#!/usr/bin/env sh

#####################################
# dd-gz - dd compressing on the fly #
#                                   #
# Author: q3aql@duck.com            #
# License: GPL v2.0                 #
data_version=2024-08-10             #
#####################################

# Check dependencies
path_check="/usr/bin /bin /usr/local/bin $HOME/.local/bin $(brew --prefix 2> /dev/null)/bin"
dependencies="dd gzip dirname basename"
dependencies_found=""
dependencies_not_found=""
for checkPath in $path_check ; do
  for checkDependencies in $dependencies ; do
    if [ -f $checkPath/$checkDependencies ] ; then
      dependencies_found="$dependencies_found $checkDependencies"
    fi
  done
done
for notFound in $dependencies ; do
  check_found_one=$(echo $dependencies_found | grep " $notFound")
  check_found_two=$(echo $dependencies_found | grep "$notFound ")
  if_not_found="$check_found_one$check_found_two"
  if [ -z "$if_not_found" ] ; then
    dependencies_not_found="$dependencies_not_found $notFound"
  fi
done
# Show if all tools are installed
if [ -z "$dependencies_not_found" ] ; then
  echo > /dev/null
else
  echo "$(basename $0): Some required tools are not installed:$dependencies_not_found"
  exit 1
fi

# Function to check root permissions
check_root() {
  mkdir -p /etc/root 2> /dev/null
  rootperm=$?
  if [ $rootperm -eq 0 ] ; then
    rm -rf /etc/root
  else
    echo "$(basename $0): Root permission is required to perform this operation"
    exit
  fi
}

help() {
  echo "$(basename $0) - dd compressing on the fly ($data_version)"
  echo "Syntax backup: $(basename $0) backup /dev/<device> /path/<output>.gz"
  echo "Syntax restore: $(basename $0) restore /path/<input>.gz /dev/<device>"
  exit 1
}

create_backup() {
  check_root
  device_input=$1
  output_file=$2
  if [ -z "$device_input" ] ; then
    echo "$(basename $0): No input device entered"
    exit 1
  fi
  if [ ! -e "$device_input" ] ; then
    echo "$(basename $0): Device $device_input was not found"
    exit 1
  fi
  if [ -z $output_file ] ; then
    echo "$(basename $0): No output file entered"                                                                                                                                                                   
    exit 1
  fi
  dir_output_file=$(dirname $output_file)
  if [ ! -d "$dir_output_file" ] ; then
    echo "$(basename $0): Directory $dir_output_file was not found"
    exit 1
  fi
  echo "$(basename $0) is running backup"
  echo "Device: $device_input"
  echo "Output: $output_file"
  dd if="$device_input" status=progress | gzip -9 > "$output_file"
}

restore_backup() {
  check_root
  input_file=$1
  device_output=$2
  if [ -z "$input_file" ] ; then
    echo "$(basename $0): No input file entered"
    exit 1
  fi
  if [ ! -f "$input_file" ] ; then
    echo "$(basename $0): Input file $input_file was not found"
    exit 1
  fi
  if [ -z "$device_output" ] ; then
    echo "$(basename $0): No output device entered"
    exit 1
  fi
  if [ ! -e "$device_output" ] ; then
    echo "$(basename $0): Device $device_output was not found"
    exit 1
  fi
  echo "$(basename $0) is restoring backup"
  echo "Input: $input_file"
  echo "Device: $device_output"
  gzip -d -k -c "$input_file" | dd of="$device_output" status=progress
}

# Main
if [ -z $1 ] ; then
  help
elif [ "$1" = "backup" ] ; then
 create_backup "$2" "$3" 
elif [ "$1" = "restore" ] ; then
 restore_backup "$2" "$3"
else
  help
fi