#!/bin/bash
#=======================================================================
#           FILE: cd-umount.sh
#          USAGE: cd-umount.sh [<Imageverzeichnis>]
#    DESCRIPTION:
#        OPTIONS:
#   REQUIREMENTS:
#           BUGS:
#          NOTES:
#         AUTHOR: Jonas Tobias Hopusch <hopusch.jonastobias@fh-swf.de>
#        COMPANY: Fachhochschule Südwestfalen
#        VERSION: 1
#        CREATED: 2023-01-10T16:32Z
#       REVISION:
#=======================================================================
#-----------------------------------------------------------------------
#   Abort script if undefined veriables are referenced
#   and properly handle pipe failure
#-----------------------------------------------------------------------
set -uo pipefail

#-----------------------------------------------------------------------
#   Script configuration
#-----------------------------------------------------------------------
imageFileEnding='.image'
defaultTargetDir="$HOME/CDs/"

#-----------------------------------------------------------------------
#   Check if fuseiso and fusermount are present
#-----------------------------------------------------------------------
if ! which 'fuseiso' >/dev/null 2>&1; then
    echo 'fuseiso is not installed'
    exit 1
elif ! which 'fusermount' >/dev/null 2>&1; then
    echo 'fusermount is not installed'
    exit 1
fi

#-----------------------------------------------------------------------
#   Determine target directory
#-----------------------------------------------------------------------
if [ -v 1 ]; then
    targetDir="$1"
else
    targetDir="$defaultTargetDir"
fi

#-----------------------------------------------------------------------
#   Search for matching images
#-----------------------------------------------------------------------

#shellcheck disable=SC2006
readarray -t imageFiles \
     <<<"`find "$targetDir" -type f -iname "*$imageFileEnding" 2>/dev/null`" \
    >/dev/null 2>&1

#-----------------------------------------------------------------------
#   Per Image, do the following
#-----------------------------------------------------------------------
amountOfImages="${#imageFiles[@]}"
successfullyUnmountedImages=0
for image in "${imageFiles[@]}"; do
    # Count how many there are in total
    #((amountOfImages++))

    # Validate that it is a valid regular file
    if ! [ -f "$image" ]; then
        echo "$image is not a regular file. Skipping."
        continue
    fi

    # Determine the location the image should be unmounted from
    mountDirName="${image:0:((${#image} - ${#imageFileEnding}))}"
    if ! [ -d "$mountDirName" ]; then
        echo "Directory $mountDirName does not exist. Skipping!"
        continue
    fi

    # Check if there's already an image mounted at the destination
    #shellcheck disable=SC2006
    fullPathMountDir="`cd "$mountDirName" && pwd`"
    if ! grep "^fuseiso $fullPathMountDir " /proc/mounts >/dev/null 2>&1; then
        echo "No image is mounted to $mountDirName. Skipping"
        continue
    fi

    # Attempt to mount the image to the destination directory
    if fusermount -u "$mountDirName"; then
        echo "$image has been unmounted from $mountDirName"
        ((successfullyUnmountedImages++))
    fi

    rmdir "$mountDirName"
done

find "$targetDir/" -mindepth 1 -maxdepth 1 -type d -delete 2>/dev/null

echo "$successfullyUnmountedImages/$amountOfImages images have been unmounted successfully"