package mmdb

import (
	"errors"
	"net/netip"

	"git.kor-elf.net/kor-elf-shield/geoip2"
	"git.kor-elf.net/kor-elf-shield/geoip2/internal/pkg"
	"git.kor-elf.net/kor-elf-shield/geoip2/internal/service/maxmind/mmdb"

	oschwaldGeoip2 "github.com/oschwald/geoip2-golang/v2"
)

const (
	DownloadURLCityLite = "https://download.maxmind.com/geoip/databases/GeoLite2-City/download?suffix=tar.gz"
	NameDirNameCityLite = "GeoLite2-City"
)

// City is a structure that contains information about the IP address.
type City struct {
	// lang is a language.
	lang language
}

// NewCity creates a new City instance.
// @param download - an interface for downloading MaxMind GeoIP2 database
// @param logger - a logger
// @param dir - a directory for storing MaxMind GeoIP2 database
// @return geoip2.RefreshableGeoIP2 - a MaxMind GeoIP2 database service
func NewCity(download *Download, logger geoip2.Logger, dir string, language language) geoip2.RefreshableGeoIP2 {
	city := &City{
		lang: language,
	}

	newDir := pkg.NewDir(dir, NameDirNameCityLite)
	return mmdb.NewMMDB(download, city.infoCity, logger, newDir)
}

// infoCity returns information about the IP address.
// @param ip - IP address
// @param reader - MaxMind GeoIP2 database reader
// @return geoip2.Info - information about the IP address
// @return error - an error if the IP address could not be found
func (c *City) infoCity(ip netip.Addr, reader *oschwaldGeoip2.Reader) (geoip2.Info, error) {
	record, err := reader.City(ip)
	if err != nil {
		return geoip2.Info{}, err
	}
	if !record.HasData() {
		return geoip2.Info{}, errors.New(geoip2.ErrNotFound)
	}

	var timeZone string
	if record.Location.HasData() {
		timeZone = record.Location.TimeZone
	}

	return geoip2.Info{
		IP:               ip,
		ISOCode:          record.Country.ISOCode,
		Country:          c.country(record.Country),
		City:             c.city(record.City),
		CitySubdivisions: c.subdivisions(record.Subdivisions),
		TimeZone:         timeZone,
		Continent:        c.continent(record.Continent),
	}, nil
}

func (c *City) continent(continent oschwaldGeoip2.Continent) string {
	if !continent.HasData() {
		return ""
	}

	switch c.lang {
	case LanguageRussian:
		return continent.Names.Russian
	case LanguageEnglish:
		return continent.Names.English
	case LanguageBrazilianPortuguese:
		return continent.Names.BrazilianPortuguese
	case LanguageSimplifiedChinese:
		return continent.Names.SimplifiedChinese
	case LanguageJapanese:
		return continent.Names.Japanese
	case LanguageGerman:
		return continent.Names.German
	case LanguageFrench:
		return continent.Names.French
	case LanguageSpanish:
		return continent.Names.Spanish
	default:
		return continent.Names.English
	}
}

func (c *City) country(country oschwaldGeoip2.CountryRecord) string {
	if !country.HasData() {
		return ""
	}

	switch c.lang {
	case LanguageRussian:
		return country.Names.Russian
	case LanguageEnglish:
		return country.Names.English
	case LanguageBrazilianPortuguese:
		return country.Names.BrazilianPortuguese
	case LanguageSimplifiedChinese:
		return country.Names.SimplifiedChinese
	case LanguageJapanese:
		return country.Names.Japanese
	case LanguageGerman:
		return country.Names.German
	case LanguageFrench:
		return country.Names.French
	case LanguageSpanish:
		return country.Names.Spanish
	default:
		return country.Names.English
	}
}

func (c *City) city(city oschwaldGeoip2.CityRecord) string {
	if !city.HasData() {
		return ""
	}

	switch c.lang {
	case LanguageRussian:
		return city.Names.Russian
	case LanguageEnglish:
		return city.Names.English
	case LanguageBrazilianPortuguese:
		return city.Names.BrazilianPortuguese
	case LanguageSimplifiedChinese:
		return city.Names.SimplifiedChinese
	case LanguageJapanese:
		return city.Names.Japanese
	case LanguageGerman:
		return city.Names.German
	case LanguageFrench:
		return city.Names.French
	case LanguageSpanish:
		return city.Names.Spanish
	default:
		return city.Names.English
	}
}

func (c *City) subdivisions(subdivisions []oschwaldGeoip2.CitySubdivision) []string {
	var citySubdivisions []string

	if len(subdivisions) == 0 {
		return citySubdivisions
	}

	for _, subdivision := range subdivisions {
		citySubdivisions = append(citySubdivisions, c.subdivision(subdivision))
	}

	return citySubdivisions
}

func (c *City) subdivision(subdivision oschwaldGeoip2.CitySubdivision) string {
	if !subdivision.HasData() {
		return ""
	}

	switch c.lang {
	case LanguageRussian:
		return subdivision.Names.Russian
	case LanguageEnglish:
		return subdivision.Names.English
	case LanguageBrazilianPortuguese:
		return subdivision.Names.BrazilianPortuguese
	case LanguageSimplifiedChinese:
		return subdivision.Names.SimplifiedChinese
	case LanguageJapanese:
		return subdivision.Names.Japanese
	case LanguageGerman:
		return subdivision.Names.German
	case LanguageFrench:
		return subdivision.Names.French
	case LanguageSpanish:
		return subdivision.Names.Spanish
	default:
		return subdivision.Names.English
	}
}