package oci

import "sort"

// History is a convenience type for storing a list of containers,
// sorted by creation date in descendant order.
type History []*Container

// Len returns the number of containers in the history.
func (history *History) Len() int {
	return len(*history)
}

// Less compares two containers and returns true if the second one
// was created before the first one.
func (history *History) Less(i, j int) bool {
	containers := *history
	// FIXME: state access should be serialized
	return containers[j].state.Created.Before(containers[i].state.Created)
}

// Swap switches containers i and j positions in the history.
func (history *History) Swap(i, j int) {
	containers := *history
	containers[i], containers[j] = containers[j], containers[i]
}

// sort orders the history by creation date in descendant order.
func (history *History) sort() {
	sort.Sort(history)
}
