Cache user information

lib/helpers/database/users_database_helper.dart

@@ -0,0 +1,62 @@
+import 'package:comunic/models/user.dart';
+
+import 'database_contract.dart';
+import 'database_helper.dart';
+
+/// User database helper
+///
+/// @author Pierre HUBERT
+
+class UsersDatabaseHelper {
+  /// Insert a user in the database
+  Future<void> _insertDB(User user) async {
+    await (await DatabaseHelper.get())
+        .insert(UserTableContract.TABLE_NAME, user.toMap());
+  }
+
+  /// Update a user in the database
+  Future<void> _updateDB(User user) async {
+    await (await DatabaseHelper.get()).update(
+      UserTableContract.TABLE_NAME,
+      user.toMap(),
+      where: "${UserTableContract.C_ID} = ?",
+      whereArgs: [user.id],
+    );
+  }
+
+  /// Get a user from the database with a specified [id]
+  ///
+  /// Returns null if none found
+  Future<User> get(int id) async {
+    List<Map> maps = await (await DatabaseHelper.get()).query(
+      UserTableContract.TABLE_NAME,
+      where: '${UserTableContract.C_ID} = ?',
+      whereArgs: [id],
+    );
+
+    if (maps.length > 0) return User.fromMap(maps[0]);
+
+    return null;
+  }
+
+  /// Check out whether a user information specified with its [id] is present
+  /// or not in the local database
+  Future<bool> has(int id) async {
+    return (await get(id)) != null;
+  }
+
+  /// Insert or update information about a user (depends of the presence
+  /// of previous user information in the database
+  Future<void> insertOrUpdate(User user) async {
+    if (await has(user.id))
+      await _updateDB(user);
+    else
+      await _insertDB(user);
+  }
+
+  /// Insert or update an important amount of user information
+  Future<void> insertOrUpdateAll(List<User> list) async {
+    for(int i = 0; i < list.length; i++)
+      await insertOrUpdate(list[i]);
+  }
+}