#!/bin/bash

# devices
VM_HW_HDD=${VM_HW_HDD:-ide}
VM_HW_HDD_FORMAT=${VM_HW_HDD_FORMAT:-raw}
VM_DISK_1_FORMAT=${VM_HW_HDD_FORMAT}
VM_HW_NET=${VM_HW_NET:-rtl8139}

if [ -n "$( cat /etc/redhat-release | grep Fedora )" ]; then 
  QEMU_BINARY="/usr/bin/qemu-kvm"
else 
  QEMU_BINARY="/usr/libexec/qemu-kvm"
  if grep -q -i "release 5" /etc/redhat-release; then 
    export SL5=1
    export PATH="$PATH:/sbin:/usr/sbin"
  fi
fi

gen_general_options () {
    local name=$1
    local cpus=$2
    local memory=$3
    if [ -n "$SL5" ]; then 
        echo "--name $name -cpu qemu64 -smp $cpus -m $memory -vnc none -vga cirrus "
    else
        echo "--name $name -cpu qemu64 -enable-kvm -nodefconfig -nodefaults -smp $cpus -m $memory -rtc base=localtime -vnc none -vga cirrus "
    fi
}

qemu_add_disk () {
    local imgpath=$1
    local imgformat=$2
    echo "-drive file=$imgpath,if=${VM_HW_HDD},format=${imgformat:-raw} "
}

qemu_add_vvfat () {
    local dirpath=$1
    echo "-drive file=fat:rw:$dirpath "
}

qemu_add_iso () {
    local isopath=$1
    echo "-drive file=$isopath,media=cdrom,if=ide "
}

qemu_add_mactap () {
    local macaddr=$1
    local tapcdev=$2
    echo "-net nic,model=$VM_HW_NET,macaddr=${macaddr} -net tap,fd=100 100<>${tapcdev} "
}

qemu_add_bridgednet () {
    local macaddr=$1
    local tapdev=$2
    if [ -n "$SL5" ]; then 
        echo "-net nic,model=$VM_HW_NET,vlan=0,macaddr=${macaddr} -net tap,vlan=0,ifname=${tapdev},script=no,downscript=no "
    else
        echo "-device $VM_HW_NET,netdev=net0,mac=${macaddr} -netdev tap,id=net0,ifname=${tapdev},script=no,downscript=no "
    fi
}

check_vvfat_support () {
    local dirpath=$( mktemp -d )
    $QEMU_BINARY -nodefconfig -nodefaults -vnc none -drive file=fat:rw:$dirpath >/dev/null 2>&1 &
    local qemu_pid=$!
    sleep 1
    ps -p $qemu_pid >/dev/null 2>&1
    local exit_code=$?
    [ $exit_code -eq 0 ] && kill $qemu_pid
    return $exit_code
}

check_vm_running () {
    ps -p $VM_QEMU_PID >/dev/null 2>&1 
    return $?
}

destroy_vm () {
    kill $VM_QEMU_PID
    sleep 10
    kill -9 $VM_QEMU_PID
}

# general VM settings
qemu_opts=$( gen_general_options "$VM_NAME" "${VM_CPUS:-1}" "$VM_MEMORY_SIZE" )

# disk images
diskidx=1
diskvar="VM_DISK_$diskidx"
while [ -n "${!diskvar}" ]; do
   diskformat="${diskvar}_FORMAT"
   qemu_opts="$qemu_opts $( qemu_add_disk \"${!diskvar}\" ${!diskformat} ) "
   diskidx=$(( diskidx + 1 ))
   diskvar="VM_DISK_$diskidx"
done

# vvfat disk mappings
check_vvfat_support && vvfat_supported=1
diskidx=1
diskvar="VM_VVFAT_DISK_$diskidx"
while [ -n "${!diskvar}" ]; do
   if [ -n "$vvfat_supported" ]; then
       qemu_opts="$qemu_opts $( qemu_add_vvfat \"${!diskvar}\" ) "
   else
       # no VVFAT support in QEMU
       echo "WARNING: There is no VVFAT support on WN hypervisor. Falling back to general VFAT image method."
       datadir=${!diskvar}
       sudo diskimg-manage -c -d "$datadir" -i "${datadir%/}.img" -u "$(whoami)" 1>&2
       echo "sudo diskimg-manage -e -d \"$datadir\" -i \"${datadir%/}.img\"" | add2_cleanup_script
       qemu_opts="$qemu_opts $( qemu_add_disk \"${datadir%/}.img\" ) "
   fi
   diskidx=$(( diskidx + 1 ))
   diskvar="VM_VVFAT_DISK_$diskidx"
done

# ISO images
diskidx=1
diskvar="VM_CD_DISK_$diskidx"
while [ -n "${!diskvar}" ]; do
   qemu_opts="$qemu_opts $( qemu_add_iso ${!diskvar} ) "
   diskidx=$(( diskidx + 1 ))
   diskvar="VM_CD_DISK_$diskidx"
done

# networking
if [ "$VM_NET_TYPE" = "direct" ]; then 
  # add tap device and obtain character device file
  r_debug "DEBUG: Creating network interface: sudo macvtap-manage -m $VM_NET_MAC -i $VM_NET_INT -u $(whoami)"
  tapcdev=$( sudo macvtap-manage -m "$VM_NET_MAC" -i "$VM_NET_INT" -u "$(whoami)" 2>/dev/null ) || return 2
  echo "sudo macvtap-manage -m \"$VM_NET_MAC\" -d"  | add2_cleanup_script
  qemu_opts="$qemu_opts $( qemu_add_mactap "$VM_NET_MAC" "${tapcdev}" )"
elif [ "$VM_NET_TYPE" = "bridge" ]; then
  r_debug "DEBUG: Creating network interface: sudo brtap-manage -a -b $VM_NET_INT -u $(whoami)"
  tapdev=$( sudo brtap-manage -a -b "$VM_NET_INT" -u "$(whoami)" 2>/dev/null ) || return 2
  echo "sudo brtap-manage -b \"$VM_NET_INT\" -t \"$tapdev\" -d" | add2_cleanup_script
  qemu_opts="$qemu_opts $( qemu_add_bridgednet "$VM_NET_MAC" "${tapdev}" )"
fi

# run QEMU
r_debug "DEBUG: Running qemu with the following options: $qemu_opts"
eval "$QEMU_BINARY $qemu_opts" &
if [ $? -eq 0 ]; then 
    export VM_QEMU_PID=$!
    sleep 1
    check_vm_running
else
    false
fi