/*
Copyright 2021 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 apiserver

import (
	"context"
	"encoding/json"
	"fmt"
	"path"
	"strings"
	"testing"

	apierrors "k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/api/meta"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/apimachinery/pkg/util/managedfields"
	clientset "k8s.io/client-go/kubernetes"
	"k8s.io/client-go/kubernetes/scheme"
	deploymentstorage "k8s.io/kubernetes/pkg/registry/apps/deployment/storage"
	replicasetstorage "k8s.io/kubernetes/pkg/registry/apps/replicaset/storage"
	statefulsetstorage "k8s.io/kubernetes/pkg/registry/apps/statefulset/storage"
	replicationcontrollerstorage "k8s.io/kubernetes/pkg/registry/core/replicationcontroller/storage"
)

type scaleTest struct {
	kind     string
	resource string
	path     string
	validObj string
}

func TestScaleAllResources(t *testing.T) {
	client, closeFn := setup(t)
	defer closeFn()

	tests := []scaleTest{
		{
			kind:     "Deployment",
			resource: "deployments",
			path:     "/apis/apps/v1",
			validObj: validAppsV1("Deployment"),
		},
		{
			kind:     "StatefulSet",
			resource: "statefulsets",
			path:     "/apis/apps/v1",
			validObj: validAppsV1("StatefulSet"),
		},
		{
			kind:     "ReplicaSet",
			resource: "replicasets",
			path:     "/apis/apps/v1",
			validObj: validAppsV1("ReplicaSet"),
		},
		{
			kind:     "ReplicationController",
			resource: "replicationcontrollers",
			path:     "/api/v1",
			validObj: validV1ReplicationController(),
		},
	}

	for _, test := range tests {
		t.Run(test.kind, func(t *testing.T) {
			validObject := []byte(test.validObj)

			// Create the object
			_, err := client.CoreV1().RESTClient().Patch(types.ApplyPatchType).
				AbsPath(test.path).
				Namespace("default").
				Resource(test.resource).
				Name("test").
				Param("fieldManager", "apply_test").
				Body(validObject).
				Do(context.TODO()).Get()
			if err != nil {
				t.Fatalf("Failed to create object using apply: %v", err)
			}
			obj := retrieveObject(t, client, test.path, test.resource)
			assertReplicasValue(t, obj, 1)
			assertReplicasOwnership(t, obj, "apply_test")

			// Call scale subresource to update replicas
			_, err = client.CoreV1().RESTClient().
				Patch(types.MergePatchType).
				AbsPath(test.path).
				Namespace("default").
				Resource(test.resource).
				Name("test").
				SubResource("scale").
				Param("fieldManager", "scale_test").
				Body([]byte(`{"spec":{"replicas": 5}}`)).
				Do(context.TODO()).Get()
			if err != nil {
				t.Fatalf("Failed to scale object: %v", err)
			}
			obj = retrieveObject(t, client, test.path, test.resource)
			assertReplicasValue(t, obj, 5)
			assertReplicasOwnership(t, obj, "scale_test")

			// Re-apply the original object, it should fail with conflict because replicas have changed
			_, err = client.CoreV1().RESTClient().Patch(types.ApplyPatchType).
				AbsPath(test.path).
				Namespace("default").
				Resource(test.resource).
				Name("test").
				Param("fieldManager", "apply_test").
				Body(validObject).
				Do(context.TODO()).Get()
			if !apierrors.IsConflict(err) {
				t.Fatalf("Expected conflict when re-applying the original object, but got: %v", err)
			}

			// Re-apply forcing the changes should succeed
			_, err = client.CoreV1().RESTClient().Patch(types.ApplyPatchType).
				AbsPath(test.path).
				Namespace("default").
				Resource(test.resource).
				Name("test").
				Param("fieldManager", "apply_test").
				Param("force", "true").
				Body(validObject).
				Do(context.TODO()).Get()
			if err != nil {
				t.Fatalf("Error force-updating: %v", err)
			}
			obj = retrieveObject(t, client, test.path, test.resource)
			assertReplicasValue(t, obj, 1)
			assertReplicasOwnership(t, obj, "apply_test")

			// Run "Apply" with a scale object with a different number of replicas. It should generate a conflict.
			_, err = client.CoreV1().RESTClient().Patch(types.ApplyPatchType).
				AbsPath(test.path).
				Namespace("default").
				Resource(test.resource).
				SubResource("scale").
				Name("test").
				Param("fieldManager", "apply_scale").
				Body([]byte(`{"kind":"Scale","apiVersion":"autoscaling/v1","metadata":{"name":"test","namespace":"default"},"spec":{"replicas":17}}`)).
				Do(context.TODO()).Get()
			if !apierrors.IsConflict(err) {
				t.Fatalf("Expected conflict error but got: %v", err)
			}
			if !strings.Contains(err.Error(), "apply_test") {
				t.Fatalf("Expected conflict with `apply_test` manager when but got: %v", err)
			}

