refactor local metadata helpers

internal/service/local_metadata_helpers.go

@@ -0,0 +1,74 @@
+package service
+
+import (
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+func firstRemoteURL(baseDir string, values ...string) string {
+	for _, value := range values {
+		value = cleanXMLText(value)
+		if value == "" {
+			continue
+		}
+		if isHTTPURL(value) {
+			return value
+		}
+		if filepath.IsAbs(value) && fileExists(value) {
+			return filepath.Clean(value)
+		}
+		if baseDir != "" {
+			local := filepath.Join(baseDir, filepath.FromSlash(value))
+			if fileExists(local) {
+				return filepath.Clean(local)
+			}
+		}
+	}
+	return ""
+}
+
+func firstText(values ...string) string {
+	for _, value := range values {
+		if text := cleanXMLText(value); text != "" {
+			return text
+		}
+	}
+	return ""
+}
+
+func cleanXMLText(value string) string {
+	return strings.TrimSpace(value)
+}
+
+func joinNFOValues(values []string) string {
+	out := make([]string, 0, len(values))
+	seen := map[string]struct{}{}
+	for _, value := range values {
+		for _, part := range strings.Split(value, ",") {
+			part = cleanXMLText(part)
+			if part == "" {
+				continue
+			}
+			key := strings.ToLower(part)
+			if _, ok := seen[key]; ok {
+				continue
+			}
+			seen[key] = struct{}{}
+			out = append(out, part)
+		}
+	}
+	return strings.Join(out, ",")
+}
+
+func yearFromDate(value string) int {
+	if len(value) < 4 {
+		return 0
+	}
+	year, _ := strconv.Atoi(value[:4])
+	return year
+}
+
+func samePath(a, b string) bool {
+	return strings.EqualFold(filepath.Clean(a), filepath.Clean(b))
+}