#!/bin/bash

TAG=""
while getopts "t:" opt; do
  case $opt in
    t) TAG="$OPTARG" ;;
    *) echo "Invalid option: -$OPTARG" >&2; exit 1 ;;
  esac
done
shift $((OPTIND-1))

cd /data/backup/mysql || exit 1
if [ -n "$TAG" ]; then
  BACKUP_DIR="./$(date +%Y%m%d%H%M%S)_${TAG}"
else
  BACKUP_DIR="./$(date +%Y%m%d%H%M%S)"
fi

mkdir -p "$BACKUP_DIR"

MYSQL_USER="root"
MYSQL_PASSWORD="ENC(VN13kACOdhyl7xYqbgDMTMP0fK4dwoCkFe0AQW0VEt7/tpwx96GzRVY6eIpwlASM)"
MYSQL_HOST="127.0.0.1"

if [[ "$MYSQL_PASSWORD" =~ ^ENC\(.*\)$ ]]; then
    encrypted_pwd="${MYSQL_PASSWORD:4:-1}"
    if ! MYSQL_PASSWORD=$(java -cp /data/secure/jasypt-agent.jar com.jasypt.agent.DecryptionCLI $encrypted_pwd \
     2>&1); then
        echo -e "\033[31m[Fatal Error] Password decryption failed. Reason:"
        echo "$MYSQL_PASSWORD" | grep -iE "error|exception"
        exit 1
    fi
fi

# Function to execute MySQL command
mysql_exec() {
    docker exec -i mysql mysql -u "$MYSQL_USER" -p"$MYSQL_PASSWORD" -h "$MYSQL_HOST" -N -e "$1" 2>/dev/null
}

# Function to restore MySQL state (called on exit)
restore_mysql_state() {
    if [ "$READ_ONLY_SET" = "true" ]; then
        echo "Restoring MySQL state..."
        mysql_exec "SET GLOBAL read_only = OFF;" || echo "[Warning] Failed to set read_only = OFF"
        echo "MySQL state restored"
    fi
}

# Set trap to ensure MySQL state is restored even on error
trap restore_mysql_state EXIT ERR

# Pre-backup: Set read-only and stop slave
echo "Setting MySQL to read-only mode..."
if ! mysql_exec "SET GLOBAL read_only = ON;"; then
    echo "[Critical Error] Failed to set read_only = ON"
    exit 1
fi
READ_ONLY_SET="true"

echo "Stopping slave replication..."
if ! mysql_exec "STOP REPLICA;"; then
    echo "[Warning] Failed to stop replica (may not be a slave server or already stopped)"
fi

# Get GTID position using SELECT @@global.gtid_executed;
echo "Getting GTID position..."
GTID_EXECUTED=$(mysql_exec "SELECT @@global.gtid_executed;")
if [ -n "$GTID_EXECUTED" ]; then
    # Remove newlines and literal \n strings
    GTID_EXECUTED=$(echo "$GTID_EXECUTED" | tr -d '\n' | sed 's/\\n//g' | tr -s ' ')
    echo "GTID Executed: $GTID_EXECUTED"
    # Write GTID to file for restore use
    echo "$GTID_EXECUTED" > "$BACKUP_DIR/gtid_executed.txt"
else
    echo "[Warning] Failed to get GTID executed information"
fi

# Get database list for backup
if [ $# -eq 0 ]; then
  # When no arguments, get all non-system databases
  databases=$(mysql_exec "SHOW DATABASES;" | grep -Ev "(Database|information_schema|performance_schema|mysql|skywalking|sys)")

  # Convert to array and check empty values
  readarray -t db_list <<< "$databases" || {
    echo "ERROR: No valid databases found or failed to retrieve database list"
    restore_mysql_state
    exit 1
  }
else
  # Use arguments as database list when provided
  db_list=("$@")
fi

# Check if database list is empty
if [ ${#db_list[@]} -eq 0 ]; then
  echo "ERROR: No databases to backup"
  restore_mysql_state
  exit 1
fi

backup_list_str="$BACKUP_DIR.7z"
# Perform backup
for db in "${db_list[@]}"; do
  echo "Backing up database: $db"
  backup_list_str="$backup_list_str $db"
  if ! docker exec -i mysql mysqldump -u "$MYSQL_USER" -p"$MYSQL_PASSWORD" -h "$MYSQL_HOST" --set-gtid-purged=OFF --single-transaction --databases "$db" > "$BACKUP_DIR/$db.sql"; then
    echo "[Critical Error] Failed to backup database $db, aborting"
    restore_mysql_state
    exit 1
  fi
done

# Post-backup: Restore MySQL state (before compression)
echo "Restoring MySQL to read-write mode..."
mysql_exec "SET GLOBAL read_only = OFF;" || echo "[Warning] Failed to set read_only = OFF"

# Clear the trap since we've successfully restored
READ_ONLY_SET="false"
trap - EXIT ERR

# Compress backup files
if ! 7zz a "$BACKUP_DIR.7z" "$BACKUP_DIR" >/dev/null; then
  echo "Compression failed. Please check disk space or 7z installation"
  exit 1
fi

# Cleanup temporary files
rm -rf "$BACKUP_DIR"
echo "Backup completed: $BACKUP_DIR.7z"
echo $backup_list_str >> backup_list.txt

echo "Backup process completed successfully"