package main

import (
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"path/filepath"
	"sync"

	v1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/kubernetes"
	corev1 "k8s.io/client-go/kubernetes/typed/core/v1"
	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/client-go/util/homedir"
)

var (
	home       = homedir.HomeDir()
	kubeconfig = flag.String("kubeconfig", filepath.Join(home, ".kube", "config"), "(optional) absolute path to the kubeconfig file")
	namespace  = flag.String("namespace", "apps", "namespace for the pods")
	stream     = flag.Bool("stream", false, "if set, livestream logs")
)

func main() {
	flag.Parse()

	config, err := clientcmd.BuildConfigFromFlags("", *kubeconfig)
	if err != nil {
		panic(err)
	}

	clientset, err := kubernetes.NewForConfig(config)
	if err != nil {
		panic(err)
	}

	podsClient := clientset.CoreV1().Pods(*namespace)

	pods, err := podsClient.List(metav1.ListOptions{})
	if err != nil {
		panic(err)
	}

	var wg sync.WaitGroup
	wg.Add(len(pods.Items))

	for _, pod := range pods.Items {
		if len(pod.Spec.Containers) != 1 {
			wg.Add(len(pod.Spec.Containers) - 1)
		}

		for _, ctr := range pod.Spec.Containers {
			go dumpLogs(podsClient, &wg, pod.Name, ctr.Name)
		}
	}

	wg.Wait()
}

func dumpLogs(podsClient corev1.PodExpansion, wg *sync.WaitGroup, podName, ctrName string) {
	defer wg.Done()

	w := lineSplittingWriter{
		writer: prefixWriter(fmt.Sprintf("%25s | ", ctrName), os.Stdout),
	}

	req := podsClient.GetLogs(podName, &v1.PodLogOptions{
		Container: ctrName,
		Follow:    *stream,
	})

	st, err := req.Stream()
	if err != nil {
		log.Printf("can't get logs for pod %s container %s: %v", podName, ctrName, err)
		return
	}
	defer st.Close()

	io.Copy(w, st)
}