#!/usr/bin/env bash
set -o errexit
set -o nounset
set -o pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
# shellcheck source=00_env.sh
. "$SCRIPT_DIR/00_env.sh"

DEVICES=""
SERVERS=""
OUTPUT=""

usage() {
  printf 'Usage: %s --fs <filesystem> --devices "/dev/sdb /dev/sdc" --servers "node1,node2" --failure-group <number> --pool <storage_pool> --usage <dataOnly|metadataOnly|dataAndMetadata> [--output <path>]\n' "$(basename "$0")"
}

while [[ "$#" -gt 0 ]]; do
  case "$1" in
    --fs) FILESYSTEM="${2:-}"; shift 2 ;;
    --devices) DEVICES="${2:-}"; shift 2 ;;
    --servers) SERVERS="${2:-}"; shift 2 ;;
    --failure-group) FAILURE_GROUP="${2:-}"; shift 2 ;;
    --pool) STORAGE_POOL="${2:-}"; shift 2 ;;
    --usage) USAGE="${2:-}"; shift 2 ;;
    --output) OUTPUT="${2:-}"; shift 2 ;;
    -h|--help) usage; exit 0 ;;
    *) critical "Unknown argument: $1"; usage; exit 2 ;;
  esac
done

if [[ -z "$FILESYSTEM" || -z "$DEVICES" || -z "$SERVERS" || -z "$FAILURE_GROUP" || -z "$STORAGE_POOL" || -z "$USAGE" ]]; then
  critical "Missing required input"
  usage
  exit 2
fi

if ! [[ "$FAILURE_GROUP" =~ ^-?[0-9]+$ ]]; then
  critical "--failure-group must be an integer"
  exit 2
fi

if ! usage_value_valid "$USAGE"; then
  critical "--usage must be one of: dataOnly, metadataOnly, dataAndMetadata"
  exit 2
fi

if [[ -z "$OUTPUT" ]]; then
  OUTPUT="/tmp/gpfs_nsd_${FILESYSTEM}_${TIMESTAMP}.stanza"
fi

safe_fs="$(printf '%s' "$FILESYSTEM" | tr -c '[:alnum:]_' '_')"

{
  printf '# Generated GPFS NSD stanza for filesystem %s\n' "$FILESYSTEM"
  printf '# Review with storage and cluster teams before use.\n\n'
  for device in $DEVICES; do
    if [[ "$device" != /dev/* ]]; then
      critical "Device must be an absolute /dev path: $device"
      exit 2
    fi

    device_base="$(basename "$device" | tr -c '[:alnum:]_' '_')"
    nsd_name="nsd_${safe_fs}_${device_base}"
    printf '%%nsd:\n'
    printf '  device=%s\n' "$device"
    printf '  nsd=%s\n' "$nsd_name"
    printf '  servers=%s\n' "$SERVERS"
    printf '  usage=%s\n' "$USAGE"
    printf '  failureGroup=%s\n' "$FAILURE_GROUP"
    printf '  pool=%s\n\n' "$STORAGE_POOL"
  done
} > "$OUTPUT"

ok "Generated NSD stanza: $OUTPUT"
warning "This script only writes a stanza file. It does not create NSDs or modify GPFS."