/*
Copyright 2017 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 monitoring

import (
	"fmt"
	"strings"

	gcm "google.golang.org/api/monitoring/v3"
	corev1 "k8s.io/api/core/v1"
	extensions "k8s.io/api/extensions/v1beta1"
	rbac "k8s.io/api/rbac/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/kubernetes/test/e2e/framework"
	"os/exec"
)

var (
	CustomMetricName    = "foo"
	UnusedMetricName    = "unused"
	CustomMetricValue   = int64(448)
	UnusedMetricValue   = int64(446)
	StackdriverExporter = "stackdriver-exporter"
	// HPAPermissions is a ClusterRoleBinding that grants unauthenticated user permissions granted for
	// HPA for testing purposes, i.e. it should grant permission to read custom metrics.
	HPAPermissions = &rbac.ClusterRoleBinding{
		ObjectMeta: metav1.ObjectMeta{
			Name: "custom-metrics-reader",
		},
		RoleRef: rbac.RoleRef{
			APIGroup: "rbac.authorization.k8s.io",
			Kind:     "ClusterRole",
			Name:     "system:controller:horizontal-pod-autoscaler",
		},
		Subjects: []rbac.Subject{
			{
				APIGroup: "rbac.authorization.k8s.io",
				Kind:     "Group",
				Name:     "system:unauthenticated",
			},
		},
	}
	StagingDeploymentsLocation = "https://raw.githubusercontent.com/GoogleCloudPlatform/k8s-stackdriver/master/custom-metrics-stackdriver-adapter/deploy/staging/"
	AdapterForOldResourceModel = "adapter_old_resource_model.yaml"
	AdapterForNewResourceModel = "adapter_new_resource_model.yaml"
	AdapterDefault             = AdapterForOldResourceModel
	ClusterAdminBinding        = "e2e-test-cluster-admin-binding"
)

// CustomMetricContainerSpec allows to specify a config for StackdriverExporterDeployment
// with multiple containers exporting different metrics.
type CustomMetricContainerSpec struct {
	Name        string
	MetricName  string
	MetricValue int64
}

// SimpleStackdriverExporterDeployment is a Deployment of simple application that exports a metric of
// fixed value to Stackdriver in a loop.
func SimpleStackdriverExporterDeployment(name, namespace string, replicas int32, metricValue int64) *extensions.Deployment {
	return StackdriverExporterDeployment(name, namespace, replicas,
		[]CustomMetricContainerSpec{
			{
				Name:        StackdriverExporter,
				MetricName:  CustomMetricName,
				MetricValue: metricValue,
			},
		})
}

// StackdriverExporterDeployment is a Deployment of an application that can expose
// an arbitrary amount of metrics of fixed value to Stackdriver in a loop. Each metric
// is exposed by a different container in one pod.
// The metric names and values are configured via the containers parameter.
func StackdriverExporterDeployment(name, namespace string, replicas int32, containers []CustomMetricContainerSpec) *extensions.Deployment {
	podSpec := corev1.PodSpec{Containers: []corev1.Container{}}
	for _, containerSpec := range containers {
		podSpec.Containers = append(podSpec.Containers, stackdriverExporterContainerSpec(containerSpec.Name, namespace, containerSpec.MetricName, containerSpec.MetricValue))
	}

	return &extensions.Deployment{
		ObjectMeta: metav1.ObjectMeta{
			Name:      name,
			Namespace: namespace,
		},
		Spec: extensions.DeploymentSpec{
			Selector: &metav1.LabelSelector{
				MatchLabels: map[string]string{"name": name},
			},
			Template: corev1.PodTemplateSpec{
				ObjectMeta: metav1.ObjectMeta{
					Labels: map[string]string{
						"name": name,
					},
				},
				Spec: podSpec,
			},
			Replicas: &replicas,
		},
	}
}

