#!/usr/bin/env bash
# create-vm.sh -- Interactive KVM/libvirt VM creator with cloud-init
set -euo pipefail

IMGDIR="/var/lib/libvirt/images"

# -- Preflight ----------------------------------------------------------------
for cmd in virsh virt-install qemu-img xorriso curl; do
  if ! command -v "$cmd" &>/dev/null; then
    echo "ERROR: '$cmd' is required but not installed." >&2
    exit 1
  fi
done

if ! systemctl is-active --quiet libvirtd; then
  echo "ERROR: libvirtd is not running. Start it with: systemctl start libvirtd" >&2
  exit 1
fi

# -- 1. VM Name ---------------------------------------------------------------
echo ""
echo "=== KVM VM Creator ==="
echo ""
while true; do
  read -rp "VM name: " VMNAME
  VMNAME="${VMNAME// /-}"
  if [[ -z "$VMNAME" ]]; then
    echo "  Name cannot be empty."
  elif virsh dominfo "$VMNAME" &>/dev/null 2>&1; then
    echo "  '${VMNAME}' is already in use -- pick another name."
  else
    break
  fi
done

# -- 2. Distro ----------------------------------------------------------------
echo ""
echo "Select distro:"
select DISTRO in "AlmaLinux" "Debian" "Ubuntu"; do
  [[ -n "$DISTRO" ]] && break
done

# -- 3. Version ---------------------------------------------------------------
echo ""
echo "Select version:"
case $DISTRO in
  AlmaLinux)
    select VERSION in "8" "9"; do
      [[ -n "$VERSION" ]] && break
    done
    case $VERSION in
      8)
        OS_VARIANT="almalinux8"
        BASE_URL="https://repo.almalinux.org/almalinux/8/cloud/x86_64/images"
        IMGFILE=$(curl -q -LSsf "${BASE_URL}/" \
          | grep -oE 'AlmaLinux-8-GenericCloud-[0-9.]+-[0-9]+\.x86_64\.qcow2' \
          | sort -V | tail -1)
        ;;
      9)
        OS_VARIANT="almalinux9"
        BASE_URL="https://repo.almalinux.org/almalinux/9/cloud/x86_64/images"
        IMGFILE=$(curl -q -LSsf "${BASE_URL}/" \
          | grep -oE 'AlmaLinux-9-GenericCloud-[0-9.]+-[0-9]+\.x86_64\.qcow2' \
          | sort -V | tail -1)
        ;;
    esac
    IMG_URL="${BASE_URL}/${IMGFILE}"
    ;;

  Debian)
    select VERSION in "11 (Bullseye)" "12 (Bookworm)"; do
      [[ -n "$VERSION" ]] && break
    done
    case $VERSION in
      "11"*)
        OS_VARIANT="debian11"
        IMGFILE="debian-11-genericcloud-amd64.qcow2"
        IMG_URL="https://cloud.debian.org/images/cloud/bullseye/latest/${IMGFILE}"
        ;;
      "12"*)
        OS_VARIANT="debian12"
        IMGFILE="debian-12-genericcloud-amd64.qcow2"
        IMG_URL="https://cloud.debian.org/images/cloud/bookworm/latest/${IMGFILE}"
        ;;
    esac
    ;;

  Ubuntu)
    select VERSION in "20.04 (Focal)" "22.04 (Jammy)" "24.04 (Noble)"; do
      [[ -n "$VERSION" ]] && break
    done
    case $VERSION in
      "20.04"*)
        OS_VARIANT="ubuntu20.04"
        IMGFILE="focal-server-cloudimg-amd64.img"
        IMG_URL="https://cloud-images.ubuntu.com/focal/current/${IMGFILE}"
        ;;
      "22.04"*)
        OS_VARIANT="ubuntu22.04"
        IMGFILE="jammy-server-cloudimg-amd64.img"
        IMG_URL="https://cloud-images.ubuntu.com/jammy/current/${IMGFILE}"
        ;;
      "24.04"*)
        OS_VARIANT="ubuntu24.04"
        IMGFILE="noble-server-cloudimg-amd64.img"
        IMG_URL="https://cloud-images.ubuntu.com/noble/current/${IMGFILE}"
        ;;
    esac
    ;;
esac

# -- 4. VM Specs (vCPU + RAM) -------------------------------------------------
echo ""
echo "What specs should the VM have?"
select SPECS in \
  "Micro    (1 vCPU,  512MB RAM)" \
  "Tiny     (1 vCPU,  1GB   RAM)" \
  "Small    (2 vCPU,  2GB   RAM)" \
  "Standard (2 vCPU,  4GB   RAM)" \
  "Medium   (4 vCPU,  4GB   RAM)" \
  "Large    (4 vCPU,  8GB   RAM)" \
  "XLarge   (8 vCPU,  8GB   RAM)" \
  "2XLarge  (8 vCPU,  16GB  RAM)" \
  "4XLarge  (16 vCPU, 32GB  RAM)" \
  "Custom"; do
  case $SPECS in
    "Micro"*)    VCPUS=1;  RAM=512;   break ;;
    "Tiny"*)     VCPUS=1;  RAM=1024;  break ;;
    "Small"*)    VCPUS=2;  RAM=2048;  break ;;
    "Standard"*) VCPUS=2;  RAM=4096;  break ;;
    "Medium"*)   VCPUS=4;  RAM=4096;  break ;;
    "Large"*)    VCPUS=4;  RAM=8192;  break ;;
    "XLarge"*)   VCPUS=8;  RAM=8192;  break ;;
    "2XLarge"*)  VCPUS=8;  RAM=16384; break ;;
    "4XLarge"*)  VCPUS=16; RAM=32768; break ;;
    "Custom")
      read -rp "  vCPUs: "    VCPUS
      read -rp "  RAM (MB): " RAM
      break ;;
  esac
done

