From 30f616d3ab4a6a75da97178c537296a4fbf3271e Mon Sep 17 00:00:00 2001
From: Artur Glavic <artur.glavic@psi.ch>
Date: Thu, 26 Feb 2026 12:54:33 +0100
Subject: [PATCH] Add option to append Rqz datasets

---
 eos/options.py                |  8 ++++++++
 eos/reduction_reflectivity.py | 19 +++++++++++++++++--
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/eos/options.py b/eos/options.py
index 1d66432..233e41e 100644
--- a/eos/options.py
+++ b/eos/options.py
@@ -543,6 +543,14 @@ class ReflectivityOutputConfig(ArgParsable):
                 },
             )
 
+    append: bool = field(
+            default=False,
+            metadata={
+                'group': 'output',
+                'help': 'if file already exists, append result as additional ORSO dataset (only Rqz.ort)',
+                },
+            )
+
     def _output_format_list(self, outputFormat):
         format_list = []
         if OutputFomatOption.ort in outputFormat\
diff --git a/eos/reduction_reflectivity.py b/eos/reduction_reflectivity.py
index 4a9756e..d95ab0f 100644
--- a/eos/reduction_reflectivity.py
+++ b/eos/reduction_reflectivity.py
@@ -329,8 +329,23 @@ class ReflectivityReduction:
     def save_Rqz(self):
         fname = os.path.join(self.config.output.outputPath, f'{self.config.output.outputName}.Rqz.ort')
         logging.warning(f'    {fname}')
-        theSecondLine = f' {self.header.experiment.title} | {self.header.experiment.start_date} | sample {self.header.sample.name} | R(q_z)'
-        fileio.save_orso(self.datasetsRqz, fname, data_separator='\n', comment=theSecondLine)
+        if os.path.exists(fname) and self.config.output.append:
+            logging.info('        file already exists, append as new dataset')
+            with open(fname, 'r') as f:
+                f.readline()
+                theSecondLine = f.readline()[3:]
+            prev_data = fileio.load_orso(fname)
+            prev_names = [di.info.data_set for di in prev_data]
+            for i, di in enumerate(self.datasetsRqz):
+                while di.info.data_set in prev_names:
+                    if di.info.data_set.startswith('Nr '):
+                        di.info.data_set = f'Nr {i+len(prev_data)} :'+di.info.data_set.split(':', 1)[1]
+                        break
+                    di.info.data_set = di.info.data_set+'_'
+            fileio.save_orso(prev_data+self.datasetsRqz, fname, data_separator='\n', comment=theSecondLine)
+        else:
+            theSecondLine = f' {self.header.experiment.title} | {self.header.experiment.start_date} | sample {self.header.sample.name} | R(q_z)'
+            fileio.save_orso(self.datasetsRqz, fname, data_separator='\n', comment=theSecondLine)
 
     def save_Rtl(self):
         fname = os.path.join(self.config.output.outputPath, f'{self.config.output.outputName}.Rlt.ort')