new list based on template

lib/add_form.dart

@@ -84,11 +84,9 @@ class _AddFormState extends State<AddForm> {
               DropdownButtonFormField<int>(
                 focusNode: _TemplateFocusNode,
                 value: _templatChoice,
-                onChanged: (value) {
-                  setState() {
-                    _templatChoice = (value != null) ? value : -1;
-                  }
-                },
+                onChanged: (value) => setState(() {
+                  _templatChoice = value!;
+                }),
                 decoration:
                     const InputDecoration(labelText: "Starting Template"),
                 items: generateDropdown(),
@@ -101,11 +99,16 @@ class _AddFormState extends State<AddForm> {
         child: Icon(Icons.save_alt),
         onPressed: () async {
           if (_formKey.currentState!.validate()) {
-            DBHelper.dbHelper.insertList(data.List(
-              _listLabel,
-              isTemplate: type.index == 1,
-            ));
-            // TODO implement template starting point
+            int id = await DBHelper.dbHelper.insertList(
+              data.List(
+                _listLabel,
+                isTemplate: type.index == 1,
+                // TODO Add description to lists
+              ),
+            );
+            if (_templatChoice >= 0 && _templatChoice < templates.length) {
+              DBHelper.dbHelper.copyList(templates[_templatChoice].id!, id);
+            }
             Navigator.pop(context); // TODO replace route with checklist page
           }
         },

lib/box_checker.dart

@@ -53,6 +53,10 @@ class _MainListPageState extends State<MainListPage> {
     });
   }
 
+  Future<void> _removeList(data.List list) async {
+    DBHelper.dbHelper.deleteList(list);
+  }
+
   @override
   void initState() {
     _loadData(data.Page.lists);
@@ -84,17 +88,66 @@ class _MainListPageState extends State<MainListPage> {
             child: ListView.builder(
                 itemCount: lists.length,
                 itemBuilder: (context, index) {
-                  return Card(
-                    child: ListTile(
-                      onTap: () {
-                        Navigator.push(
-                            context,
-                            MaterialPageRoute(
-                                builder: (context) =>
-                                    CheckList(id: lists[index].id!)));
-                      },
-                      title: Text(lists[index].name),
-                      subtitle: Text(lists[index].id.toString()),
+                  return Dismissible(
+                    direction: DismissDirection.startToEnd,
+                    key: Key(lists[index].id.toString()),
+                    background: Card(
+                      color: Colors.red,
+                      child: Row(
+                        children: const [
+                          Padding(
+                            padding: EdgeInsets.all(10),
+                            child: Icon(Icons.delete),
+                          ),
+                        ],
+                      ),
+                    ),
+                    confirmDismiss: (direction) async {
+                      if (direction != DismissDirection.startToEnd) {
+                        return false;
+                      }
+
+                      showDialog(
+                          context: context,
+                          builder: (context) {
+                            return AlertDialog(
+                              title: const Text('Are you sure?'),
+                              content: const Text(
+                                  'You are about to delete this permently'),
+                              actions: [
+                                TextButton(
+                                    onPressed: () =>
+                                        Navigator.pop(context, false),
+                                    child: const Text('Cancel')),
+                                TextButton(
+                                    onPressed: () =>
+                                        Navigator.pop(context, true),
+                                    child: const Text('OK')),
+                              ],
+                            );
+                          }).then((value) {
+                        if (value) {
+                          setState(() {
+                            _removeList(lists[index]);
+                            lists.removeAt(index);
+                          });
+                        }
+
+                        return value;
+                      });
+                    },
+                    child: Card(
+                      child: ListTile(
+                        onTap: () {
+                          Navigator.push(
+                              context,
+                              MaterialPageRoute(
+                                  builder: (context) =>
+                                      CheckList(id: lists[index].id!)));
+                        },
+                        title: Text(lists[index].name),
+                        subtitle: Text(lists[index].id.toString()),
+                      ),
                     ),
                   );
                 })),

lib/db_helper.dart

@@ -77,6 +77,35 @@ class DBHelper {
     return db.insert("List", l.toMap());
   }
 
+  Future<int> deleteList(data.List l) async {
+    Database db = await database;
+
+    db.delete("Item", where: 'list_id = ?', whereArgs: [l.id]);
+    return db.delete("List", where: 'id = ?', whereArgs: [l.id]);
+  }
+
+  Future<void> copyList(int oldID, int newID) async {
+    Database db = await database;
+    print('$newID, $oldID');
+
+    var batch = db.batch();
+    db.execute("""
+      CREATE TEMPORARY TABLE list_copy AS
+        SELECT check_text, status, list_id
+        FROM Item
+        WHERE list_id = ?
+    """, [oldID]);
+    db.update("list_copy", {'list_id': newID});
+    db.rawInsert("""
+      INSERT INTO Item(check_text, status, list_id)
+      SELECT * FROM list_copy
+    """);
+    db.execute("""
+      DROP TABLE list_copy
+    """);
+    batch.commit();
+  }
+
   Future<int> insertItem(data.Check item) async {
     Database db = await database;