refactor selection

7 files changed, 294 insertions, 25 deletions

diff --git a/lib/nes/app/ui/CMakeLists.txt b/lib/nes/app/ui/CMakeLists.txt
index 2faed29..0980e97 100644
--- a/lib/nes/app/ui/CMakeLists.txt
+++ b/lib/nes/app/ui/CMakeLists.txt
@@ -2,6 +2,9 @@ target_sources(
 	nes
 	PRIVATE
 		action.hh
+		selection.hh
 		screen.hh
 		screen-title.hh
-		screen-title.cc)
\ No newline at end of file
+		screen-title.cc
+		screen-browser.hh
+		screen-browser.cc)
\ No newline at end of file
diff --git a/lib/nes/app/ui/action.hh b/lib/nes/app/ui/action.hh
index 2994f37..52e5ba6 100644
--- a/lib/nes/app/ui/action.hh
+++ b/lib/nes/app/ui/action.hh
@@ -6,6 +6,10 @@ namespace nes::app
 	enum class action
 	{
 		none,
-		load_game,
+		go_to_title,
+		go_to_browser,
+		go_to_settings,
+		go_to_help,
+		launch_game,
 	};
 } // namespace nes::app
\ No newline at end of file
diff --git a/lib/nes/app/ui/screen-browser.cc b/lib/nes/app/ui/screen-browser.cc
new file mode 100644
index 0000000..da2d82d
--- /dev/null
+++ b/lib/nes/app/ui/screen-browser.cc
@@ -0,0 +1,71 @@
+#include "nes/app/ui/screen-browser.hh"
+#include "nes/app/graphics/renderer.hh"
+#include "nes/app/graphics/color.hh"
+#include "nes/app/input/input-device-keyboard.hh"
+#include "nes/common/string-builder.hh"
+
+namespace nes::app
+{
+	auto screen_browser::selection_impl::render_item(
+		renderer& renderer, i32 const& item, i32 const x, i32 const y, u32 const width, color const color) const -> void
+	{
+		renderer.render_text_format(x, y, color, text_attributes{}.set_max_width(width), "Item {}", item);
+	}
+
+	auto screen_browser::selection_impl::load_page(int (&items)[5], u32 const page) -> u32
+	{
+		for (auto i = u32{ 0 }; i < 5; ++i)
+		{
+			items[i] = static_cast<i32>(page * 5 + i);
+		}
+		return 5;
+	}
+
+	screen_browser::screen_browser(input_device_keyboard& keyboard)
+		: keyboard_{ keyboard }
+	{
+		selection_.set_page_count(2);
+	}
+
+	auto screen_browser::render(renderer& renderer) -> void
+	{
+		renderer.render_fill(color::background_primary);
+		renderer.render_rect(0, 0, 32, 3, color::background_secondary);
+
+		renderer.render_text(2, 1, "Load Game", color::foreground_primary);
+		renderer.render_text_format(
+			30, 1, color::foreground_secondary, text_attributes{}.set_alignment(text_alignment::right),
+			"Page {}/{}", selection_.get_current_page() + 1, selection_.get_page_count());
+
+		selection_.render(renderer);
+	}
+
+	auto screen_browser::process_events() -> action
+	{
+		while (auto const event = keyboard_.poll_event())
+		{
+			if (event == input_event::key_down(key::space))
+			{
+				selection_.go_next();
+			}
+			else if (event == input_event::key_down(key::arrow_up))
+			{
+				selection_.go_up();
+			}
+			else if (event == input_event::key_down(key::arrow_down))
+			{
+				selection_.go_down();
+			}
+			else if (event == input_event::key_down(key::backspace))
+			{
+				return action::go_to_title;
+			}
+			else if (event == input_event::key_down(key::enter))
+			{
+				return action::launch_game;
+			}
+		}
+
+		return action::none;
+	}
+} // namespace nes::app
\ No newline at end of file
diff --git a/lib/nes/app/ui/screen-browser.hh b/lib/nes/app/ui/screen-browser.hh
new file mode 100644
index 0000000..eb66266
--- /dev/null
+++ b/lib/nes/app/ui/screen-browser.hh
@@ -0,0 +1,32 @@
+#pragma once
+
+#include "nes/app/ui/screen.hh"
+#include "nes/app/ui/selection.hh"
+
+namespace nes::app
+{
+	class input_device_keyboard;
+
+	/// An interface which allows the user to browse the filesystem for a game.
+	class screen_browser final : public screen
+	{
+		class selection_impl final : public selection<i32, 5>
+		{
+		public:
+			using selection::selection;
+
+		protected:
+			auto render_item(renderer&, i32 const&, i32 x, i32 y, u32 width, color) const -> void override;
+			auto load_page(i32(&)[5], u32 page) -> u32 override;
+		};
+
+		input_device_keyboard& keyboard_;
+		selection_impl selection_{ 2, 5, 28 };
+
+	public:
+		explicit screen_browser(input_device_keyboard&);
+
+		auto render(renderer&) -> void override;
+		auto process_events() -> action override;
+	};
+} // namespace nes::app
\ No newline at end of file
diff --git a/lib/nes/app/ui/screen-title.cc b/lib/nes/app/ui/screen-title.cc
index 5a2f757..32a6ea6 100644
--- a/lib/nes/app/ui/screen-title.cc
+++ b/lib/nes/app/ui/screen-title.cc
@@ -2,13 +2,35 @@
 #include "nes/app/graphics/renderer.hh"
 #include "nes/app/graphics/color.hh"
 #include "nes/app/graphics/tiles/banner.hh"
-#include "nes/app/input/input-manager.hh"
+#include "nes/app/input/input-device-keyboard.hh"
 
