#!/bin/bash

# Load environment variables from .env file
if [ -f .env ]; then
  export $(grep -v '^#' .env | xargs)
else
  echo ".env file not found! Please create it with the necessary configuration."
  exit 1
fi

# Ensure BACKUP_PATH is set
if [ -z "$BACKUP_PATH" ]; then
  echo "BACKUP_PATH not set in .env file!"
  exit 1
fi

# Extract unique database prefixes (DB1, DB2, ...)
DATABASE_PREFIXES=$(env | grep -o 'DB[0-9]*_' | sort -u)

# Loop through each database configuration prefix
for PREFIX in $DATABASE_PREFIXES; do
  HOST_VAR="${PREFIX}HOST"
  PORT_VAR="${PREFIX}PORT"
  USER_VAR="${PREFIX}USER"
  FORMAT_VAR="${PREFIX}DUMP_FORMAT"

  HOST=${!HOST_VAR}
  PORT=${!PORT_VAR}
  USER=${!USER_VAR}
  DUMP_FORMAT=${!FORMAT_VAR:-"custom"} # Default to "custom" if not set

  if [ -z "$HOST" ] || [ -z "$PORT" ] || [ -z "$USER" ]; then
    echo "Incomplete configuration for $PREFIX. Skipping..."
    continue
  fi

  # Create a directory for each server using host and port, only if it doesn't exist
  SERVER_DIR="$BACKUP_PATH/${HOST}_${PORT}"
  if [ ! -d "$SERVER_DIR" ]; then
    echo "Creating backup directory: $SERVER_DIR"
    mkdir -p "$SERVER_DIR"
  else
    echo "Backup directory $SERVER_DIR already exists, skipping creation."
  fi

  # Get a list of all databases for this server, excluding template databases
  echo "Fetching databases for $HOST:$PORT ..."
  DATABASES=$(psql -h "$HOST" -p "$PORT" -U "$USER" -d postgres -t -c "SELECT datname FROM pg_database WHERE datistemplate = false;")

  # Loop over each database and create a backup
  for DB_NAME in $DATABASES; do
    # Set file extension based on DUMP_FORMAT
    EXTENSION="dump"
    if [[ "$DUMP_FORMAT" == "sql" ]]; then
      EXTENSION="sql.gz"
    fi

    # Set backup file path within the server-specific directory
    BACKUP_FILE="$SERVER_DIR/$DB_NAME.$EXTENSION"

    echo "Dumping '$DB_NAME' on $HOST:$PORT to $BACKUP_FILE"

    # Perform the backup based on the specified format
    if [[ "$DUMP_FORMAT" == "custom" ]]; then
      pg_dump -h "$HOST" -p "$PORT" -U "$USER" -Fc --compress="zstd:$ZSTD_LEVEL" "$DB_NAME" -f "$BACKUP_FILE"
    elif [[ "$DUMP_FORMAT" == "sql" ]]; then
      pg_dump -h "$HOST" -p "$PORT" -U "$USER" "$DB_NAME" | gzip -$GZIP_LEVEL > "$BACKUP_FILE"
    else
      echo "Invalid DUMP_FORMAT for $PREFIX: $DUMP_FORMAT. Skipping..."
      continue
    fi

    du -sh $BACKUP_FILE
  done
done

echo "Backup process completed."