#!/bin/bash
#

#RESULT_POSSIBLE=("init","start","start_backup","create","backup","restore","suppr")

# Constante d'éxecutions.
Version="0.6"
USAGE="vm-start [ NAME COMMAND [PARAMETER] ] [OPTION]

Script to manage virtual machine easily.

NAME is the name of the virtual machine to use.

COMMAND available
    init                Create the conf file in conf/NAME_var.sh
    start               Start the virtual machine using the variabes in conf/NAME_var.sh
    start-backup        Start the virtual machine using the backup volume if it exists.
    create              Create the virtual machine using the conf in conf/NAME_var.sh
    backup              Create a backup file for the vm
    restore             Restore the virtual machine using to backup file
    suppr               Suppr all data related to the virtual machine other than the conf file.

COMMAND TODO
    suppr-all           Suppr all data related to the vm even the conf file #TODO

PARAMETTER available
    -h, --help          Print this help and exit
    -v, --version       Print the version of this program and quit

OPTION available
    nproc=<nb proc>     Def the number of proc of the vm
    memory=<mem>        Def the qty of memory allocated to the vm
    size=<size>         Def the size that should be allocated by create
    uefi                Select if there will be an UEFI by default.
                        can be either set or unset. By default is unset.
    options=<option>    additinal options to give to qemu. By default is
                        -display gtk -vga qxl
"
MAIN_LOCATION="$HOME/virtual_machine/"
OPTION="-display gtk \
    -vga qxl"

        # other options choices
        #
        #-display sdl
        #-usbdevice tablet \



HELP() {
    echo "$USAGE"
    exit 0
}

INIT() {
    echo "INIT for vm $1"
    NAME=$1
    read -p "How many proccessor will you use ? " -r NPROC
    read -p "How much memory will you need ? " -r MEMORY
    read -p "Do you want to forward ssh port (y/n) " -r entry

    if [[ $entry =~ ^[yY]$ ]]
    then
        FORWARD=",hostfwd=tcp::10022-:22" # forward VM 22 port to Host 10022 
    else
        FORWARD=""
    fi

    mkdir -p conf
    cat << EOF > "conf/$NAME-vm_var.sh"
NAME="$NAME"
VMHOSTNAME="\$NAME-vm"
NPROC="$NPROC"
MEMORY="$MEMORY"
FORWARD="$FORWARD"
LOCATION="\$NAME-sandbox/"
EOF
    chmod +x conf/$NAME-vm_var.sh

}

START() {
    qemu-system-x86_64 \
        -enable-kvm \
        -cpu host \
        -smp $NPROC \
        -net nic \
        -net user$FORWARD,hostname=$VMHOSTNAME \
        -m $MEMORY \
        -drive file=${MAIN_LOCATION}${LOCATION}${VMHOSTNAME}.cow \
        $OPTION \
        -daemonize

}

START_BACKUP() {
    qemu-system-x86_64 \
        -enable-kvm \
        -cpu host \
        -smp $NPROC \
        -net nic \
        -net user$FORWARD,hostname=$VMHOSTNAME \
        -m $MEMORY \
        -drive file=${MAIN_LOCATION}${LOCATION}${VMHOSTNAME}.cow.backup \
        $OPTION \
        -daemonize

}

CREATE() {

    if [ -z ${SIZE+x} ] 
    then
        SIZE="40G"
    fi

    if [ ! -f "${MAIN_LOCATION}${LOCATION}${VMHOSTNAME}.cow" ]
    then
        echo "create directory ${MAIN_LOCATION}${LOCATION}"
        mkdir -p ${MAIN_LOCATION}${LOCATION}
        qemu-img create -f qcow2 ${MAIN_LOCATION}${LOCATION}${VMHOSTNAME}.cow $SIZE
    fi

    if [ "${UEFI}" == "set" ]
    then
        echo "create UEFIVAR"
        if [ ! -f ${MAIN_LOCATION}${LOCATION}OVMF_VARS.4m.fd ]
        then
            cp /usr/share/edk2/x64/OVMF_VARS.4m.fd ${MAIN_LOCATION}${LOCATION}
        else
            echo "INFO, UEFIVAR already existing"
        fi
    fi


    qemu-system-x86_64 \
        -enable-kvm \
        -cpu host \
        -smp $NPROC \
        -net nic \
        -net user$FORWARD,hostname=$VMHOSTNAME \
        -m $MEMORY \
        -drive file=${MAIN_LOCATION}${LOCATION}${VMHOSTNAME}.cow \
        -boot d \
        -drive file="$1",media=cdrom \
        $OPTION
}

