/*
Copyright 2024 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 patch

import (
	"context"
	"strings"
	"testing"
	"time"

	"github.com/google/go-cmp/cmp"

	appsv1 "k8s.io/api/apps/v1"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/equality"
	"k8s.io/apimachinery/pkg/api/meta"
	"k8s.io/apimachinery/pkg/api/resource"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apimachinery/pkg/util/wait"
	"k8s.io/apiserver/pkg/admission"
	"k8s.io/apiserver/pkg/admission/plugin/cel"
	celconfig "k8s.io/apiserver/pkg/apis/cel"
	"k8s.io/apiserver/pkg/cel/environment"
	"k8s.io/client-go/openapi/openapitest"
	"k8s.io/utils/ptr"
)

func TestApplyConfiguration(t *testing.T) {
	deploymentGVR := schema.GroupVersionResource{Group: "apps", Version: "v1", Resource: "deployments"}
	deploymentGVK := schema.GroupVersionKind{Group: "apps", Version: "v1", Kind: "Deployment"}
	tests := []struct {
		name              string
		expression        string
		gvr               schema.GroupVersionResource
		object, oldObject runtime.Object
		expectedResult    runtime.Object
		expectedErr       string
	}{
		{
			name: "apply configuration add to listType=map",
			expression: `Object{
					spec: Object.spec{
						template: Object.spec.template{
							spec: Object.spec.template.spec{
								volumes: [Object.spec.template.spec.volumes{
									name: "y"
								}]
							}
						}
					}
				}`,
			gvr: deploymentGVR,
			object: &appsv1.Deployment{Spec: appsv1.DeploymentSpec{
				Template: corev1.PodTemplateSpec{
					Spec: corev1.PodSpec{
						Volumes: []corev1.Volume{{Name: "x"}},
					},
				},
			}},
			expectedResult: &appsv1.Deployment{Spec: appsv1.DeploymentSpec{
				Template: corev1.PodTemplateSpec{
					Spec: corev1.PodSpec{
						Volumes: []corev1.Volume{{Name: "x"}, {Name: "y"}},
					},
				},
			}},
		},
		{
			name: "apply configuration update listType=map entry",
			expression: `Object{
					spec: Object.spec{
						template: Object.spec.template{
							spec: Object.spec.template.spec{
								volumes: [Object.spec.template.spec.volumes{
									name: "y",
									hostPath: Object.spec.template.spec.volumes.hostPath{
										path: "a"
									}
								}]
							}
						}
					}
				}`,
			gvr: deploymentGVR,
			object: &appsv1.Deployment{Spec: appsv1.DeploymentSpec{
				Template: corev1.PodTemplateSpec{
					Spec: corev1.PodSpec{
						Volumes: []corev1.Volume{{Name: "x"}, {Name: "y"}},
					},
				},
			}},
			expectedResult: &appsv1.Deployment{Spec: appsv1.DeploymentSpec{
				Template: corev1.PodTemplateSpec{
					Spec: corev1.PodSpec{
						Volumes: []corev1.Volume{{Name: "x"}, {Name: "y", VolumeSource: corev1.VolumeSource{HostPath: &corev1.HostPathVolumeSource{Path: "a"}}}},
					},
				},
			}},
		},
		{
			name: "apply configuration with conditionals",
			expression: `Object{
					spec: Object.spec{
						replicas: object.spec.replicas % 2 == 0?object.spec.replicas + 1:object.spec.replicas
					}
				}`,
			gvr:            deploymentGVR,
			object:         &appsv1.Deployment{Spec: appsv1.DeploymentSpec{Replicas: ptr.To[int32](2)}},
			expectedResult: &appsv1.Deployment{Spec: appsv1.DeploymentSpec{Replicas: ptr.To[int32](3)}},
		},
		{
			name: "apply configuration with old object",
			expression: `Object{
					spec: Object.spec{
						replicas: oldObject.spec.replicas % 2 == 0?oldObject.spec.replicas + 1:oldObject.spec.replicas
					}
				}`,
			gvr:            deploymentGVR,
			object:         &appsv1.Deployment{Spec: appsv1.DeploymentSpec{Replicas: ptr.To[int32](1)}},
			oldObject:      &appsv1.Deployment{Spec: appsv1.DeploymentSpec{Replicas: ptr.To[int32](2)}},
			expectedResult: &appsv1.Deployment{Spec: appsv1.DeploymentSpec{Replicas: ptr.To[int32](3)}},
		},
		{
			name: "complex apply configuration initialization",
			expression: `Object{
					spec: Object.spec{
						replicas: 1,
						template: Object.spec.template{
							metadata: Object.spec.template.metadata{
								labels: {"app": "nginx"}
							},
							spec: Object.spec.template.spec{
								containers: [Object.spec.template.spec.containers{
									name: "nginx",
									image: "nginx:1.14.2",
									ports: [Object.spec.template.spec.containers.ports{
										containerPort: 80
									}],
									resources: Object.spec.template.spec.containers.resources{
										limits: {"cpu": "128M"},
									}
								}]
							}
						}
					}
				}`,

