/*
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 (
	"bytes"
	"context"
	"fmt"
	"net/http"
	"time"

	v1 "k8s.io/api/core/v1"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/kubernetes/scheme"
	restclient "k8s.io/client-go/rest"
	"k8s.io/client-go/tools/remotecommand"
)

const (
	// How often to poll for conditions.
	Poll = 2 * time.Second
)

// CreateKubeNamespace creates a new Kubernetes Namespace for a test.
func CreateKubeNamespace(baseName string, kubeClientSet kubernetes.Interface) (*v1.Namespace, error) {
	ns := &v1.Namespace{
		ObjectMeta: metav1.ObjectMeta{
			GenerateName: fmt.Sprintf("e2e-tests-%v-", baseName),
		},
	}

	return kubeClientSet.CoreV1().Namespaces().Create(context.TODO(), ns, metav1.CreateOptions{})
}

// DeleteKubeNamespace will delete a namespace resource.
func DeleteKubeNamespace(namespace string, kubeClientSet kubernetes.Interface) error {
	return kubeClientSet.CoreV1().Namespaces().Delete(context.TODO(), namespace, metav1.DeleteOptions{})
}

// WaitForKubeNamespaceNotExist will wait for the namespace with the given name
// to not exist for up to 2 minutes.
func WaitForKubeNamespaceNotExist(namespace string, kubeClientSet kubernetes.Interface) error {
	return wait.PollImmediate(Poll, time.Minute*2, namespaceNotExist(kubeClientSet, namespace))
}

func namespaceNotExist(c kubernetes.Interface, namespace string) wait.ConditionFunc {
	return func() (bool, error) {
		_, err := c.CoreV1().Namespaces().Get(context.TODO(), namespace, metav1.GetOptions{})
		if apierrors.IsNotFound(err) {
			return true, nil
		}
		if err != nil {
			return false, err
		}
		return false, nil
	}
}

// ExecCmd exec command on specific pod and wait the command's output.
func ExecCmd(client kubernetes.Interface, config *restclient.Config, podName, namespace string,
	command string) (string, error) {
	cmd := []string{
		"sh",
		"-c",
		command,
	}

	req := client.CoreV1().RESTClient().Post().Resource("pods").Name(podName).
		Namespace(namespace).SubResource("exec")
	option := &v1.PodExecOptions{
		Command: cmd,
		Stdin:   false,
		Stdout:  true,
		Stderr:  true,
		TTY:     false,
	}
	req.VersionedParams(
		option,
		scheme.ParameterCodec,
	)
	exec, err := remotecommand.NewSPDYExecutor(config, "POST", req.URL())
	if err != nil {
		return "", err
	}
	var stdout, stderr bytes.Buffer
	err = exec.Stream(remotecommand.StreamOptions{
		Stdout: &stdout,
		Stderr: &stderr,
		Tty:    false,
	})
	if err != nil {
		return "", fmt.Errorf("unable to exec stream: %w: \n%s\n%s", err, stdout.String(), stderr.String())
	}

	return stdout.String() + stderr.String(), nil
}

// WaitForPodsRunning waits for a given amount of time until a group of Pods is running in the given namespace.
func WaitForPodsRunning(kubeClientSet kubernetes.Interface, expectedReplicas int, namespace string, opts metav1.ListOptions) (*v1.PodList, error) {
	var pods *v1.PodList
	err := wait.PollImmediate(1*time.Second, time.Minute*5, func() (bool, error) {
		pl, err := kubeClientSet.CoreV1().Pods(namespace).List(context.TODO(), opts)
		if err != nil {
			return false, nil
		}

		r := 0
		for i := range pl.Items {
			if pl.Items[i].Status.Phase == v1.PodRunning {
				r++
			}
		}

		if r == expectedReplicas {
			pods = pl
			return true, nil
		}

		return false, nil
	})
	return pods, err
}

// WaitForPodsReady waits for a given amount of time until a group of Pods is running in the given namespace.
func WaitForPodsReady(kubeClientSet kubernetes.Interface, expectedReplicas int, namespace string, opts metav1.ListOptions) error {
	return wait.PollImmediate(1*time.Second, time.Minute*5, func() (bool, error) {
		pl, err := kubeClientSet.CoreV1().Pods(namespace).List(context.TODO(), opts)
		if err != nil {
			return false, nil
		}

		r := 0
		for i := range pl.Items {
			if isRunning, _ := podRunningReady(&pl.Items[i]); isRunning {
				r++
			}
		}

		if r == expectedReplicas {
			return true, nil
		}

		return false, nil
	})
}

// podRunningReady checks whether pod p's phase is running and it has a ready
// condition of status true.
func podRunningReady(p *v1.Pod) (bool, error) {
	// Check the phase is running.
	if p.Status.Phase != v1.PodRunning {
		return false, fmt.Errorf("want pod '%s' on '%s' to be '%v' but was '%v'",
			p.ObjectMeta.Name, p.Spec.NodeName, v1.PodRunning, p.Status.Phase)
	}
	// Check the ready condition is true.

	if !isPodReady(p) {
		return false, fmt.Errorf("pod '%s' on '%s' didn't have condition {%v %v}; conditions: %v",
			p.ObjectMeta.Name, p.Spec.NodeName, v1.PodReady, v1.ConditionTrue, p.Status.Conditions)
	}
	return true, nil
}

func isPodReady(p *v1.Pod) bool {
	for _, condition := range p.Status.Conditions {
		if condition.Type != v1.ContainersReady {
			continue
		}

		return condition.Status == v1.ConditionTrue
	}

	return false
}

// WaitForURL tests the provided url. Once a http 200 is returned the func returns with no error.
// Timeout is 5min.
func WaitForURL(url string) error {
	return wait.PollImmediate(2*time.Second, time.Minute*5, func() (bool, error) {
		req, err := http.NewRequest(http.MethodGet, url, nil)
		if err != nil {
			return false, nil
		}
		res, err := http.DefaultClient.Do(req)
		if err != nil {
			return false, nil
		}
		defer res.Body.Close()
		if res.StatusCode == http.StatusOK {
			return true, nil
		}
		return false, err
	})
}