algún avance con copilot en apgar

lib/ai/formula_screen.dart

@@ -1,3 +1,4 @@
+// dart
 import 'package:flutter/material.dart';
 import 'package:flutter_markdown/flutter_markdown.dart';
 import '../formula_models.dart';
@@ -15,9 +16,6 @@ class FormulaScreen extends StatefulWidget {
   State<FormulaScreen> createState() => _FormulaScreenState();
 }
 
-// TODO: Create VariableWidget. Depending on VariableSpec.values, it can be a ValueDropdown or a D4rtEditingController
-//       The d4rtValue will be FormulaResult?
-
 //// Start of D4rtEditingController class ////
 class D4rtEditingController extends TextEditingController {
   String? _lastError;
@@ -59,19 +57,25 @@ class _FormulaScreenState extends State<FormulaScreen> {
   final _formKey = GlobalKey<FormState>();
   final Map<String, D4rtEditingController> _inputControllers = {};
   final Map<String, String?> _selectedUnits = {};
+  final Map<String, String?> _selectedValues = {}; // for string dropdowns
   String? _result;
   String? _selectedOutputUnit;
 
-
   @override
   void initState() {
     super.initState();
     // Initialize controllers and units with listeners
     for (final input in widget.formula.input) {
-      _inputControllers[input.name] = D4rtEditingController();
       _selectedUnits[input.name] = input.unit;
+      if (input.values != null && input.values!.isNotEmpty) {
+        // string/categorical variable -> use dropdown
+        _selectedValues[input.name] = input.values!.first;
+      } else {
+        // numeric variable -> use D4rtEditingController
+        _inputControllers[input.name] = D4rtEditingController();
         _inputControllers[input.name]!.addListener(_evaluateFormula);
       }
+    }
     _selectedOutputUnit = widget.formula.output.unit;
   }
 
@@ -91,34 +95,41 @@ class _FormulaScreenState extends State<FormulaScreen> {
     try {
       final inputValues = <String, dynamic>{};
       for (final input in widget.formula.input) {
+        // string/categorical variable
+        if (input.values != null && input.values!.isNotEmpty) {
+          final selected = _selectedValues[input.name];
+          if (selected == null) {
+            _result = "";
+            return;
+          }
+          inputValues[input.name] = selected;
+          continue;
+        }
+
+        // numeric variable - must have controller
         final controller = _inputControllers[input.name]!;
-        if (controller.d4rtValue == null) {
-          //throw FormulaEvaluationException("Field ${input.name} is invalid");
+        final val = controller.d4rtValue;
+        if (val == null) {
           _result = "";
           return;
         }
 
-        late final dynamic convertedValue;
-
-        switch (controller.d4rtValue) {
-          case NumberResult nr:
-            // Convert input to base unit if needed
-            // Always convert from dropdown unit to variable's base unit
+        dynamic convertedValue;
+        if (val is NumberResult) {
           if (input.unit != null) {
             convertedValue = widget.corpus.convert(
-                nr.value,
+              val.value,
               _selectedUnits[input.name]!,
               input.unit as String,
             );
           } else {
-              convertedValue = nr.value;
+            convertedValue = val.value;
           }
-
-          case StringResult sr:
-            convertedValue = sr.value;
-          default:
+        } else if (val is StringResult) {
+          convertedValue = val.value;
+        } else {
           throw FormulaEvaluationException(
-              "Field ${input.name} has unsupported type ${controller.d4rtValue!.runtimeType}",
+            "Field ${input.name} has unsupported type ${val.runtimeType}",
           );
         }
 
@@ -131,14 +142,15 @@ class _FormulaScreenState extends State<FormulaScreen> {
       // Convert output to selected unit if needed
       String? unit = widget.formula.output.unit;
       if (unit != null) {
-        _result = widget.corpus
-            .convert(result, unit, _selectedOutputUnit!)
-            .toStringAsFixed(2);
+        final converted = widget.corpus.convert(result, unit, _selectedOutputUnit!);
+        if (converted is num) {
+          _result = converted.toStringAsFixed(2);
         } else {
-        _result = result;
+          _result = converted.toString();
+        }
+      } else {
+        _result = result?.toString();
       }
-
-      //print( "_evaluateFormula: result:${result} _result:${_result}");
 
       setState(() {});
     } catch (e, stack) {
@@ -269,12 +281,51 @@ class _FormulaScreenState extends State<FormulaScreen> {
   }
 
   Widget _buildVariableRow(VariableSpec variable) {
+    final isCategorical = variable.values != null && variable.values!.isNotEmpty;
+
     return Padding(
       padding: const EdgeInsets.symmetric(vertical: 8.0),
       child: Row(
         children: [
           Text(variable.name),
           const Spacer(),
+          if (isCategorical) ...[
+            SizedBox(
+              width: 150,
+              child: DropdownButtonFormField<String>(
+                value: _selectedValues[variable.name],
+                items: variable.values!
+                    .map((v) => DropdownMenuItem<String>(value: v, child: Text(v)))
+                    .toList(),
+                onChanged: (v) {
+                  setState(() {
+                    _selectedValues[variable.name] = v;
+                  });
+                  _evaluateFormula();
+                },
+                decoration: const InputDecoration(
+                  border: UnderlineInputBorder(),
+                ),
+                validator: (value) {
+                  if (value == null || value.isEmpty) return 'Required';
+                  return null;
+                },
+              ),
+            ),
+            const SizedBox(width: 8),
+            if (variable.unit != null)
+              UnitDropdown(
+                corpus: widget.corpus,
+                variable: variable,
+                selectedUnit: _selectedUnits[variable.name],
+                onUnitChanged: (unit) {
+                  setState(() {
+                    _selectedUnits[variable.name] = unit;
+                  });
+                  _evaluateFormula();
+                },
+              ),
+          ] else ...[
             SizedBox(
               width: 100,
               child: TextFormField(
@@ -296,6 +347,7 @@ class _FormulaScreenState extends State<FormulaScreen> {
               ),
             ),
             const SizedBox(width: 8),
+            if (variable.unit != null)
               UnitDropdown(
                 corpus: widget.corpus,
                 variable: variable,
@@ -308,6 +360,7 @@ class _FormulaScreenState extends State<FormulaScreen> {
                 },
               ),
           ],
+        ],
       ),
     );
   }