#!/bin/bash
# Tier-1 dispatch for metrics_server component operations.
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
cd "$SCRIPT_DIR"

[ -f "${SCRIPT_DIR}/env-metrics_server" ] && source "${SCRIPT_DIR}/env-metrics_server"

METRICS_SERVER_NAME="${METRICS_SERVER_NAME:-metrics-server}"
METRICS_SERVER_NAMESPACE="${METRICS_SERVER_NAMESPACE:-kube-system}"
METRICS_SERVER_PORT="${METRICS_SERVER_PORT:-4443}"

CMD_TSK="${CMD_TSK:-${1:-install}}"

source "${SCRIPT_DIR}/metrics_server-lib.sh"

_resolve_kubeconfig() {
  if [ -n "${KUBECONFIG:-}" ] && [ -f "$KUBECONFIG" ]; then
    return
  fi
  for candidate in /var/lib/k0s/pki/admin.conf /etc/kubernetes/admin.conf /root/.kube/config; do
    if [ -f "$candidate" ]; then
      export KUBECONFIG="$candidate"
      return
    fi
  done
  echo "ERROR: kubeconfig not found — set KUBECONFIG explicitly" >&2; exit 1
}

_do_install() {
  for manifest in serviceaccount.yaml clusterrole.yaml clusterrolebinding.yaml rolebinding.yaml \
                  deployment.yaml service.yaml apiservice.yaml; do
    local path="$SCRIPT_DIR/manifests/${manifest}"
    [ -f "$path" ] && _kubectl apply -f "$path"
  done
  echo "Waiting for ${METRICS_SERVER_NAME} pod to be ready..."
  _wait_for_pod 180
  echo "${METRICS_SERVER_NAME} installed in namespace ${METRICS_SERVER_NAMESPACE}"
}

_do_update() {
  _kubectl apply -f "$SCRIPT_DIR/manifests/deployment.yaml"
  _kubectl rollout restart "deployment/${METRICS_SERVER_NAME}" --namespace "$METRICS_SERVER_NAMESPACE"
  _wait_for_pod 180
  echo "${METRICS_SERVER_NAME} updated"
}

_do_delete() {
  for manifest in apiservice.yaml deployment.yaml service.yaml clusterrolebinding.yaml \
                  clusterrole.yaml rolebinding.yaml serviceaccount.yaml; do
    local path="$SCRIPT_DIR/manifests/${manifest}"
    [ -f "$path" ] && _kubectl delete -f "$path" --ignore-not-found
  done
  echo "${METRICS_SERVER_NAME} deleted from namespace ${METRICS_SERVER_NAMESPACE}"
}

_do_restart() {
  _kubectl rollout restart "deployment/${METRICS_SERVER_NAME}" --namespace "$METRICS_SERVER_NAMESPACE"
  _wait_for_pod 180
  echo "${METRICS_SERVER_NAME} restarted"
}

_do_health() {
  _kubectl wait pod \
    --namespace "$METRICS_SERVER_NAMESPACE" \
    --selector "app=metrics-server" \
    --for=condition=Ready \
    --timeout="10s" >/dev/null 2>&1 \
    && echo "HEALTHY: ${METRICS_SERVER_NAME} pod ready" \
    || { echo "UNHEALTHY: ${METRICS_SERVER_NAME} pod not ready" >&2; exit 1; }
}

_resolve_kubeconfig

case "$CMD_TSK" in
  install)  [ -f "$SCRIPT_DIR/run-init.sh" ]    && exec bash "$SCRIPT_DIR/run-init.sh";    _do_install  ;;
  update)   [ -f "$SCRIPT_DIR/run-update.sh" ]  && exec bash "$SCRIPT_DIR/run-update.sh";  _do_update   ;;
  delete)   [ -f "$SCRIPT_DIR/run-delete.sh" ]  && exec bash "$SCRIPT_DIR/run-delete.sh";  _do_delete   ;;
  restart)  [ -f "$SCRIPT_DIR/run-restart.sh" ] && exec bash "$SCRIPT_DIR/run-restart.sh"; _do_restart  ;;
  health)   _do_health ;;
  *)        echo "ERROR: unknown CMD_TSK='${CMD_TSK}'. Valid: install|update|delete|restart|health" >&2; exit 1 ;;
esac