From aef49e7f11a78b2c340cd849bf8a765f0741a46d Mon Sep 17 00:00:00 2001
From: Romain BOULLARD <romain.boullard@protonmail.com>
Date: Tue, 8 Sep 2026 22:31:28 +0200
Subject: [PATCH] Add factory

---
 Bigfoot/Libs/Utils/Include/Utils/Factory.hpp | 75 ++++++++++++++++
 Bigfoot/Tests/Utils/Factory.cpp              | 95 ++++++++++++++++++++
 2 files changed, 170 insertions(+)
 create mode 100644 Bigfoot/Libs/Utils/Include/Utils/Factory.hpp
 create mode 100644 Bigfoot/Tests/Utils/Factory.cpp

diff --git a/Bigfoot/Libs/Utils/Include/Utils/Factory.hpp b/Bigfoot/Libs/Utils/Include/Utils/Factory.hpp
new file mode 100644
index 0000000..75cfd88
--- /dev/null
+++ b/Bigfoot/Libs/Utils/Include/Utils/Factory.hpp
@@ -0,0 +1,75 @@
+/*********************************************************************
+ * \file   Factory.hpp
+ *
+ * \author Romain BOULLARD
+ * \date   September 2026
+ *********************************************************************/
+#ifndef BIGFOOT_UTILS_FACTORY_HPP
+#define BIGFOOT_UTILS_FACTORY_HPP
+#include <EASTL/unique_ptr.h>
+#include <EASTL/utility.h>
+#include <ankerl/unordered_dense.h>
+
+namespace Bigfoot
+{
+template<class TYPE, class KEY, class CREATEFUNCTION>
+class Factory
+{
+  public:
+    /**
+     * Register a key inside the factory
+     *
+     * \param p_key The key
+     * \param p_function The create function
+     * \return True if the key has been registered, false if it was already registered
+     */
+    [[nodiscard]]
+    bool Register(const KEY p_key, CREATEFUNCTION&& p_function)
+    {
+        if (m_createFunctions.find(p_key) == m_createFunctions.end())
+        {
+            m_createFunctions.emplace(p_key, eastl::move(p_function));
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Create an instance from the factory
+     *
+     * \param p_key The key to create. Needs to have been registered with Register()
+     * \param p_args Arguments for the creation
+     * \return The created instance. nullptr is returned if the key has not been registered
+     */
+    template<typename... ARGS>
+    [[nodiscard]]
+    eastl::unique_ptr<TYPE> Create(const KEY p_key, ARGS&&... p_args) const
+    {
+        if (const auto createFunction = m_createFunctions.find(p_key); createFunction != m_createFunctions.end())
+        {
+            return createFunction->second(eastl::forward<ARGS>(p_args)...);
+        }
+
+        return nullptr;
+    }
+
+    /**
+     * Remove a key and its associated create function from the factory
+     *
+     * \param p_key The key to remove
+     */
+    void Remove(const KEY p_key)
+    {
+        m_createFunctions.erase(p_key);
+    }
+
+  private:
+    /**
+     * The mapping between keys and create functions
+     */
+    ankerl::unordered_dense::map<KEY, CREATEFUNCTION> m_createFunctions;
+};
+}   // namespace Bigfoot
+
+#endif
diff --git a/Bigfoot/Tests/Utils/Factory.cpp b/Bigfoot/Tests/Utils/Factory.cpp
new file mode 100644
index 0000000..289fc2b
--- /dev/null
+++ b/Bigfoot/Tests/Utils/Factory.cpp
@@ -0,0 +1,95 @@
+/*********************************************************************
+ * \file   Factory.cpp
+ *
+ * \author Romain BOULLARD
+ * \date   September 2026
+ *********************************************************************/
+#include <Utils/Factory.hpp>
+
+#include <EASTL/functional.h>
+#include <EASTL/unique_ptr.h>
+#include <gtest/gtest.h>
+
+namespace Bigfoot
+{
+class Widget
+{
+  public:
+    virtual ~Widget() = default;
+
+    [[nodiscard]]
+    virtual std::uint32_t GetValue() const = 0;
+};
+
+class WidgetA final: public Widget
+{
+  public:
+    explicit WidgetA(const std::uint32_t p_value):
+        m_value(p_value)
+    {
+    }
+
+    [[nodiscard]]
+    std::uint32_t GetValue() const override
+    {
+        return m_value;
+    }
+
+  private:
+    std::uint32_t m_value;
+};
+
+enum class WidgetKeys
+{
+    WidgetA
+};
+
+using WidgetFactory = Factory<Widget, WidgetKeys, eastl::function<eastl::unique_ptr<Widget>(std::uint32_t)>>;
+
+/****************************************************************************************/
+
+class FactoryFixture: public ::testing::Test
+{
+  protected:
+    static eastl::unique_ptr<Widget> CreateWidgetA(const std::uint32_t p_value)
+    {
+        return eastl::make_unique<WidgetA>(p_value);
+    }
+
+    WidgetFactory m_factory;
+};
+
+/****************************************************************************************/
+
+TEST_F(FactoryFixture, Register_ShouldReturnTrueOnSuccess)
+{
+    EXPECT_TRUE(m_factory.Register(WidgetKeys::WidgetA, &CreateWidgetA));
+}
+
+/****************************************************************************************/
+
+TEST_F(FactoryFixture, Register_ShouldReturnFalseOnKeyDuplication)
+{
+    std::ignore = m_factory.Register(WidgetKeys::WidgetA, &CreateWidgetA);
+
+    EXPECT_FALSE(m_factory.Register(WidgetKeys::WidgetA, &CreateWidgetA));
+}
+
+/****************************************************************************************/
+
+TEST_F(FactoryFixture, Create_ShouldReturnAValidInstanceIfKeyIsRegistered)
+{
+    std::ignore = m_factory.Register(WidgetKeys::WidgetA, &CreateWidgetA);
+
+    const eastl::unique_ptr<Widget> widget = m_factory.Create(WidgetKeys::WidgetA, 42);
+
+    EXPECT_EQ(widget->GetValue(), 42);
+}
+
+/****************************************************************************************/
+
+TEST_F(FactoryFixture, Create_ShouldReturnNullptrIfKeyIsNotRegistered)
+{
+    EXPECT_EQ(m_factory.Create(WidgetKeys::WidgetA, 42), nullptr);
+}
+}   // namespace Bigfoot