From 3bd2a3f3859cfad6a20262168d89cf3b8cbb1a97 Mon Sep 17 00:00:00 2001
From: Avatarsia <info@avatarsia.de>
Date: Thu, 30 Apr 2026 14:42:50 +0200
Subject: [PATCH] feat(mahnwesen): expose {FRIST}, {DATUMRECHNUNG},
 {MAHNDATUM}, {TAGE} placeholders

The mahnwesen template engine previously only exposed {DATUM}, {BELEGNR},
{OFFEN}, {MAHNGEBUEHR}, {HEUTE}, {RECHNUNG} via the ParseVars mapping.
The legacy block computing {DATUM*}/{TAGE}/{MAHNDATUM} is commented out,
so dunning templates referencing a calendar-bound deadline ("bis zum X")
had no working placeholder for the deadline date.

This adds:
- {FRIST}        = mahnwesen_datum + mahn_tage (mahnwesen.tage from system
                   settings), formatted dd.mm.yyyy
- {DATUMRECHNUNG} = invoice date (alias to {DATUM} for clarity)
- {MAHNDATUM}    = current dunning issue date in dd.mm.yyyy
- {TAGE}         = configured grace days for the current dunning level

Also fixes a use-before-define on $tage at line 678 by replacing the
no-op `if($tage<=0)$tage=0;` with a single `max(0,(int)mahn_tage)`
assignment that pulls from the mahnwesen table (system settings).

Guards 0000-00-00 mahnwesen_datum to avoid bogus future-date arithmetic.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 www/pages/mahnwesen.php | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/www/pages/mahnwesen.php b/www/pages/mahnwesen.php
index 61d48e449..9b1b56d5b 100644
--- a/www/pages/mahnwesen.php
+++ b/www/pages/mahnwesen.php
@@ -675,7 +675,12 @@ function MahnwesenMessage($rechnung_id) {
 
           $offen = $this->app->erp->GetSaldoDokument($rechnung_id, 'rechnung');
 
-          if($tage <=0) $tage = 0;
+          $tage = max(0, (int)$rechnungarr['mahn_tage']);
+
+          $mahnwesen_datum_valid = !empty($mahnwesen_datum) && $mahnwesen_datum !== '0000-00-00';
+          $frist_de = $mahnwesen_datum_valid
+              ? date('d.m.Y', strtotime($mahnwesen_datum.' +'.$tage.' days'))
+              : '';
 
 /*          $datummahnung= $this->app->DB->Select("SELECT DATE_FORMAT(DATE_ADD('$mahnwesen_datum', INTERVAL $tage DAY),'%d.%m.%Y')");
           $datumrechnungzahlungsziel= $this->app->DB->Select("SELECT DATE_FORMAT(DATE_ADD('$datum_sql', INTERVAL $zahlungszieltage DAY),'%d.%m.%Y')");
@@ -726,6 +731,10 @@ function MahnwesenMessage($rechnung_id) {
             'rechnung' => $belegnr,
             'belegnr' => $belegnr,
             'datum' => $datum_sql,
+            'datumrechnung' => $datum_sql,
+            'frist' => $frist_de,
+            'mahndatum' => $mahnwesen_datum_deutsch,
+            'tage' => $tage,
             'offen' => $this->app->erp->EUR(-$offen['betrag'])." ".$offen['waehrung'],
             'mahngebuehr' => $this->app->erp->EUR($rechnungarr['mahn_gebuehr']),
             'heute' => $rechnungarr['heute']