Add include guards and header comments to sources

41 files changed, 291 insertions, 2 deletions

diff --git a/src/game/client/gui/background.cc b/src/game/client/gui/background.cc
index 81fb764..e0e0684 100644
--- a/src/game/client/gui/background.cc
+++ b/src/game/client/gui/background.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: background.cc
+// Description: Background texture rendering when you're not in-game
+
 #include "client/pch.hh"
 
 #include "client/gui/background.hh"
diff --git a/src/game/client/gui/background.hh b/src/game/client/gui/background.hh
index 51497d1..1f7fef9 100644
--- a/src/game/client/gui/background.hh
+++ b/src/game/client/gui/background.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: background.hh
+// Description: Background texture rendering when you're not in-game
+
+#ifndef CLIENT_GUI_BACKGROUND_HH
+#define CLIENT_GUI_BACKGROUND_HH
 #pragma once
 
 namespace background
@@ -6,3 +13,5 @@ void init(void);
 void shutdown(void);
 void layout(void);
 } // namespace background
+
+#endif
diff --git a/src/game/client/gui/bother.cc b/src/game/client/gui/bother.cc
index 7309bbc..2308b4a 100644
--- a/src/game/client/gui/bother.cc
+++ b/src/game/client/gui/bother.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: bother.cc
+// Description: Bother servers with a status request
+
 #include "client/pch.hh"
 
 #include "client/gui/bother.hh"
diff --git a/src/game/client/gui/bother.hh b/src/game/client/gui/bother.hh
index ed4f84f..d702bde 100644
--- a/src/game/client/gui/bother.hh
+++ b/src/game/client/gui/bother.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: bother.hh
+// Description: Bother servers with a status request
+
+#ifndef CLIENT_GUI_BOTHER_HH
+#define CLIENT_GUI_BOTHER_HH
 #pragma once
 
 struct BotherResponseEvent final {
@@ -19,3 +26,5 @@ void update_late(void);
 void ping(unsigned int identity, std::string_view host, std::uint16_t port);
 void cancel(unsigned int identity);
 } // namespace bother
+
+#endif
diff --git a/src/game/client/gui/chat.cc b/src/game/client/gui/chat.cc
index f962e5d..9613aa5 100644
--- a/src/game/client/gui/chat.cc
+++ b/src/game/client/gui/chat.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: chat.cc
+// Description: Client chat handling
+
 #include "client/pch.hh"
 
 #include "client/gui/chat.hh"
diff --git a/src/game/client/gui/chat.hh b/src/game/client/gui/chat.hh
index 91c3740..afe1965 100644
--- a/src/game/client/gui/chat.hh
+++ b/src/game/client/gui/chat.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: chat.hh
+// Description: Client chat handling
+
+#ifndef CLIENT_GUI_CHAT_HH
+#define CLIENT_GUI_CHAT_HH
 #pragma once
 
 namespace client_chat
@@ -15,3 +22,5 @@ void clear(void);
 void refresh_timings(void);
 void print(const std::string& string);
 } // namespace client_chat
+
+#endif
diff --git a/src/game/client/gui/crosshair.cc b/src/game/client/gui/crosshair.cc
index 088796d..29314b9 100644
--- a/src/game/client/gui/crosshair.cc
+++ b/src/game/client/gui/crosshair.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: crosshair.cc
+// Description: Crosshair rendering
+
 #include "client/pch.hh"
 
 #include "client/gui/crosshair.hh"
diff --git a/src/game/client/gui/crosshair.hh b/src/game/client/gui/crosshair.hh
index 6789e1e..0775bb2 100644
--- a/src/game/client/gui/crosshair.hh
+++ b/src/game/client/gui/crosshair.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: crosshair.hh
+// Description: Crosshair rendering
+
+#ifndef CLIENT_GUI_CROSSHAIR_HH
+#define CLIENT_GUI_CROSSHAIR_HH
 #pragma once
 
 namespace crosshair
@@ -6,3 +13,5 @@ void init(void);
 void shutdown(void);
 void layout(void);
 } // namespace crosshair
+
+#endif
diff --git a/src/game/client/gui/direct_connection.cc b/src/game/client/gui/direct_connection.cc
index d7cea64..2b75a44 100644
--- a/src/game/client/gui/direct_connection.cc
+++ b/src/game/client/gui/direct_connection.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: direct_connection.cc
+// Description: Direct connection screen
+
 #include "client/pch.hh"
 