// StackdriverExporterPod is a Pod of simple application that exports a metric of fixed value to
// Stackdriver in a loop.
func StackdriverExporterPod(podName, namespace, podLabel, metricName string, metricValue int64) *corev1.Pod {
	return &corev1.Pod{
		ObjectMeta: metav1.ObjectMeta{
			Name:      podName,
			Namespace: namespace,
			Labels: map[string]string{
				"name": podLabel,
			},
		},
		Spec: corev1.PodSpec{
			Containers: []corev1.Container{stackdriverExporterContainerSpec(StackdriverExporter, namespace, metricName, metricValue)},
		},
	}
}

func stackdriverExporterContainerSpec(name string, namespace string, metricName string, metricValue int64) corev1.Container {
	return corev1.Container{
		Name:            name,
		Image:           "k8s.gcr.io/sd-dummy-exporter:v0.2.0",
		ImagePullPolicy: corev1.PullPolicy("Always"),
		Command: []string{
			"/bin/sh",
			"-c",
			strings.Join([]string{
				"./sd_dummy_exporter",
				"--pod-id=$(POD_ID)",
				"--pod-name=$(POD_NAME)",
				"--namespace=" + namespace,
				"--metric-name=" + metricName,
				fmt.Sprintf("--metric-value=%v", metricValue),
				"--use-old-resource-model",
				"--use-new-resource-model",
			}, " "),
		},
		Env: []corev1.EnvVar{
			{
				Name: "POD_ID",
				ValueFrom: &corev1.EnvVarSource{
					FieldRef: &corev1.ObjectFieldSelector{
						FieldPath: "metadata.uid",
					},
				},
			},
			{
				Name: "POD_NAME",
				ValueFrom: &corev1.EnvVarSource{
					FieldRef: &corev1.ObjectFieldSelector{
						FieldPath: "metadata.name",
					},
				},
			},
		},
		Ports: []corev1.ContainerPort{{ContainerPort: 80}},
	}
}

// PrometheusExporterDeployment is a Deployment of simple application with two containers
// one exposing a metric in prometheus format and second a prometheus-to-sd container
// that scrapes the metric and pushes it to stackdriver.
func PrometheusExporterDeployment(name, namespace string, replicas int32, metricValue int64) *extensions.Deployment {
	return &extensions.Deployment{
		ObjectMeta: metav1.ObjectMeta{
			Name:      name,
			Namespace: namespace,
		},
		Spec: extensions.DeploymentSpec{
			Selector: &metav1.LabelSelector{
				MatchLabels: map[string]string{"name": name},
			},
			Template: corev1.PodTemplateSpec{
				ObjectMeta: metav1.ObjectMeta{
					Labels: map[string]string{
						"name": name,
					},
				},
				Spec: prometheusExporterPodSpec(CustomMetricName, metricValue, 8080),
			},
			Replicas: &replicas,
		},
	}
}

func prometheusExporterPodSpec(metricName string, metricValue int64, port int32) corev1.PodSpec {
	return corev1.PodSpec{
		Containers: []corev1.Container{
			{
				Name:            "prometheus-exporter",
				Image:           "k8s.gcr.io/prometheus-dummy-exporter:v0.1.0",
				ImagePullPolicy: corev1.PullPolicy("Always"),
				Command: []string{"/prometheus_dummy_exporter", "--metric-name=" + metricName,
					fmt.Sprintf("--metric-value=%v", metricValue), fmt.Sprintf("=--port=%d", port)},
				Ports: []corev1.ContainerPort{{ContainerPort: port}},
			},
			{
				Name:            "prometheus-to-sd",
				Image:           "k8s.gcr.io/prometheus-to-sd:v0.3.1",
				ImagePullPolicy: corev1.PullPolicy("Always"),
				Command: []string{"/monitor", fmt.Sprintf("--source=:http://localhost:%d", port),
					"--stackdriver-prefix=custom.googleapis.com", "--pod-id=$(POD_ID)", "--namespace-id=$(POD_NAMESPACE)"},
				Env: []corev1.EnvVar{
					{
						Name: "POD_ID",
						ValueFrom: &corev1.EnvVarSource{
							FieldRef: &corev1.ObjectFieldSelector{
								FieldPath: "metadata.uid",
							},
						},
					},
					{
						Name: "POD_NAMESPACE",
						ValueFrom: &corev1.EnvVarSource{
							FieldRef: &corev1.ObjectFieldSelector{
								FieldPath: "metadata.namespace",
							},
						},
					},
				},
			},
		},
	}
}

