/*
Copyright 2018 The Kubernetes Authors.

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 nodegroupset

import (
	"fmt"

	"k8s.io/autoscaler/cluster-autoscaler/cloudprovider"
	"k8s.io/autoscaler/cluster-autoscaler/config"
	"k8s.io/autoscaler/cluster-autoscaler/context"
	"k8s.io/autoscaler/cluster-autoscaler/utils/errors"
	schedulerframework "k8s.io/kubernetes/pkg/scheduler/framework"
)

// ScaleUpInfo contains information about planned scale-up of a single NodeGroup
type ScaleUpInfo struct {
	// Group is the group to be scaled-up
	Group cloudprovider.NodeGroup
	// CurrentSize is the current size of the Group
	CurrentSize int
	// NewSize is the size the Group will be scaled-up to
	NewSize int
	// MaxSize is the maximum allowed size of the Group
	MaxSize int
}

// String is used for printing ScaleUpInfo for logging, etc
func (s ScaleUpInfo) String() string {
	return fmt.Sprintf("{%v %v->%v (max: %v)}", s.Group.Id(), s.CurrentSize, s.NewSize, s.MaxSize)
}

// NodeGroupSetProcessor finds nodegroups that are similar and allows balancing scale-up between them.
type NodeGroupSetProcessor interface {
	FindSimilarNodeGroups(context *context.AutoscalingContext, nodeGroup cloudprovider.NodeGroup,
		nodeInfosForGroups map[string]*schedulerframework.NodeInfo) ([]cloudprovider.NodeGroup, errors.AutoscalerError)

	BalanceScaleUpBetweenGroups(context *context.AutoscalingContext, groups []cloudprovider.NodeGroup, newNodes int) ([]ScaleUpInfo, errors.AutoscalerError)
	CleanUp()
}

// NoOpNodeGroupSetProcessor returns no similar node groups and doesn't do any balancing.
type NoOpNodeGroupSetProcessor struct {
}

// FindSimilarNodeGroups returns a list of NodeGroups similar to the one provided in parameter.
func (n *NoOpNodeGroupSetProcessor) FindSimilarNodeGroups(context *context.AutoscalingContext, nodeGroup cloudprovider.NodeGroup,
	nodeInfosForGroups map[string]*schedulerframework.NodeInfo) ([]cloudprovider.NodeGroup, errors.AutoscalerError) {
	return []cloudprovider.NodeGroup{}, nil
}

// BalanceScaleUpBetweenGroups splits a scale-up between provided NodeGroups.
func (n *NoOpNodeGroupSetProcessor) BalanceScaleUpBetweenGroups(context *context.AutoscalingContext, groups []cloudprovider.NodeGroup, newNodes int) ([]ScaleUpInfo, errors.AutoscalerError) {
	return []ScaleUpInfo{}, nil
}

// CleanUp performs final clean up of processor state.
func (n *NoOpNodeGroupSetProcessor) CleanUp() {}

// NewDefaultNodeGroupSetProcessor creates an instance of NodeGroupSetProcessor.
func NewDefaultNodeGroupSetProcessor(ignoredLabels []string, ratioOpts config.NodeGroupDifferenceRatios) NodeGroupSetProcessor {
	return &BalancingNodeGroupSetProcessor{
		Comparator: CreateGenericNodeInfoComparator(ignoredLabels, ratioOpts),
	}
}