 namespace nes::app
 {
-	screen_title::screen_title(input_manager& input_manager)
-		: input_manager_{ input_manager }
+	auto screen_title::selection_impl::render_item(
+		renderer& renderer, item const& item, i32 const x, i32 const y, u32 const width, color const color) const -> void
 	{
+		auto const attrs = text_attributes{}
+			.set_max_width(width);
+		switch (item)
+		{
+			case item::load_game: renderer.render_text(x, y, "Load Game", color, attrs); break;
+			case item::settings: renderer.render_text(x, y, "Settings", color, attrs); break;
+			case item::help: renderer.render_text(x, y, "Help", color, attrs); break;
+		}
+	}
+
+	auto screen_title::selection_impl::load_page(item (&items)[3], u32) -> u32
+	{
+		items[0] = item::load_game;
+		items[1] = item::settings;
+		items[2] = item::help;
+		return 3;
+	}
+
+	screen_title::screen_title(input_device_keyboard& keyboard)
+		: keyboard_{ keyboard }
+	{
+		selection_.set_page_count(1);
 	}
 
 	auto screen_title::render(renderer& renderer) -> void
@@ -16,32 +38,33 @@ namespace nes::app
 		renderer.render_fill(color::background_primary);
 		renderer.render_image(2, 4, tiles::banner);
 
-		if (selected_item_ == item::load_game) { renderer.render_text(10, 16, ">", color::accent_primary); }
-		renderer.render_text(12, 16, "Load Game", selected_item_ == item::load_game ? color::accent_primary : color::foreground_primary);
-
-		if (selected_item_ == item::settings) { renderer.render_text(10, 19, ">", color::accent_primary); }
-		renderer.render_text(12, 19, "Settings", selected_item_ == item::settings ? color::accent_primary : color::foreground_primary);
-
-		if (selected_item_ == item::help) { renderer.render_text(10, 22, ">", color::accent_primary); }
-		renderer.render_text(12, 22, "Help", selected_item_ == item::help ? color::accent_primary : color::foreground_primary);
+		selection_.render(renderer);
 	}
 
 	auto screen_title::process_events() -> action
 	{
-		while (auto event = input_manager_.get_keyboard().poll_event())
+		while (auto const event = keyboard_.poll_event())
 		{
 			if (event == input_event::key_down(key::space))
 			{
-				switch (selected_item_)
-				{
-					case item::load_game: selected_item_ = item::settings; break;
-					case item::settings: selected_item_ = item::help; break;
-					case item::help: selected_item_ = item::load_game; break;
-				}
+				selection_.go_next();
+			}
+			else if (event == input_event::key_down(key::arrow_up))
+			{
+				selection_.go_up();
+			}
+			else if (event == input_event::key_down(key::arrow_down))
+			{
+				selection_.go_down();
 			}
 			else if (event == input_event::key_down(key::enter))
 			{
-				return action::load_game;
+				switch (*selection_.get_selected())
+				{
+					case item::load_game: return action::go_to_browser;
+					case item::settings: return action::go_to_settings;
+					case item::help: return action::go_to_help;
+				}
 			}
 		}
 
diff --git a/lib/nes/app/ui/screen-title.hh b/lib/nes/app/ui/screen-title.hh
index 2ebc78a..6384c3e 100644
--- a/lib/nes/app/ui/screen-title.hh
+++ b/lib/nes/app/ui/screen-title.hh
@@ -1,10 +1,11 @@
 #pragma once
 
 #include "nes/app/ui/screen.hh"
+#include "nes/app/ui/selection.hh"
 
 namespace nes::app
 {
-	class input_manager;
+	class input_device_keyboard;
 
 	/// The main title screen for the emulator, used as an entrypoint for the UI.
 	///
@@ -18,11 +19,21 @@ namespace nes::app
 			help,
 		};
 
