package algo

// Author: Weisen Pan
// Date: 2023-10-24


import (
	corev1 "k8s.io/api/core/v1"
)

// AffinityQueue is a data structure used to sort pods by Affinity.
type AffinityQueue struct {
	pods []*corev1.Pod
}

// NewAffinityQueue creates and returns a new AffinityQueue instance.
func NewAffinityQueue(pods []*corev1.Pod) *AffinityQueue {
	return &AffinityQueue{
		pods: pods,
	}
}

// Len returns the number of pods in the AffinityQueue.
func (aff *AffinityQueue) Len() int {
	return len(aff.pods)
}

// Swap swaps the positions of two pods in the AffinityQueue.
func (aff *AffinityQueue) Swap(i, j int) {
	aff.pods[i], aff.pods[j] = aff.pods[j], aff.pods[i]
}

// Less returns true if the pod at index 'i' has a non-nil NodeSelector.
func (aff *AffinityQueue) Less(i, j int) bool {
	return aff.pods[i].Spec.NodeSelector != nil
}