#!/usr/bin/env bash
# init_grafana_oauth.sh
#
# Bootstrap the Google-OAuth secret that kps-grafana mounts as env vars
# (GF_AUTH_GOOGLE_CLIENT_ID / GF_AUTH_GOOGLE_CLIENT_SECRET) for its native
# auth.google sign-in flow. Companion to:
#   - deploy/gcp/gke/grafana-google-oidc-secret.example.yaml (envsubst template)
#   - monitoring/kps-values-gke.yaml (Helm overrides for grafana subchart)
#
# Auth model:
#   - Anyone in the @knoey.com Workspace can sign in (auth.google.allowed_domains).
#   - chrisfu@knoey.com + ron@knoey.com get Admin (role_attribute_path JMESPath).
#   - Everyone else @knoey.com gets Editor.
#
# Usage:
#   ./etc/init_grafana_oauth.sh
#
# Env vars (resolved from etc/secrets/* if not set in the shell):
#   GRAFANA_GOOGLE_CLIENT_ID      ← from etc/secrets/grafana-google-oidc-client-id
#   GRAFANA_GOOGLE_CLIENT_SECRET  ← from etc/secrets/grafana-google-oidc-client-secret
#
# Optional:
#   APP_CLUSTER_KUBECONTEXT     (default: $KUBECONTEXT then ambient)
#   NAMESPACE                   (default: monitoring)
#
# Pre-reqs:
#   - OAuth 2.0 client created at GCP Console (see the secret template
#     deploy/gcp/gke/grafana-google-oidc-secret.example.yaml for the
#     exact authorized redirect URI + consent screen settings).
#   - Two values saved into etc/secrets/grafana-google-oidc-client-{id,secret}
#     (chmod 0600 each; etc/secrets/ is gitignored except for .keep).
#
# After this script runs and the Secret is in place, the next `helm upgrade`
# (or kubectl-apply of the chart's rendered manifest) of kps-grafana picks
# up the Secret via `envFromSecret: grafana-google-oidc`. Verify with:
#   kubectl --context=$APP_CLUSTER_KUBECONTEXT -n monitoring exec -it kps-grafana-0 -c grafana -- \
#     env | grep GF_AUTH_GOOGLE_

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
GKE_MANIFEST_DIR="$REPO_ROOT/deploy/gcp/gke"

NAMESPACE="${NAMESPACE:-monitoring}"
KCTX="${APP_CLUSTER_KUBECONTEXT:-${KUBECONTEXT:-}}"

if [[ -n "$KCTX" ]]; then
  KCTX_FLAG=(--context="$KCTX")
else
  KCTX_FLAG=()
fi

log() { printf "[%s] %s\n" "$(date +%H:%M:%S)" "$*"; }
die() { log "ERROR: $*" >&2; exit 1; }

resolve_secret() {
  local var="$1" file="$2" val="${!1:-}"
  if [[ -z "$val" && -f "$REPO_ROOT/etc/secrets/$file" ]]; then
    val="$(cat "$REPO_ROOT/etc/secrets/$file")"
  fi
  if [[ -z "$val" ]]; then
    die "missing $var (set the env var, or save the value into etc/secrets/$file)"
  fi
  printf '%s' "$val"
}

for tool in kubectl envsubst; do
  command -v "$tool" >/dev/null 2>&1 || die "required tool not found: $tool"
done

GRAFANA_GOOGLE_CLIENT_ID="$(resolve_secret GRAFANA_GOOGLE_CLIENT_ID grafana-google-oidc-client-id)"
GRAFANA_GOOGLE_CLIENT_SECRET="$(resolve_secret GRAFANA_GOOGLE_CLIENT_SECRET grafana-google-oidc-client-secret)"
export GRAFANA_GOOGLE_CLIENT_ID GRAFANA_GOOGLE_CLIENT_SECRET

SECRET_TMPL="$GKE_MANIFEST_DIR/grafana-google-oidc-secret.example.yaml"
[[ -f "$SECRET_TMPL" ]] || die "missing manifest: $SECRET_TMPL"

log "==> grafana google-oauth bootstrap"
log "    namespace : $NAMESPACE"
log "    kubectx   : ${KCTX:-<ambient>}"

log "Applying grafana-google-oidc Secret ..."
envsubst '${GRAFANA_GOOGLE_CLIENT_ID} ${GRAFANA_GOOGLE_CLIENT_SECRET}' \
  < "$SECRET_TMPL" \
  | kubectl "${KCTX_FLAG[@]}" -n "$NAMESPACE" apply -f -

log "==> grafana google-oauth secret applied."
echo ""
echo "  Next steps:"
echo "    1. Apply the Helm values override at monitoring/kps-values-gke.yaml:"
echo "         helm upgrade --reuse-values kps prometheus-community/kube-prometheus-stack \\"
echo "                      --namespace $NAMESPACE \\"
echo "                      -f $REPO_ROOT/monitoring/kps-values-gke.yaml"
echo "    2. Patch knoe-svc-kong-config to add the /grafana route (see"
echo "       deploy/opentofu/k3s/manifests/knoe/kong-configmap.yaml for the canonical source)."
echo "    3. Restart Kong:  kubectl rollout restart deployment/knoe-svc-kong -n knoe-system"
echo "    4. Browser-test:  https://svc.knoe.dev/grafana → Google sign-in → Grafana"
echo ""