package work

import (
	"context"
	"encoding/json"
	"net/http"

	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/klog/v2"
	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"

	workv1alpha1 "github.com/karmada-io/karmada/pkg/apis/work/v1alpha1"
	"github.com/karmada-io/karmada/pkg/resourceinterpreter/default/native/prune"
)

// MutatingAdmission mutates API request if necessary.
type MutatingAdmission struct {
	decoder *admission.Decoder
}

// Check if our MutatingAdmission implements necessary interface
var _ admission.Handler = &MutatingAdmission{}
var _ admission.DecoderInjector = &MutatingAdmission{}

// Handle yields a response to an AdmissionRequest.
func (a *MutatingAdmission) Handle(ctx context.Context, req admission.Request) admission.Response {
	work := &workv1alpha1.Work{}

	err := a.decoder.Decode(req, work)
	if err != nil {
		return admission.Errored(http.StatusBadRequest, err)
	}
	klog.V(2).Infof("Mutating work(%s) for request: %s", work.Name, req.Operation)

	var manifests []workv1alpha1.Manifest

	for _, manifest := range work.Spec.Workload.Manifests {
		workloadObj := &unstructured.Unstructured{}
		err := json.Unmarshal(manifest.Raw, workloadObj)
		if err != nil {
			klog.Errorf("Failed to unmarshal work(%s) manifest to Unstructured", work.Name)
			return admission.Errored(http.StatusInternalServerError, err)
		}

		err = prune.RemoveIrrelevantField(workloadObj, prune.RemoveJobTTLSeconds)
		if err != nil {
			klog.Errorf("Failed to remove irrelevant field for work(%s): %v", work.Name, err)
			return admission.Errored(http.StatusInternalServerError, err)
		}

		workloadJSON, err := workloadObj.MarshalJSON()
		if err != nil {
			klog.Errorf("Failed to marshal workload of work(%s)", work.Name)
			return admission.Errored(http.StatusInternalServerError, err)
		}
		manifests = append(manifests, workv1alpha1.Manifest{RawExtension: runtime.RawExtension{Raw: workloadJSON}})
	}

	work.Spec.Workload.Manifests = manifests
	marshaledBytes, err := json.Marshal(work)
	if err != nil {
		return admission.Errored(http.StatusInternalServerError, err)
	}

	return admission.PatchResponseFromRaw(req.Object.Raw, marshaledBytes)
}

// InjectDecoder implements admission.DecoderInjector interface.
// A decoder will be automatically injected.
func (a *MutatingAdmission) InjectDecoder(d *admission.Decoder) error {
	a.decoder = d
	return nil
}
