save formula, not tested

lib/ai/formula_editor.dart

@@ -5,6 +5,8 @@ import 'package:flutter_markdown_plus/flutter_markdown_plus.dart';
 import 'package:markdown/markdown.dart' as markdown;
 import '../formula_models.dart';
 import '../corpus.dart';
+import '../database/database_service.dart';
+import '../service_locator.dart';
 import 'formula_screen.dart';
 import 'unit_dropdown.dart';
 
@@ -13,11 +15,13 @@ import 'unit_dropdown.dart';
 class FormulaEditor extends StatefulWidget {
   final Formula formula;
   final Corpus corpus;
+  final Function(Formula)? onSave; // Callback when formula is saved
 
   const FormulaEditor({
     super.key,
     required this.formula,
     required this.corpus,
+    this.onSave,
   });
 
   @override
@@ -181,7 +185,7 @@ class _FormulaEditorState extends State<FormulaEditor> {
     }
   }
 
-  void _saveFormula() {
+  Future<void> _saveFormula() async {
     if (!_validateFormula()) {
       return;
     }
@@ -189,14 +193,34 @@ class _FormulaEditorState extends State<FormulaEditor> {
     final formula = _buildFormula();
     if (formula == null) return;
 
-    // For now, just show a success message
-    // In a real implementation, this would save to database
+    try {
+      final database = getDatabase();
+      
+      // Update corpus in memory
+      widget.corpus.updateFormula(formula);
+      
+      // Update database
+      final updated = await database.updateFormula(formula);
+      
+      if (!updated) {
+        // If formula wasn't found (e.g., name changed), add it as new
+        await database.addFormula(formula);
+      }
+      
+      // Call the onSave callback if provided
+      widget.onSave?.call(formula);
+      
+      // Show success message
       ScaffoldMessenger.of(context).showSnackBar(
         SnackBar(
           content: Text('Formula "${formula.name}" saved successfully!'),
           backgroundColor: Theme.of(context).colorScheme.primary,
         ),
       );
+    } catch (e, stack) {
+      print('Error saving formula: $e\n$stack');
+      _showErrorDialog('Error saving formula: $e');
+    }
   }
 
   void _showErrorDialog(String message) {

lib/ai/formula_list.dart

@@ -80,6 +80,12 @@ class _FormulaListState extends State<FormulaList> {
         builder: (context) => FormulaEditor(
           formula: formula,
           corpus: widget.corpus,
+          onSave: (updatedFormula) {
+            // Refresh the formula list after saving
+            setState(() {
+              // The corpus has been updated, so we just need to rebuild
+            });
+          },
         ),
       ),
     );

lib/ai/formula_screen.dart

@@ -184,6 +184,12 @@ class _FormulaScreenState extends State<FormulaScreen> {
                   builder: (context) => FormulaEditor(
                     formula: widget.formula,
                     corpus: widget.corpus,
+                    onSave: (updatedFormula) {
+                      // Refresh the screen after saving
+                      setState(() {
+                        // The corpus has been updated, refresh the displayed formula
+                      });
+                    },
                   ),
                 ),
               );

lib/corpus.dart

@@ -63,6 +63,27 @@ class Corpus{
     return _allFormulas.get(name);
   }
 
+  /// Updates a formula in the corpus
+  void updateFormula(Formula formula) {
+    if (!_allFormulas.containsKey(formula.name)) {
+      throw ArgumentError("Formula not found: ${formula.name}");
+    }
+    
+    // Remove old tags
+    final oldFormula = _allFormulas[formula.name]!;
+    for (final tag in oldFormula.tags) {
+      _tags[tag]?.removeWhere((f) => f.name == formula.name);
+    }
+    
+    // Update the formula
+    _allFormulas[formula.name] = formula;
+    
+    // Add new tags
+    for (final tag in formula.tags) {
+      _tags[tag]?.add(formula);
+    }
+  }
+
   final Multimap<String, String> _baseToUnits = Multimap.create();
   final Map<String, UnitSpec> _allUnits = {};
 

lib/database/database_service.dart

@@ -35,4 +35,59 @@ extension CorpusDatabaseExtension on FormulasDatabase {
       await insertFormulaElement(element.toStringLiteral());
     }
   }
+
+  // Method to update a formula in the database by name
+  Future<bool> updateFormula(models.Formula formula) async {
+    final elements = await getAllFormulaElements();
+    
+    for (final element in elements) {
+      try {
+        final parsed = models.parseCorpusElements('[${element.elementText}]');
+        if (parsed.isNotEmpty && parsed.first is models.Formula) {
+          final existingFormula = parsed.first as models.Formula;
+          if (existingFormula.name == formula.name) {
+            // Update this element
+            await updateFormulaElement(
+              element.id, 
+              formula.toStringLiteral()
+            );
+            return true;
+          }
+        }
+      } catch (e) {
+        print('Error parsing database element during update: $e');
+        continue;
+      }
+    }
+    
+    return false; // Formula not found
+  }
+
+  // Method to add a new formula to the database
+  Future<void> addFormula(models.Formula formula) async {
+    await insertFormulaElement(formula.toStringLiteral());
+  }
+
+  // Method to delete a formula from the database by name
+  Future<bool> deleteFormula(String formulaName) async {
+    final elements = await getAllFormulaElements();
+    
+    for (final element in elements) {
+      try {
+        final parsed = models.parseCorpusElements('[${element.elementText}]');
+        if (parsed.isNotEmpty && parsed.first is models.Formula) {
+          final existingFormula = parsed.first as models.Formula;
+          if (existingFormula.name == formulaName) {
+            await deleteFormulaElement(element.id);
+            return true;
+          }
+        }
+      } catch (e) {
+        print('Error parsing database element during delete: $e');
+        continue;
+      }
+    }
+    
+    return false; // Formula not found
+  }
 }