// Изменено: 2026-03-11
// functions.go — CRUD handlers для Function CRD.
// Принимает JSON, создаёт/обновляет/удаляет k8s ресурсы Function.
// Namespace берётся из URL: /v1/namespaces/{namespace}/functions/{name}

package handler

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

	"k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"sigs.k8s.io/controller-runtime/pkg/client"

	slessv1alpha1 "gitea-naeel.giteak8s.services.ngcloud.ru/naeel/sless/api/v1alpha1"
)

// functionRequest — тело запроса для создания/обновления функции.
type functionRequest struct {
	Name       string            `json:"name"`
	Runtime    string            `json:"runtime"`
	Entrypoint string            `json:"entrypoint"`
	MemoryMB   int32             `json:"memory_mb"`
	TimeoutSec int32             `json:"timeout_sec"`
	Env        map[string]string `json:"env_vars"`
	S3Bucket   string            `json:"s3_bucket"`
	S3Key      string            `json:"s3_key"`
}

// functionResponse — ответ при чтении функции.
type functionResponse struct {
	Name       string                      `json:"name"`
	Namespace  string                      `json:"namespace"`
	Runtime    string                      `json:"runtime"`
	Entrypoint string                      `json:"entrypoint"`
	MemoryMB   int32                       `json:"memory_mb"`
	TimeoutSec int32                       `json:"timeout_sec"`
	Env        map[string]string           `json:"env_vars"`
	S3Bucket   string                      `json:"s3_bucket"`
	S3Key      string                      `json:"s3_key"`
	Phase      slessv1alpha1.FunctionPhase `json:"phase"`
	ImageRef   string                      `json:"image_ref"`
	Message    string                      `json:"message,omitempty"`
}

// fnToResponse конвертирует CRD в ответ API.
func fnToResponse(fn *slessv1alpha1.Function) functionResponse {
	return functionResponse{
		Name:       fn.Name,
		Namespace:  fn.Namespace,
		Runtime:    fn.Spec.Runtime,
		Entrypoint: fn.Spec.Entrypoint,
		MemoryMB:   fn.Spec.MemoryMB,
		TimeoutSec: fn.Spec.TimeoutSec,
		Env:        fn.Spec.Env,
		S3Bucket:   fn.Spec.S3Bucket,
		S3Key:      fn.Spec.S3Key,
		Phase:      fn.Status.Phase,
		ImageRef:   fn.Status.ImageRef,
		Message:    fn.Status.Message,
	}
}

// ListFunctions — GET /v1/namespaces/{namespace}/functions
func (h *Handler) ListFunctions(w http.ResponseWriter, r *http.Request) {
	ns := namespace(r)
	list := &slessv1alpha1.FunctionList{}
	if err := h.K8s.List(r.Context(), list, client.InNamespace(ns)); err != nil {
		writeJSON(w, http.StatusInternalServerError, errResp(err.Error()))
		return
	}
	result := make([]functionResponse, 0, len(list.Items))
	for i := range list.Items {
		result = append(result, fnToResponse(&list.Items[i]))
	}
	writeJSON(w, http.StatusOK, result)
}

// CreateFunction — POST /v1/namespaces/{namespace}/functions
func (h *Handler) CreateFunction(w http.ResponseWriter, r *http.Request) {
	ns := namespace(r)
	var req functionRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeJSON(w, http.StatusBadRequest, errResp("invalid JSON: "+err.Error()))
		return
	}
	if req.Name == "" || req.Runtime == "" {
		writeJSON(w, http.StatusBadRequest, errResp("name and runtime are required"))
		return
	}
	if req.Entrypoint == "" {
		writeJSON(w, http.StatusBadRequest, errResp("entrypoint is required"))
		return
	}
	if req.MemoryMB <= 0 || req.MemoryMB > 4096 {
		writeJSON(w, http.StatusBadRequest, errResp("memory_mb must be between 1 and 4096"))
		return
	}