			// Same as before but force. Only the new manager should own .spec.replicas
			_, err = client.CoreV1().RESTClient().Patch(types.ApplyPatchType).
				AbsPath(test.path).
				Namespace("default").
				Resource(test.resource).
				SubResource("scale").
				Name("test").
				Param("fieldManager", "apply_scale").
				Param("force", "true").
				Body([]byte(`{"kind":"Scale","apiVersion":"autoscaling/v1","metadata":{"name":"test","namespace":"default"},"spec":{"replicas":17}}`)).
				Do(context.TODO()).Get()
			if err != nil {
				t.Fatalf("Error updating object by applying scale and forcing: %v ", err)
			}
			obj = retrieveObject(t, client, test.path, test.resource)
			assertReplicasValue(t, obj, 17)
			assertReplicasOwnership(t, obj, "apply_scale")

			// Replace scale object
			_, err = client.CoreV1().RESTClient().Put().
				AbsPath(test.path).
				Namespace("default").
				Resource(test.resource).
				SubResource("scale").
				Name("test").
				Param("fieldManager", "replace_test").
				Body([]byte(`{"kind":"Scale","apiVersion":"autoscaling/v1","metadata":{"name":"test","namespace":"default"},"spec":{"replicas":7}}`)).
				Do(context.TODO()).Get()
			if err != nil {
				t.Fatalf("Error replacing object: %v", err)
			}
			obj = retrieveObject(t, client, test.path, test.resource)
			assertReplicasValue(t, obj, 7)
			assertReplicasOwnership(t, obj, "replace_test")

			// Apply the same number of replicas, both managers should own the field
			_, err = client.CoreV1().RESTClient().Patch(types.ApplyPatchType).
				AbsPath(test.path).
				Namespace("default").
				Resource(test.resource).
				SubResource("scale").
				Name("test").
				Param("fieldManager", "co_owning_test").
				Body([]byte(`{"kind":"Scale","apiVersion":"autoscaling/v1","metadata":{"name":"test","namespace":"default"},"spec":{"replicas":7}}`)).
				Do(context.TODO()).Get()
			if err != nil {
				t.Fatalf("Error updating object: %v", err)
			}
			obj = retrieveObject(t, client, test.path, test.resource)
			assertReplicasValue(t, obj, 7)
			assertReplicasOwnership(t, obj, "replace_test", "co_owning_test")

			// Scaling again should make this manager the only owner of replicas
			_, err = client.CoreV1().RESTClient().Patch(types.MergePatchType).
				AbsPath(test.path).
				Namespace("default").
				Resource(test.resource).
				SubResource("scale").
				Name("test").
				Param("fieldManager", "scale_test").
				Body([]byte(`{"spec":{"replicas": 5}}`)).
				Do(context.TODO()).Get()
			if err != nil {
				t.Fatalf("Error scaling object: %v", err)
			}
			obj = retrieveObject(t, client, test.path, test.resource)
			assertReplicasValue(t, obj, 5)
			assertReplicasOwnership(t, obj, "scale_test")
		})
	}
}

func TestScaleUpdateOnlyStatus(t *testing.T) {
	client, closeFn := setup(t)
	defer closeFn()

	resource := "deployments"
	path := "/apis/apps/v1"
	validObject := []byte(validAppsV1("Deployment"))

	// Create the object
	_, err := client.CoreV1().RESTClient().Patch(types.ApplyPatchType).
		AbsPath(path).
		Namespace("default").
		Resource(resource).
		Name("test").
		Param("fieldManager", "apply_test").
		Body(validObject).
		Do(context.TODO()).Get()
	if err != nil {
		t.Fatalf("Failed to create object using apply: %v", err)
	}
	obj := retrieveObject(t, client, path, resource)
	assertReplicasValue(t, obj, 1)
	assertReplicasOwnership(t, obj, "apply_test")

	// Call scale subresource to update replicas
	_, err = client.CoreV1().RESTClient().
		Patch(types.MergePatchType).
		AbsPath(path).
		Namespace("default").
		Resource(resource).
		Name("test").
		SubResource("scale").
		Param("fieldManager", "scale_test").
		Body([]byte(`{"status":{"replicas": 42}}`)).
		Do(context.TODO()).Get()
	if err != nil {
		t.Fatalf("Failed to scale object: %v", err)
	}
	obj = retrieveObject(t, client, path, resource)
	assertReplicasValue(t, obj, 1)
	assertReplicasOwnership(t, obj, "apply_test")
}

