#!/usr/bin/env bash
# deregister-runner.sh — remove a runner registration from Gitea via the API.
#
# act_runner has no "unregister" command, so deregistration is done through the
# Gitea REST API. This requires an *API* token (not a registration token) with
# admin rights, plus the runner id or name. Run this before retiring or renaming
# a runner to keep the Gitea UI clean, then delete the local config to start fresh.
#
# Usage:
#   GITEA_INSTANCE_URL=https://git.example.com \
#   GITEA_API_TOKEN=<admin-api-token> \
#   ./scripts/deregister-runner.sh <runner-name|runner-id>
set -euo pipefail

: "${GITEA_INSTANCE_URL:?GITEA_INSTANCE_URL must be set (e.g. https://git.example.com)}"
: "${GITEA_API_TOKEN:?GITEA_API_TOKEN must be set (an admin API token, not a registration token)}"

TARGET="${1:-}"
if [ -z "${TARGET}" ]; then
    echo "[FATAL] Provide the runner name or id as the first argument." >&2
    echo "Usage: $0 <runner-name|runner-id>" >&2
    exit 1
fi

API="${GITEA_INSTANCE_URL%/}/api/v1"
AUTH="Authorization: token ${GITEA_API_TOKEN}"

# Resolve a runner name to an id if a non-numeric target was given.
if [[ "${TARGET}" =~ ^[0-9]+$ ]]; then
    RUNNER_ID="${TARGET}"
else
    echo "Resolving runner id for name '${TARGET}' ..."
    RUNNER_ID="$(curl -fsS -H "${AUTH}" "${API}/admin/actions/runners" \
        | jq -r --arg n "${TARGET}" '.runners[] | select(.name==$n) | .id' | head -1)"
    if [ -z "${RUNNER_ID}" ]; then
        echo "[FATAL] No runner found with name '${TARGET}'." >&2
        exit 1
    fi
fi

echo "Deregistering runner id ${RUNNER_ID} from ${GITEA_INSTANCE_URL} ..."
http_code="$(curl -fsS -o /dev/null -w '%{http_code}' \
    -X DELETE -H "${AUTH}" "${API}/admin/actions/runners/${RUNNER_ID}")"

if [ "${http_code}" = "204" ]; then
    echo "Deregistration complete (runner id ${RUNNER_ID} removed)."
    echo "Remove the local config to start fresh: rm config/runner.yaml"
else
    echo "[FATAL] Unexpected HTTP status ${http_code} from delete request." >&2
    exit 1
fi