# The hive this container runs on, read at boot rather than built in, so an
# agent's closure does not carry it.
#
# hive-priv writes `/etc/hyperhive-hive-facts` into the container before every
# start (`HYPERHIVE_HIVE_NAME`, `HYPERHIVE_HIVE_DOMAIN`, one `KEY=value` line
# each). Two readers hand those lines on:
#
# - an environment generator, for the container's systemd: it passes them to
#   every unit it starts, `machinectl shell` sessions (`hivectl choom`)
#   included, since those are transient units of the same manager. A unit's
#   own `Environment=` still overrides them.
# - `/etc/set-environment`, for login shells that no unit starts:
#   `nixos-container root-login` / `run` (nsenter + `su -l`, which resets the
#   environment) and getty logins.
#
# Tested by `checks.script-test-agent-hive-facts`.
{
  config,
  lib,
  pkgs,
  ...
}:
let
  userName = config.services.hyperhive.agent.user.name;

  # Shell builtins only: nothing is assumed on PATH this early. Only the two
  # known keys are passed on. `|| [ -n "$key" ]` keeps a last line that has
  # no trailing newline.
  generator = pkgs.writeShellScript "hyperhive-hive-facts" ''
    hive=unknown
    if [ -r /etc/hyperhive-hive-facts ]; then
      while IFS='=' read -r key value || [ -n "$key" ]; do
        case "$key" in
          HYPERHIVE_HIVE_NAME) hive=$value ;;
          HYPERHIVE_HIVE_DOMAIN) ;;
          *) continue ;;
        esac
        printf '%s=%s\n' "$key" "$value"
      done < /etc/hyperhive-hive-facts
    fi
    # Names claude's remote-control sessions `<hive>-<agent>`.
    printf 'CLAUDE_REMOTE_CONTROL_SESSION_NAME_PREFIX=%s-%s\n' "$hive" ${lib.escapeShellArg userName}
  '';

  # Sourced by every shell's `/etc/set-environment`, so POSIX sh only. Each
  # line is exported as one word and never evaluated.
  profile = pkgs.writeText "hyperhive-hive-facts.sh" ''
    while IFS= read -r __hyperhive_fact; do
      case "$__hyperhive_fact" in
        ?*=*) export "$__hyperhive_fact" ;;
      esac
    done <<__HYPERHIVE_FACTS__
    $(${generator})
    __HYPERHIVE_FACTS__
    unset __hyperhive_fact
  '';
in
{
  environment.etc."systemd/system-environment-generators/50-hyperhive-hive-facts".source = generator;
  environment.etc."hyperhive/hive-facts.sh".source = profile;
  environment.extraInit = ". /etc/hyperhive/hive-facts.sh";
}