first commit

pkg/datasource/fields/field.go

@@ -0,0 +1,185 @@
+package fields
+
+import (
+	"bytes"
+	"context"
+	"database/sql/driver"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"math"
+	"time"
+
+	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
+)
+
+const (
+	timeFormat = "2006-01-02 15:04:05"
+	dateFormat = "2006-01-02"
+)
+
+type STPoint struct {
+	Lng float64
+	Lat float64
+}
+
+type Time time.Time
+
+func (t *Time) UnmarshalJSON(data []byte) (err error) {
+	now, err := time.ParseInLocation(`"`+timeFormat+`"`, string(data), time.Local)
+	*t = Time(now)
+	return
+}
+
+func (t *Time) MarshalJSON() ([]byte, error) {
+	b := make([]byte, 0, len(timeFormat)+2)
+	b = append(b, '"')
+	b = time.Time(*t).AppendFormat(b, timeFormat)
+	b = append(b, '"')
+	return b, nil
+}
+
+func (t *Time) String() string {
+	return time.Time(*t).Format(timeFormat)
+}
+
+func (t *Time) Value() (driver.Value, error) {
+	return time.Time(*t).Format(timeFormat), nil
+}
+
+func (t *Time) Time() time.Time {
+	return time.Time(*t)
+}
+
+func NowTime() Time {
+	return Time(time.Now())
+}
+
+type Date time.Time
+
+func (t *Date) UnmarshalJSON(data []byte) (err error) {
+	now, err := time.ParseInLocation(`"`+dateFormat+`"`, string(data), time.Local)
+	*t = Date(now)
+	return
+}
+
+func (t *Date) MarshalJSON() ([]byte, error) {
+	b := make([]byte, 0, len(dateFormat)+2)
+	b = append(b, '"')
+	b = time.Time(*t).AppendFormat(b, dateFormat)
+	b = append(b, '"')
+	return b, nil
+}
+
+func (t *Date) String() string {
+	return time.Time(*t).Format(dateFormat)
+}
+
+func (t *Date) FromStr(s string) error {
+	now, err := time.ParseInLocation(dateFormat, string(s), time.Local)
+	*t = Date(now)
+	return err
+}
+
+func (t *Date) Time() time.Time {
+	return time.Time(*t)
+}
+
+type Month time.Time
+
+const (
+	monthFormat = "2006-01"
+)
+
+func (t *Month) UnmarshalJSON(data []byte) (err error) {
+	if len(data) <= 2 {
+		return nil
+	}
+	now, err := time.ParseInLocation(`"`+monthFormat+`"`, string(data), time.Local)
+	*t = Month(now)
+	return
+}
+
+func (t *Month) MarshalJSON() ([]byte, error) {
+	b := make([]byte, 0, len(monthFormat)+2)
+	b = append(b, '"')
+	b = time.Time(*t).AppendFormat(b, monthFormat)
+	b = append(b, '"')
+	return b, nil
+}
+
+func (t *Month) String() string {
+	return time.Time(*t).Format(monthFormat)
+}
+
+type Point struct {
+	Lat float64 `json:"lat"`
+	Lng float64 `json:"lng"`
+}
+
+func (p Point) Value() (driver.Value, error) {
+	return fmt.Sprintf("POINT(%f %f)", p.Lng, p.Lat), nil
+}
+
+func (p *Point) Scan(src interface{}) error {
+	switch src.(type) {
+	case []byte:
+		var b = src.([]byte)
+		if len(b) != 25 {
+			return errors.New(fmt.Sprintf("Expected []bytes with length 25, got %d", len(b)))
+		}
+		var longitude float64
+		var latitude float64
+		buf := bytes.NewReader(b[9:17])
+		err := binary.Read(buf, binary.LittleEndian, &longitude)
+		if err != nil {
+			return err
+		}
+		buf = bytes.NewReader(b[17:25])
+		err = binary.Read(buf, binary.LittleEndian, &latitude)
+		if err != nil {
+			return err
+		}
+		p.Lng = longitude
+		p.Lat = latitude
+	default:
+		return errors.New(fmt.Sprintf("Expected []byte for Location type, got  %T", src))
+	}
+	return nil
+}
+
+func (loc Point) GormDataType() string {
+	return "point"
+}
+
+func (loc Point) GormValue(ctx context.Context, db *gorm.DB) clause.Expr {
+	return clause.Expr{
+		SQL:  "ST_PointFromText(?)",
+		Vars: []interface{}{fmt.Sprintf("POINT(%f %f)", loc.Lng, loc.Lat)},
+	}
+}
+
+func (p Point) DistanceTo(other Point) float64 {
+	const earthRadius = 6371000 // 地球半径，单位为米
+
+	lat1 := p.Lat * math.Pi / 180
+	lng1 := p.Lng * math.Pi / 180
+	lat2 := other.Lat * math.Pi / 180
+	lng2 := other.Lng * math.Pi / 180
+
+	dlat := lat2 - lat1
+	dlng := lng2 - lng1
+
+	a := math.Sin(dlat/2)*math.Sin(dlat/2) +
+		math.Cos(lat1)*math.Cos(lat2)*math.Sin(dlng/2)*math.Sin(dlng/2)
+	c := 2 * math.Atan2(math.Sqrt(a), math.Sqrt(1-a))
+
+	distance := earthRadius * c
+	// point1 := Point{Lat: 40.7128, Lng: -74.0060}
+	// point2 := Point{Lat: 34.0522, Lng: -118.2437}
+	// distance := point1.DistanceTo(point2)
+	// fmt.Printf("Distance between points: %.2f km\n", distance)
+	// fmt.Printf("Distance between points: %d meters\n", distance)
+	return distance
+}