package api

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

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

	"github.com/vasyakrg/dns-autoresolver/internal/service"
)

func writeJSON(w http.ResponseWriter, status int, v any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(v)
}

func writeErr(w http.ResponseWriter, status int, msg string) {
	writeJSON(w, status, map[string]string{"error": msg})
}

func (a *API) handleCheck(w http.ResponseWriter, r *http.Request) {
	did, err := uuid.Parse(chi.URLParam(r, "did"))
	if err != nil {
		writeErr(w, http.StatusBadRequest, "invalid domain id")
		return
	}
	cs, err := a.Svc.Check(r.Context(), did)
	if err != nil {
		log.Printf("api: check failed: %v", err)
		writeErr(w, http.StatusInternalServerError, "internal error")
		return
	}
	writeJSON(w, http.StatusOK, toChangesetResponse(cs))
}

func (a *API) handleApply(w http.ResponseWriter, r *http.Request) {
	did, err := uuid.Parse(chi.URLParam(r, "did"))
	if err != nil {
		writeErr(w, http.StatusBadRequest, "invalid domain id")
		return
	}
	var req applyRequest
	if r.Body != nil {
		r.Body = http.MaxBytesReader(w, r.Body, 1<<20) // 1 MiB
		// пустое тело допустимо → значения по умолчанию (prune=false);
		// любая другая ошибка decode (битый JSON, неверные типы) → 400
		if err := json.NewDecoder(r.Body).Decode(&req); err != nil && !errors.Is(err, io.EOF) {
			writeErr(w, http.StatusBadRequest, "invalid request body")
			return
		}
	}
	cs, err := a.Svc.Apply(r.Context(), did, service.ApplyRequest{
		ApplyUpdates: req.ApplyUpdates, ApplyPrunes: req.ApplyPrunes,
	})
	if err != nil {
		log.Printf("api: apply failed: %v", err)
		writeErr(w, http.StatusInternalServerError, "internal error")
		return
	}
	writeJSON(w, http.StatusOK, toChangesetResponse(cs))
}