package ipgeo

import (
	"net"
	"path/filepath"
	"strings"
	"tyapi-server/internal/domains/security/entities"

	"github.com/lionsoul2014/ip2region/binding/golang/xdb"
	"go.uber.org/zap"
)

// Location IP解析后的地理信息
type Location struct {
	Country  string
	Province string
	City     string
	ISP      string
	Region   string
}

// Locator IP地理定位器
type Locator struct {
	logger   *zap.Logger
	searcher *xdb.Searcher
}

// NewLocator 创建定位器，优先读取 resources/ipgeo/ip2region.xdb
func NewLocator(logger *zap.Logger) *Locator {
	locator := &Locator{logger: logger}
	dbPath := filepath.Join("resources", "ipgeo", "ip2region.xdb")

	cBuff, err := xdb.LoadContentFromFile(dbPath)
	if err != nil {
		logger.Warn("加载ip2region库失败，将使用降级定位", zap.String("db_path", dbPath), zap.Error(err))
		return locator
	}

	header, err := xdb.LoadHeaderFromBuff(cBuff)
	if err != nil {
		logger.Warn("读取ip2region头信息失败，将使用降级定位", zap.Error(err))
		return locator
	}
	version, err := xdb.VersionFromHeader(header)
	if err != nil {
		logger.Warn("解析ip2region版本失败，将使用降级定位", zap.Error(err))
		return locator
	}

	searcher, err := xdb.NewWithBuffer(version, cBuff)
	if err != nil {
		logger.Warn("初始化ip2region搜索器失败，将使用降级定位", zap.Error(err))
		return locator
	}
	locator.searcher = searcher

	logger.Info("ip2region定位器初始化成功", zap.String("db_path", dbPath))
	return locator
}

// LookupByIP 根据IP定位，失败返回 false
func (l *Locator) LookupByIP(ip string) (Location, bool) {
	if ip == "" || isPrivateOrLocalIP(ip) || l.searcher == nil {
		return Location{}, false
	}

	region, err := l.searcher.SearchByStr(ip)
	if err != nil {
		l.logger.Debug("ip2region查询失败", zap.String("ip", ip), zap.Error(err))
		return Location{}, false
	}
	loc := parseRegion(region)
	if loc.Region == "" {
		return Location{}, false
	}
	return loc, true
}

// ToGeoPoint 将记录转换为地球飞线起点
func (l *Locator) ToGeoPoint(record entities.SuspiciousIPRecord) (fromName string, lng float64, lat float64) {
	// 默认降级坐标：北京
	const defaultLng = 116.4074
	const defaultLat = 39.9042

	loc, ok := l.LookupByIP(record.IP)
	if !ok {
		return record.IP, defaultLng, defaultLat
	}

	cityName := strings.TrimSpace(loc.City)
	if cityName == "" || cityName == "0" {
		cityName = strings.TrimSpace(loc.Province)
	}
	if cityName == "" || cityName == "0" {
		return record.IP, defaultLng, defaultLat
	}

	coord, exists := CityCoordinates[cityName]
	if !exists {
		// 降级：未命中城市映射，回默认坐标
		return cityName, defaultLng, defaultLat
	}
	return cityName, coord.Lng, coord.Lat
}

func parseRegion(region string) Location {
	parts := strings.Split(region, "|")
	for len(parts) < 5 {
		parts = append(parts, "")
	}
	return Location{
		Country:  normalizeField(parts[0]),
		Region:   normalizeField(parts[1]),
		Province: normalizeField(parts[2]),
		City:     normalizeField(parts[3]),
		ISP:      normalizeField(parts[4]),
	}
}

func normalizeField(s string) string {
	s = strings.TrimSpace(s)
	if s == "0" {
		return ""
	}
	return s
}

func isPrivateOrLocalIP(ip string) bool {
	parsed := net.ParseIP(ip)
	if parsed == nil {
		return true
	}
	return parsed.IsLoopback() || parsed.IsPrivate() || parsed.IsUnspecified() || parsed.IsLinkLocalUnicast()
}