d4t_formulas/lib/database/formulas_database.dart

import 'package:drift/drift.dart';
import 'package:drift/native.dart';
import 'package:path/path.dart' as p;
import 'package:path_provider/path_provider.dart';
import 'dart:io';

part 'formulas_database.g.dart';

// Define the FORMULAELEMENT table to store both formulas and units as text
class FormulaElements extends Table {
  IntColumn get id => integer().autoIncrement()();
  TextColumn get elementText => text()();
}

@DriftDatabase(tables: [FormulaElements])
class FormulasDatabase extends _$FormulasDatabase {
  FormulasDatabase() : super(_openConnection());

  @override
  int get schemaVersion => 1;

  // Method to insert a new formula element (either formula or unit)
  Future<int> insertFormulaElement(String elementText) {
    return into(formulaElements).insert(FormulaElementsCompanion.insert(elementText: elementText));
  }

  // Method to get all formula elements
  Future<List<FormulaElement>> getAllFormulaElements() {
    return select(formulaElements).get();
  }

  // Method to get a formula element by ID
  Future<FormulaElement?> getFormulaElementById(int id) {
    return (select(formulaElements)..where((tbl) => tbl.id.equals(id))).getSingleOrNull();
  }

  // Method to update a formula element
  Future<void> updateFormulaElement(int id, String newElementText) {
    return (update(formulaElements)..where((tbl) => tbl.id.equals(id)))
        .write(FormulaElementsCompanion.insert(elementText: newElementText));
  }

  // Method to delete a formula element
  Future<void> deleteFormulaElement(int id) {
    return (delete(formulaElements)..where((tbl) => tbl.id.equals(id))).go();
  }
}

LazyDatabase _openConnection() {
  return LazyDatabase(() async {
    // Determine the platform-specific database directory
    Directory dbDirectory;
    
    if (Platform.isLinux || Platform.isWindows || Platform.isMacOS) {
      final appSupportDir = await getApplicationSupportDirectory();
      dbDirectory = Directory(p.join(appSupportDir.path, 'd4rt_formulas'));
    } else {
      dbDirectory = await getApplicationDocumentsDirectory();
    }
    
    // Ensure the directory exists
    await dbDirectory.create(recursive: true);
    
    // Create the database file in the platform-specific directory
    final file = File(p.join(dbDirectory.path, 'formulas.sqlite'));
    return NativeDatabase.createInBackground(file);
  });
}