// Unless explicitly stated otherwise all files in this repository are licensed
// under the Apache License Version 2.0.
// This product includes software developed at Datadog (https://www.datadoghq.com/).
// Copyright 2016-2019 Datadog, Inc.

/*
Copyright 2015 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 pod

import (
	"sort"
	"time"

	v1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"

	"github.com/datadog/extendeddaemonset/pkg/controller/utils/affinity"
)

// GetContainerStatus extracts the status of container "name" from "statuses".
// It also returns if "name" exists.
func GetContainerStatus(statuses []v1.ContainerStatus, name string) (v1.ContainerStatus, bool) {
	for i := range statuses {
		if statuses[i].Name == name {
			return statuses[i], true
		}
	}
	return v1.ContainerStatus{}, false
}

// GetExistingContainerStatus extracts the status of container "name" from "statuses",
// It also returns if "name" exists.
func GetExistingContainerStatus(statuses []v1.ContainerStatus, name string) v1.ContainerStatus {
	status, _ := GetContainerStatus(statuses, name)
	return status
}

// IsPodScheduled return true if it is already assigned to a Node
func IsPodScheduled(pod *v1.Pod) (string, bool) {
	isScheduled := pod.Spec.NodeName != ""
	nodeName := affinity.GetNodeNameFromAffinity(pod.Spec.Affinity)
	return nodeName, isScheduled
}

// IsPodAvailable returns true if a pod is available; false otherwise.
// Precondition for an available pod is that it must be ready. On top
// of that, there are two cases when a pod can be considered available:
// 1. minReadySeconds == 0, or
// 2. LastTransitionTime (is set) + minReadySeconds < current time
func IsPodAvailable(pod *v1.Pod, minReadySeconds int32, now metav1.Time) bool {
	if IsPodReady(pod) {
		return true
	}

	c := GetPodReadyCondition(pod.Status)
	minReadySecondsDuration := time.Duration(minReadySeconds) * time.Second
	if minReadySeconds == 0 || !c.LastTransitionTime.IsZero() && c.LastTransitionTime.Add(minReadySecondsDuration).Before(now.Time) {
		return true
	}
	return false
}

// IsPodReady returns true if a pod is ready; false otherwise.
func IsPodReady(pod *v1.Pod) bool {
	return IsPodReadyConditionTrue(pod.Status)
}

// IsPodReadyConditionTrue returns true if a pod is ready; false otherwise.
func IsPodReadyConditionTrue(status v1.PodStatus) bool {
	condition := GetPodReadyCondition(status)
	return condition != nil && condition.Status == v1.ConditionTrue
}

// GetPodReadyCondition extracts the pod ready condition from the given status and returns that.
// Returns nil if the condition is not present.
func GetPodReadyCondition(status v1.PodStatus) *v1.PodCondition {
	_, condition := GetPodCondition(&status, v1.PodReady)
	return condition
}

// GetPodCondition extracts the provided condition from the given status and returns that.
// Returns nil and -1 if the condition is not present, and the index of the located condition.
func GetPodCondition(status *v1.PodStatus, conditionType v1.PodConditionType) (int, *v1.PodCondition) {
	if status == nil {
		return -1, nil
	}
	return GetPodConditionFromList(status.Conditions, conditionType)
}

// GetPodConditionFromList extracts the provided condition from the given list of condition and
// returns the index of the condition and the condition. Returns -1 and nil if the condition is not present.
func GetPodConditionFromList(conditions []v1.PodCondition, conditionType v1.PodConditionType) (int, *v1.PodCondition) {
	if conditions == nil {
		return -1, nil
	}
	for i := range conditions {
		if conditions[i].Type == conditionType {
			return i, &conditions[i]
		}
	}
	return -1, nil
}

// HasPodSchedulerIssue returns true if a pod remained unscheduled for more than 10 minutes
// or if it stayed in `Terminating` state for longer than its grace period.
func HasPodSchedulerIssue(pod *v1.Pod) bool {
	_, isScheduled := IsPodScheduled(pod)
	if !isScheduled && pod.CreationTimestamp.Add(10*time.Minute).Before(time.Now()) {
		return true
	}

	if pod.DeletionTimestamp != nil && pod.DeletionGracePeriodSeconds != nil &&
		pod.DeletionTimestamp.Add(time.Duration(*pod.DeletionGracePeriodSeconds)*time.Second).Before(time.Now()) {
		return true
	}

	return false
}

// UpdatePodCondition updates existing pod condition or creates a new one. Sets LastTransitionTime to now if the
// status has changed.
// Returns true if pod condition has changed or has been added.
func UpdatePodCondition(status *v1.PodStatus, condition *v1.PodCondition) bool {
	condition.LastTransitionTime = metav1.Now()
	// Try to find this pod condition.
	conditionIndex, oldCondition := GetPodCondition(status, condition.Type)

	if oldCondition == nil {
		// We are adding new pod condition.
		status.Conditions = append(status.Conditions, *condition)
		return true
	}
	// We are updating an existing condition, so we need to check if it has changed.
	if condition.Status == oldCondition.Status {
		condition.LastTransitionTime = oldCondition.LastTransitionTime
	}

	isEqual := condition.Status == oldCondition.Status &&
		condition.Reason == oldCondition.Reason &&
		condition.Message == oldCondition.Message &&
		condition.LastProbeTime.Equal(&oldCondition.LastProbeTime) &&
		condition.LastTransitionTime.Equal(&oldCondition.LastTransitionTime)

	status.Conditions[conditionIndex] = *condition
	// Return true if one of the fields have changed.
	return !isEqual
}

// IsEvicted returns whether the status corresponds to an evicted pod
func IsEvicted(status *v1.PodStatus) bool {
	if status.Phase == v1.PodFailed && status.Reason == "Evicted" {
		return true
	}
	return false
}

// SortPodByCreationTime return the pods sorted by creation time
// from the newer to the older
func SortPodByCreationTime(pods []*v1.Pod) []*v1.Pod {
	sort.Sort(podByCreationTimestamp(pods))
	return pods
}

type podByCreationTimestamp []*v1.Pod

func (o podByCreationTimestamp) Len() int      { return len(o) }
func (o podByCreationTimestamp) Swap(i, j int) { o[i], o[j] = o[j], o[i] }

func (o podByCreationTimestamp) Less(i, j int) bool {
	if o[i].CreationTimestamp.Equal(&o[j].CreationTimestamp) {
		return o[i].Name > o[j].Name
	}
	return o[j].CreationTimestamp.Before(&o[i].CreationTimestamp)
}
