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

#********************************************#
#                                            #
#  Rewind v6.0                               #
#  A CLI tool to backup and restore termux   #
#  Author : https://github.com/laraib07      #
#                                            #
#********************************************#


#variables
readonly SOURCE="$HOME"
readonly DEST='/storage/emulated/0/Termux/Backup'
readonly PKGS_SRC="$PREFIX/var/log/apt/history.log"
readonly program_name=$(basename "$0")

#colors
R='\e[1;31m' # red
G='\e[1;32m' # green
W='\e[1;37m' # white bold
off='\e[0m'  # turn off color
t='       '    # tab
OK=" $W[$G - $W]$off"
EXC=" $W[$R ! $W]$off"


# Banner
read -r -d '' BANNER << EOF
$W■──────────────────────────────────■
│$R   █▀▀█ █▀▀ █   █  ▀  █▀▀▄ █▀▀▄  $W │
│$R   █▄▄▀ █▀▀ █▄█▄█ ▀█▀ █  █ █  █  $W │
│$R   ▀ ▀▀ ▀▀▀  ▀ ▀  ▀▀▀ ▀  ▀ ▀▀▀   $W │
■──────────────────────────────────■$off
EOF


# FUNCTIONS
function show_help() {
    printf  "${off}Usage: ${W}rewind${off} [-hv] [-b|-r [home|pkgs]]\n
    -h               print this usage
    -v               print version
    -b [home|pkgs]   backup home and/or packages
    -r [home|pkgs]   restore home and/or packages\n"
}


function show_version() {
    grep "#$" "$0"
}


function error() {
    printf "${program_name}: $*\n" >&2
}


function check_internet() {
    if ping -q -w 1 -c 1 8.8.8.8 &> /dev/null;then
        return 0
    fi
    return 1
}


function backup_home() {
    printf  "${EXC} Backing up home\n"
    printf  "${t}Be patient...\n\n"

    if tar -I pigz -cf ${DEST}/backup.tmp -C ${SOURCE} . ; then
        mv ${DEST}/backup.tmp ${DEST}/home.bak
        printf  "${OK} home backed up and can be found in\n"
        printf  "${t}${DEST}/home.bak\n\n"

    else
        error "backup failed."
    fi
}


function backup_pkgs(){
    printf  "${EXC} Backing up packages\n\n"

    # Grep pkgs 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 ' ${PKGS_SRC})


    # 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 installed pkgs in output
    declare -A tmp_array

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

    printf "${t}%s\n" "${!tmp_array[@]}" | tee  ${DEST}/pkgs.bak

    printf  "\n${OK} Packages backed up and can be found in\n"
    printf  "${t}${DEST}/pkgs.bak\n\n"
}


function backup() {
    if [[ ! -d "${DEST}" ]]; then
        mkdir -p "${DEST}"
    fi

    printf "${BANNER}\n\n"

    case "$1" in
        home )
            backup_home
            ;;
        pkgs )
            backup_pkgs
            ;;
        '' )
            backup_home
            backup_pkgs
            ;;
        * )
            error "invalid argument"
            show_help
            exit 1
            ;;
    esac
}


function restore_home() {
    if [[ -f "${DEST}"/home.bak ]]; then
        printf  "${EXC} Restoring home\n"
        printf  "${t}Be patient...\n\n"

        if tar -I pigz -xf ${DEST}/home.bak -C ${SOURCE} ; then
            printf  "${OK} home restored\n"
            printf  "${t}start a new session.\n\n"
        fi

    else
        error "home backup not found in ${DEST}"
        exit 1
    fi
}


function restore_pkgs() {
    if ! check_internet; then
        error 'no internet connection.'
        exit 1
    fi

    if [[ -f "${DEST}/pkgs.bak" ]]; then
        printf  "${EXC} Restoring packages\n"
        printf  "${t}Be patient...\n\n"

        if apt-get install -y $(awk '{print $1}' ${DEST}/pkgs.bak ) ; then

            printf  "${OK} packages restored\n"
            printf  "${t}start a new session.\n\n"
        fi

    else
        error "packages backup not found in ${DEST}"
        exit 1
    fi
}


function restore() {
    printf "${BANNER}\n\n"

    case "$1" in
        home )
            restore_home
            ;;
        pkgs )
            restore_pkgs
            ;;
        '' )
            restore_home
            restore_pkgs
            ;;
        * )
            error "invalid argument"
            show_help
            exit 1
            ;;
    esac
}


function install_dependencies()
{
    # checking net connection
    if check_internet ; then
        printf  "${EXC} Installing Dependencies...\n"

        apt-get update  && apt-get upgrade -y
        apt-get install -y tar pigz

        if  [[ $(type -P tar) && $(type -P pigz) ]];then
            printf  "${OK} Dependencies Installed...\n"
        fi

    else
        error "network connection failed"
        exit 1
    fi
}


function getopts_get_optional_argument() {
    eval next_token=\${$OPTIND}
    if [[ -n $next_token && $next_token != -* ]]; then
        OPTIND=$((OPTIND + 1))
        OPTARG=$next_token
    else
        OPTARG=""
    fi
}


# remove temporary files in SOURCE if any signal received.
function cleanup() {
    rm -f "${DEST}/backup.tmp"
    error  "\nprogramme terminated unexpectedly\n"
    exit 1
}

# trapping signal
trap cleanup  1 2 3 15 20

# installing required programmes
if  ! [[ $(type -P tar) && $(type -P pigz) ]];then
    install_dependencies
fi


# checking storage permission
while ! [ -w /storage/emulated/0/ ];do
    printf  "${EXC} Grant storage Permission${off}\n"
    termux-setup-storage
    sleep 5
done


# Driver Code
while getopts ":hvbr" arg ; do
    case "${arg}" in
        h ) show_help ;;
        v ) show_version ;;
        b )
            getopts_get_optional_argument $@
            backup "${OPTARG}"
            ;;
        r )
            getopts_get_optional_argument $@
            restore "${OPTARG}"
            ;;
        \?) error "unknown option\n"; exit 1 ;;
        : ) error "no arguments"; show_help; exit 1 ;;
    esac
done


if [[ -z "$1" ]]; then
    error "no options provided"
    printf "try 'rewind -h' for help.\n"
    exit 1
fi


exit 0