Backups

#!/bin/bash

# The script receives the path to a file, creates a backup folder in
# the folder where the file is, creates a folder whose name is the
# same as the basename of the file and, in the folder, makes a copy of
# the file with a timestamp as the new basename. The script expects
# that espeak and gio should be installed. If espeak isn't installed
# the script will try to use notify-send instead. If gio isn't
# installed the script will skip marking the backup folder with an
# icon.

####### Functions #######

function announce()
{
    if command -v espeak; then
        espeak -v whisper "$1"
    else
        notify-send "Backups" "$1"          \
                    -u "normal"             \
                    -i "dialog-information" \
                    -t 3000
    fi
}

function leave()
{
    if [ "$2" -eq 1 ]; then
        announcement_text="${1} Exiting!"
    else
        announcement_text="$1"
    fi

    announce "$announcement_text"
    exit "$2"
}

####### Main #######

PATH_TO_SOURCE_FILE="$1"

if [ -d "$PATH_TO_SOURCE_FILE" ]; then
    leave "The target object is not a file." 1
fi

PATH_TO_SOURCE_FILE_DIRECTORY="${PATH_TO_SOURCE_FILE%/*}"

cd "$PATH_TO_SOURCE_FILE_DIRECTORY" || \
    leave "Couldn't switch to the target directory." 1

BACKUP_FILE_BASENAME=$(date +%F_%T)
FILE_EXTENSION=${PATH_TO_SOURCE_FILE##*.}
BACKUP_FILE_DIRECTORY_NAME=$(basename "$PATH_TO_SOURCE_FILE" ".${FILE_EXTENSION}")

BACKUP_DIRECTORY_PATH="backup/${BACKUP_FILE_DIRECTORY_NAME}"

mkdir -p -- "$BACKUP_DIRECTORY_PATH" || leave "Couldn't create a directory." 1

if command -v gio; then
    gio set "backup" -t stringv metadata::emblems "emblem-package"
    touch "backup"
else
    announce "Gio is not installed. The root backup folder won't be marked with \
the 'emblem-package' icon. No big deal actually."
fi

BACKUP_FILE_PATH="${BACKUP_DIRECTORY_PATH}/${BACKUP_FILE_BASENAME}.${FILE_EXTENSION}"

LAST_BACKUP_FILE=$(find "$BACKUP_DIRECTORY_PATH" -maxdepth 1 -type f | sort | tail -n 1)

if cmp "$PATH_TO_SOURCE_FILE" "$LAST_BACKUP_FILE"; then
    leave "The backup is up-to-date." 1
else
    cp -- "$PATH_TO_SOURCE_FILE" "$BACKUP_FILE_PATH" || \
        leave "Couldn't copy the file." 1
fi

leave "Done!" 0