package geo

import (
	"fmt"
	"net"

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

// GeoPoint holds geographic information for an IP address.
type GeoPoint struct {
	IP          string
	Lat         float64
	Lon         float64
	Country     string
	CountryCode string
	Count       int
}

// GeoLookup wraps the geoip2 database reader.
// If no database path is configured, all lookups return nil (no-op).
type GeoLookup struct {
	db *geoip2.Reader
}

// NewGeoLookup creates a GeoLookup. If path is empty, returns a disabled (no-op) lookup.
// Returns an error if path is non-empty but the file cannot be opened.
func NewGeoLookup(path string) (*GeoLookup, error) {
	if path == "" {
		return &GeoLookup{}, nil
	}
	db, err := geoip2.Open(path)
	if err != nil {
		return nil, fmt.Errorf("geoip2 open %q: %w", path, err)
	}
	return &GeoLookup{db: db}, nil
}

// IsEnabled returns true if a GeoIP2 database is loaded.
func (g *GeoLookup) IsEnabled() bool {
	return g.db != nil
}

// Close releases the database if open.
func (g *GeoLookup) Close() {
	if g.db != nil {
		g.db.Close()
	}
}

// Lookup returns a GeoPoint for the given IP, or nil if the database is not loaded
// or the IP is nil/not found.
func (g *GeoLookup) Lookup(ip net.IP) *GeoPoint {
	if g.db == nil || ip == nil {
		return nil
	}
	record, err := g.db.City(ip)
	if err != nil {
		return nil
	}
	return &GeoPoint{
		IP:          ip.String(),
		Lat:         record.Location.Latitude,
		Lon:         record.Location.Longitude,
		Country:     record.Country.Names["en"],
		CountryCode: record.Country.IsoCode,
	}
}