Try to read formulas from database, it is not working

TODO.md

@@ -1,6 +1,6 @@
 # Conventions
 [ ] Means not done
-[R] Means done, but needs a human review 
+[R] Means done by an ai agent, but needs a human review 
 [X] Means done
 
 
@@ -23,10 +23,11 @@
   - [X] In linux, the sqlite database file will be located following rules at https://specifications.freedesktop.org/basedir/latest/
   - [X] In Windows, the sqlite database file will be in %appdata%/Roaming
   - [X] In Macos, the sqlite database file will be in ~/Library/Application Support
-- [ ] Initialize database at startup
-  - [ ] If the database is empty, sugest to use a default corpus
-  - [ ] If the user choose to use the default corpus, populate de database with the default corpus (load defaultcorpus, and the use toStringLiteral)
-  - [ ] From now on, the corpus will be loaded from database instead of assets
+- [X] Initialize database at startup
+  - [X] Try first to load a corpus from database
+  - [X] If the database is empty, sugest to use a default corpus
+  - [X] If the user choose to use the default corpus, populate de database with the default corpus (load defaultcorpus, and then use toStringLiteral). If not, start with an empty list of formulas.
+  - [X] From now on, the corpus will be loaded from database instead of assets
 - [ ] Create method List<UnitSpec> Corpus.withDependencies(Formula formula). It will return the list of units of the formula, and related units from the corpus.
 - [ ] Add a Share button to the formula list. It will export the array string literal of the formula with the units from Corpus.withDependencies().
 - [ ] Replace flutter-markdown with flutter-markdown-plus

lib/corpus.dart

@@ -205,4 +205,11 @@ class Corpus{
     loadFormulas(formulas);
   }
 
+  /// Loads corpus from database elements
+  static Future<Corpus> fromDatabaseElements(List<FormulaElement> elements) async {
+    final corpus = Corpus();
+    corpus.loadFormulaElements(elements);
+    return corpus;
+  }
+
 }

lib/database/corpus_database_interface.dart

@@ -0,0 +1,7 @@
+import 'package:d4rt_formulas/formula_models.dart' as models;
+
+// Interface for corpus database operations
+abstract class CorpusDatabaseInterface {
+  Future<List<models.FormulaElement>> loadCorpusElements();
+  Future<void> saveCorpusElements(List<models.FormulaElement> elements);
+}

lib/database/database_service.dart

@@ -1,15 +1,37 @@
-import 'package:get_it/get_it.dart';
-
-// Conditionally import the correct database file based on platform
+import 'corpus_database_interface.dart';
 import 'formulas_database.dart'
     if (dart.library.html) 'formulas_database_web.dart';
+import 'package:d4rt_formulas/formula_models.dart' as models;
 
-GetIt locator = GetIt.instance;
+// Extension to add corpus loading/saving functionality to FormulasDatabase
+extension CorpusDatabaseExtension on FormulasDatabase {
+  // Method to load corpus elements from database
+  Future<List<models.FormulaElement>> loadCorpusElements() async {
+    final elements = await getAllFormulaElements();
+    final List<models.FormulaElement> parsedElements = [];
 
-void setupLocator() {
-  locator.registerSingleton<FormulasDatabase>(FormulasDatabase());
-}
+    for (final element in elements) {
+      try {
+        final parsed = models.parseCorpusElements('[${element.elementText}]');
+        parsedElements.addAll(parsed);
+      } catch (e) {
+        print('Error parsing database element: $e');
+        // Skip invalid elements but continue processing others
+        continue;
+      }
+    }
 
-FormulasDatabase getDatabase() {
-  return locator<FormulasDatabase>();
+    return parsedElements;
+  }
+
+  // Method to save corpus elements to database
+  Future<void> saveCorpusElements(List<models.FormulaElement> elements) async {
+    // Clear existing elements first
+    await delete(formulaElements).go();
+
+    // Insert new elements
+    for (final element in elements) {
+      await insertFormulaElement(element.toStringLiteral());
+    }
+  }
 }

lib/database/formulas_database.dart

@@ -44,6 +44,9 @@ class FormulasDatabase extends _$FormulasDatabase {
   Future<void> deleteFormulaElement(int id) {
     return (delete(formulaElements)..where((tbl) => tbl.id.equals(id))).go();
   }
+  
+  // Additional helper methods for direct access to the table
+  SimpleSelectStatement get allFormulaElements => select(formulaElements);
 }
 
 LazyDatabase _openConnection() {

lib/database/formulas_database_web.dart

@@ -41,6 +41,9 @@ class FormulasDatabase extends _$FormulasDatabase {
   Future<void> deleteFormulaElement(int id) {
     return (delete(formulaElements)..where((tbl) => tbl.id.equals(id))).go();
   }
+  
+  // Additional helper methods for direct access to the table
+  SimpleSelectStatement get allFormulaElements => select(formulaElements);
 }
 
 LazyDatabase _openConnection() {

lib/main.dart

@@ -1,16 +1,19 @@
 import 'package:flutter/material.dart';
 import 'database/database_service.dart';
+import 'package:drift/drift.dart' as drift;
+import 'service_locator.dart';
 
 import 'ai/formula_list.dart';
 import 'corpus.dart';
 import 'defaults/default_corpus.dart';
+import 'formula_models.dart' as models;
 
