/*
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 util

import (
	"context"
	"fmt"
	"os"
	"strings"

	apiv1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	clientset "k8s.io/client-go/kubernetes"
)

// ParseNameNS parses a string searching a namespace and name
func ParseNameNS(input string) (string, string, error) {
	nsName := strings.Split(input, "/")
	if len(nsName) != 2 {
		return "", "", fmt.Errorf("invalid format (namespace/name) found in '%v'", input)
	}

	return nsName[0], nsName[1], nil
}

// GetNodeIPOrName returns the IP address or the name of a node in the cluster
func GetNodeIPOrName(ctx context.Context, kubeClient clientset.Interface, name string) string {
	node, err := kubeClient.CoreV1().Nodes().Get(ctx, name, metav1.GetOptions{})
	if err != nil {
		return ""
	}

	ip := ""

	for _, address := range node.Status.Addresses {
		if address.Type == apiv1.NodeExternalIP {
			if address.Address != "" {
				ip = address.Address
				break
			}
		}
	}

	// Report the external IP address of the node
	if ip != "" {
		return ip
	}

	for _, address := range node.Status.Addresses {
		if address.Type == apiv1.NodeInternalIP {
			if address.Address != "" {
				ip = address.Address
				break
			}
		}
	}

	return ip
}

// PodInfo contains runtime information about the pod running the Ingres controller
type PodInfo struct {
	Name      string
	Namespace string
	NodeIP    string
	// Labels selectors of the running pod
	// This is used to search for other Ingress controller pods
	Labels map[string]string
}

// GetPodDetails returns runtime information about the pod:
// name, namespace and IP of the node where it is running
func GetPodDetails(ctx context.Context, kubeClient clientset.Interface) (*PodInfo, error) {
	podName := os.Getenv("POD_NAME")
	podNs := os.Getenv("POD_NAMESPACE")

	if podName == "" || podNs == "" {
		return nil, fmt.Errorf("unable to get POD information (missing POD_NAME or POD_NAMESPACE environment variable")
	}

	pod, _ := kubeClient.CoreV1().Pods(podNs).Get(ctx, podName, metav1.GetOptions{})
	if pod == nil {
		return nil, fmt.Errorf("unable to get POD information")
	}

	return &PodInfo{
		Name:      podName,
		Namespace: podNs,
		NodeIP:    GetNodeIPOrName(ctx, kubeClient, pod.Spec.NodeName),
		Labels:    pod.GetLabels(),
	}, nil
}