package app

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

// ---------------------------------------------------------------------
// EN: `handleDNSUpstreams` is an HTTP handler for dns upstreams.
// RU: `handleDNSUpstreams` - HTTP-обработчик для dns upstreams.
// ---------------------------------------------------------------------
func handleDNSUpstreams(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodGet:
		writeJSON(w, http.StatusOK, loadDNSUpstreamsConf())
	case http.MethodPost:
		var cfg DNSUpstreams
		if r.Body != nil {
			defer r.Body.Close()
			if err := json.NewDecoder(io.LimitReader(r.Body, 1<<20)).Decode(&cfg); err != nil && err != io.EOF {
				http.Error(w, "bad json", http.StatusBadRequest)
				return
			}
		}
		if err := saveDNSUpstreamsConf(cfg); err != nil {
			http.Error(w, "write error", http.StatusInternalServerError)
			return
		}
		writeJSON(w, http.StatusOK, map[string]any{
			"ok":  true,
			"cfg": loadDNSUpstreamsConf(),
		})
	default:
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
	}
}

func handleDNSUpstreamPool(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodGet:
		items := loadDNSUpstreamPoolState()
		writeJSON(w, http.StatusOK, DNSUpstreamPoolState{Items: items})
	case http.MethodPost:
		var body DNSUpstreamPoolState
		if r.Body != nil {
			defer r.Body.Close()
			if err := json.NewDecoder(io.LimitReader(r.Body, 1<<20)).Decode(&body); err != nil && err != io.EOF {
				http.Error(w, "bad json", http.StatusBadRequest)
				return
			}
		}
		if err := saveDNSUpstreamPoolState(body.Items); err != nil {
			http.Error(w, "write error", http.StatusInternalServerError)
			return
		}
		writeJSON(w, http.StatusOK, DNSUpstreamPoolState{Items: loadDNSUpstreamPoolState()})
	default:
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
	}
}