package handler

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

	"github.com/go-chi/chi/v5"

	"financeiro-carvalho/internal/model"
	"financeiro-carvalho/internal/repository"
	"financeiro-carvalho/internal/service"
)

type CategoryHandler struct {
	svc     *service.CategoryService
	gameSvc *service.GameService
}

func NewCategoryHandler(svc *service.CategoryService, gameSvc *service.GameService) *CategoryHandler {
	return &CategoryHandler{svc: svc, gameSvc: gameSvc}
}

func (h *CategoryHandler) List(w http.ResponseWriter, r *http.Request) {
	cats, err := h.svc.List(r.Context())
	if err != nil {
		respondError(w, http.StatusInternalServerError, "failed to list categories")
		return
	}
	if cats == nil {
		cats = []model.Category{}
	}
	respondJSON(w, http.StatusOK, cats)
}

func (h *CategoryHandler) Create(w http.ResponseWriter, r *http.Request) {
	var in model.CategoryInput
	if err := json.NewDecoder(r.Body).Decode(&in); err != nil {
		respondError(w, http.StatusBadRequest, "invalid JSON")
		return
	}
	cat, err := h.svc.Create(r.Context(), in)
	if err != nil {
		respondError(w, http.StatusBadRequest, err.Error())
		return
	}
	h.gameSvc.OnCategoryBudgetSet(r.Context(), cat.ID, cat.Name, in.MonthlyBudget)
	respondJSON(w, http.StatusCreated, cat)
}

func (h *CategoryHandler) Update(w http.ResponseWriter, r *http.Request) {
	id, err := strconv.Atoi(chi.URLParam(r, "id"))
	if err != nil {
		respondError(w, http.StatusBadRequest, "invalid id")
		return
	}
	var in model.CategoryInput
	if err := json.NewDecoder(r.Body).Decode(&in); err != nil {
		respondError(w, http.StatusBadRequest, "invalid JSON")
		return
	}
	cat, err := h.svc.Update(r.Context(), id, in)
	if errors.Is(err, repository.ErrNotFound) {
		respondError(w, http.StatusNotFound, "category not found")
		return
	}
	if err != nil {
		respondError(w, http.StatusBadRequest, err.Error())
		return
	}
	h.gameSvc.OnCategoryBudgetSet(r.Context(), cat.ID, cat.Name, in.MonthlyBudget)
	respondJSON(w, http.StatusOK, cat)
}

func (h *CategoryHandler) Delete(w http.ResponseWriter, r *http.Request) {
	id, err := strconv.Atoi(chi.URLParam(r, "id"))
	if err != nil {
		respondError(w, http.StatusBadRequest, "invalid id")
		return
	}
	err = h.svc.Delete(r.Context(), id)
	switch {
	case errors.Is(err, repository.ErrNotFound):
		respondError(w, http.StatusNotFound, "category not found")
	case errors.Is(err, service.ErrDefaultCategory):
		respondError(w, http.StatusConflict, err.Error())
	case errors.Is(err, service.ErrHasTransactions):
		respondError(w, http.StatusConflict, err.Error())
	case err != nil:
		respondError(w, http.StatusInternalServerError, "failed to delete")
	default:
		w.WriteHeader(http.StatusNoContent)
	}
}