refactor(document): extract title composition into shared DocumentTitleFactory (#726)

Move DocumentTitleFormatter from importing into the document package and
introduce DocumentTitleFactory there as the single source of truth for the
{index} – {dateLabel} – {location} formula. DocumentImporter now consumes the
factory instead of owning the composition; the document package owns the rule,
importing depends on it (not the reverse). No behavioral change — importer
title assertions and the #666 fixture parity test stay green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/src/main/java/org/raddatz/familienarchiv/document/DocumentTitleFactory.java

@@ -0,0 +1,37 @@
+package org.raddatz.familienarchiv.document;
+
+import org.springframework.stereotype.Component;
+
+/**
+ * Single source of truth for the auto-generated document title
+ * {@code {index} – {dateLabel} – {location}}.
+ *
+ * <p>The {@code document} package owns this formula; {@code importing} consumes it
+ * (see ADR for issue #726). The leading {@code index} is the document's
+ * {@code originalFilename}; the date label is the honest German label produced by
+ * {@link DocumentTitleFormatter} (the Java half of the #666 date-label split); the
+ * trailing location is the {@code meta_location} verbatim, omitted when blank.
+ */
+@Component
+public class DocumentTitleFactory {
+
+    static final String SEPARATOR = " – ";
+
+    /**
+     * Composes the auto-title from the document's current state. The date segment is
+     * dropped for UNKNOWN precision or a null date (the honest "no date" case); the
+     * location segment is dropped when blank.
+     */
+    public String build(Document doc) {
+        StringBuilder title = new StringBuilder(doc.getOriginalFilename());
+        if (doc.getDocumentDate() != null && doc.getMetaDatePrecision() != DatePrecision.UNKNOWN) {
+            title.append(SEPARATOR).append(DocumentTitleFormatter.formatTitleDate(
+                    doc.getDocumentDate(), doc.getMetaDatePrecision(),
+                    doc.getMetaDateEnd(), doc.getMetaDateRaw()));
+        }
+        if (doc.getLocation() != null && !doc.getLocation().isBlank()) {
+            title.append(SEPARATOR).append(doc.getLocation());
+        }
+        return title.toString();
+    }
+}

backend/src/main/java/org/raddatz/familienarchiv/document/DocumentTitleFormatter.java

@@ -1,6 +1,4 @@
-package org.raddatz.familienarchiv.importing;
+package org.raddatz.familienarchiv.document;
-
-import org.raddatz.familienarchiv.document.DatePrecision;
 
 import java.time.LocalDate;
 import java.time.format.DateTimeFormatter;

backend/src/main/java/org/raddatz/familienarchiv/importing/DocumentImporter.java

@@ -5,6 +5,7 @@ import lombok.extern.slf4j.Slf4j;
 import org.raddatz.familienarchiv.document.DatePrecision;
 import org.raddatz.familienarchiv.document.Document;
 import org.raddatz.familienarchiv.document.DocumentService;
+import org.raddatz.familienarchiv.document.DocumentTitleFactory;
 import org.raddatz.familienarchiv.document.DocumentStatus;
 import org.raddatz.familienarchiv.document.ThumbnailAsyncRunner;
 import org.raddatz.familienarchiv.exception.DomainException;
@@ -74,6 +75,7 @@ public class DocumentImporter {
             Pattern.compile("[A-Za-z\\u00C0-\\u00D6\\u00D8-\\u00F6\\u00F8-\\u00FF]{1,4}-+\\d+x?");
 
     private final DocumentService documentService;
+    private final DocumentTitleFactory documentTitleFactory;
     private final PersonService personService;
     private final TagService tagService;
     private final S3Client s3Client;
@@ -181,7 +183,7 @@ public class DocumentImporter {
         applyAttribution(doc, row);
         applyDates(doc, row);
         applyAuthoritativeAssociations(doc, row);
-        applyFileMetadata(doc, s3Key, contentType, status, index);
+        applyFileMetadata(doc, s3Key, contentType, status);
         applyComputedFlags(doc);
         return doc;
     }
@@ -217,14 +219,15 @@ public class DocumentImporter {
         attachTag(doc, row.get("tags"));
     }
 
-    // S3 key, content type, status, and the index-derived title.
+    // S3 key, content type, status, and the index-derived title. The title formula lives in
+    // the document package's DocumentTitleFactory (single source of truth, #726); by this point
+    // applyDates has populated the date/location and originalFilename carries the index.
     private void applyFileMetadata(Document doc, String s3Key, String contentType,
-                                   DocumentStatus status, String index) {
+                                   DocumentStatus status) {
         doc.setStatus(status);
         doc.setFilePath(s3Key);
         doc.setContentType(contentType);
-        doc.setTitle(buildTitle(index, doc.getDocumentDate(), doc.getMetaDatePrecision(),
+        doc.setTitle(documentTitleFactory.build(doc));
-                doc.getMetaDateEnd(), doc.getMetaDateRaw(), doc.getLocation()));
     }
 
     // metadataComplete: a document counts as fully described if any of the three "who/when"
@@ -235,20 +238,6 @@ public class DocumentImporter {
                 || !doc.getReceivers().isEmpty());
     }
 
