✨ Add Meta with TextMarshaler

models/meta.go

@@ -1 +1,53 @@
 package models
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"regexp"
+	"strconv"
+	"time"
+)
+
+type Meta struct {
+	Key   string
+	Value any
+}
+
+func (m Meta) MarshalText() ([]byte, error) {
+	if regexp.MustCompile(`\s`).MatchString(m.Key) {
+		return []byte{}, fmt.Errorf("whitespace is now allowed in key: %s", m.Key)
+	}
+	buff := &bytes.Buffer{}
+	buff.WriteRune('@')
+	buff.WriteString(m.Key)
+	buff.WriteRune(' ')
+	switch v := m.Value.(type) {
+	default:
+		return nil, fmt.Errorf("Unknown type %T", v)
+	case nil:
+		return []byte{}, nil
+	case string:
+		buff.WriteString(v)
+	case int:
+		buff.WriteString(strconv.Itoa(v))
+	case float64:
+		buff.WriteString(strconv.FormatFloat(v, 'f', -1, 64))
+	case json.Number:
+		buff.WriteString(v.String())
+	case json.RawMessage:
+		buff.Write(v)
+	case []byte:
+		buff.Write(v)
+	case byte:
+		buff.WriteByte(v)
+	case rune:
+		buff.WriteString(string(v))
+	case bool:
+		buff.WriteString(strconv.FormatBool(v))
+	case time.Time:
+		buff.WriteString(v.Format(time.RFC3339))
+	}
+
+	return buff.Bytes(), nil
+}