package main

import (
	"flag"
	"fmt"
	"io"

	"felis.lolicon.best/internal/apis/felis/v1alpha1"
	"felis.lolicon.best/internal/operator"
	"k8s.io/apimachinery/pkg/runtime"
	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/cache"
	metricsserver "sigs.k8s.io/controller-runtime/pkg/metrics/server"
)

// cmdOperator runs the MinecraftServer controller-manager (spec §5). It builds
// the scheme, wires the Reconciler with the production RCON prober, and blocks
// on the manager until the process receives a termination signal.
func cmdOperator(args []string, _, stderr io.Writer) int {
	fs := flag.NewFlagSet("operator", flag.ContinueOnError)
	fs.SetOutput(stderr)
	metricsAddr := fs.String("metrics-bind-address", ":8080", "address the metric endpoint binds to")
	// namespace MUST equal the [k8s] namespace felis-api is configured with, and
	// the deployment manifests (felis manifests) render both from one value. It
	// scopes the manager's cache (informers) to a single namespace so the operator
	// can run under a namespaced Role instead of cluster-admin (spec §21). The
	// default matches config.defaultNamespace, so an unconfigured deployment
	// agrees; a mismatch would silently scope the cache to the wrong namespace and
	// every reconcile would see zero servers — hence the watched namespace is
	// logged at startup so a divergence surfaces immediately rather than silently.
	namespace := fs.String("namespace", "minecraft", "namespace to watch; must match felis-api's [k8s] namespace")
	if err := fs.Parse(args); err != nil {
		return 2
	}

	scheme := runtime.NewScheme()
	utilruntime.Must(clientgoscheme.AddToScheme(scheme))
	utilruntime.Must(v1alpha1.AddToScheme(scheme))

	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
		Scheme:  scheme,
		Metrics: metricsserver.Options{BindAddress: *metricsAddr},
		// Scope every informer to the single watched namespace. Without this the
		// cached client (mgr.GetClient) would LIST/WATCH cluster-wide, which a
		// namespaced Role cannot grant — the operator would fail closed at runtime
		// or, worse, demand cluster-admin. With it, the platform.OperatorRole
		// (get/list/watch in one namespace) is exactly sufficient.
		Cache: cache.Options{
			DefaultNamespaces: map[string]cache.Config{*namespace: {}},
		},
	})
	if err != nil {
		fmt.Fprintf(stderr, "felis operator: create manager: %v\n", err)
		return 1
	}
	fmt.Fprintf(stderr, "felis operator: watching namespace %q\n", *namespace)

	r := &operator.Reconciler{
		Client: mgr.GetClient(),
		Scheme: mgr.GetScheme(),
		Prober: operator.RconProber{},
	}
	if err := r.SetupWithManager(mgr); err != nil {
		fmt.Fprintf(stderr, "felis operator: setup controller: %v\n", err)
		return 1
	}

	if err := mgr.Start(ctrl.SetupSignalHandler()); err != nil {
		fmt.Fprintf(stderr, "felis operator: manager exited: %v\n", err)
		return 1
	}
	return 0
}