Add instrument selector to work editor

lib/editors/work.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 
 import '../backend.dart';
 import '../database.dart';
+import '../selectors/instruments.dart';
 import '../selectors/person.dart';
 
 class WorkEditor extends StatefulWidget {
@@ -20,6 +21,7 @@ class _WorkEditorState extends State<WorkEditor> {
 
   Backend backend;
   Person composer;
+  List<Instrument> instruments = [];
 
   @override
   void initState() {
@@ -36,7 +38,8 @@ class _WorkEditorState extends State<WorkEditor> {
 
     backend = Backend.of(context);
 
-    if (widget.work != null && widget.work.composer != null) {
+    if (widget.work != null) {
+      if (widget.work.composer != null) {
         () async {
           final person =
               await backend.db.personById(widget.work.composer).getSingle();
@@ -49,6 +52,19 @@ class _WorkEditorState extends State<WorkEditor> {
           }
         }();
       }
+
+      () 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;
+          });
+        }
+      }();
+    }
   }
 
   @override
@@ -94,6 +110,26 @@ class _WorkEditorState extends State<WorkEditor> {
               }
             },
           ),
+          ListTile(
+            title: Text('Instruments'),
+            subtitle: Text(instruments.isNotEmpty
+                ? instruments.map((i) => i.name).join(', ')
+                : 'Select instruments'),
+            onTap: () async {
+              final List<Instrument> selection = await Navigator.push(
+                  context,
+                  MaterialPageRoute(
+                    builder: (context) => InstrumentsSelector(),
+                    fullscreenDialog: true,
+                  ));
+
+              if (selection != null) {
+                setState(() {
+                  instruments = selection;
+                });
+              }
+            },
+          ),
         ],
       ),
     );