// CreateAdapter creates Custom Metrics - Stackdriver adapter
// adapterDeploymentFile should be a filename for adapter deployment located in StagingDeploymentLocation
func CreateAdapter(adapterDeploymentFile string) error {
	// A workaround to make the work on GKE. GKE doesn't normally allow to create cluster roles,
	// which the adapter deployment does. The solution is to create cluster role binding for
	// cluster-admin role and currently used service account.
	err := createClusterAdminBinding()
	if err != nil {
		return err
	}
	adapterURL := StagingDeploymentsLocation + adapterDeploymentFile
	err = exec.Command("wget", adapterURL).Run()
	if err != nil {
		return err
	}
	stat, err := framework.RunKubectl("create", "-f", adapterURL)
	framework.Logf(stat)
	return err
}

func createClusterAdminBinding() error {
	stdout, stderr, err := framework.RunCmd("gcloud", "config", "get-value", "core/account")
	if err != nil {
		framework.Logf(stderr)
		return err
	}
	serviceAccount := strings.TrimSpace(stdout)
	framework.Logf("current service account: %q", serviceAccount)
	stat, err := framework.RunKubectl("create", "clusterrolebinding", ClusterAdminBinding, "--clusterrole=cluster-admin", "--user="+serviceAccount)
	framework.Logf(stat)
	return err
}

// CreateDescriptors creates descriptors for metrics: CustomMetricName and UnusedMetricName.
func CreateDescriptors(service *gcm.Service, projectId string) error {
	_, err := service.Projects.MetricDescriptors.Create(fmt.Sprintf("projects/%s", projectId), &gcm.MetricDescriptor{
		Name:       CustomMetricName,
		ValueType:  "INT64",
		Type:       "custom.googleapis.com/" + CustomMetricName,
		MetricKind: "GAUGE",
	}).Do()
	if err != nil {
		return err
	}
	_, err = service.Projects.MetricDescriptors.Create(fmt.Sprintf("projects/%s", projectId), &gcm.MetricDescriptor{
		Name:       UnusedMetricName,
		ValueType:  "INT64",
		Type:       "custom.googleapis.com/" + UnusedMetricName,
		MetricKind: "GAUGE",
	}).Do()
	return err
}

// CleanupDescriptors deletes descriptors for metrics: CustomMetricName and UnusedMetricName.
// TODO: Cleanup time series as well
func CleanupDescriptors(service *gcm.Service, projectId string) {
	_, err := service.Projects.MetricDescriptors.Delete(fmt.Sprintf("projects/%s/metricDescriptors/custom.googleapis.com/%s", projectId, CustomMetricName)).Do()
	if err != nil {
		framework.Logf("Failed to delete descriptor for metric '%s': %v", CustomMetricName, err)
	}
	_, err = service.Projects.MetricDescriptors.Delete(fmt.Sprintf("projects/%s/metricDescriptors/custom.googleapis.com/%s", projectId, UnusedMetricName)).Do()
	if err != nil {
		framework.Logf("Failed to delete descriptor for metric '%s': %v", CustomMetricName, err)
	}
}

// CleanupAdapter deletes Custom Metrics - Stackdriver adapter deployments.
func CleanupAdapter(adapterDeploymentFile string) {
	stat, err := framework.RunKubectl("delete", "-f", adapterDeploymentFile)
	framework.Logf(stat)
	if err != nil {
		framework.Logf("Failed to delete adapter deployments: %s", err)
	}
	err = exec.Command("rm", adapterDeploymentFile).Run()
	if err != nil {
		framework.Logf("Failed to delete adapter deployment file: %s", err)
	}
	cleanupClusterAdminBinding()
}

func cleanupClusterAdminBinding() {
	stat, err := framework.RunKubectl("delete", "clusterrolebinding", ClusterAdminBinding)
	framework.Logf(stat)
	if err != nil {
		framework.Logf("Failed to delete cluster admin binding: %s", err)
	}
}