package handler

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

	"github.com/go-chi/chi/v5"
	"github.com/prabhupadasays/spsays-bff/internal/repository"
	"github.com/prabhupadasays/spsays-bff/internal/service"
	"github.com/prabhupadasays/spsays-bff/pkg/response"
)

// FeedbackCategoryHandler serves the /feedback form's categories: the
// public list, and their management in the admin panel.
type FeedbackCategoryHandler struct {
	svc *service.FeedbackCategoryService
}

func NewFeedbackCategoryHandler(svc *service.FeedbackCategoryService) *FeedbackCategoryHandler {
	return &FeedbackCategoryHandler{svc: svc}
}

func writeCategoryError(w http.ResponseWriter, err error) {
	switch {
	case errors.Is(err, repository.ErrFeedbackCategoryNotFound):
		response.Error(w, http.StatusNotFound, err.Error())
	case errors.Is(err, repository.ErrFeedbackCategoryInUse),
		errors.Is(err, repository.ErrFeedbackCategoryExists),
		errors.Is(err, service.ErrCategoryLastActive):
		response.Error(w, http.StatusConflict, err.Error())
	case errors.Is(err, service.ErrCategoryLabel), errors.Is(err, service.ErrCategoryDescription):
		response.Error(w, http.StatusBadRequest, err.Error())
	default:
		response.Error(w, http.StatusInternalServerError, "feedback category request failed")
	}
}

// Public — GET /feedback/categories: the form's options, in order.
func (h *FeedbackCategoryHandler) Public(w http.ResponseWriter, r *http.Request) {
	list, err := h.svc.Active(r.Context())
	if err != nil {
		writeCategoryError(w, err)
		return
	}
	response.JSON(w, http.StatusOK, list)
}

// List — GET /admin/feedback/categories: all, with usage counts.
func (h *FeedbackCategoryHandler) List(w http.ResponseWriter, r *http.Request) {
	list, err := h.svc.All(r.Context())
	if err != nil {
		writeCategoryError(w, err)
		return
	}
	response.JSON(w, http.StatusOK, list)
}

type categoryReq struct {
	Label       string `json:"label"`
	Description string `json:"description"`
	Archived    bool   `json:"archived"`
}

func (h *FeedbackCategoryHandler) Create(w http.ResponseWriter, r *http.Request) {
	var req categoryReq
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		response.Error(w, http.StatusBadRequest, "invalid request body")
		return
	}
	c, err := h.svc.Create(r.Context(), req.Label, req.Description)
	if err != nil {
		writeCategoryError(w, err)
		return
	}
	response.JSON(w, http.StatusCreated, c)
}

func (h *FeedbackCategoryHandler) Update(w http.ResponseWriter, r *http.Request) {
	var req categoryReq
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		response.Error(w, http.StatusBadRequest, "invalid request body")
		return
	}
	if err := h.svc.Update(r.Context(), chi.URLParam(r, "key"), req.Label, req.Description, req.Archived); err != nil {
		writeCategoryError(w, err)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

func (h *FeedbackCategoryHandler) Delete(w http.ResponseWriter, r *http.Request) {
	if err := h.svc.Delete(r.Context(), chi.URLParam(r, "key")); err != nil {
		writeCategoryError(w, err)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

// Reorder — PUT /admin/feedback/categories/order {"keys": [...]}.
func (h *FeedbackCategoryHandler) Reorder(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Keys []string `json:"keys"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil || len(req.Keys) == 0 {
		response.Error(w, http.StatusBadRequest, "keys are required")
		return
	}
	if err := h.svc.Reorder(r.Context(), req.Keys); err != nil {
		writeCategoryError(w, err)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}