path: root/pkg/model/place.go

package model

import (
	"database/sql/driver"
	"fmt"
	"math"
	"regexp"
	"strconv"
	"time"

	"github.com/uptrace/bun"
)

type Place struct {
	bun.BaseModel `bun:"table:places,alias:p"`

	GUID      string `bun:",pk,unique"`
	Position  *Point `bun:"type:geometry(Point, 4326)"`
	Img       string
	Name      string
	Count     int
	CreatedAt time.Time `bun:",nullzero,notnull,default:current_timestamp"`
	UpdatedAt time.Time `bun:",nullzero,notnull,default:current_timestamp"`
	DeletedAt time.Time `bun:",soft_delete,nullzero"`
}

type Point struct {
	Lat float64
	Lon float64
}

func (p *Point) Value() (driver.Value, error) {
	return fmt.Sprintf(`SRID=4326;POINT(%f %f)`, p.Lon, p.Lat), nil
}

func (p *Point) Scan(src any) (err error) {
	re := regexp.MustCompile(`/\((.+?) (.+?)\)/`)
	s := ""
	//nolint:revive
	switch src := src.(type) {
	case string:
		s = src
	case []uint8:
		s = string(src)
	default:
		return fmt.Errorf("unsupported data type: %T", src)
	}
	//nolint:gomnd
	subs := re.FindAllString(s, 2)

	lon, err := strconv.ParseFloat(subs[0], 64)
	if err != nil {
		return err
	}

	lat, err := strconv.ParseFloat(subs[1], 64)
	if err != nil {
		return err
	}

	p.Lat = lat
	p.Lon = lon

	return nil
}

const radius = 6371 // Earth's mean radius in kilometers

func degrees2radians(degrees float64) float64 {
	return degrees * math.Pi / 180
}

func (p *Point) Distance(destination *Point) float64 {
	degreesLat := degrees2radians(destination.Lat - p.Lat)
	degreesLong := degrees2radians(destination.Lon - p.Lon)
	a := (math.Sin(degreesLat/2)*math.Sin(degreesLat/2) +
		math.Cos(degrees2radians(p.Lat))*
			math.Cos(degrees2radians(destination.Lat))*math.Sin(degreesLong/2)*
			math.Sin(degreesLong/2))
	c := 2 * math.Atan2(math.Sqrt(a), math.Sqrt(1-a))
	d := radius * c

	return d
}