#!/usr/bin/env bash
set -euo pipefail

usage() {
  cat <<'USAGE'
Usage:
  scripts/resolve-machine-alias.sh [--hostname <name>] [--field alias|suffix|agent-id|all] [--tool <tool>]

Defaults:
  --hostname: current host shortname (hostname -s)
  --field: all
  --tool: openclaw

Reads mapping from policies/MACHINE-ALIASES.yaml.
USAGE
}

HOSTNAME_INPUT="$(hostname -s 2>/dev/null || hostname)"
FIELD="all"
TOOL="openclaw"

while [[ $# -gt 0 ]]; do
  case "$1" in
    --hostname)
      HOSTNAME_INPUT="${2:-}"
      shift 2
      ;;
    --field)
      FIELD="${2:-}"
      shift 2
      ;;
    --tool)
      TOOL="${2:-}"
      shift 2
      ;;
    -h|--help)
      usage
      exit 0
      ;;
    *)
      echo "ERROR: unknown arg: $1" >&2
      usage
      exit 1
      ;;
  esac
done

case "$FIELD" in
  alias|suffix|agent-id|all) ;;
  *)
    echo "ERROR: --field must be one of alias|suffix|agent-id|all" >&2
    exit 1
    ;;
esac

REPO_ROOT="$(git rev-parse --show-toplevel 2>/dev/null || true)"
if [[ -z "$REPO_ROOT" ]]; then
  echo "ERROR: run inside collective-memory-repo" >&2
  exit 2
fi

MAP_FILE="$REPO_ROOT/policies/MACHINE-ALIASES.yaml"
if [[ ! -f "$MAP_FILE" ]]; then
  echo "ERROR: mapping file not found: $MAP_FILE" >&2
  exit 2
fi

trim() {
  local s="$1"
  s="${s#${s%%[![:space:]]*}}"
  s="${s%${s##*[![:space:]]}}"
  printf '%s' "$s"
}

contains_csv_value() {
  local csv="$1"
  local needle="$2"
  IFS=',' read -r -a parts <<< "$csv"
  for p in "${parts[@]}"; do
    if [[ "$(trim "$p")" == "$needle" ]]; then
      return 0
    fi
  done
  return 1
}

record_hostname=""
record_aliases=""
record_suffix=""
matched_alias=""
matched_suffix=""
matched_hostname=""
found="false"

finalize_record() {
  if [[ "$found" == "true" || -z "$record_hostname" ]]; then
    return
  fi

  if [[ "$HOSTNAME_INPUT" == "$record_hostname" ]]; then
    found="true"
  elif contains_csv_value "$record_aliases" "$HOSTNAME_INPUT"; then
    found="true"
  fi

  if [[ "$found" == "true" ]]; then
    matched_hostname="$record_hostname"
    matched_suffix="$record_suffix"

    if contains_csv_value "$record_aliases" "$HOSTNAME_INPUT"; then
      matched_alias="$HOSTNAME_INPUT"
    else
      IFS=',' read -r first_alias _ <<< "$record_aliases"
      matched_alias="$(trim "$first_alias")"
    fi
  fi
}

while IFS= read -r raw_line || [[ -n "$raw_line" ]]; do
  line="${raw_line%%#*}"
  line="$(trim "$line")"
  [[ -z "$line" ]] && continue

  if [[ "$line" =~ ^-[[:space:]]hostname:[[:space:]]*(.+)$ ]]; then
    finalize_record
    record_hostname="$(trim "${BASH_REMATCH[1]}")"
    record_aliases=""
    record_suffix=""
    continue
  fi

  if [[ "$line" =~ ^aliases:[[:space:]]*(.+)$ ]]; then
    record_aliases="$(trim "${BASH_REMATCH[1]}")"
    continue
  fi

  if [[ "$line" =~ ^default_agent_suffix:[[:space:]]*(.+)$ ]]; then
    record_suffix="$(trim "${BASH_REMATCH[1]}")"
    continue
  fi
done < "$MAP_FILE"

finalize_record

if [[ "$found" != "true" ]]; then
  # fallback: use normalized hostname directly
  fallback_suffix="$(printf '%s' "$HOSTNAME_INPUT" | tr '[:upper:]' '[:lower:]' | tr -cs 'a-z0-9-' '-')"
  fallback_suffix="${fallback_suffix#-}"
  fallback_suffix="${fallback_suffix%-}"
  [[ -z "$fallback_suffix" ]] && fallback_suffix="host"

  matched_hostname="$HOSTNAME_INPUT"
  matched_alias="$fallback_suffix"
  matched_suffix="$fallback_suffix"
fi

agent_id="${TOOL}-${matched_suffix}"

case "$FIELD" in
  alias)
    printf '%s\n' "$matched_alias"
    ;;
  suffix)
    printf '%s\n' "$matched_suffix"
    ;;
  agent-id)
    printf '%s\n' "$agent_id"
    ;;
  all)
    cat <<OUT
hostname=$matched_hostname
alias=$matched_alias
suffix=$matched_suffix
agent_id=$agent_id
OUT
    ;;
esac