Minor refactor (#3924)

* Move SceneFilenameParser to scene package
* Move Timestamp marshalling to internal/api, use gqlgen Int64 parser

internal/api/models.go

@@ -0,0 +1,57 @@
+package api
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"strconv"
+	"time"
+
+	"github.com/99designs/gqlgen/graphql"
+	"github.com/stashapp/stash/pkg/logger"
+	"github.com/stashapp/stash/pkg/utils"
+)
+
+var ErrTimestamp = errors.New("cannot parse Timestamp")
+
+func MarshalTimestamp(t time.Time) graphql.Marshaler {
+	if t.IsZero() {
+		return graphql.Null
+	}
+
+	return graphql.WriterFunc(func(w io.Writer) {
+		_, err := io.WriteString(w, strconv.Quote(t.Format(time.RFC3339Nano)))
+		if err != nil {
+			logger.Warnf("could not marshal timestamp: %v", err)
+		}
+	})
+}
+
+func UnmarshalTimestamp(v interface{}) (time.Time, error) {
+	if tmpStr, ok := v.(string); ok {
+		if len(tmpStr) == 0 {
+			return time.Time{}, fmt.Errorf("%w: empty string", ErrTimestamp)
+		}
+
+		switch tmpStr[0] {
+		case '>', '<':
+			d, err := time.ParseDuration(tmpStr[1:])
+			if err != nil {
+				return time.Time{}, fmt.Errorf("%w: cannot parse %v-duration: %v", ErrTimestamp, tmpStr[0], err)
+			}
+			t := time.Now()
+			// Compute point in time:
+			if tmpStr[0] == '<' {
+				t = t.Add(-d)
+			} else {
+				t = t.Add(d)
+			}
+
+			return t, nil
+		}
+
+		return utils.ParseDateStringAsTime(tmpStr)
+	}
+
+	return time.Time{}, fmt.Errorf("%w: not a string", ErrTimestamp)
+}