			gvr:    deploymentGVR,
			object: &appsv1.Deployment{Spec: appsv1.DeploymentSpec{}},
			expectedResult: &appsv1.Deployment{Spec: appsv1.DeploymentSpec{
				Replicas: ptr.To[int32](1),
				Template: corev1.PodTemplateSpec{
					ObjectMeta: metav1.ObjectMeta{
						Labels: map[string]string{"app": "nginx"},
					},
					Spec: corev1.PodSpec{
						Containers: []corev1.Container{{
							Name:  "nginx",
							Image: "nginx:1.14.2",
							Ports: []corev1.ContainerPort{
								{ContainerPort: 80},
							},
							Resources: corev1.ResourceRequirements{
								Limits: corev1.ResourceList{corev1.ResourceName("cpu"): resource.MustParse("128M")},
							},
						}},
					},
				},
			}},
		},
		{
			name: "apply configuration with change to atomic",
			expression: `Object{
					spec: Object.spec{
						selector: Object.spec.selector{
							matchLabels: {"l": "v"}
						}
					}
				}`,
			gvr:         deploymentGVR,
			object:      &appsv1.Deployment{Spec: appsv1.DeploymentSpec{Replicas: ptr.To[int32](1)}},
			expectedErr: "error applying patch: invalid ApplyConfiguration: may not mutate atomic arrays, maps or structs: .spec.selector",
		},
		{
			name: "apply configuration with invalid type name",
			expression: `Object{
					spec: Object.specx{
						replicas: 1
					}
				}`,
			gvr:         deploymentGVR,
			object:      &appsv1.Deployment{Spec: appsv1.DeploymentSpec{Replicas: ptr.To[int32](1)}},
			expectedErr: "type mismatch: unexpected type name \"Object.specx\", expected \"Object.spec\", which matches field name path from root Object type",
		},
		{
			name: "apply configuration with invalid field name",
			expression: `Object{
					spec: Object.spec{
						replicasx: 1
					}
				}`,
			gvr:         deploymentGVR,
			object:      &appsv1.Deployment{Spec: appsv1.DeploymentSpec{Replicas: ptr.To[int32](1)}},
			expectedErr: "error applying patch: failed to convert patch object to typed object: .spec.replicasx: field not declared in schema",
		},
		{
			name:        "apply configuration with invalid return type",
			expression:  `"I'm a teapot!"`,
			gvr:         deploymentGVR,
			object:      &appsv1.Deployment{Spec: appsv1.DeploymentSpec{Replicas: ptr.To[int32](1)}},
			expectedErr: "must evaluate to Object but got string",
		},
		{
			name:        "apply configuration with invalid initializer return type",
			expression:  `Object.spec.metadata{}`,
			gvr:         deploymentGVR,
			object:      &appsv1.Deployment{Spec: appsv1.DeploymentSpec{Replicas: ptr.To[int32](1)}},
			expectedErr: "must evaluate to Object but got Object.spec.metadata",
		},
		{
			name: "apply configuration with duplicate env vars in original object",
			expression: `Object{
					spec: Object.spec{
						replicas: 3
					}
				}`,
			gvr: deploymentGVR,
			object: &appsv1.Deployment{
				Spec: appsv1.DeploymentSpec{
					Replicas: ptr.To[int32](1),
					Template: corev1.PodTemplateSpec{
						Spec: corev1.PodSpec{
							Containers: []corev1.Container{{
								Name: "nginx",
								Env: []corev1.EnvVar{
									{Name: "test", Value: "a"},
									{Name: "test", Value: "b"},
								},
							}},
						},
					},
				},
			},
			expectedResult: &appsv1.Deployment{
				Spec: appsv1.DeploymentSpec{
					Replicas: ptr.To[int32](3),
					Template: corev1.PodTemplateSpec{
						Spec: corev1.PodSpec{
							Containers: []corev1.Container{{
								Name: "nginx",
								Env: []corev1.EnvVar{
									{Name: "test", Value: "a"},
									{Name: "test", Value: "b"},
								},
							}},
						},
					},
				},
			},
		},
		// This test verifies that modifying an existing environment variable works correctly,
		// even if the original object contains duplicates.
		// Because 'env' is defined with `listType=map` and `listMapKey=name` in the schema,
		// Structured Merge Diff (SMD) treats 'name' as the unique key.
		// When the patch updates the entry with name="test", SMD merges the changes.
		// As a side effect of the merge process on a map-type list, duplicate entries for the
		// same key in the original object are consolidated into a single entry in the result.
		// This matches the behavior of Server-Side Apply (SSA) and kubectl apply.
		{
			name: "apply configuration modify existing env variable",
			expression: `Object{
					spec: Object.spec{
						template: Object.spec.template{
							spec: Object.spec.template.spec{
								containers: [Object.spec.template.spec.containers{
									name: "nginx",
									env: [Object.spec.template.spec.containers.env{
										name: "test",
										value: "c"
									}]
								}]
							}
						}
					}
				}`,
			gvr: deploymentGVR,
			object: &appsv1.Deployment{
				Spec: appsv1.DeploymentSpec{
					Replicas: ptr.To[int32](1),
					Template: corev1.PodTemplateSpec{
						Spec: corev1.PodSpec{
							Containers: []corev1.Container{{
								Name: "nginx",
								Env: []corev1.EnvVar{
									{Name: "test", Value: "a"},
									{Name: "test", Value: "b"},
									{Name: "foo", Value: "bar"},
								},
							}},
						},
					},
				},
			},
			expectedResult: &appsv1.Deployment{
				Spec: appsv1.DeploymentSpec{
					Replicas: ptr.To[int32](1),
					Template: corev1.PodTemplateSpec{
						Spec: corev1.PodSpec{
							Containers: []corev1.Container{{
								Name: "nginx",
								Env: []corev1.EnvVar{
									{Name: "test", Value: "c"},
									{Name: "foo", Value: "bar"},
								},
							}},
						},
					},
				},
			},
		},
	}

