/*
Copyright 2021 The Rook Authors. 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 csi

import (
	"regexp"

	"github.com/google/go-cmp/cmp"
	cephv1 "github.com/rook/rook/pkg/apis/ceph.rook.io/v1"
	opcontroller "github.com/rook/rook/pkg/operator/ceph/controller"
	v1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/resource"
	"sigs.k8s.io/controller-runtime/pkg/event"
	"sigs.k8s.io/controller-runtime/pkg/predicate"
)

// predicateController is the predicate function to trigger reconcile on operator configuration cm change
func predicateController() predicate.Funcs {
	return predicate.Funcs{
		CreateFunc: func(e event.CreateEvent) bool {
			// if the operator configuration file is created we want to reconcile
			if cm, ok := e.Object.(*v1.ConfigMap); ok {
				// We don't want to use cm.Generation here, it case the operator was stopped and the
				// ConfigMap was created
				return cm.Name == opcontroller.OperatorSettingConfigMapName
			}

			// If a Ceph Cluster is created we want to reconcile the csi driver
			if cephCluster, ok := e.Object.(*cephv1.CephCluster); ok {
				// This allows us to avoid a double reconcile of the CSI controller if this is not
				// the first generation of the CephCluster. So only return true if this is the very
				// first instance of the CephCluster
				// Corner case is when the cluster is created but the operator is down AND the cm
				// does not exist... However, these days the operator config map is part of the
				// operator.yaml so it's probably acceptable?
				return cephCluster.Generation == 1
			}

			return false
		},

		UpdateFunc: func(e event.UpdateEvent) bool {
			resourceQtyComparer := cmp.Comparer(func(x, y resource.Quantity) bool { return x.Cmp(y) == 0 })
			if old, ok := e.ObjectOld.(*v1.ConfigMap); ok {
				if new, ok := e.ObjectNew.(*v1.ConfigMap); ok {
					if old.Name == opcontroller.OperatorSettingConfigMapName && new.Name == opcontroller.OperatorSettingConfigMapName {
						diff := cmp.Diff(old.Data, new.Data, resourceQtyComparer)
						logger.Debugf("operator configmap diff:\n %s", diff)
						return findCSIChange(diff)
					}
				}
			}

			return false
		},

		DeleteFunc: func(e event.DeleteEvent) bool {
			return false
		},

		GenericFunc: func(e event.GenericEvent) bool {
			return false
		},
	}
}

func findCSIChange(str string) bool {
	var re = regexp.MustCompile(`(?m)^(\+|-).*(\"ROOK_CSI_|\"CSI_).*,$`)
	found := re.FindAllString(str, -1)
	if len(found) > 0 {
		for _, match := range found {
			// logger.Debugf("ceph csi config changed with: %q", match)
			logger.Infof("ceph csi config changed with: %q", match)
		}
		return true
	}

	return false
}