#!/bin/bash
set -e
set -o pipefail

LOGFILE="extend-lvm.log"
MODE="LIVE"
USER_DISK=""

GREEN="\e[32m"
RESET="\e[0m"

usage() {
    echo "Uso: $0 [test|--test] [--disk <device>|--disk=<device>]"
    echo "Esempi:"
    echo "  $0 test"
    echo "  $0 --disk /dev/sdb"
    echo "  $0 --test --disk=sdb"
}

while [ $# -gt 0 ]; do
    case "$1" in
        test|--test)
            MODE="TEST"
            ;;
        --disk)
            shift
            if [ -z "$1" ]; then
                echo "ERRORE: --disk richiede un valore" >&2
                usage >&2
                exit 1
            fi
            USER_DISK="$1"
            ;;
        --disk=*)
            USER_DISK="${1#*=}"
            ;;
        -h|--help)
            usage
            exit 0
            ;;
        *)
            echo "ERRORE: argomento non riconosciuto: $1" >&2
            usage >&2
            exit 1
            ;;
    esac
    shift
done

log() {
    echo "$(date '+%F %T') | $1" | tee -a "$LOGFILE"
}

run() {
    if [ "$MODE" == "TEST" ]; then
        log "[TEST] $*"
    else
        log "[RUN]  $*"
        eval "$@"
    fi
}

log "=========================================="
log "Avvio script LVM Auto Expand ($MODE)"

if [ "$EUID" -ne 0 ]; then
    log "ERRORE: eseguire come root"
    exit 1
fi

for cmd in lsblk df awk grep findmnt lvs pvcreate vgextend lvextend flock tr; do
    if ! command -v "$cmd" >/dev/null 2>&1; then
        log "ERRORE: comando richiesto non trovato: $cmd"
        exit 1
    fi
done

LOCKFILE="/var/lock/auto-lvm-add-disk.lock"
if [ ! -d "/var/lock" ]; then
    LOCKFILE="/tmp/auto-lvm-add-disk.lock"
fi

exec 200>"$LOCKFILE"
if ! flock -n 200; then
    log "ERRORE: script già in esecuzione (lock: $LOCKFILE)"
    exit 1
fi
log "Lock acquisito: $LOCKFILE"

# --- Spazio iniziale ---
START_SIZE=$(df -BG / | awk 'NR==2 {print $2}' | tr -d 'G')

# --- Forza rescan SCSI ---
log "Scansione bus SCSI..."
for host in /sys/class/scsi_host/host*; do
    run "echo '- - -' > $host/scan"
done
sleep 2

# --- Trova disco nuovo ---
log "Rilevo il nuovo disco..."
DISK=""

if [ -n "$USER_DISK" ]; then
    if [[ "$USER_DISK" == /dev/* ]]; then
        DISK="$USER_DISK"
    else
        DISK="/dev/$USER_DISK"
    fi

    if [ ! -b "$DISK" ]; then
        log "ERRORE: disco specificato non valido: $DISK"
        exit 1
    fi

    DISK_TYPE=$(lsblk -ndo TYPE "$DISK")
    DISK_FSTYPE=$(lsblk -ndo FSTYPE "$DISK")

    if [ "$DISK_TYPE" != "disk" ]; then
        log "ERRORE: il device specificato non è un disco: $DISK"
        exit 1
    fi

    if [ -n "$DISK_FSTYPE" ]; then
        log "ERRORE: il disco specificato contiene già un filesystem: $DISK"
        exit 1
    fi

    if lsblk "$DISK" | grep -q part; then
        log "ERRORE: il disco specificato contiene partizioni: $DISK"
        exit 1
    fi

    log "Disco specificato da CLI: $DISK"
else
    NEW_DISK=""
    for d in $(lsblk -ndo NAME,TYPE,FSTYPE | awk '$2=="disk" && $3=="" {print $1}'); do
        if ! lsblk /dev/$d | grep -q part; then
            NEW_DISK="$d"
            break
        fi
    done

    if [ -z "$NEW_DISK" ]; then
        log "ERRORE: nessun disco nuovo trovato"
        exit 1
    fi

    DISK="/dev/$NEW_DISK"
fi

DISK_SIZE=$(lsblk -ndo SIZE $DISK)

log "Nuovo disco corretto: ${GREEN}$DISK ($DISK_SIZE)${RESET}"

# --- VG e LV del mountpoint root ---
ROOT_SOURCE=$(findmnt -n -o SOURCE /)
if [ -z "$ROOT_SOURCE" ] || [[ "$ROOT_SOURCE" != /dev/* ]]; then
    log "ERRORE: impossibile determinare il device root da /"
    exit 1
fi

ROOT_FSTYPE=$(findmnt -n -o FSTYPE /)
LV="$ROOT_SOURCE"
VG=$(lvs --noheadings -o vg_name "$LV" 2>/dev/null | awk '{$1=$1; print}')

if [ -z "$VG" ]; then
    log "ERRORE: il device root ($LV) non risulta un Logical Volume LVM"
    exit 1
fi

log "Volume Group: $VG"
log "Logical Volume: $LV"
log "Filesystem root: $ROOT_FSTYPE"

# --- Operazioni ---
run "pvcreate $DISK"
run "vgextend $VG $DISK"
run "lvextend -l +100%FREE $LV"

case "$ROOT_FSTYPE" in
    ext2|ext3|ext4)
        if ! command -v resize2fs >/dev/null 2>&1; then
            log "ERRORE: resize2fs non trovato ma richiesto per filesystem $ROOT_FSTYPE"
            exit 1
        fi
        run "resize2fs $LV"
        ;;
    xfs)
        if ! command -v xfs_growfs >/dev/null 2>&1; then
            log "ERRORE: xfs_growfs non trovato ma richiesto per filesystem xfs"
            exit 1
        fi
        run "xfs_growfs /"
        ;;
    *)
        log "ERRORE: filesystem root non supportato: $ROOT_FSTYPE"
        exit 1
        ;;
esac

# --- Spazio finale ---
END_SIZE=$(df -BG / | awk 'NR==2 {print $2}' | tr -d 'G')
DELTA=$((END_SIZE - START_SIZE))

echo -e "${GREEN}"
echo "====================================="
echo "   LVM EXTENSION COMPLETATA"
echo "-------------------------------------"
echo " Disco aggiunto : $DISK"
echo " Dimensione    : $DISK_SIZE"
echo " Spazio prima  : ${START_SIZE}G"
echo " Spazio dopo   : ${END_SIZE}G"
echo " Aumento       : +${DELTA}G"
echo "====================================="
echo -e "${RESET}"

log "Spazio iniziale: ${START_SIZE}G"
log "Spazio finale  : ${END_SIZE}G"
log "Aumento        : +${DELTA}G"
log "Operazione completata"
log "=========================================="