# -- 5. Disk Size (always GB) -------------------------------------------------
echo ""
echo "Select disk size:"
select DISKOPT in \
  "10"   \
  "20"   \
  "40"   \
  "60"   \
  "80"   \
  "100"  \
  "200"  \
  "500"  \
  "1000" \
  "Custom"; do
  case $DISKOPT in
    "Custom")
      read -rp "  Disk size (GB): " DISK
      DISK="${DISK//[^0-9]/}"
      break ;;
    *)
      DISK="$DISKOPT"
      break ;;
  esac
done

# -- 6. Networking ------------------------------------------------------------
echo ""
echo "Which network setup?"
select NET in \
  "NAT (default)" \
  "Bridge (br0)" \
  "Isolated (no internet)"; do
  case $NET in
    "NAT"*)      NETWORK="network=default,model=virtio";  break ;;
    "Bridge"*)   NETWORK="bridge=br0,model=virtio";       break ;;
    "Isolated"*) NETWORK="network=isolated,model=virtio"; break ;;
  esac
done

# -- Summary + confirm --------------------------------------------------------
echo ""
echo "+----------------------------------------------+"
printf "| %-44s |\n" "VM Summary"
echo "+----------------------------------------------+"
printf "| %-14s %-29s |\n" "Name:"      "$VMNAME"
printf "| %-14s %-29s |\n" "Distro:"    "$DISTRO $VERSION"
printf "| %-14s %-29s |\n" "vCPUs:"     "$VCPUS"
printf "| %-14s %-29s |\n" "RAM:"       "${RAM}MB"
printf "| %-14s %-29s |\n" "Disk:"      "${DISK}GB"
printf "| %-14s %-29s |\n" "Network:"   "$NET"
echo "+----------------------------------------------+"
read -rp "Proceed? [y/N] " CONFIRM
[[ "${CONFIRM,,}" != "y" ]] && echo "Aborted." && exit 0

# -- Download base image (skip if cached) ------------------------------------
BASE_IMG="${IMGDIR}/${IMGFILE}"
if [[ -f "$BASE_IMG" ]]; then
  echo "Using cached image: ${BASE_IMG}"
else
  echo "Downloading ${IMGFILE}..."
  curl -q -LSsf -o "$BASE_IMG" "$IMG_URL"
  echo "Done: $(du -h "$BASE_IMG" | cut -f1)"
fi

# -- Create VM disk (thin overlay) -------------------------------------------
VM_IMG="${IMGDIR}/${VMNAME}.qcow2"
qemu-img create -f qcow2 -b "$BASE_IMG" -F qcow2 "$VM_IMG" "${DISK}G"

# -- Cloud-init seed ISO ------------------------------------------------------
SEED_ISO="${IMGDIR}/${VMNAME}-seed.iso"
TMPD="$(mktemp -d -t "${VMNAME}-XXXXXX")"
trap 'rm -rf "$TMPD"' EXIT

cat > "${TMPD}/meta-data" <<EOF
instance-id: ${VMNAME}
local-hostname: ${VMNAME}
EOF

cat > "${TMPD}/user-data" <<'EOF'
#cloud-config
chpasswd:
  list: |
    root:almalinux
  expire: false
ssh_pwauth: true
disable_root: false
runcmd:
  - growpart /dev/vda 1 || growpart /dev/vda 4 || true
  - xfs_growfs / || resize2fs /dev/vda1 || true
EOF

xorriso -as mkisofs \
  -output "$SEED_ISO" \
  -volid cidata \
  -joliet -rock \
  "${TMPD}/user-data" "${TMPD}/meta-data" 2>/dev/null

# -- Create and start VM ------------------------------------------------------
echo ""
echo "Creating VM '${VMNAME}'..."
virt-install \
  --name        "$VMNAME" \
  --memory      "$RAM" \
  --vcpus       "$VCPUS" \
  --disk        "${VM_IMG},device=disk,bus=virtio" \
  --disk        "${SEED_ISO},device=cdrom" \
  --os-variant  "$OS_VARIANT" \
  --network     "$NETWORK" \
  --graphics    none \
  --console     pty,target_type=serial \
  --import \
  --noautoconsole \
  --boot        hd

# -- Wait for IP --------------------------------------------------------------
echo "Waiting for IP address..."
IP=""
for i in $(seq 1 30); do
  IP=$(virsh domifaddr "$VMNAME" 2>/dev/null | awk '/ipv4/{print $4}' | cut -d/ -f1)
  [[ -n "$IP" ]] && break
  sleep 2
done

echo ""
echo "+----------------------------------------------+"
printf "| VM '%-40s' |\n" "${VMNAME} is running"
echo "+----------------------------------------------+"
if [[ -n "$IP" ]]; then
  printf "| %-14s %-29s |\n" "IP:"       "$IP"
  printf "| %-14s %-29s |\n" "SSH:"      "ssh root@${IP}"
  printf "| %-14s %-29s |\n" "Password:" "almalinux"
else
  printf "| %-14s %-29s |\n" "IP:" "(run: virsh domifaddr ${VMNAME})"
fi
printf "| %-14s %-29s |\n" "Console:"  "virsh console ${VMNAME}"
echo "+----------------------------------------------+"
printf "| %-14s %-29s |\n" "Start:"    "virsh start ${VMNAME}"
printf "| %-14s %-29s |\n" "Stop:"     "virsh shutdown ${VMNAME}"
printf "| %-14s %-29s |\n" "Force off:" "virsh destroy ${VMNAME}"
printf "| %-14s %-29s |\n" "Delete:"   "virsh undefine ${VMNAME} --remove-all-storage"
echo "+----------------------------------------------+"