#!/bin/bash
set -Eeuo pipefail

DATE="$(date +'%Y-%m-%d_%H-%M')"
BACKUP_DIR="/home/debian/backup"
LOG_DIR="/home/debian/Gestion_sondes/Logs"
mkdir -p "$LOG_DIR" "$BACKUP_DIR"

LOG_FILE="$LOG_DIR/backup_$DATE.log"
exec > >(tee -a "$LOG_FILE") 2>&1

# Verrou anti-doublon
exec 9>/tmp/backup_mysql.lock
flock -n 9 || { echo "🔒 Un autre backup est en cours. Abandon."; exit 1; }

BACKUP_FILE="$BACKUP_DIR/mysql_backup_$DATE.sql"

# Cible NAS via WireGuard / LAN
NAS_HOST="192.168.1.250"      # à adapter avec l'IP locale réelle du NAS
NAS_PORT="4422"                # mettre 4422 seulement si DSM écoute réellement sur 4422 en local
NAS_USER="Michel"
NAS_DIR="/volume1/VPS/Gravelines"

SSH_KEY="/home/debian/.ssh/id_ed25519"
SSH_OPTS="-i $SSH_KEY -p $NAS_PORT \
  -o BatchMode=yes -o PreferredAuthentications=publickey \
  -o PasswordAuthentication=no -o PubkeyAuthentication=yes \
  -o StrictHostKeyChecking=accept-new -o ConnectTimeout=10 \
  -o ServerAliveInterval=30 -o ServerAliveCountMax=2"

# Credentials MySQL
MYSQL_DEFAULTS="/home/debian/.my.cnf"

# PATH minimal pour cron
export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

echo "🔷 Démarrage $(date '+%F %T') sur $(hostname -s)"
echo "🔷 Dossier local  : $BACKUP_DIR"
echo "🔷 Dossier NAS    : $NAS_DIR (hôte $NAS_HOST)"

# 1) Pré-check SSH & droits écriture NAS
echo "🔷 Test SSH NAS…"
if ! ssh $SSH_OPTS "$NAS_USER@$NAS_HOST" "mkdir -p '$NAS_DIR' && test -w '$NAS_DIR' && echo __SSH_OK__"; then
  echo "❌ Impossible d'écrire sur $NAS_HOST:$NAS_DIR (clé SSH ? user ? droits ? SSH NAS activé ?)"
  exit 20
fi

# 2) Dump MySQL
echo "🔷 Dump MySQL…"
if [[ -f "$MYSQL_DEFAULTS" ]]; then
  DUMP="mysqldump --defaults-file=$MYSQL_DEFAULTS --all-databases --single-transaction --quick --lock-tables=false --routines --events --triggers"
else
  DUMP="mysqldump --all-databases --single-transaction --quick --lock-tables=false --routines --events --triggers"
fi

# Baisse de priorité
IONICE="$(command -v ionice >/dev/null 2>&1 && echo 'ionice -c2 -n7' || true)"
NICE="$(command -v nice >/dev/null 2>&1 && echo 'nice -n 10' || true)"

bash -c "$IONICE $NICE $DUMP > '$BACKUP_FILE'"

# Vérification locale
if [[ ! -s "$BACKUP_FILE" ]]; then
  echo "❌ Fichier de backup vide : $BACKUP_FILE"
  exit 21
fi

LOCAL_SIZE=$(stat -c%s "$BACKUP_FILE" 2>/dev/null || wc -c < "$BACKUP_FILE")
echo "✅ Dump OK : $BACKUP_FILE ($LOCAL_SIZE octets)"

# 3) Transfert NAS
scp -O -P 4422 -i /home/debian/.ssh/id_ed25519 \
  -o BatchMode=yes -o PreferredAuthentications=publickey -o PasswordAuthentication=no \
  -o StrictHostKeyChecking=accept-new \
  "$BACKUP_FILE" "$NAS_USER@$NAS_HOST:$NAS_DIR/"

# 4) Vérification taille distante = locale
BASENAME="$(basename "$BACKUP_FILE")"
REMOTE_SIZE=$(ssh -p 4422 -i /home/debian/.ssh/id_ed25519 \
  -o BatchMode=yes -o PreferredAuthentications=publickey -o PasswordAuthentication=no \
  -o StrictHostKeyChecking=accept-new \
  "$NAS_USER@$NAS_HOST" "wc -c < '$NAS_DIR/$BASENAME'" || echo 0)

if [[ "$REMOTE_SIZE" != "$LOCAL_SIZE" ]]; then
  echo "❌ Taille différente après transfert (local=$LOCAL_SIZE, distant=$REMOTE_SIZE)"
  exit 22
fi

echo "✅ Transfert OK → $NAS_HOST:$NAS_DIR/$BASENAME"