	compiler, err := cel.NewCompositedCompiler(environment.MustBaseEnvSet(environment.DefaultCompatibilityVersion()))
	if err != nil {
		t.Fatal(err)
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	tcManager := NewTypeConverterManager(nil, openapitest.NewEmbeddedFileClient())
	go tcManager.Run(ctx)

	err = wait.PollUntilContextTimeout(ctx, 100*time.Millisecond, time.Second, true, func(context.Context) (done bool, err error) {
		converter := tcManager.GetTypeConverter(deploymentGVK)
		return converter != nil, nil
	})
	if err != nil {
		t.Fatal(err)
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			accessor := &ApplyConfigurationCondition{Expression: tc.expression}
			compileResult := compiler.CompileMutatingEvaluator(accessor, cel.OptionalVariableDeclarations{HasPatchTypes: true}, environment.StoredExpressions)

			patcher := applyConfigPatcher{expressionEvaluator: compileResult}

			scheme := runtime.NewScheme()
			err := appsv1.AddToScheme(scheme)
			if err != nil {
				t.Fatal(err)
			}

			var gvk schema.GroupVersionKind
			gvks, _, err := scheme.ObjectKinds(tc.object)
			if err != nil {
				t.Fatal(err)
			}
			if len(gvks) == 1 {
				gvk = gvks[0]
			} else {
				t.Fatalf("Failed to find gvk for type: %T", tc.object)
			}

			metaAccessor, err := meta.Accessor(tc.object)
			if err != nil {
				t.Fatal(err)
			}

			typeAccessor, err := meta.TypeAccessor(tc.object)
			if err != nil {
				t.Fatal(err)
			}
			typeAccessor.SetKind(gvk.Kind)
			typeAccessor.SetAPIVersion(gvk.GroupVersion().String())

			attrs := admission.NewAttributesRecord(tc.object, tc.oldObject, gvk,
				metaAccessor.GetNamespace(), metaAccessor.GetName(), tc.gvr,
				"", admission.Create, &metav1.CreateOptions{}, false, nil)
			vAttrs := &admission.VersionedAttributes{
				Attributes:         attrs,
				VersionedKind:      gvk,
				VersionedObject:    tc.object,
				VersionedOldObject: tc.oldObject,
			}

			r := Request{
				MatchedResource:     tc.gvr,
				VersionedAttributes: vAttrs,
				ObjectInterfaces:    admission.NewObjectInterfacesFromScheme(scheme),
				OptionalVariables:   cel.OptionalVariableBindings{},
				TypeConverter:       tcManager.GetTypeConverter(gvk),
			}

			patched, err := patcher.Patch(ctx, r, celconfig.RuntimeCELCostBudget)
			if len(tc.expectedErr) > 0 {
				if err == nil {
					t.Fatalf("expected error: %s", tc.expectedErr)
				} else {
					if !strings.Contains(err.Error(), tc.expectedErr) {
						t.Fatalf("expected error: %s, got: %s", tc.expectedErr, err.Error())
					}
					return
				}
			}
			if err != nil && len(tc.expectedErr) == 0 {
				t.Fatalf("unexpected error: %v", err)
			}

			got, err := runtime.DefaultUnstructuredConverter.ToUnstructured(patched)
			if err != nil {
				t.Fatal(err)
			}

			wantTypeAccessor, err := meta.TypeAccessor(tc.expectedResult)
			if err != nil {
				t.Fatal(err)
			}
			wantTypeAccessor.SetKind(gvk.Kind)
			wantTypeAccessor.SetAPIVersion(gvk.GroupVersion().String())

			want, err := runtime.DefaultUnstructuredConverter.ToUnstructured(tc.expectedResult)

			if err != nil {
				t.Fatal(err)
			}
			if !equality.Semantic.DeepEqual(want, got) {
				t.Errorf("unexpected result, got diff:\n%s\n", cmp.Diff(want, got))
			}
		})
	}
}
