// Copyright (c) 2026 Tigera, Inc. All rights reserved.

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package extensions

import (
	"context"

	corev1 "k8s.io/api/core/v1"
	"k8s.io/client-go/kubernetes"

	"github.com/projectcalico/calico/operator/pkg/components"
)

// StartupExtension is the variant's hook into the operator's startup, before any
// controller registers.
type StartupExtension interface {
	// VerifyAPIsExist reports whether the APIs the variant's controllers watch are
	// served. The operator exits when they are not, so the kubelet retries it once
	// the CRDs are installed.
	VerifyAPIsExist(cs kubernetes.Interface) error

	// VerifyClusterState rejects a cluster whose existing state contradicts the
	// bootstrap configuration the operator was given.
	VerifyClusterState(ctx context.Context, cs kubernetes.Interface, bootConfig *corev1.ConfigMap) error

	// ProtectedNamespaces are the namespaces the variant manages. The operator must
	// not run in one of them.
	ProtectedNamespaces() []string

	// Controllers are the reconcilers the variant adds to the core set. They are added
	// after the core controllers, so a variant can watch resources those own.
	Controllers() []Controller

	// Images are the images the variant supplies for the variant it resolved as. The
	// daemon registers them before any controller renders, so a build serving several
	// variants ships the images the Installation asked for.
	Images() components.Build
}

// noopStartup runs the core operator's behavior unchanged.
type noopStartup struct{}

func (noopStartup) VerifyAPIsExist(kubernetes.Interface) error {
	return nil
}

func (noopStartup) VerifyClusterState(context.Context, kubernetes.Interface, *corev1.ConfigMap) error {
	return nil
}

func (noopStartup) ProtectedNamespaces() []string {
	return nil
}

func (noopStartup) Controllers() []Controller {
	return nil
}

func (noopStartup) Images() components.Build {
	return components.Build{}
}