Part parameters (#224)

* Adds class representing the PartParameter model

* Adds API method for determining support for PartParmaters

* Display part parameter count in part detail widget

* Adds user setting for controlling if part parameters are displayed

* Fix URL for model

* Widget for displaying part parameters

* linting

lib/widget/part_detail.dart

@@ -10,11 +10,13 @@ import "package:inventree/helpers.dart";
 import "package:inventree/inventree/bom.dart";
 import "package:inventree/inventree/part.dart";
 import "package:inventree/inventree/stock.dart";
+import "package:inventree/preferences.dart";
 
 import "package:inventree/widget/attachment_widget.dart";
 import "package:inventree/widget/bom_list.dart";
 import "package:inventree/widget/part_list.dart";
 import "package:inventree/widget/part_notes.dart";
+import "package:inventree/widget/part_parameter_widget.dart";
 import "package:inventree/widget/progress.dart";
 import "package:inventree/widget/category_display.dart";
 import "package:inventree/widget/refreshable_state.dart";
@@ -47,6 +49,10 @@ class _PartDisplayState extends RefreshableState<PartDetailWidget> {
 
   InvenTreePart? parentPart;
 
+  int parameterCount = 0;
+
+  bool showParameters = false;
+
   int attachmentCount = 0;
 
   int bomCount = 0;
@@ -132,6 +138,24 @@ class _PartDisplayState extends RefreshableState<PartDetailWidget> {
       }
     });
 
+    // Request the number of parameters for this part
+    if (InvenTreeAPI().supportsPartParameters) {
+
+      showParameters = await InvenTreeSettingsManager().getValue(INV_PART_SHOW_PARAMETERS, true) as bool;
+
+      InvenTreePartParameter().count(
+          filters: {
+            "part": part.pk.toString(),
+          }
+      ).then((int value) {
+        if (mounted) {
+          setState(() {
+            parameterCount = value;
+          });
+        }
+      });
+    }
+
     // Request the number of attachments
     InvenTreePartAttachment().count(
       filters: {
@@ -510,20 +534,6 @@ class _PartDisplayState extends RefreshableState<PartDetailWidget> {
       );
     }
 
-
-    // TODO - Add request tests?
-    /*
-    if (part.isTrackable) {
-      tiles.add(ListTile(
-          title: Text(L10().testsRequired),
-          leading: FaIcon(FontAwesomeIcons.tasks),
-          trailing: Text("${part.testTemplateCount}"),
-          onTap: null,
-        )
-      );
-    }
-     */
-
     // Notes field
     tiles.add(
       ListTile(
@@ -539,6 +549,24 @@ class _PartDisplayState extends RefreshableState<PartDetailWidget> {
       )
     );
 
+    if (showParameters) {
+      tiles.add(
+          ListTile(
+              title: Text(L10().parameters),
+              leading: FaIcon(FontAwesomeIcons.thList, color: COLOR_CLICK),
+              trailing: parameterCount > 0 ? Text(parameterCount.toString()) : null,
+              onTap: () {
+                Navigator.push(
+                  context,
+                  MaterialPageRoute(
+                    builder: (context) => PartParameterWidget(part)
+                  )
+                );
+              }
+          )
+      );
+    }
+
     tiles.add(
       ListTile(
         title: Text(L10().attachments),

lib/widget/part_parameter_widget.dart

@@ -0,0 +1,105 @@
+import "package:flutter/material.dart";
+import "package:inventree/inventree/model.dart";
+
+import "package:inventree/l10.dart";
+import "package:inventree/inventree/part.dart";
+import "package:inventree/widget/paginator.dart";
+import "package:inventree/widget/refreshable_state.dart";
+
+/*
+ * Widget for displaying a list of parameters associated with a given Part instance
+ */
+class PartParameterWidget extends StatefulWidget {
+
+  const PartParameterWidget(this.part);
+
+  final InvenTreePart part;
+
+  @override
+  _ParameterWidgetState createState() => _ParameterWidgetState();
+}
+
+
+class _ParameterWidgetState extends RefreshableState<PartParameterWidget> {
+  _ParameterWidgetState();
+
+  @override
+  String getAppBarTitle(BuildContext context) {
+    return L10().parameters;
+  }
+
+  @override
+  List<Widget> getAppBarActions(BuildContext context) {
+    return [];
+  }
+
+  @override
+  Widget getBody(BuildContext context) {
+
+    Map<String, String> filters = {
+      "part": widget.part.pk.toString()
+    };
+
+    return Column(
+      children: [
+        Expanded(
+          child: PaginatedParameterList(
+            filters,
+            false,
+          )
+        )
+      ],
+    );
+  }
+}
+
+
+/*
+ * Widget for displaying a paginated list of Part parameters
+ */
+class PaginatedParameterList extends PaginatedSearchWidget {
+
+  const PaginatedParameterList(Map<String, String> filters, bool showSearch) : super(filters: filters, showSearch: showSearch);
+
+  @override
+  _PaginatedParameterState createState() => _PaginatedParameterState();
+}
+
+
+class _PaginatedParameterState extends PaginatedSearchState<PaginatedParameterList> {
+
+  _PaginatedParameterState() : super();
+
+  @override
+  String get prefix => "parameters_";
+
+  @override
+  Map<String, String> get orderingOptions => {
+    // TODO
+  };
+
+  @override
+  Map<String, Map<String, dynamic>> get filterOptions => {
+    // TODO
+  };
+
+  @override
+  Future<InvenTreePageResponse?> requestPage(int limit, int offset, Map<String, String> params) async {
+
+    final page = await InvenTreePartParameter().listPaginated(limit, offset, filters: params);
+
+    return page;
+  }
+
+  @override
+  Widget buildItem(BuildContext context, InvenTreeModel model) {
+
+    InvenTreePartParameter parameter = model as InvenTreePartParameter;
+
+    return ListTile(
+      title: Text(parameter.name),
+      subtitle: Text(parameter.description),
+      trailing: Text(parameter.valueString),
+    );
+  }
+}