first commit

Made-with: Cursor

internal/utils/pagination.go

@@ -0,0 +1,59 @@
+package utils
+
+import (
+	"encoding/base64"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/google/uuid"
+)
+
+const (
+	DefaultLimit = 50
+	MaxLimit     = 200
+)
+
+type CursorParams struct {
+	CursorTime *time.Time
+	CursorID   *uuid.UUID
+	Limit      int32
+}
+
+func ParseCursor(cursor string) (*time.Time, *uuid.UUID, error) {
+	if cursor == "" {
+		return nil, nil, nil
+	}
+	raw, err := base64.RawURLEncoding.DecodeString(cursor)
+	if err != nil {
+		return nil, nil, fmt.Errorf("invalid cursor encoding")
+	}
+	parts := strings.SplitN(string(raw), "|", 2)
+	if len(parts) != 2 {
+		return nil, nil, fmt.Errorf("invalid cursor format")
+	}
+	t, err := time.Parse(time.RFC3339Nano, parts[0])
+	if err != nil {
+		return nil, nil, fmt.Errorf("invalid cursor time")
+	}
+	id, err := uuid.Parse(parts[1])
+	if err != nil {
+		return nil, nil, fmt.Errorf("invalid cursor id")
+	}
+	return &t, &id, nil
+}
+
+func EncodeCursor(t time.Time, id uuid.UUID) string {
+	raw := fmt.Sprintf("%s|%s", t.Format(time.RFC3339Nano), id.String())
+	return base64.RawURLEncoding.EncodeToString([]byte(raw))
+}
+
+func ClampLimit(limit int) int32 {
+	if limit <= 0 {
+		return DefaultLimit
+	}
+	if limit > MaxLimit {
+		return MaxLimit
+	}
+	return int32(limit)
+}