#!/usr/bin/env bash
# rig forgejo-runner remove — take the service down and wipe this box's
# registration. Convergent: a box with nothing installed exits 0.
#
# There is no --local flag here, and its absence is the design. The GitHub
# sibling offers --local as an ESCAPE HATCH from a real deregistration
# handshake (config.sh remove --token, against an endpoint that mints removal
# tokens). Forgejo has no such handshake and no such endpoint: local is the
# only thing removal can ever be. Shipping the flag would advertise a
# server-side alternative that does not exist, and an operator would spend the
# afternoon hunting for the token that turns it off.
set -euo pipefail

HERE="$(cd "$(dirname "$(readlink -f "${BASH_SOURCE[0]}")")" && pwd)"
# shellcheck source=SCRIPTDIR/lib/forgejo-runner-config.sh
. "$HERE/lib/forgejo-runner-config.sh"

log()  { printf 'rig-forgejo-runner: %s\n' "$*"; }
warn() { printf 'rig-forgejo-runner: WARNING: %s\n' "$*" >&2; }
die()  { printf 'rig-forgejo-runner: ERROR: %s\n' "$1" >&2; exit "${2:-1}"; }

usage() {
  cat <<'EOF'
usage: rig forgejo-runner remove [--user <name>]

  --user <name>   unprivileged service user (default: the tenant user `ci`
                  when it exists, else forgejo-runner)

Stops and disables the systemd service, then wipes this box's registration.
The binary and the user stay put, so a later `rig forgejo-runner install`
re-registers without downloading anything.

Forgejo has no runner deregistration endpoint, so this is always local-only:
the box is cleaned, and the runner stays listed as offline in the instance
until you delete it under Actions > Runners. No token is needed or asked for.

Convergent: safe to re-run; a box with no runner installed exits 0.
EOF
}

# --- args (validated before the root check, so errors are testable) ---------
RUNNER_USER=""
while [ $# -gt 0 ]; do
  case "$1" in
    --user)
      [ $# -ge 2 ] || die "--user needs a value" 2
      RUNNER_USER="$2"; shift 2 ;;
    --local)
      # Named rather than "unknown flag": it is the GitHub sibling's spelling,
      # and the answer is that removal here is ALWAYS what --local means.
      die "--local is not a flag here: Forgejo has no deregistration endpoint, so 'rig forgejo-runner remove' is always local-only. Re-run it without the flag, then delete the offline runner in the instance's Actions > Runners." 2 ;;
    -h|--help) usage; exit 0 ;;
    *) die "unknown flag: $1" 2 ;;
  esac
done

if [ -z "$RUNNER_USER" ]; then
  if id -u ci >/dev/null 2>&1; then RUNNER_USER="ci"; else RUNNER_USER="forgejo-runner"; fi
fi

# --- validation ------------------------------------------------------------
[ "$RUNNER_USER" != "root" ] || die "runner user must not be root" 2

# --- guards ----------------------------------------------------------------
[ "$(id -u)" -eq 0 ] || die "must run as root"

UNIT=/etc/systemd/system/forgejo-runner.service

# --- nothing to remove? -----------------------------------------------------
if ! id -u "$RUNNER_USER" >/dev/null 2>&1; then
  log "no ${RUNNER_USER} user on this box; nothing to remove"
  exit 0
fi
USER_HOME="$(getent passwd "$RUNNER_USER" | cut -d: -f6)"
RUNNER_DIR="$USER_HOME/forgejo-runner"
if [ ! -e "$RUNNER_DIR/.runner" ] && [ ! -e "$UNIT" ]; then
  log "no runner registered in ${RUNNER_DIR}; nothing to remove"
  exit 0
fi

INSTANCE="$(forgejo_runner_instance "$RUNNER_DIR")"
RUNNER_NAME="$(forgejo_runner_name "$RUNNER_DIR")"

# --- service ---------------------------------------------------------------
# First, in both paths: stopping after the registration is wiped would strand a
# running daemon polling with credentials that no longer exist on disk.
if [ -e "$UNIT" ]; then
  log "stopping and disabling forgejo-runner.service"
  systemctl stop forgejo-runner >/dev/null 2>&1 || true
  systemctl disable forgejo-runner >/dev/null 2>&1 || true
  rm -f "$UNIT"
  systemctl daemon-reload
else
  log "no service installed; skipping"
fi

# --- registration -----------------------------------------------------------
if [ -e "$RUNNER_DIR/.runner" ]; then
  rm -f "$RUNNER_DIR/.runner"
  log "wiped the local registration"
fi
rm -f "$RUNNER_DIR/.rig-labels"

# END WITH THE ABSENCE ASSERT: "removed" is a claim, and claims get verified
# (the `rig uninstall` precedent).
leftover=""
[ -e "$RUNNER_DIR/.runner" ] && leftover="$leftover $RUNNER_DIR/.runner"
[ -e "$UNIT" ] && leftover="$leftover $UNIT"
if [ -n "$leftover" ]; then
  printf 'rig-forgejo-runner: remove INCOMPLETE — still present:%s\n' "$leftover" >&2
  exit 1
fi

log "runner removed; the binary stays for a future rig forgejo-runner install"
warn "the runner${RUNNER_NAME:+ ${RUNNER_NAME}} is still listed as offline in ${INSTANCE:-the instance} — delete it under Actions > Runners. Forgejo has no deregistration endpoint, so rig cannot do this for you."