#!/bin/bash
#============================================================================
#title          : TUBS
#description    : The Ultimate Backup Script (Linux) Version 2
#author         : Janic Voser Xelon
#date           : 2022-04-08
#updated        : 2022-04-09
#version        : 2.0
#usage          : chmod +x tubs.sh && ./tubs.sh
#notes          :
#bash_version   :
#============================================================================

# Config
## Configfile
#CONFIG_FILE=/etc/tubs/config # Any Config File
CONFIG_FILE="$PWD/tubs.config"

# Functions
## Colorful Information
function blue(){ # The blue color is used for inforation
    echo -e '\e[34m'"$1"'\e[0m'
}
function cyan(){ # The cyan color is only used for help
    echo -e '\e[0;36m'"$1"'\e[0m'
}
function green(){ # The green color is used for successful steps
    echo -e '\e[32m'"$1"'\e[0m'
}
function magenta(){ # The magenta color is used for warnings & important Information
    echo -e '\e[35m'"$1"'\e[0m'
}
function red(){ # The red color is used for failed steps
    echo -e '\e[31m'"$1"'\e[0m' && exit 1
}
## Critical Error
function critical_error {
    red "Critical error during: $1"
}
## Load Config
function load_config {
    if [ -e "$CONFIG_FILE" ]
    then
        blue "Loading Config"
        source "$CONFIG_FILE" || critical_error "Reading Configfile"
    else
        red "Configfile not Found"
    fi  
}
## Create destination Structure
function create_dst {
    mkdir -p "$BACKUP_DST_FULL" || critical_error "Creating Directory BACKUP_DST_FULL"
    mkdir -p "$BACKUP_DST_INC" || critical_error "Creating Directory BACKUP_DST_INC"
}
## Check destination
function check_dst {
    if [ -e "$BACKUP_DST" ]
    then
        blue "Backup destinantion existing"
    else
        red "Backup destination not existing"
    fi
    mkdir -p "$BACKUP_DST_INC_PATH" || critical_error "Error while creating incremental backup-directory ($BACKUP_DST_INC_PATH)"
    mkdir -p "$BACKUP_DST_FULL_LOGS" || critical_error "Error while creating log directory ($BACKUP_DST_FULL_LOGS)"
}
## Check sources
function check_src {
    for src_dir in "${BACKUP_SRC_ARRAY[@]}"
    do
        if [[ "$src_dir" =~ ^*[/] ]]
        then
            critical_error "$src_dir is ending with slash please remove it"
        fi
        if ! [ -d "$src_dir" ]
        then
            critical_error "$src_dir is not a directory"
        fi
        green "Source $src_dir is valid"
    done
}
## Check Incremental Date
function check_inc {
    if ! [ -e "$BACKUP_LAST_FILE" ]
    then
        magenta "Missing last successfull backup file, just using the day before"
        LAST_BACKUP="$(date --date="yesterday" "$DATE_FORMAT")"
    else
        LAST_BACKUP="$(cat "$BACKUP_LAST_FILE")"
        if ! [[ $LAST_BACKUP =~ ^[0-9]{4}(-[0-9]{2}){2}_[0-9]{2}-[0-9]{2} ]]
        then
            magenta "Content of last successfull backup file was not valid"
            LAST_BACKUP="$(date --date="yesterday" "$DATE_FORMAT")"
        fi
    fi
    BACKUP_DST_INC_PATH="$BACKUP_DST_INC/$BACKUP_PREFIX$LAST_BACKUP"
}
## Check Prerequirements
function check_prereq {
    command -v rsync &> /dev/null || critical_error "Missing rsync"
    green "All requirements are saturated"
}
## Last successful backup
function last_backup {
    if touch "$BACKUP_LAST_FILE" &> /dev/null
    then
        echo "$BACKUP_DATE" > "$BACKUP_LAST_FILE"
    else
        critical_error "Can not write Last successful backup file"
    fi
}
## Backup all
function backup_all {
    blue "Starting Backup Processes"
    for src_dir in "${BACKUP_SRC_ARRAY[@]}"
    do
        src_dir_name="$(echo "$src_dir" | rev | cut -d / -f 1 | rev)"
        cat << EOF >> "$BACKUP_DST_FULL_LOGS/$src_dir_name.log"

################################################################################
#############################TUBS $BACKUP_DATE##############################
################################################################################

EOF
        rsync "$RSYNC_ARGS" --backup --delete --backup-dir="$BACKUP_DST_INC_PATH/" "$src_dir" "$BACKUP_DST_FULL/$src_dir_name" >> "$BACKUP_DST_FULL_LOGS/$src_dir_name.log" &
    done
    green "All backup processes started successfull"
    blue "Waiting for processes to finish"
    # wait for all pids
    jobs=$(jobs -p)
    for process in $jobs
    do
        wait "$process" || critical_error "Process: $process failed"
    done
    green "All Processes finished"
}
## Pre Backup Script
function pre_backup_script {
    if [ -e "$PRE_BACKUP_SCRIPT" ]
    then
        if [ -x "$PRE_BACKUP_SCRIPT" ]
        then
            blue "Executing Pre-Backup-Script"
            $PRE_BACKUP_SCRIPT
            green "Pre-Backup-Script finished"
        else
            magenta "Pre-Backup-Script is not executable"
        fi
    else
        blue "No Pre-Backup-Script found"
    fi
}
## Post Backup Script
function post_backup_script {
    if [ -e "$POST_BACKUP_SCRIPT" ]
    then
        if [ -x "$POST_BACKUP_SCRIPT" ]
        then
            blue "Executing Post-Backup-Script"
            $POST_BACKUP_SCRIPT
            green "Post-Backup-Script finished"
        else
            magenta "Post-Backup-Script is not executable"
        fi
    else
        blue "No Pre-Backup-Script found"
    fi
}
## Generate Variables
load_config # Load config first (Variables are dependent on it)
BACKUP_DATE="$(date "$DATE_FORMAT")"
BACKUP_DST_FULL="$BACKUP_DST/FULL"
BACKUP_DST_FULL_LOGS="$BACKUP_DST_FULL/logs"
BACKUP_DST_INC="$BACKUP_DST/INCREMENTAL"
BACKUP_LAST_FILE="$BACKUP_DST/LAST_SUCCESSFULL_BACKUP"

# Main Script
## Load config
if [ -n "$1" ]
then
    case "$1" in
        help)
            cyan "Execute this script with one of the following arguments"
            cyan "  - help      --> Display help (your reading it right now)"
            cyan "  - init      --> Initialize the backup Structure"
            cyan "  - backup    --> Do the accual backup"
            cyan "  - restore   --> Restore all the data from a certain day"
        ;;
        init)
            blue "Starting initialisation"
            create_dst
            blue "Initialisation was successfull"
        ;;
        backup)
            green "TUBS started"
            check_inc
            check_dst
            check_src
            check_prereq
            last_backup
            pre_backup_script
            backup_all
            post_backup_script
            green "TUBS finished"
        ;;
        restore)
            magenta "I am kinda sorry this is not implemented yet"
            exit
        ;;
        *)
            red "Your supplied argument was not valid use help if you don't know what you are doing"
        ;;
    esac
    exit
else
    cyan "Please supply a valid argument or execute with help flag"
fi