#!/bin/bash
# Script per espansione disco VM (auto-detect)
# Autore: Mattia Tadini
# Nome File: expand_disk.sh
# Revisione: 3.3.2
# expand-disk.sh — ONLY growpart: hot-extend LVM (EXT4/XFS) su MBR/GPT
# Flow: rescan → (MBR+logica) growpart <estesa> → growpart <pvpart> → partprobe/reread → pvresize → lvextend → resize FS


set -euo pipefail
log(){ echo "[$(date +'%F %T')] $*"; }
warn(){ echo "[$(date +'%F %T')] [WARN] $*" >&2; }
die(){ echo "ERROR: $*" >&2; exit 1; }

# ----- CLI -----
DRY_RUN=false; AUTO_YES=false; FORCE_DISK=""; FORCE_PART=""; LV_TARGET=""; VG_TARGET=""
while (( "$#" )); do
  case "$1" in
    -n|--dry-run) DRY_RUN=true; shift;;
    -y|--yes) AUTO_YES=true; shift;;
    --disk) FORCE_DISK="${2:-}"; shift 2;;
    --part) FORCE_PART="${2:-}"; shift 2;;
    --lv)   LV_TARGET="${2:-}"; shift 2;;
    --vg)   VG_TARGET="${2:-}"; shift 2;;
    -h|--help)
cat <<'EOF'
Uso: expand_disk.sh [opzioni]
  -n, --dry-run        Simula (growpart --dry-run), nessuna modifica.
  -y, --yes            Con --dry-run applica subito dopo senza prompt.
  --disk /dev/sdX      Forza disco del PV (es. /dev/sda, /dev/nvme0n1).
  --part N             Forza numero partizione del PV (es. 5).
  --lv /dev/VG/LV      Forza LV (default: LV montato su /).
  --vg NOME            Forza VG (default: VG dell'LV di /).
Note: usa SOLO growpart per le partizioni.
EOF
      exit 0;;
    *) die "Opzione sconosciuta: $1";;
  esac
done

# ----- prerequisiti -----
need(){ command -v "$1" >/dev/null 2>&1 || die "Comando non trovato: $1"; }
[ "$(id -u)" -eq 0 ] || die "Esegui come root."
for c in findmnt lsblk sfdisk partprobe blockdev pvs vgs lvs pvresize lvextend growpart; do need "$c"; done

FSTYPE="$(findmnt -no FSTYPE /)"
case "$FSTYPE" in
  ext4) need resize2fs ;;
  xfs)  need xfs_growfs ;;
  *)    warn "Filesystem '$FSTYPE' non gestito automaticamente: dopo lvextend ridimensiona manualmente." ;;
esac

# ----- util -----
pretty(){ command -v numfmt >/dev/null 2>&1 && numfmt --to=iec --suffix=B "$1" || echo "${1}B"; }
parse_disk_part(){
  local pv="$1"
  if [[ "$pv" =~ ^/dev/(sd[a-z]+)([0-9]+)$ ]];           then echo "${BASH_REMATCH[1]} ${BASH_REMATCH[2]}"; return; fi
  if [[ "$pv" =~ ^/dev/(vd[a-z]+)([0-9]+)$ ]];           then echo "${BASH_REMATCH[1]} ${BASH_REMATCH[2]}"; return; fi
  if [[ "$pv" =~ ^/dev/(xvd[a-z]+)([0-9]+)$ ]];          then echo "${BASH_REMATCH[1]} ${BASH_REMATCH[2]}"; return; fi
  if [[ "$pv" =~ ^/dev/(nvme[0-9]+n[0-9]+)p([0-9]+)$ ]]; then echo "${BASH_REMATCH[1]} ${BASH_REMATCH[2]}"; return; fi
  echo " "
}
pttype(){ lsblk -no PTTYPE "/dev/$1" 2>/dev/null | head -n1; }

# detection estesa MBR: solo LETTURA, niente awk complicato
find_extended_part(){
  local disk="$1"
  # Prendi solo righe con /dev/<disk>[1-4]
  # Poi matcha (case-insensitive) type= 0x05 / 0x0f / 0x85 / 5 / f / extended
  local line
  while IFS= read -r line; do
    case "$line" in
      /dev/"$disk"[1-4]*)
        if echo "$line" | grep -Eiq 'type *= *(0x0?f|0x05|0x85|f|5|extended)'; then
          # Estrai numero finale della partizione
          echo "${line##*/$disk}" | sed -E 's/[^0-9]*([0-9]+).*/\1/'; return 0
        fi
      ;;
    esac
  done < <(sfdisk -d "/dev/$disk" 2>/dev/null | sed -n 's/^[[:space:]]*//;p')
  return 1
}

sync_pt(){ partprobe "/dev/$1" || true; blockdev --rereadpt "/dev/$1" || true; udevadm settle || true; }

# ----- discovery -----
ROOT_DEV="$(findmnt -no SOURCE /)"
LV_PATH="${LV_TARGET:-$(lvs --noheadings -o lv_path "$ROOT_DEV" | xargs)}"
VG_NAME="${VG_TARGET:-$(lvs --noheadings -o vg_name "$ROOT_DEV" | xargs)}"
[ -n "$LV_PATH" ] && [ -n "$VG_NAME" ] || die "Impossibile determinare LV/VG (usa --lv/--vg)."