-    // The title carries the date at the HONEST precision (never a fabricated day) via the
-    // shared DocumentTitleFormatter, plus the location — kept under 20 lines by delegating.
-    private static String buildTitle(String index, LocalDate date, DatePrecision precision,
-                                     LocalDate end, String raw, String location) {
-        StringBuilder title = new StringBuilder(index);
-        if (date != null && precision != DatePrecision.UNKNOWN) {
-            title.append(" – ").append(DocumentTitleFormatter.formatTitleDate(date, precision, end, raw));
-        }
-        if (location != null && !location.isBlank()) {
-            title.append(" – ").append(location);
-        }
-        return title.toString();
-    }
-
     // ─── attribution routing — register-first, always retain raw ─────────────────────
 
     private Person resolveSender(String slug, String rawName) {

backend/src/test/java/org/raddatz/familienarchiv/document/DocumentTitleFactoryTest.java

@@ -0,0 +1,82 @@
+package org.raddatz.familienarchiv.document;
+
+import org.junit.jupiter.api.Test;
+
+import java.time.LocalDate;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * The auto-title composition {@code {index} – {dateLabel} – {location}} in isolation.
+ * The honest date-label forms themselves are pinned by {@link DocumentTitleFormatterTest}
+ * against the shared #666 fixture; here we assert only how the factory composes the
+ * three segments and which segments it omits.
+ */
+class DocumentTitleFactoryTest {
+
+    private final DocumentTitleFactory factory = new DocumentTitleFactory();
+
+    private static Document.DocumentBuilder doc(String index) {
+        return Document.builder()
+                .originalFilename(index)
+                .metaDatePrecision(DatePrecision.UNKNOWN);
+    }
+
+    @Test
+    void index_only_when_no_date_and_no_location() {
+        assertThat(factory.build(doc("C-0029").build())).isEqualTo("C-0029");
+    }
+
+    @Test
+    void index_and_year_date() {
+        Document d = doc("C-0029")
+                .documentDate(LocalDate.of(1928, 1, 15))
+                .metaDatePrecision(DatePrecision.YEAR)
+                .build();
+        assertThat(factory.build(d)).isEqualTo("C-0029 – 1928");
+    }
+
+    @Test
+    void index_date_and_location() {
+        Document d = doc("C-0029")
+                .documentDate(LocalDate.of(1928, 1, 15))
+                .metaDatePrecision(DatePrecision.YEAR)
+                .location("Berlin")
+                .build();
+        assertThat(factory.build(d)).isEqualTo("C-0029 – 1928 – Berlin");
+    }
+
+    @Test
+    void location_without_date_attaches_directly_to_index() {
+        Document d = doc("C-0029").location("Berlin").build();
+        assertThat(factory.build(d)).isEqualTo("C-0029 – Berlin");
+    }
+
+    @Test
+    void unknown_precision_omits_the_date_segment() {
+        Document d = doc("C-0029")
+                .documentDate(LocalDate.of(1928, 1, 15))
+                .metaDatePrecision(DatePrecision.UNKNOWN)
+                .build();
+        assertThat(factory.build(d)).isEqualTo("C-0029");
+    }
+
+    @Test
+    void blank_location_is_omitted() {
+        Document d = doc("C-0029")
+                .documentDate(LocalDate.of(1928, 1, 15))
+                .metaDatePrecision(DatePrecision.YEAR)
+                .location("   ")
+                .build();
+        assertThat(factory.build(d)).isEqualTo("C-0029 – 1928");
+    }
+
+    @Test
+    void day_precision_renders_the_full_german_label() {
+        Document d = doc("C-0029")
+                .documentDate(LocalDate.of(1928, 1, 15))
+                .metaDatePrecision(DatePrecision.DAY)
+                .build();
+        assertThat(factory.build(d)).isEqualTo("C-0029 – 15. Januar 1928");
+    }
+}

backend/src/test/java/org/raddatz/familienarchiv/document/DocumentTitleFormatterTest.java

@@ -1,10 +1,9 @@
-package org.raddatz.familienarchiv.importing;
+package org.raddatz.familienarchiv.document;
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import org.junit.jupiter.api.DynamicTest;
 import org.junit.jupiter.api.TestFactory;
-import org.raddatz.familienarchiv.document.DatePrecision;
 
 import java.nio.file.Files;
 import java.nio.file.Path;

backend/src/test/java/org/raddatz/familienarchiv/importing/DocumentImporterTest.java

@@ -11,6 +11,7 @@ import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
 import org.raddatz.familienarchiv.document.Document;
 import org.raddatz.familienarchiv.document.DocumentService;
+import org.raddatz.familienarchiv.document.DocumentTitleFactory;
 import org.raddatz.familienarchiv.document.DocumentStatus;
 import org.raddatz.familienarchiv.document.ThumbnailAsyncRunner;
 import org.raddatz.familienarchiv.person.Person;
@@ -59,8 +60,10 @@ class DocumentImporterTest {
         // override this stub locally (load_skipsFile_whenMagicByteCheckThrowsIoException).
         lenient().when(fileStreamOpener.open(any(File.class)))
                 .thenAnswer(inv -> new java.io.FileInputStream(inv.getArgument(0, File.class)));
-        importer = new DocumentImporter(documentService, personService, tagService, s3Client,
+        // Real factory (pure, dependency-free) so the title-content assertions below exercise
-                thumbnailAsyncRunner, fileStreamOpener);
+        // the shared composition rather than a stub — the #726 single source of truth.
+        importer = new DocumentImporter(documentService, new DocumentTitleFactory(), personService,
+                tagService, s3Client, thumbnailAsyncRunner, fileStreamOpener);
         ReflectionTestUtils.setField(importer, "bucketName", "test-bucket");
     }