Work editor: Initialize from WorkInfo

mobile/lib/editors/work.dart

@@ -157,10 +157,13 @@ class _PartTileState extends State<PartTile> {
 /// If the user is finished editing, the result will be returned as a [WorkInfo]
 /// object.
 class WorkEditor extends StatefulWidget {
-  final Work work;
+  /// The work to edit.
+  ///
+  /// If this is null, a new work will be created.
+  final WorkInfo workInfo;
 
   WorkEditor({
-    this.work,
+    this.workInfo,
   });
 
   @override
@@ -170,9 +173,6 @@ class WorkEditor extends StatefulWidget {
 class _WorkEditorState extends State<WorkEditor> {
   final titleController = TextEditingController();
 
-  BackendState backend;
-
-  String title = '';
   Person composer;
   List<Instrument> instruments = [];
   List<PartData> parts = [];
@@ -181,71 +181,26 @@ class _WorkEditorState extends State<WorkEditor> {
   void initState() {
     super.initState();
 
-    if (widget.work != null) {
+    if (widget.workInfo != null) {
-      titleController.text = widget.work.title;
+      titleController.text = widget.workInfo.work.title;
-    }
+      // TODO: Theoretically this includes the composers of all parts.
-  }
+      composer = widget.workInfo.composers.first;
+      instruments = List.from(widget.workInfo.instruments);
 
-  @override
+      for (final partInfo in widget.workInfo.parts) {
-  void didChangeDependencies() {
-    super.didChangeDependencies();
-
-    backend = Backend.of(context);
-
-    if (widget.work != null) {
-      if (widget.work.composer != null) {
-        () async {
-          final person =
-              await backend.db.personById(widget.work.composer).getSingle();
-
-          // We don't want to override a newly selected composer.
-          if (composer == null) {
-            setState(() {
-              composer = person;
-            });
-          }
-        }();
-      }
-
-      () async {
-        final selection =
-            await backend.db.instrumentsByWork(widget.work.id).get();
-
-        // We don't want to override already selected instruments.
-        if (instruments.isEmpty) {
-          setState(() {
-            instruments = selection;
-          });
-        }
-      }();
-
-      () async {
-        final dbParts = await backend.db.workParts(widget.work.id).get();
-        for (final dbPart in dbParts) {
-          final partInstruments =
-              await backend.db.instrumentsByWork(dbPart.id).get();
-
-          Person partComposer;
-
-          if (dbPart.composer != null) {
-            partComposer =
-                await backend.db.personById(dbPart.composer).getSingle();
-          }
-
-          setState(() {
         parts.add(PartData(
-              title: dbPart.title,
+          title: partInfo.work.title,
-              composer: partComposer,
+          composer: partInfo.composer,
-              instruments: partInstruments,
+          instruments: List.from(partInfo.instruments),
         ));
-          });
       }
-      }();
     }
   }
 
   @override
   Widget build(BuildContext context) {
+    final backend = Backend.of(context);
+
     final List<Widget> partTiles = [];
     for (var i = 0; i < parts.length; i++) {
       final part = parts[i];
@@ -297,7 +252,7 @@ class _WorkEditorState extends State<WorkEditor> {
           FlatButton(
             child: Text('DONE'),
             onPressed: () async {
-              final workId = widget.work?.id ?? generateId();
+              final workId = widget?.workInfo?.work?.id ?? generateId();
 
               List<PartInfo> partInfos = [];
               for (var i = 0; i < parts.length; i++) {

mobile/lib/screens/person.dart

@@ -47,17 +47,21 @@ class PersonScreen extends StatelessWidget {
                 final work = snapshot.data[index];
                 return ListTile(
                   title: Text(work.title),
-                  onTap: () => Navigator.push(
+                  onTap: () async {
+                    final workInfo = await backend.db.getWorkInfo(work);
+
+                    Navigator.push(
                       context,
                       MaterialPageRoute(
                         builder: (context) => WorkScreen(
-                        work: work,
+                          workInfo: workInfo,
-                      ),
                         ),
                       ),
                     );
                   },
                 );
+              },
+            );
           } else {
             return Container();
           }

mobile/lib/screens/work.dart

@@ -6,10 +6,10 @@ import '../editors/work.dart';
 import '../widgets/texts.dart';
 
 class WorkScreen extends StatelessWidget {
-  final Work work;
+  final WorkInfo workInfo;
 
   WorkScreen({
-    this.work,
+    this.workInfo,
   });
 
   @override
@@ -18,7 +18,7 @@ class WorkScreen extends StatelessWidget {
 
     return Scaffold(
       appBar: AppBar(
-        title: Text(work.title),
+        title: Text(workInfo.work.title),
         actions: <Widget>[
           IconButton(
             icon: const Icon(Icons.edit),
@@ -27,7 +27,7 @@ class WorkScreen extends StatelessWidget {
                 context,
                 MaterialPageRoute(
                   builder: (context) => WorkEditor(
-                    work: work,
+                    workInfo: workInfo,
                   ),
                   fullscreenDialog: true,
                 ),
@@ -37,7 +37,7 @@ class WorkScreen extends StatelessWidget {
         ],
       ),
       body: StreamBuilder<List<Recording>>(
-        stream: backend.db.recordingsByWork(work.id).watch(),
+        stream: backend.db.recordingsByWork(workInfo.work.id).watch(),
         builder: (context, snapshot) {
           if (snapshot.hasData) {
             return ListView.builder(