#!/bin/bash

# ************************************* #
#                                       #
#               sshbackup               #
#                                       #
# ************************************* # 

#  ****  config section  ****
version="0.4.0"
author="david@socialnerds.org"

configfile="$HOME/.sshbackup"
#rsync options.
rsyncoptions="-qpogEthrzl --numeric-ids --no-motd"
#dotglob option removes bug while rsyncing folder with no visible files in it.
remotecmd="shopt -s dotglob; /usr/bin/sudo /usr/bin/rsync"
localcmd="/usr/bin/rsync"

versions=999
config=0
sshkey=0
list=0
options=$*


#  ****  function definitions  ****
bashtrap()
{
    echo
    echo "CTRL+C detected."
    echo "commiting suicide."
    exit 1
}

usage()
{
    echo
    echo "usage: sshbackup <options> source destination [versions]"
    echo "source/destination example: [[user@]server:]/path/to/files"
    echo
    echo "OPTIONS:"
    echo "   -h, --help                show this message"
    echo "   -v, --version             version information"
    echo
    echo "   -l, --list <file>         list of sources and destinations"
    echo "   -c, --config <file>       alternate config file [~/.sshbackup]"
    echo "   -s, --sshkey <file>       alternate sshkey [~/.ssh/id_rsa]"
    echo
}

version()
{
    echo
    echo -e "vesion: \033[1;37m$version\033[0m"
    echo "author: $author"
    echo
}

interactive()
{
    tty -s
    return $?
}

amiroot()
{
    if [ $(id -u) -eq 0 ]; then
        return 0
    else
        return 1
    fi
}

preflight()
{
    #amiroot?
    if ( ! amiroot ); then
        echo "aborting mission. you must be root"
        return 1
    fi

    #source and destination path?
    if [ -z $sourcepath ]; then
        echo "aborting mission. no source path given."
        return 1
    elif [ -z $destpath ]; then
        echo "aborting mission. no destination path given."
        return 1
    fi

    #if there is a remote source or destination check for ssh key
    if [[ $sourcepath =~ .*@.* ]] || [[ $destpath =~ .*@.* ]]; then
        
        #get executing user id
        local userid=$(id -u)

        #find out where executing users $HOME is
        while read line; do
            line=$(echo $line | sed 's/ //g')
            line=$(echo $line | sed 's/:/ /g')
            if [ $(echo $line | awk '{print $3}') -eq $userid ]; then
                local home=$(echo $line | awk '{print $6}')
            fi
        done < /etc/passwd

        if [ -z $sshkeyfile ]; then
            sshkeyfile="$home/.ssh/id_rsa"
        fi
        if [ -r $sshkeyfile ]; then
            #ssh key found
            :
        else
            if ( interactive ); then
                echo "no ssh key found"
                echo -e "do you want to create a ssh key pair? [y/n] \c"
                read choice
                if [ -z $choice ]; then
                    echo "aborting mission. no ssh key found."
                    return 1
                elif [ $choice == "y" ] || [ $choice == "Y" ]; then
                    #creating ssh key pair
                    ssh-keygen
                    #TODO: key should also be deployed to remote side
                    return 1    #for now i'll break up here
                fi
            else
                echo "aborting mission. no ssh key found."
                return 1
            fi
        fi
    fi

    return 0
}

sshbackup()
{
    #creating local rsync options var
    local cmdopt="$rsyncoptions"

    #move existing versions
    local num=$versions
    while [ -d "$destpath/0" ]; do
        if [ -d "$destpath/$num" ]; then
            mv $destpath/$num $destpath/$((num+1))
        fi
        let num--
    done

    #create destpath if not existing
    mkdir -p $destpath/0

    #add link-destination option if existing
    if [ -d $destpath/1 ]; then
        cmdopt="$cmdopt --link-dest=$destpath/1"
    fi

    #run rsync
    $localcmd $cmdopt -e "ssh -q -i $sshkeyfile" --rsync-path="$remotecmd" $sourcepath $destpath/0
    if [ $? -ne "0" ]; then
        return 1
    fi

    #removing obsolet version(s)
    local i=1
    while [ -d $destpath/$((versions+i)) ]; do
        rm -rf $destpath/$((versions+i))
        let i++
    done

    return 0

}


#  ****  start of script  ****

#initialize bashtrap
trap bashtrap INT

#  ****  option handler  ****
#end script if no options are given
if [ -z $1 ]; then
    usage
    exit 0
fi

for option in $options; do
    case "$option" in
        -h|--help)
            usage
            exit 0
            ;;
        -v|--version)
            version
            exit 0
            ;;
        -c|--config)
            config=1
            ;;
        -l|--list)
            list=1
            ;;
        -s|--sshkey)
            sshkey=1
            ;;
        *)
            if [ $config -eq 1 ]; then
                if [ -r "$option" ]; then
                    configfile=$option
                    config=0
                else
                    echo "aborting mission. cannot read configfile. [$option]"
                    exit 1
                fi
            elif [ $sshkey -eq 1 ]; then
                if [ -r $option ]; then
                    sshkeyfile=$option
                    sshkey=0
                else
                    echo "aborting mission. cannot read sshkeyfile. [$option]"
                    exit 1
                fi
            elif [ $list -eq 1 ]; then
                if [ -r $option ]; then
                    listfile=$option
                    list=0
                else
                    echo "aborting mission. cannot read listfile. [$option]"
                    exit 1
                fi
            else
                if [[ $option =~ ^-.* ]]; then
                    echo "aborting mission. unknown option given. [$option]"
                    usage
                    exit 1
                #TODO: what if source or destination is a number?
                elif [ -z "${option//[0-9]/}" ]; then
                    versions="$option"
                else
                    if [ -z "$sourcepath" ]; then
                        if [[ $option =~ .*@.* ]]; then
                            sourcepath="${option%/}/*"
                        elif [[ $option =~ ^/.* ]]; then
                            sourcepath="${option%/}/*"
                        else
                            sourcepath="$(pwd)/${option%/}/*"
                        fi
                    else
                        if [ -z "$destpath" ]; then
                            if [[ $option =~ ^/.* ]]; then
                                destpath="${option%/}"
                            else
                                destpath="$(pwd)/${option%/}"
                            fi
                        fi
                    fi
                fi
            fi
            ;;
    esac
done

#read config if there is one
if [ -r "$configfile" ]; then
    source "$configfile"
fi

#read list if listfile is given
if [ -r "$listfile" ]; then
    while read line; do
        #find first letter
        fletter=${line:0:1}
        if [ -z $fletter ]; then
            #skip line it's empty
            :
        elif [ $fletter = "#" ]; then
            #skip line it's a comment
            :
        else
            sourcepath=""
            destpath=""
            for option in $line; do
                if [ -z "${option//[0-9]/}" ]; then
                    versions="$option"
                else
                    if [ -z "$sourcepath" ]; then
                        if [[ $option =~ .*@.* ]]; then
                            sourcepath="${option%/}/*"
                        elif [[ $option =~ ^/.* ]]; then
                            sourcepath="${option%/}/*"
                        else
                            sourcepath="$(pwd)/${option%/}/*"
                        fi
                    else
                        if [ -z "$destpath" ]; then
                            if [[ $option =~ ^/.* ]]; then
                                destpath="${option%/}"
                            else
                                destpath="$(pwd)/${option%/}"
                            fi
                        fi
                    fi
                fi
            done

            if ( preflight ); then
                sshbackup
            fi
        fi
    done < "$listfile"
else
    if ( preflight ); then
        sshbackup
    fi
fi

exit 0
#  ****  end of script  ****