select_fixture_families() {
  local requested=("$@")
  local family
  local candidate
  local found
  local use_all=false
  FIXTURE_FAMILIES=()
  if [[ "${#requested[@]}" = 0 ]]; then
    requested=(all)
  fi
  for family in "${requested[@]}"; do
    case "$family" in
      all) use_all=true ;;
      base | durable | coordination | oidc | target) ;;
      *)
        printf 'unknown fixture family: %s\n' "$family" >&2
        return 1
        ;;
    esac
  done
  if [[ "$use_all" = true ]]; then
    requested=(durable coordination oidc target)
  fi
  for candidate in durable coordination oidc target; do
    found=false
    for family in "${requested[@]}"; do
      if [[ "$family" = "$candidate" ]]; then
        found=true
      fi
    done
    if [[ "$found" = true ]]; then
      FIXTURE_FAMILIES+=("$candidate")
    fi
  done
}

fixture_has_family() {
  local expected="$1"
  local family
  for family in "${FIXTURE_FAMILIES[@]}"; do
    if [[ "$family" = "$expected" ]]; then
      return
    fi
  done
  return 1
}

expand_fixture_matrix() {
  local coordination_providers=(-)
  local oidc_providers=(-)
  local target_providers=(-)
  local coordination
  local oidc
  local target
  local lane=0
  select_fixture_families "$@" || return
  if fixture_has_family coordination; then
    coordination_providers=(redis dragonfly)
  fi
  if fixture_has_family oidc; then
    oidc_providers=(keycloak zitadel)
  fi
  if fixture_has_family target; then
    target_providers=(garage versitygw)
  fi
  for coordination in "${coordination_providers[@]}"; do
    for oidc in "${oidc_providers[@]}"; do
      for target in "${target_providers[@]}"; do
        lane=$((lane + 1))
        printf '%03d\t%s\t%s\t%s\n' "$lane" "$coordination" "$oidc" "$target"
      done
    done
  done
}