#!/bin/bash

IFS=$'\n'
LOG='/root/backup-usb.log'
USB_DISK=""
USB_PARTITION=""
USB_MOUNT="/mnt/usb"
LUKS_PASS_URL="192.168.1.199:9999/andthepasswordis"
LUKS_PASS=""

function log() {
    echo -e "`date +'%d/%m/%Y %H:%M:%S'` | $1"
    echo -e "`date +'%d/%m/%Y %H:%M:%S'` | $1" >> $LOG
}

function usage() {
    echo
    echo -e "./backup.sh \e[93m--help \e[39m"
    echo -e "./backup.sh \e[93m--mount \e[39m"
    echo -e "./backup.sh \e[93m--umount \e[39m"
    echo -e "./backup.sh \e[92m--src=\e[39m/mnt/data \e[96m--dst=\e[39m/backup"
    echo -e "./backup.sh \e[92m--src=\e[39m/mnt/vmachines/storage \e[96m--dst=\e[39m/backup/data/VMachines"
    echo -e "./backup.sh \e[92m--src=\e[39m/data/backup \e[96m--dst=\e[39m/backup \e[91m--delete=\e[39myes"
    echo
    echo -e " $1"
    echo
    exit
}

function get_luks_password() {
    LUKS_PASS=$(curl -s $LUKS_PASS_URL | jq -r ".password")
    if [ -z "$LUKS_PASS" ]; then
        log "[FAIL] to get LUKS password"
        return 1
    else
        log "[ OK ] get LUKS password"
        return 0
    fi
}


function find_usb() {
    for DISK in `ls -l /dev/disk/by-id/usb* | grep -v part | awk -F/ '{print $NF}'`; do
        DEV="/dev/$DISK"
        for PARTITION in `ls -1 $DEV* | grep "[0-9]$"`; do
            cryptsetup isLuks $PARTITION
            if [ $? = 0 ]; then
                USB_PARTITION=$PARTITION
                return 0
            fi
        done
        log "[FAIL] to find encrypted USB partition"
        return 1
    done
    log "[FAIL] to find encrypted USB disk"
    return 1
}

function mount_usb() {
    echo $LUKS_PASS | cryptsetup luksOpen $USB_PARTITION crypted_usb
    if [ $? = 0 ]; then
        log "[ OK ] $USB_PARTITION decrypted"
        /usr/bin/mount /dev/mapper/crypted_usb /mnt/usb
        if [ $? = 0 ]; then
            log "[ OK ] $USB_PARTITION mounted"
            return 0
        else
            log "[FAIL] $USB_PARTITION mounted"
            return 1
        fi  
    else
        log "[FAIL] $USB_PARTITION decrypted"
        return 1
    fi
    exit
}

function check_space () {
    src_size=$(du -s "$SRC" | awk '{print $1}')
    dst_size=$(df $MNT | grep "^/" | awk {'print $4'})
    log "$SRC usage size: $src_size"
    log "$MNT$DIR available size: $dst_size"
    if [ "$dst_size" -gt "$src_size" ]; then
        log "[ OK ] enought available space"
        return 0
    else
        log "[FAIL] not enought available space"
        return 1
    fi
}

function sync_files() {
    SRC_PATH=`dirname "$SRC"`
    SRC_DIR=`basename "$SRC"`
    DST_DIR=$USB_MOUNT$DST
    log "[ OK ] source     : ${SRC_DIR}" 
    log "[ OK ] destination: ${DST_DIR}/${SRC_DIR}" 
    log "------------ RSYNC STARTED ---------"
    cd $SRC_PATH
    if [ "$DELETE" == "yes" ]; then
        rsync -av --stats \
                  --temp-dir=/tmp \
                  --links \
                  --human-readable \
                  --no-owner \
                  --no-group \
                  --include ".*" \
                  --delete \
                  "$SRC_DIR" "$DST_DIR" | tee -a $LOG
    else
        rsync -av  \
                  --stats \
                  --temp-dir=/tmp \
                  --include ".*" \
                  --links \
                  --human-readable \
                  --no-owner \
                  --no-group \
                  "$SRC_DIR" "$DST_DIR" | tee -a  $LOG
    fi
    cd /root
    log "------------ RSYNC ENDED -----------"
    return 0
}


function check_copy () {
    cd ${SRC}
    find * -type f -exec ls -s {} \; > /root/backup-src.log
    cd ${DST_DIR}/${SRC_DIR}
    find * -type f -exec ls -s {} \; > /root/backup-dst.log
    cd

    if diff -r /root/backup-src.log /root/backup-dst.log; then
        log "[ OK ] files check"
    else  
        log "[FAIL] files check"
    fi

    return 0
}

function umount_usb() {
    if /usr/bin/umount $USB_MOUNT; then
        if [ $? = 0 ]; then
            log "[ OK ] umount usb disk"
            cryptsetup luksClose /dev/mapper/crypted_usb
            if [ $? = 0 ]; then
                log "[ OK ] close disk encryption"
                return 0 
            else
                log "[FAIL] close disk encryption"
                return 1
            fi
        else
            log "[FAIL] umount usb disk"
        fi
    else
        log "[FAIL] to find mounted usb disk"
    fi
}

function statistics_usb() {
    USBTOTAL=$(df -h | grep $USB_MOUNT | awk '{print $2}')
    USBUSAGE=$(df -h | grep $USB_MOUNT | awk '{print $5}')
    USBUSED=$(df -h | grep $USB_MOUNT | awk '{print $3}')
    USBFREE=$(df -h | grep $USB_MOUNT | awk '{print $4}')
    log "USB DISK Total : ${USBTOTAL}"
    log "USB DISK Usage : ${USBUSAGE}"
    log "USB DISK Used  : ${USBUSED}"
    log "USB DISK Free  : ${USBFREE}"
}

function mount() {
    if find_usb; then
        if get_luks_password; then
            mount_usb
        fi
    fi
    exit
}

function umount() {
    umount_usb
    exit
}

function check_depentencies() {
    commands=(rsync cryptsetup curl jq)
    for command in "${commands[@]}"
    do
        if ! command -v ${command} > /dev/null; then
            log "Command $command not found"
            exit
        fi
    done
}

function main () {
    log ""
    log "BACKUP STARTED ===================="
    log "SOURCE        : $SRC"
    log "DESTINATION   : $USB_MOUNT$DST"
    log "WITH DELETE   : ${DELETE:-"No (default)"}"
    log ""
    if check_depentencies; then
        if get_luks_password; then
            if find_usb; then
                if mount_usb; then
                    sync_files
                fi
                statistics_usb
                umount_usb
            fi
        fi
    fi
}

for i in "$@"
do
    case $i in
        --help)
            usage
            ;;
        --mount)
            mount
            ;;      
        --umount)
            umount
            ;;
        --getpass)
            get_luks_password
            ;;
        --src=*)
            SRC="${i#*=}"
            shift
            ;;
        --dst=*)
            DST="${i#*=}"
            shift
            ;;
        --delete=*)
            DELETE="${i#*=}"
            shift
            ;;
        *)
            usage
            ;;
    esac
done

[ -z "$SRC" ] && usage "option \e[92m'--src'\e[39m is missing"
[ -z "$DST" ] && usage "option \e[92m'--dst'\e[39m is missing"

main