#!/data/data/com.termux/files/usr/bin/bash

# TERBR - Termux Backup/Restore Tool
# Copyright (C) 2020  MrAlpha786
#
#  This program is free software: you can redistribute it
# and/ or modify it under the terms of the GNU General Public
# License as published by the Free Software Foundation either
# version 3 of the License, or (at your option) any later
# version.
#
#  This program is distributed in the hope that it will be
# useful, but WITHOUT ANY WARRANTY; without even the implied
# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
# PURPOSE.  See the GNU General Public License for more
# details.
#
#  You should have received a copy of the GNU General
# Public License along with this program.  If not, see
# <https://www.gnu.org/licenses/>.
#
# Author: MrAlpha786     (github/MrAlpha786)
#
#colors and other variable
R='\033[1;31m'
B='\033[1;34m'
C='\033[0;36m'
G='\033[1;32m'
Y='\033[1;33m'
N='\033[0m'
TERBR_COMMAND='tar'
TERBR_DIRS='home'
TERBR_BACKUP_FILE="/storage/emulated/0/termux_backup$(date +%m%d%Y_%H%M%S).bak"
readonly BACKUP_SRC='/data/data/com.termux/files'
readonly TERBR_HISTFILE=$PREFIX/var/log/apt/history.log
readonly TERBR_PKGS=~/pkglist.out

function banner () {
  echo
  echo -e "$B ┌───────────────────────┐"
  echo -e "$B │$C ▀█▀ █▀▀ █▀▀▄ █▀▄ █▀▀▄ $B│"
  echo -e "$B │$C ─█─ █▀▀ █▐█▀ █▀█ █▐█▀ $B│"
  echo -e "$B │$C ─▀─ ▀▀▀ ▀─▀▀ ▀▀─ ▀─▀▀ $B│"
  echo -e "$B └───────────────────────┘"
  echo -e "$G  -> Author: MrAlpha786 $N"
  echo
}

function list_packages () {
  # Grep 'histfile' and create two arrays
  # one of installed pkgs and one of removed pkgs
  while IFS= read -r line; do
    line=${line/-y/}
    if [[ "$line" =~ ' install ' ]]; then
      installed+=(${line##* install })
    else
      removed+=(${line##* remove })
      removed+=(${line##* purge })
    fi
  done < <(grep -E ' install | remove | purge ' ${TERBR_HISTFILE})

  # For every removed pkg, if it's also in installed pkgs
  # remove it from installed pkgs
  for pkg in "${removed[@]}";do
    for i in "${!installed[@]}";do
    if [[ "${installed[$i]}" == "$pkg" ]]; then
      unset installed[$i]
      break
    fi
    done
  done

  # Remove any duplicates
  # And put them in TERBR_PKGS
  declare -A tmp_array

  for i in "${installed[@]}"; do
    [[ $i ]] && IFS=" " tmp_array["${i:- }"]=1
  done

  echo -e "${G} Saving installed packages to '${TERBR_PKGS}'\n"

  printf '%s\n' "${!tmp_array[@]}" > $TERBR_PKGS

  if [ -n "${TERBR_VERBOSE}" ];then
      echo -e "$G [*] Installed Packages $N\n"
      nl "${TERBR_PKGS}"
  fi
}

function backup () {
  cd $BACKUP_SRC

  list_packages || error_exit

  echo -e "${G} Saving Backup to '${TERBR_BACKUP_FILE}'\n"
  echo -e "${Y} [*] Backing Up Files.............."
  echo -e "${R} [!] It may take a while. Please wait...$N\n"

  ${TERBR_COMMAND} "${TERBR_BACKUP_FILE}" ${TERBR_DIRS} | nl || error_exit

  echo -e "${G} [!] Backup Done! "
}

function restore () {
  cd $BACKUP_SRC

  echo -e "${G} Restoring from '${TERBR_RESTORE_FILE}'\n"
  echo -e "${Y} [*] Restoring Files..............."
  echo -e "${R} [!] It may take a while. Please wait...\n"

  ${TERBR_COMMAND} "${TERBR_RESTORE_FILE}" ${TERBR_DIRS} | nl || error_exit

  echo -e "${G} [!] Restore Done! "
}

function usage () {
  echo -e "Usage: $(basename $0) -[hvVbr] "
  echo -e "Create Termux Backup and Restore it.\n"
  echo -e "    -b           Take backup"
  echo -e "    -r [FILE]    Restore backup"
  echo -e "    -p           List Installed Packages"
  echo -e "    -v           Verbose output"
  echo -e "    -h           Print usage"
  echo -e "    -V           Print version"
}

function version () {
  echo "Terbr - Termux Backup and Restore Tool"
  echo "A tool to Backup and Restore Termux"
  echo "Copyright (C) 2020  MrAlpha786"
  echo "This program is free software: you can redistribute it and/or modify it under the terms of the GNU GPL as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version."
  echo
  echo "This program is distributed WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
  echo
  echo "Author: MrAlpha786 (github.com/MrAlpha786)"
}

#Print message to standard error
function print_error () {
    echo "$(basename $0): $1" >&2
}

# Cleanup on unexpected error
function error_exit () {
  SIGNAL=$?
  rm -f "${TERBR_BACKUP_FILE}"
  exit ${SIGNAL}
}

# Trap signals
trap 'error_exit' 1 2 3 15 20

while getopts ':hvVpbr:' arg; do
  case $arg in
    b) unset TERBR_RESTORE; TERBR_BACKUP=1;;
    r) unset TERBR_BACKUP; TERBR_RESTORE=1; TERBR_RESTORE_FILE="${OPTARG}";;
    p) TERBR_PKG_LIST=1;;
    v) TERBR_VERBOSE=1;;
    h) usage; exit;;
    V) version; exit;;
    :) print_error "'${OPTARG}' option requires an argument."; usage >&2; exit 1;;
    ?) print_error "unknown option '${OPTARG}'."; usage >&2; exit 1;;
  esac
done

# Show usage if no option is provided
if [ ${OPTIND} -eq 1 ]; then
  usage >&2; exit 1
fi

# Check Storage Permission
if [ ! -w /storage/emulated/0/ ]; then
  termux-setup-storage
fi

# Check if pigz is installed
if type -p pigz &> /dev/null; then
  TERBR_COMMAND+=' -I pigz'
else
  TERBR_COMMAND+=' -z'
fi

# Enable verbose
if [ -n "${TERBR_VERBOSE}" ]; then
    TERBR_COMMAND+=' -v'
fi

# display terbr banner
banner

# list installed packages
if [ -n "${TERBR_PKG_LIST}" ]; then
    list_packages
fi

# Backup
if [ -n "${TERBR_BACKUP}" ]; then
  TERBR_COMMAND+=' -cf'
  backup
fi

# Restore
if [ -n "${TERBR_RESTORE}" ]; then
  # Check if file to restore exists.
  if [ ! -f "${TERBR_RESTORE_FILE}" ]; then
    print_error "${TERBR_RESTORE_FILE}: No such file or directory exists."
    exit 1
  fi

  TERBR_COMMAND+=' -xf'
  restore
fi

exit 0