package utils

import (
	"encoding/json"
	"github.com/ipipdotnet/ipdb-go"
	"net"
	"net/http"
	"strings"
)

const (
	remoteAddrHeader = "X-NAV-REMOTE-IP"
)

type errorMessage struct {
	Error string `json:"error"`
}

func ResponseWithError(resp http.ResponseWriter, statusCode int, message string) {
	resp.Header().Set("Content-Type", "text/plain")
	resp.WriteHeader(statusCode)
	resp.Write([]byte("error: " + message))
}

func ResponseWithJsonError(resp http.ResponseWriter, statusCode int, message string) {
	resp.Header().Set("Content-Type", "application/json")
	resp.WriteHeader(statusCode)
	encoder := json.NewEncoder(resp)
	err := encoder.Encode(&errorMessage{
		Error: message,
	})
	if err != nil {
		// This should never happen
		panic("json marshal failed, check code")
	}
}

func GetRemoteIP(req *http.Request) string {
	if addr := req.Header.Get(remoteAddrHeader); addr != "" {
		if net.ParseIP(addr).To4() == nil {
			return ""
		}
		return addr
	}
	host, _, err := net.SplitHostPort(req.RemoteAddr)
	if err != nil {
		return ""
	}
	if net.ParseIP(host).To4() == nil {
		return ""
	}
	return host
}

func BuildLocation(info *ipdb.CityInfo) string {
	ret := ""
	if info.CountryName != "" {
		ret += info.CountryName + " "
	}
	if info.RegionName != "" {
		ret += info.RegionName + " "
	}
	if info.CityName != "" {
		ret += info.CityName + " "
	}
	return strings.TrimSpace(ret)
}