#!/usr/bin/bash
#

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

# Constante d'éxecutions.
Version="0.7.0-developpement_day"
USAGE="vm-start [PARAMETTER] [ NAME COMMAND [OPTION] ]

Script to manage virtual machine easily.

NAME is the name of the virtual machine to use.

PARAMETTER available
    -h, --help              Print this help and exit
    -v, --version           Print the version of this program and quit
    -l, --list              Print the list of all availables machines and quit <TODO>

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

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
    create_disk=<loc_disk>  Def a create disk to boot on. Is necessary for using create, or need the variable INSTALLATION_DISK_LOCATION to be set.
"

MAIN_LOCATION="$HOME/virtual_machine"
# if MAIN_LOCATION doesn't exists, create the folder.
if [ -f "$MAIN_LOCATION" ]
then
    mkdir "$MAIN_LOCATION" || exit 0 #Exit in case the folder can't be created.
    echo "$MAIN_LOCATION created to contain all virtual machines."
fi

OPTION="-display gtk \
    -usbdevice tablet"

        # other options choices
        #
        #-display sdl
        #-vga qxl
        #-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 echo "$entry" | grep -q "^[yY]$" 
    then
        FORWARD=",hostfwd=tcp::10022-:22" # forward VM 22 port to Host 10022 
    fi

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

}

start_the_vm() {
    qemu-system-x86_64 \
        -enable-kvm \
        -cpu host \
        -smp "$NPROC" \
        -net nic \
        -net user"$FORWARD",hostname="$VMHOSTNAME" \
        -m "$MEMORY" \
        -drive file="${MAIN_LOCATION}/${LOCATION}/${VMDRIVE}",index=2,id=maindrive,media=disk \
        $OPTION

}

START() {
    start_the_vm

}

START_BACKUP() {
    VMDRIVE="${VMDRIVE}.backup"
    start_the_vm

}

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

    OPTION="$OPTION \
        -boot d \
        -drive file=$1,if=none,media=cdrom,id=drive-cd1 \
        -device ide-cd,drive=drive-cd1,id=cd1,bootindex=1"

    start_the_vm


}

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


BACKUP() {
    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 echo "$entry" | grep -q "^[yY]$"
    then
        cp -i "${MAIN_LOCATION}/${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 $1? (y/N)" -r entry
    if echo "$entry" | grep -q "^[yY]$"
    then 
        rm -Ri "${MAIN_LOCATION}/${LOCATION}"
    fi
}

set_uefi() {
    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"

}



# 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 [ ! -f "conf/$1-vm_var.sh" ]
then
    echo "no config file found. creating one in conf/${1}-vm_var.sh"
    INIT "$1"

    if [ "$2" == "init" ]
    then
        # Exit, it is the end of the program.
        exit 0 
    fi
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<=$#; i++)); do
    case "${!i%=*}" in
        "nproc")
            NPROC="${!i#*=}"
            ;;
        "memory")
            MEMORY="${!i#*=}"
            ;;
        "uefi")
            set_uefi
            ;;
        "create_disk")
            INSTALLATION_DISK_LOCATION="${!i#*=}"
            ;;
    esac
done


if [ "${UEFI}" == "yes" ]
then
    set_uefi
fi


case "$2" in
    "start")
        echo "starting VM $1"
        START
        ;;
    "start-backup")
        echo "starting VM rescue"
        START_BACKUP
        ;;
    "backup")
        echo "backup VM"
        BACKUP
        ;;
    "restore")
        echo "restore backup"
        RESTORE
        ;;
    "create")
        echo "creating VM"
        if [ ! "${INSTALLATION_DISK_LOCATION}" == "" ]
        then
            echo "using image disk ${INSTALLATION_DISK_LOCATION}"
            CREATE "${INSTALLATION_DISK_LOCATION}"
        else
            echo "Error, no image defined." >&2
        fi
        ;;
    "suppr")
        echo "suppressing all data of the vm $1"
        SUPPRESS "$1"
        ;;
    "init")
        echo "Init volume $1"
        INIT "$1"
        ;;
    *)
        echo "commande $2 inconnue" >&2
        HELP
esac