eq 1 ]]
then
  echo "Another Backup is currently running. Exiting." >> "$log_file" 2>&1
  exit 1
fi

info() { 
    printf "\n%s %s\n\n" "$( date )" "$*" >> "$log_file" 2>&1; 
}

trap 'echo $( date ) Backup interrupted >> "$log_file" 2>&1; exit 255' INT TERM

info "Starting backup" >> "$log_file" 2>&1

# Backup the most important directories into an archive named after
# the machine this script is currently running on:

borg create                                             \
    --verbose                                           \
    --filter AME                                        \
    --list                                              \
    --stats                                             \
    --show-rc                                           \
    --compression zstd,1                                \
    --exclude-caches                                    \
    --exclude '/home/*/.cache/*'                        \
    --exclude '/home/*/.local/share/Trash/*'            \
    --exclude '/home/*/Downloads/Videos/*'              \
    --exclude '/home/*/Downloads/Study/Video/*'         \
    --exclude "$backup_dir"                             \
    --exclude "$log_file"                               \
                                                        \
    ::"$unique_identifier-$backup_name-{now}"           \
    "$source_dir"                                       \
    >> "$log_file" 2>&1                                 

backup_exit=$?

if [[ $backup_exit == 0 ]] 
then
    info "Back up completed successfully"
else
    info "Back up error - Check ${log_file} for details"
fi


# PRUNE
info "Pruning repository" >> "$log_file" 2>&1

# Use the `prune` subcommand to maintain 7 daily, 4 weekly and 6 monthly
# archives of THIS machine. The '{hostname}-' prefix is very important to
# limit prune's operation to this machine's archives and not apply to
# other machines' archives also:

borg prune                                          \
    --list                                          \
    --stats                                         \
    --prefix "$unique_identifier-$backup_name"      \
    --show-rc                                       \
    --keep-within 2d                                \
    --keep-last 10                                  \
    --keep-daily 7                                  \
    >> "$log_file" 2>&1                             

prune_exit=$?

if [[ $prune_exit == 0 ]] 
then
    info "Pruning completed successfully"
else
    info "Pruning error - Check ${log_file} for details"
fi

# use highest exit code as global exit code
global_exit=$(( backup_exit > prune_exit ? backup_exit : prune_exit ))

echo Status Code - $global_exit >> "$log_file" 2>&1

exit ${global_exit}