#!/bin/bash
# Tier-1 dispatch for prometheus component operations.
# Delegates to generated run-{op}.sh scripts when present (manifest-plan workflow),
# or falls back to inline _do_{op} functions for direct invocation.
set -euo pipefail

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

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

PROMETHEUS_NAME="${PROMETHEUS_NAME:-prometheus}"
PROMETHEUS_NAMESPACE="${PROMETHEUS_NAMESPACE:-observability}"
PROMETHEUS_PORT="${PROMETHEUS_PORT:-9090}"
PROMETHEUS_STORAGE_CLASS="${PROMETHEUS_STORAGE_CLASS:-longhorn-retain}"
PROMETHEUS_STORAGE_SIZE="${PROMETHEUS_STORAGE_SIZE:-20Gi}"
PROMETHEUS_RETENTION="${PROMETHEUS_RETENTION:-30d}"
PROMETHEUS_SCRAPE_INTERVAL="${PROMETHEUS_SCRAPE_INTERVAL:-30s}"

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

source "${SCRIPT_DIR}/prometheus-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 namespace.yaml serviceaccount.yaml clusterrole.yaml clusterrolebinding.yaml \
                  configmap.yaml alert-rules.yaml pvc.yaml deployment.yaml service.yaml; do
    local path="$SCRIPT_DIR/manifests/${manifest}"
    [ -f "$path" ] && _kubectl apply -f "$path"
  done
  echo "Waiting for ${PROMETHEUS_NAME} pod to be ready..."
  _wait_for_pod 180
  echo "${PROMETHEUS_NAME} installed in namespace ${PROMETHEUS_NAMESPACE}"
}

_do_update() {
  for manifest in configmap.yaml alert-rules.yaml deployment.yaml; do
    local path="$SCRIPT_DIR/manifests/${manifest}"
    [ -f "$path" ] && _kubectl apply -f "$path"
  done
  _kubectl rollout restart "deployment/${PROMETHEUS_NAME}" --namespace "$PROMETHEUS_NAMESPACE"
  echo "Waiting for ${PROMETHEUS_NAME} to be ready..."
  _wait_for_pod 180
  echo "${PROMETHEUS_NAME} updated in namespace ${PROMETHEUS_NAMESPACE}"
}

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

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

_do_health() {
  local pod
  pod=$(_pod_name 2>/dev/null || true)
  if [ -z "$pod" ]; then
    echo "UNHEALTHY: no prometheus pod found in namespace ${PROMETHEUS_NAMESPACE}" >&2; exit 1
  fi
  if _kubectl exec --namespace "$PROMETHEUS_NAMESPACE" "$pod" -- \
      wget -qO- "http://localhost:${PROMETHEUS_PORT}/-/healthy" >/dev/null 2>&1; then
    echo "HEALTHY: ${PROMETHEUS_NAME} responding on /-/healthy"
  else
    echo "UNHEALTHY: ${PROMETHEUS_NAME} did not respond on /-/healthy" >&2; exit 1
  fi
}

_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