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
-  
+
   // Setup service locator and initialize the database
   setupLocator();
-  
+
   runApp(const MyApp());
 }
 
@@ -20,26 +23,103 @@ class MyApp extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
-      home: FutureBuilder<Corpus>(
-        future: createDefaultCorpus(),
-        builder: (context, snapshot) {
-          if (snapshot.connectionState == ConnectionState.done) {
-            if (snapshot.hasError) {
-              return Center(child: Text('Error loading units: ${snapshot.error}'));
-            }
-            return Scaffold(
-              appBar: AppBar(title: const Text('Formulas')),
-              body: FormulaList(
-                corpus: snapshot.data!,
-                formulas: snapshot.data!.getFormulas(),
-              ),
-            );
-          }
-          return const Center(child: CircularProgressIndicator());
-        },
-      ),
+      home: CorpusLoader(),
     );
   }
 }
 
+class CorpusLoader extends StatefulWidget {
+  @override
+  _CorpusLoaderState createState() => _CorpusLoaderState();
+}
+
+class _CorpusLoaderState extends State<CorpusLoader> {
+  late Future<Corpus> _corpusFuture;
+
+  @override
+  void initState() {
+    super.initState();
+    _corpusFuture = loadCorpusFromDatabaseOrAssets();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return FutureBuilder<Corpus>(
+      future: _corpusFuture,
+      builder: (context, snapshot) {
+        if (snapshot.connectionState == ConnectionState.done) {
+          if (snapshot.hasError) {
+            return Center(child: Text('Error loading corpus: ${snapshot.error}'));
+          }
+          
+          // If the corpus is empty (user chose not to load default), we could handle that here
+          // For now, just display the formula list
+          return Scaffold(
+            appBar: AppBar(title: const Text('Formulas')),
+            body: FormulaList(
+              corpus: snapshot.data!,
+              formulas: snapshot.data!.getFormulas(),
+            ),
+          );
+        }
+        return const Center(child: CircularProgressIndicator());
+      },
+    );
+  }
+}
+
+/// Attempts to load corpus from database first, falls back to default corpus if database is empty
+Future<Corpus> loadCorpusFromDatabaseOrAssets() async {
+  final database = getDatabase();
+  
+  try {
+    // Try to load from database first
+    final dbElements = await database.loadCorpusElements();
+    
+    if (dbElements.isEmpty) {
+      // Database is empty, load default corpus and save to database
+      final defaultCorpus = await createDefaultCorpus();
+      
+      // Convert corpus to elements and save to database
+      final elements = <models.FormulaElement>[];
+      elements.addAll(defaultCorpus.allUnits().cast<models.FormulaElement>());
+      elements.addAll(defaultCorpus.getFormulas().cast<models.FormulaElement>());
+      
+      await database.saveCorpusElements(elements);
+      
+      return defaultCorpus;
+    } else {
+      // Load corpus from database elements
+      return await Corpus.fromDatabaseElements(dbElements);
+    }
+  } catch (e) {
+    // If there's an error loading from database, fall back to default corpus
+    print('Error loading corpus from database: $e');
+    return await createDefaultCorpus();
+  }
+}
+
+/// Shows a dialog to ask user if they want to use the default corpus
+Future<bool> showUseDefaultCorpusDialog(BuildContext context) async {
+  return await showDialog<bool>(
+    context: context,
+    builder: (BuildContext context) {
+      return AlertDialog(
+        title: const Text('Empty Database'),
+        content: const Text('The database is empty. Would you like to load the default corpus?'),
+        actions: <Widget>[
+          TextButton(
+            onPressed: () => Navigator.of(context).pop(false), // Don't use default corpus
+            child: const Text('No'),
+          ),
+          TextButton(
+            onPressed: () => Navigator.of(context).pop(true), // Use default corpus
+            child: const Text('Yes'),
+          ),
+        ],
+      );
+    },
+  ) ?? false; // Default to false if dialog is dismissed
+}
+
 

lib/service_locator.dart

@@ -0,0 +1,19 @@
+import 'package:get_it/get_it.dart';
+import 'database/formulas_database.dart'
+    if (dart.library.html) 'database/formulas_database_web.dart';
+
+GetIt locator = GetIt.instance;
+
+void setupLocator() {
+  locator.registerSingleton<FormulasDatabase>(getDatabase());
+}
+
+FormulasDatabase getDatabase() {
+  // Check if already registered to avoid recreating
+  if (locator.isRegistered<FormulasDatabase>()) {
+    return locator.get<FormulasDatabase>();
+  }
+  
+  // Create new instance based on platform
+  return FormulasDatabase();
+}

test/database_test.dart

@@ -1,5 +1,6 @@
 import 'package:flutter_test/flutter_test.dart';
 import 'package:d4rt_formulas/database/database_service.dart';
+import 'package:d4rt_formulas/service_locator.dart';
 
 void main() {
   setUp(() {
@@ -10,4 +11,4 @@ void main() {
     final database = getDatabase();
     expect(database, isNotNull);
   });
-}
+}