 #include "client/gui/direct_connection.hh"
diff --git a/src/game/client/gui/direct_connection.hh b/src/game/client/gui/direct_connection.hh
index 0a09a3f..609e326 100644
--- a/src/game/client/gui/direct_connection.hh
+++ b/src/game/client/gui/direct_connection.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: direct_connection.hh
+// Description: Direct connection screen
+
+#ifndef CLIENT_GUI_DIRECT_CONNECTION_HH
+#define CLIENT_GUI_DIRECT_CONNECTION_HH
 #pragma once
 
 namespace direct_connection
@@ -5,3 +12,5 @@ namespace direct_connection
 void init(void);
 void layout(void);
 } // namespace direct_connection
+
+#endif
diff --git a/src/game/client/gui/gui_screen.hh b/src/game/client/gui/gui_screen.hh
index 2eae310..7a1da10 100644
--- a/src/game/client/gui/gui_screen.hh
+++ b/src/game/client/gui/gui_screen.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: gui_screen.hh
+// Description: GUI screen constants
+
+#ifndef CLIENT_GUI_GUI_SCREEN_HH
+#define CLIENT_GUI_GUI_SCREEN_HH
 #pragma once
 
 constexpr static unsigned int GUI_SCREEN_NONE = 0x0000U;
@@ -8,3 +15,5 @@ constexpr static unsigned int GUI_PROGRESS_BAR = 0x0004U;
 constexpr static unsigned int GUI_MESSAGE_BOX = 0x0005U;
 constexpr static unsigned int GUI_CHAT = 0x0006U;
 constexpr static unsigned int GUI_DIRECT_CONNECTION = 0x0007U;
+
+#endif
diff --git a/src/game/client/gui/hotbar.cc b/src/game/client/gui/hotbar.cc
index b38c368..edcf8a9 100644
--- a/src/game/client/gui/hotbar.cc
+++ b/src/game/client/gui/hotbar.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: hotbar.cc
+// Description: Hotbar rendering
+
 #include "client/pch.hh"
 
 #include "client/gui/hotbar.hh"
diff --git a/src/game/client/gui/hotbar.hh b/src/game/client/gui/hotbar.hh
index bba5e63..54e53d5 100644
--- a/src/game/client/gui/hotbar.hh
+++ b/src/game/client/gui/hotbar.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: hotbar.hh
+// Description: Hotbar rendering
+
+#ifndef CLIENT_GUI_HOTBAR_HH
+#define CLIENT_GUI_HOTBAR_HH
 #pragma once
 
 // TODO: design an inventory system and an item
@@ -25,3 +32,5 @@ namespace hotbar
 void next_slot(void);
 void prev_slot(void);
 } // namespace hotbar
+
+#endif
diff --git a/src/game/client/gui/imutils_button.cc b/src/game/client/gui/imutils_button.cc
index 2017e33..05da90e 100644
--- a/src/game/client/gui/imutils_button.cc
+++ b/src/game/client/gui/imutils_button.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: imutils_button.cc
+// Description: Extended button layout
+
 #include "client/pch.hh"
 
 #include "client/gui/imutils_button.hh"
diff --git a/src/game/client/gui/imutils_button.hh b/src/game/client/gui/imutils_button.hh
index 0c80694..602b723 100644
--- a/src/game/client/gui/imutils_button.hh
+++ b/src/game/client/gui/imutils_button.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: imutils_button.hh
+// Description: Extended button layout
+
+#ifndef CLIENT_GUI_IMUTILS_BUTTON_HH
+#define CLIENT_GUI_IMUTILS_BUTTON_HH
 #pragma once
 
 namespace imutils
@@ -12,3 +19,5 @@ bool selectable_button(const char* label, const ImVec2& size, bool value);
 bool toggle_button(const char* label, const ImVec2& size, bool& value);
 bool toggle_button(const char* label, bool& value);
 } // namespace imutils
+
+#endif
diff --git a/src/game/client/gui/imutils_popup.cc b/src/game/client/gui/imutils_popup.cc
index f97facb..ba997d5 100644
--- a/src/game/client/gui/imutils_popup.cc
+++ b/src/game/client/gui/imutils_popup.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: imutils_popup.cc
+// Description: Popup utilities
+
 #include "client/pch.hh"
 