func TestAllKnownVersionsAreInMappings(t *testing.T) {
	cases := []struct {
		groupKind schema.GroupKind
		mappings  managedfields.ResourcePathMappings
	}{
		{
			groupKind: schema.GroupKind{Group: "apps", Kind: "ReplicaSet"},
			mappings:  replicasetstorage.ReplicasPathMappings(),
		},
		{
			groupKind: schema.GroupKind{Group: "apps", Kind: "StatefulSet"},
			mappings:  statefulsetstorage.ReplicasPathMappings(),
		},
		{
			groupKind: schema.GroupKind{Group: "apps", Kind: "Deployment"},
			mappings:  deploymentstorage.ReplicasPathMappings(),
		},
		{
			groupKind: schema.GroupKind{Group: "", Kind: "ReplicationController"},
			mappings:  replicationcontrollerstorage.ReplicasPathMappings(),
		},
	}
	for _, c := range cases {
		knownVersions := scheme.Scheme.VersionsForGroupKind(c.groupKind)
		for _, version := range knownVersions {
			if _, ok := c.mappings[version.String()]; !ok {
				t.Errorf("missing version %v for %v mappings", version, c.groupKind)
			}
		}

		if len(knownVersions) != len(c.mappings) {
			t.Errorf("%v mappings has extra items: %v vs %v", c.groupKind, c.mappings, knownVersions)
		}
	}
}

func validAppsV1(kind string) string {
	return fmt.Sprintf(`{
	    "apiVersion": "apps/v1",
	    "kind": "%s",
	    "metadata": {
	      "name": "test"
	    },
	    "spec": {
	      "replicas": 1,
	      "selector": {
	        "matchLabels": {
	           "app": "nginx"
	        }
	      },
	      "template": {
	        "metadata": {
	          "labels": {
	            "app": "nginx"
	          }
	        },
	        "spec": {
	          "containers": [{
	            "name":  "nginx",
	            "image": "nginx:latest"
	          }]
	        }
	      }
	    }
	  }`, kind)
}

func validV1ReplicationController() string {
	return `{
	    "apiVersion": "v1",
	    "kind": "ReplicationController",
	    "metadata": {
	      "name": "test"
	    },
	    "spec": {
	      "replicas": 1,
	      "selector": {
          "app": "nginx"
	      },
	      "template": {
	        "metadata": {
	          "labels": {
	            "app": "nginx"
	          }
	        },
	        "spec": {
	          "containers": [{
	            "name":  "nginx",
	            "image": "nginx:latest"
	          }]
	        }
	      }
	    }
	  }`
}

func retrieveObject(t *testing.T, client clientset.Interface, prefix, resource string) *unstructured.Unstructured {
	t.Helper()

	urlPath := path.Join(prefix, "namespaces", "default", resource, "test")
	bytes, err := client.CoreV1().RESTClient().Get().AbsPath(urlPath).DoRaw(context.TODO())
	if err != nil {
		t.Fatalf("Failed to retrieve object: %v", err)
	}
	obj := &unstructured.Unstructured{}
	if err := json.Unmarshal(bytes, obj); err != nil {
		t.Fatalf("Error unmarshalling the retrieved object: %v", err)
	}
	return obj
}

func assertReplicasValue(t *testing.T, obj *unstructured.Unstructured, value int) {
	actualValue, found, err := unstructured.NestedInt64(obj.Object, "spec", "replicas")

	if err != nil {
		t.Fatalf("Error when retrieving replicas field: %v", err)
	}
	if !found {
		t.Fatalf("Replicas field not found")
	}

	if int(actualValue) != value {
		t.Fatalf("Expected replicas field value to be %d but got %d", value, actualValue)
	}
}

func assertReplicasOwnership(t *testing.T, obj *unstructured.Unstructured, fieldManagers ...string) {
	t.Helper()

	accessor, err := meta.Accessor(obj)
	if err != nil {
		t.Fatalf("Failed to get meta accessor for object: %v", err)
	}

	seen := make(map[string]bool)
	for _, m := range fieldManagers {
		seen[m] = false
	}

	for _, managedField := range accessor.GetManagedFields() {
		var entryJSON map[string]interface{}
		if err := json.Unmarshal(managedField.FieldsV1.Raw, &entryJSON); err != nil {
			t.Fatalf("failed to read into json")
		}

		spec, ok := entryJSON["f:spec"].(map[string]interface{})
		if !ok {
			// continue with the next managedField, as we this field does not hold the spec entry
			continue
		}

		if _, ok := spec["f:replicas"]; !ok {
			// continue with the next managedField, as we this field does not hold the spec.replicas entry
			continue
		}

		// check if the manager is one of the ones we expect
		if _, ok := seen[managedField.Manager]; !ok {
			t.Fatalf("Unexpected field manager, found %q, expected to be in: %v", managedField.Manager, seen)
		}

		seen[managedField.Manager] = true
	}

	var missingManagers []string
	for manager, managerSeen := range seen {
		if !managerSeen {
			missingManagers = append(missingManagers, manager)
		}
	}
	if len(missingManagers) > 0 {
		t.Fatalf("replicas fields should be owned by %v", missingManagers)
	}
}