FDN-01: repository & projektgerüst

Git-Repository für bestehenden archivdms-Code initialisiert, Branch-/Commit-Konvention (feature/<ticket>-<slug>-Branches, Ticket-Prefix in Commit-Nachricht) etabliert.

internal/dateformat/dateformat.go

@@ -0,0 +1,61 @@
+// Package dateformat translates a small, user-friendly token pattern (e.g.
+// "DD.MM.YYYY HH:mm") into a Go time layout ("02.01.2006 15:04"). It is a
+// neutral package imported by both internal/api and internal/tenantstore so
+// they can share one validator without importing each other (which would be a
+// circular dependency).
+//
+// Admins may enter an arbitrary token string; anything that is not a known
+// token is preserved verbatim as literal text in the resulting layout.
+package dateformat
+
+import (
+	"fmt"
+	"regexp"
+	"unicode/utf8"
+)
+
+// MaxPatternLen bounds the token pattern length, mirroring the scan-title
+// prefix limit so an oversized value can never be persisted.
+const MaxPatternLen = 40
+
+// tokenLayout maps each supported token to its Go reference-time fragment.
+// Order matters at match time (longest first) so e.g. "YYYY" is not consumed
+// as "YY"+"YY"; the regex alternation below encodes that ordering explicitly.
+var tokenLayout = map[string]string{
+	"AM/PM": "PM",
+	"YYYY":  "2006",
+	"YY":    "06",
+	"MM":    "01",
+	"DD":    "02",
+	"HH":    "15",
+	"hh":    "03",
+	"mm":    "04",
+	"ss":    "05",
+	"PM":    "PM",
+}
+
+// tokenRE matches known tokens, longest alternatives first so a greedy leftmost
+// match never splits a long token into shorter ones.
+var tokenRE = regexp.MustCompile(`AM/PM|YYYY|YY|MM|DD|HH|hh|mm|ss|PM`)
+
+// Translate converts a token pattern into a Go time layout. It fails when the
+// pattern is empty, too long, or contains no recognised token (a pattern of
+// pure literal text would make time.Format return that literal unchanged,
+// which is never what the admin intends).
+func Translate(pattern string) (goLayout string, err error) {
+	if pattern == "" {
+		return "", fmt.Errorf("Format darf nicht leer sein")
+	}
+	if utf8.RuneCountInString(pattern) > MaxPatternLen {
+		return "", fmt.Errorf("Format zu lang (max %d Zeichen)", MaxPatternLen)
+	}
+	matched := false
+	layout := tokenRE.ReplaceAllStringFunc(pattern, func(tok string) string {
+		matched = true
+		return tokenLayout[tok]
+	})
+	if !matched {
+		return "", fmt.Errorf("Format muss mindestens einen Datums-/Zeit-Platzhalter enthalten")
+	}
+	return layout, nil
+}