#!/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 (facultatif mais prudent)
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 (alias dans ~/.ssh/config)
NAS_HOST="DSM920"
NAS_DIR="/volume1/VPS/Gravelines"
SSH_OPTS="-F /home/debian/.ssh/config -o BatchMode=yes -o StrictHostKeyChecking=accept-new"

# Chemin credentials MySQL (recommandé)
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 "$NAS_HOST" "mkdir -p '$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 (format .sql, options sûres)
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 pour ne pas gêner la prod
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'"

# Sanity check
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
echo "🔷 Transfert vers le NAS…"
rsync -av --partial -e "ssh $SSH_OPTS" "$BACKUP_FILE" "$NAS_HOST:$NAS_DIR/"

# 4) Vérification taille distante = locale (robuste BusyBox)
BASENAME="$(basename "$BACKUP_FILE")"
REMOTE_SIZE=$(ssh $SSH_OPTS "$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"

# 5) Rotation locale (garder 14 fichiers)
echo "🔷 Rotation locale (garder 14 fichiers)…"
ls -1t "$BACKUP_DIR"/mysql_backup_*.sql 2>/dev/null | tail -n +15 | xargs -r rm -f


echo "🏁 Terminé $(date '+%F %T')"