mapfile -t PVS < <(pvs --noheadings -o pv_name,vg_name | awk -v vg="$VG_NAME" '$2==vg {print $1}')
[ "${#PVS[@]}" -ge 1 ] || die "Nessun PV nel VG '$VG_NAME'."
PV_DEV="${PVS[0]}"

if [[ -n "$FORCE_DISK" && -n "$FORCE_PART" ]]; then
  DISK="$(basename "$FORCE_DISK")"; PART="$FORCE_PART"
else
  read -r DISK PART < <(parse_disk_part "$PV_DEV")
fi
[ -n "$DISK" ] && [ -n "$PART" ] || die "PV $PV_DEV non è una partizione; specifica --disk /dev/XXX e --part N."

PTTYPE="$(pttype "$DISK")"
LV_SIZE_B="$(lvs --noheadings --units b --nosuffix -o lv_size "$LV_PATH" | xargs)"
VG_FREE_B="$(vgs  --noheadings --units b --nosuffix -o vg_free "$VG_NAME" | xargs)"

log "Filesystem di root: $ROOT_DEV (tipo: $FSTYPE)"
log "Target LV: $LV_PATH — VG: $VG_NAME"
log "PV: $PV_DEV → /dev/$DISK part $PART (tabella: ${PTTYPE:-unknown})"
log "LV size attuale:  $(pretty "$LV_SIZE_B")"
log "VG free attuale:  $(pretty "$VG_FREE_B")"

# ----- piano -----
echo
log "=== PIANO (ONLY growpart) ==="
echo "1) Rescan /dev/$DISK"
EXT_PART=""
if [[ "$PTTYPE" == "dos" && "$PART" -ge 5 ]]; then
  if EXT_PART="$(find_extended_part "$DISK")"; then
    echo "2) growpart /dev/$DISK $EXT_PART   (estesa)"
  else
    warn "MBR rilevato ma estesa non trovata: tenterò /dev/${DISK}2 (default comune)."
    EXT_PART="2"
    echo "2) growpart /dev/$DISK 2          (estesa, default)"
  fi
fi
echo "3) growpart /dev/$DISK $PART        (PV)"
echo "4) partprobe + rereadpt + udevadm settle"
echo "5) pvresize $PV_DEV"
echo "6) lvextend -l +100%FREE $LV_PATH"
echo "7) resize FS ($FSTYPE)"
echo

# ----- dry-run -----
if "$DRY_RUN"; then
  echo "[SIM] echo 1 > /sys/class/block/$DISK/device/rescan"
  if [[ "$PTTYPE" == "dos" && "$PART" -ge 5 ]]; then
    growpart --dry-run "/dev/$DISK" "$EXT_PART" || warn "[SIM] growpart estesa ha segnalato problemi."
  fi
  growpart --dry-run "/dev/$DISK" "$PART" || warn "[SIM] growpart PV ha segnalato problemi."
  echo "[SIM] partprobe /dev/$DISK && blockdev --rereadpt /dev/$DISK && udevadm settle"
  echo "[SIM] pvresize $PV_DEV"
  echo "[SIM] lvextend -l +100%FREE $LV_PATH"
  [[ "$FSTYPE" == "ext4" ]] && echo "[SIM] resize2fs $LV_PATH" || { [[ "$FSTYPE" == "xfs" ]] && echo "[SIM] xfs_growfs /"; }
  if ! "$AUTO_YES"; then
    read -r -p "Procedere davvero con l'ESPANSIONE? [y/N] " ans
    [[ "${ans,,}" =~ ^(y|yes)$ ]] || { log "Dry-run completato. Nessuna modifica."; exit 0; }
  fi
fi

# ----- esecuzione reale -----
log "Rescan /dev/$DISK"; echo 1 > "/sys/class/block/$DISK/device/rescan" || true

if [[ "$PTTYPE" == "dos" && "$PART" -ge 5 ]]; then
  log "growpart /dev/$DISK $EXT_PART   # estesa"
  growpart "/dev/$DISK" "$EXT_PART"
fi

log "growpart /dev/$DISK $PART        # PV"
growpart "/dev/$DISK" "$PART"

log "Sync tabella partizioni"
sync_pt "$DISK"

log "pvresize $PV_DEV"; pvresize "$PV_DEV"
log "lvextend -l +100%FREE $LV_PATH"; lvextend -l +100%FREE "$LV_PATH"

case "$FSTYPE" in
  ext4) log "resize2fs $LV_PATH"; resize2fs "$LV_PATH" ;;
  xfs)  log "xfs_growfs /";       xfs_growfs /       ;;
esac

NEW_VG_FREE="$(vgs --noheadings --units b --nosuffix -o vg_free "$VG_NAME" | xargs)"
NEW_LV_SIZE="$(lvs --noheadings --units b --nosuffix -o lv_size "$LV_PATH" | xargs)"
log "=== COMPLETATO ==="
log "LV: $(pretty "$LV_SIZE_B") → $(pretty "$NEW_LV_SIZE")"
log "VG free: $(pretty "$VG_FREE_B") → $(pretty "$NEW_VG_FREE")"
df -h /