	fn := &slessv1alpha1.Function{
		ObjectMeta: metav1.ObjectMeta{
			Name:      req.Name,
			Namespace: ns,
		},
		Spec: slessv1alpha1.FunctionSpec{
			Runtime:    req.Runtime,
			Entrypoint: req.Entrypoint,
			MemoryMB:   req.MemoryMB,
			TimeoutSec: req.TimeoutSec,
			Env:        req.Env,
			S3Bucket:   req.S3Bucket,
			S3Key:      req.S3Key,
		},
	}
	if err := h.K8s.Create(r.Context(), fn); err != nil {
		if errors.IsAlreadyExists(err) {
			// Если существующая функция в статусе Failed (build провалился, terraform не
			// добавил её в state) — удаляем её и пересоздаём, иначе клиент получит 409 навсегда.
			existing := &slessv1alpha1.Function{}
			if getErr := h.K8s.Get(r.Context(), client.ObjectKey{Name: req.Name, Namespace: ns}, existing); getErr == nil &&
				existing.Status.Phase == slessv1alpha1.FunctionPhaseFailed {
				_ = h.K8s.Delete(r.Context(), existing)
				// Создаём заново с теми же параметрами
				fn.ResourceVersion = ""
				if createErr := h.K8s.Create(r.Context(), fn); createErr != nil {
					writeJSON(w, http.StatusInternalServerError, errResp(createErr.Error()))
					return
				}
				writeJSON(w, http.StatusCreated, fnToResponse(fn))
				return
			}
			writeJSON(w, http.StatusConflict, errResp("function already exists"))
			return
		}
		writeJSON(w, http.StatusInternalServerError, errResp(err.Error()))
		return
	}
	writeJSON(w, http.StatusCreated, fnToResponse(fn))
}

// GetFunction — GET /v1/namespaces/{namespace}/functions/{name}
func (h *Handler) GetFunction(w http.ResponseWriter, r *http.Request) {
	ns := namespace(r)
	name := pathVar(r, "name")
	fn := &slessv1alpha1.Function{}
	if err := h.K8s.Get(r.Context(), client.ObjectKey{Name: name, Namespace: ns}, fn); err != nil {
		if errors.IsNotFound(err) {
			writeJSON(w, http.StatusNotFound, errResp("function not found"))
			return
		}
		writeJSON(w, http.StatusInternalServerError, errResp(err.Error()))
		return
	}
	writeJSON(w, http.StatusOK, fnToResponse(fn))
}

// UpdateFunction — PUT /v1/namespaces/{namespace}/functions/{name}
func (h *Handler) UpdateFunction(w http.ResponseWriter, r *http.Request) {
	ns := namespace(r)
	name := pathVar(r, "name")
	var req functionRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeJSON(w, http.StatusBadRequest, errResp("invalid JSON: "+err.Error()))
		return
	}

	fn := &slessv1alpha1.Function{}
	if err := h.K8s.Get(r.Context(), client.ObjectKey{Name: name, Namespace: ns}, fn); err != nil {
		if errors.IsNotFound(err) {
			writeJSON(w, http.StatusNotFound, errResp("function not found"))
			return
		}
		writeJSON(w, http.StatusInternalServerError, errResp(err.Error()))
		return
	}

	// Валидация обязательных полей — PUT семантика, нельзя обнулять критичные поля
	if req.Runtime == "" || req.Entrypoint == "" {
		writeJSON(w, http.StatusBadRequest, errResp("runtime and entrypoint are required"))
		return
	}
	if req.MemoryMB <= 0 || req.MemoryMB > 4096 {
		writeJSON(w, http.StatusBadRequest, errResp("memory_mb must be between 1 and 4096"))
		return
	}

	// Обновляем только изменяемые поля spec
	fn.Spec.Runtime = req.Runtime
	fn.Spec.Entrypoint = req.Entrypoint
	fn.Spec.MemoryMB = req.MemoryMB
	fn.Spec.TimeoutSec = req.TimeoutSec
	fn.Spec.Env = req.Env
	if req.S3Bucket != "" {
		fn.Spec.S3Bucket = req.S3Bucket
	}
	if req.S3Key != "" {
		fn.Spec.S3Key = req.S3Key
	}

	if err := h.K8s.Update(r.Context(), fn); err != nil {
		writeJSON(w, http.StatusInternalServerError, errResp(err.Error()))
		return
	}
	writeJSON(w, http.StatusOK, fnToResponse(fn))
}

// DeleteFunction — DELETE /v1/namespaces/{namespace}/functions/{name}
func (h *Handler) DeleteFunction(w http.ResponseWriter, r *http.Request) {
	ns := namespace(r)
	name := pathVar(r, "name")
	fn := &slessv1alpha1.Function{}
	if err := h.K8s.Get(r.Context(), client.ObjectKey{Name: name, Namespace: ns}, fn); err != nil {
		if errors.IsNotFound(err) {
			w.WriteHeader(http.StatusNoContent)
			return
		}
		writeJSON(w, http.StatusInternalServerError, errResp(err.Error()))
		return
	}
	if err := h.K8s.Delete(r.Context(), fn); err != nil {
		writeJSON(w, http.StatusInternalServerError, errResp(err.Error()))
		return
	}
	w.WriteHeader(http.StatusNoContent)
}