RESTORE() {
    echo "Are you sure you want to restore the rescue? (y/N)"
    read -r entry
    if [[ $entry =~ ^[yY]$ ]]
    then
        cp ${MAIN_LOCATION}${LOCATION}${VMHOSTNAME}.cow.backup ${MAIN_LOCATION}${LOCATION}${VMHOSTNAME}.cow
        echo "Done"
    fi
}


BACKUP() {
    # Should test if the folder ${MAIN_LOCATION}${LOCATION}${VMHOSTNAME}.cow exist or else it will arrive an error.
    read -p "Are you sure you want to backup the volume? If you continue the previous backup will be lost (y/N) " -r entry
    if [[ $entry =~ ^[yY]$ ]]
    then
        cp ${MAIN_LOCATION}${LOCATION}${VMHOSTNAME}.cow ${MAIN_LOCATION}${LOCATION}${VMHOSTNAME}.cow.backup
        echo "Done"
    fi
}

SUPPRESS() {
    read -p "Are you sure you want to delete all data relative to the vm $1? (y/N)" -r entry
    if [[ $entry =~ ^[yY]$ ]]
    then 
        rm -Ri ${MAIN_LOCATION}${LOCATION}
    fi
}



# gère les paramètres

for i in $@;
do
    if [ "$i" == "-h" ] || [ "$i" == "--help" ]
    then
        HELP
    elif [ "$i" == "-v" ] || [ "$i" == "--version" ]
    then
        echo "vm-start ${Version}"
        exit 0
    fi
done


# verifie au moins assez d'options pour utiliser le programme.

if [ $# -lt 2 ]
then
    echo "Error, not enough args" >&2
    HELP
fi

# vérifie que le dossier pour stocker les vms existe & change le dossier actif pour qu'il soit cellui du lanceur.

mkdir -p $MAIN_LOCATION
cd "$( dirname "$( readlink -f "$0" )" )" || exit

# Véréfie qu'il y ait bien un fichier de config pour la vm que l'on tente de démarer dans la cas contraire en génére un.
# possibilitée de générer à nouveau le fichier de config avec vm-start nom-vm init

if [ "$2" == "init" ]
then
    INIT $1
elif [ ! -f "conf/$1-vm_var.sh" ]
then
    echo "no config file found. creating one in conf/${1}-vm_var.sh"
    INIT $1
fi

#Vérifie si l'option UEFI est set dans le fichier de config. Si oui l'ajoutte aux options.

. conf/$1-vm_var.sh

for (( i=3; i<=$#; i++)); do
    if [ "${!i%=*}" == "nproc" ]
    then
        NPROC="${!i#*=}"
    elif [ "${!i%=*}" == "memory" ]
    then
        MEMORY="${!i#*=}"
    elif [ "${!i%=*}" == "uefi" ]
    then
        UEFI="set"
        OPTION="$OPTION \
            -drive if=pflash,format=raw,readonly=on,file=/usr/share/edk2/x64/OVMF_CODE.4m.fd \
            -drive if=pflash,format=raw,file=${MAIN_LOCATION}${LOCATION}OVMF_VARS.4m.fd"
    fi
done


if [ "${UEFI}" == "yes" ]
then
    UEFI="set"
    OPTION="$OPTION \
        -drive if=pflash,format=raw,readonly=on,file=/usr/share/edk2/x64/OVMF_CODE.4m.fd \
        -drive if=pflash,format=raw,file=${MAIN_LOCATION}${LOCATION}OVMF_VARS.4m.fd"
fi


if [ "$2" == "start" ]
then
    echo "starting VM $1"
    START
elif [ "$2" == "start-backup" ]
then
    echo "starting VM rescue"
    START_BACKUP
elif [ "$2" == "backup" ]
then
    echo "backup VM"
    BACKUP
elif [ "$2" == "restore" ]
then
    echo "restore VM"
    RESTORE
elif [ "$2" == "create" ]
then
    echo "creating VM"
    if [ $# -ge 3 ]
    then
        echo "using image disk $3" # Error here, please don't think that there will be only three devices, should be improve like with an install-device parametter.
        CREATE $3 # TODO
    else
        echo "$#"
        echo "Error, no image defined." >&2
    fi
elif [ "$2" == "suppr" ]
then
    echo "suppressing all data of the vm $1"
    SUPPRESS $1
else
    echo "commande $2 inconnue" >&2
    HELP
fi