From 83cf8d7ee3b7fa60b1e6afd36ea83a0c698e3bdd Mon Sep 17 00:00:00 2001
From: pierrepetersmeier <155652256+pierrepetersmeier@users.noreply.github.com>
Date: Mon, 1 Sep 2025 14:45:27 +0200
Subject: [PATCH] Correctly persist EmInput entities in CsvFileSink

---
 CHANGELOG.md                                   |  1 +
 .../edu/ie3/datamodel/io/sink/CsvFileSink.java | 18 +++++++++++++++++-
 .../datamodel/io/sink/CsvFileSinkTest.groovy   |  1 +
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5416aa3b7..6a729d9cb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed small issues in tests [#1400](https://github.com/ie3-institute/PowerSystemDataModel/issues/1400)
 - Fix transformer susceptance in readTheDocs to negative values [#1078](https://github.com/ie3-institute/PowerSystemDataModel/issues/1078)
 - Added mising fields to field validation [#1422](https://github.com/ie3-institute/PowerSystemDataModel/issues/1422)
+- Correctly persist EmInput entities in CsvFileSink [#1337](https://github.com/ie3-institute/PowerSystemDataModel/issues/1337)
 
 ### Changed
 - Updated CI-Pipeline to run task `Deploy` and `Staging` only for `Main` [#1403](https://github.com/ie3-institute/PowerSystemDataModel/issues/1403)
diff --git a/src/main/java/edu/ie3/datamodel/io/sink/CsvFileSink.java b/src/main/java/edu/ie3/datamodel/io/sink/CsvFileSink.java
index 4b08d00f6..996eceab7 100644
--- a/src/main/java/edu/ie3/datamodel/io/sink/CsvFileSink.java
+++ b/src/main/java/edu/ie3/datamodel/io/sink/CsvFileSink.java
@@ -10,6 +10,7 @@
 import edu.ie3.datamodel.io.csv.BufferedCsvWriter;
 import edu.ie3.datamodel.io.csv.CsvFileDefinition;
 import edu.ie3.datamodel.io.extractor.Extractor;
+import edu.ie3.datamodel.io.extractor.HasEm;
 import edu.ie3.datamodel.io.extractor.NestedEntity;
 import edu.ie3.datamodel.io.naming.FileNamingStrategy;
 import edu.ie3.datamodel.io.processor.ProcessorProvider;
@@ -225,14 +226,29 @@ public void persistJointGrid(JointGridContainer jointGridContainer) {
             .flatMap(Optional::stream)
             .collect(Collectors.toSet());
 
+    // extract all EmInput entities
+    Set<EmInput> emInputs =
+        systemParticipants.allEntitiesAsList().stream()
+            .filter(Objects::nonNull)
+            .map(HasEm.class::cast)
+            .map(HasEm::getControllingEm)
+            .flatMap(Optional::stream)
+            .flatMap(
+                em ->
+                    Stream.iterate(
+                        em, Objects::nonNull, current -> current.getControllingEm().orElse(null)))
+            .collect(Collectors.toSet());
+
     // persist all entities
     Stream.of(
             rawGridElements.allEntitiesAsList(),
             systemParticipants.allEntitiesAsList(),
             graphicElements.allEntitiesAsList(),
             types,
-            operators)
+            operators,
+            emInputs)
         .flatMap(Collection::stream)
+        .collect(Collectors.toSet())
         .forEach(this::persistIgnoreNested);
   }
 
diff --git a/src/test/groovy/edu/ie3/datamodel/io/sink/CsvFileSinkTest.groovy b/src/test/groovy/edu/ie3/datamodel/io/sink/CsvFileSinkTest.groovy
index 08b563aa4..d84fd302a 100644
--- a/src/test/groovy/edu/ie3/datamodel/io/sink/CsvFileSinkTest.groovy
+++ b/src/test/groovy/edu/ie3/datamodel/io/sink/CsvFileSinkTest.groovy
@@ -357,6 +357,7 @@ class CsvFileSinkTest extends Specification implements TimeSeriesTestData {
     testBaseFolderPath.resolve("storage_type_input.csv").toFile().exists()
     testBaseFolderPath.resolve("transformer_2_w_input.csv").toFile().exists()
     testBaseFolderPath.resolve("transformer_2_w_type_input.csv").toFile().exists()
+    testBaseFolderPath.resolve("em_input.csv").toFile().exists()
 
     cleanup:
     csvFileSink.shutdown()