-		input_manager& input_manager_;
-		item selected_item_{ item::load_game };
+		class selection_impl final : public selection<item, 3>
+		{
+		public:
+			using selection::selection;
+
+		protected:
+			auto render_item(renderer&, item const&, i32 x, i32 y, u32 width, color) const -> void override;
+			auto load_page(item(&)[3], u32 page) -> u32 override;
+		};
+
+		input_device_keyboard& keyboard_;
+		selection_impl selection_{ 10, 16, 11 };
 
 	public:
-		explicit screen_title(input_manager&);
+		explicit screen_title(input_device_keyboard&);
 
 		auto render(renderer&) -> void override;
 		auto process_events() -> action override;
diff --git a/lib/nes/app/ui/selection.hh b/lib/nes/app/ui/selection.hh
new file mode 100644
index 0000000..fafa4a6
--- /dev/null
+++ b/lib/nes/app/ui/selection.hh
@@ -0,0 +1,125 @@
+#pragma once
+
+#include "nes/common/types.hh"
+#include "nes/app/graphics/renderer.hh"
+#include "nes/app/graphics/color.hh"
+
+namespace nes::app
+{
+	/// A selection menu managing a fixed number of items and pagination.
+	template<typename Item, u32 PageSize>
+	class selection
+	{
+		Item items_[PageSize];
+		u32 count_{ 0 };
+		u32 page_count_{ 0 };
+		i32 x_{};
+		i32 y_{};
+		u32 width_{};
+		i32 selected_{ -1 };
+		i32 current_page_{ -1 };
+
+	public:
+		explicit selection(i32 const x, i32 const y, u32 const width)
+			: x_{ x }
+			, y_{ y }
+			, width_{ width }
+		{
+		}
+
+		virtual ~selection() = default;
+
+		selection(selection const&) = delete;
+		selection(selection&&) = delete;
+		auto operator=(selection const&) -> selection& = delete;
+		auto operator=(selection&&) -> selection& = delete;
+
+		auto set_page_count(u32 const page_count) -> void
+		{
+			page_count_ = page_count;
+			set_page(page_count_ > 0 ? 0 : -1);
+		}
+
+		auto get_page_count() const -> u32 { return page_count_; }
+		auto get_current_page() const -> i32 { return current_page_; }
+		auto get_selected() const -> Item const* { return selected_ >= 0 ? &items_[selected_] : nullptr; }
+
+		auto render(renderer& renderer) const -> void
+		{
+			for (auto i = u32{ 0 }; i < count_; ++i)
+			{
+				auto const y = y_ + static_cast<i32>(3 * i);
+				auto const is_selected = static_cast<i32>(i) == selected_;
+				auto const color = is_selected ? color::accent_primary : color::foreground_primary;
+				if (is_selected)
+				{
+					renderer.render_text(x_, y, ">", color);
+				}
+
+				render_item(renderer, items_[i], x_ + 2, y, width_ - 2, color);
+			}
+		}
+
+		auto go_next() -> void
+		{
+			if (selected_ < 0) { return; }
+
+			selected_ += 1;
+			if (selected_ == static_cast<i32>(count_)) { selected_ = 0; }
+		}
+
+		auto go_up() -> void
+		{
+			if (selected_ <= 0)
+			{
+				if (current_page_ <= 0) { return; }
+
+				set_page(current_page_ - 1, true);
+				return;
+			}
+			selected_ -= 1;
+		}
+
+		auto go_down() -> void
+		{
+			if (selected_ < 0 || selected_ + 1 == static_cast<i32>(count_))
+			{
+				if (current_page_ < 0 || current_page_ + 1 == static_cast<i32>(page_count_)) { return; }
+
+				set_page(current_page_ + 1, false);
+				return;
+			}
+			selected_ += 1;
+		}
+
+	protected:
+		/// Render an item's caption at the given position and width.
+		virtual auto render_item(renderer&, Item const&, i32 x, i32 y, u32 width, color) const -> void = 0;
+
+		/// Load the items for a page (max. PageSize items) and return the number of loaded items.
+		virtual auto load_page(Item(&)[PageSize], u32 page) -> u32 = 0;
+
+	private:
+		auto set_page(i32 const page, bool const select_last = false) -> void
+		{
+			if (page < 0)
+			{
+				current_page_ = -1;
+				count_ = 0;
+				selected_ = -1;
+				return;
+			}
+
+			current_page_ = page;
+			count_ = load_page(items_, static_cast<u32>(page));
+			if (count_ > 0)
+			{
+				selected_ = select_last ? static_cast<i32>(count_) - 1 : 0;
+			}
+			else
+			{
+				selected_ = -1;
+			}
+		}
+	};
+} // namespace nes::app
\ No newline at end of file