 #include "client/gui/imutils_popup.hh"
diff --git a/src/game/client/gui/imutils_popup.hh b/src/game/client/gui/imutils_popup.hh
index 1678f87..159503b 100644
--- a/src/game/client/gui/imutils_popup.hh
+++ b/src/game/client/gui/imutils_popup.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: imutils_popup.hh
+// Description: Popup utilities
+
+#ifndef CLIENT_GUI_IMUTILS_POPUP_HH
+#define CLIENT_GUI_IMUTILS_POPUP_HH
 #pragma once
 
 /// Returned by popup::show whenever the popup is opened
@@ -9,3 +16,5 @@ namespace imutils
 int popup(const std::string& title, const std::string& question, const std::string* choices, std::size_t num_choices,
     float font_scale = 1.75f);
 } // namespace imutils
+
+#endif
diff --git a/src/game/client/gui/imutils_text.cc b/src/game/client/gui/imutils_text.cc
index 1058c7f..1621c42 100644
--- a/src/game/client/gui/imutils_text.cc
+++ b/src/game/client/gui/imutils_text.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: imutils_text.cc
+// Description: Text with shadow
+
 #include "client/pch.hh"
 
 #include "client/gui/imutils_text.hh"
diff --git a/src/game/client/gui/imutils_text.hh b/src/game/client/gui/imutils_text.hh
index 64d06a4..0d888d4 100644
--- a/src/game/client/gui/imutils_text.hh
+++ b/src/game/client/gui/imutils_text.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: imutils_text.hh
+// Description: Text with shadow
+
+#ifndef CLIENT_GUI_IMUTILS_TEXT_HH
+#define CLIENT_GUI_IMUTILS_TEXT_HH
 #pragma once
 
 namespace imutils
@@ -7,3 +14,5 @@ void text_nw(ImDrawList* list, std::string_view text, const ImVec2& pos, ImU32 c
 void text_wr(ImDrawList* list, std::string_view text, const ImVec2& pos, ImU32 color, ImU32 shadow, ImFont* font, float wrap);
 void text_wr(ImDrawList* list, std::string_view text, const ImVec2& pos, ImU32 color, ImU32 shadow, ImFont* font, float wrap, float size);
 } // namespace imutils
+
+#endif
diff --git a/src/game/client/gui/language.cc b/src/game/client/gui/language.cc
index 8a2d8d1..4ad1f68 100644
--- a/src/game/client/gui/language.cc
+++ b/src/game/client/gui/language.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: language.cc
+// Description: Translations API
+
 #include "client/pch.hh"
 
 #include "client/gui/language.hh"
@@ -41,7 +46,7 @@ void language::init(void)
     auto file = PHYSFS_openRead(std::string(MANIFEST_PATH).c_str());
 
     if(file == nullptr) {
-        spdlog::critical("language: {}: {}", MANIFEST_PATH, physfs_error());
+        spdlog::critical("language: {}: {}", MANIFEST_PATH, physfs::last_error());
         std::terminate();
     }
 
@@ -114,7 +119,7 @@ void language::set(LanguageIterator new_language)
         auto file = PHYSFS_openRead(path.c_str());
 
         if(file == nullptr) {
-            spdlog::warn("language: {}: {}", path, physfs_error());
+            spdlog::warn("language: {}: {}", path, physfs::last_error());
             send_language_event(new_language);
             return;
         }
diff --git a/src/game/client/gui/language.hh b/src/game/client/gui/language.hh
index 20c7520..015e787 100644
--- a/src/game/client/gui/language.hh
+++ b/src/game/client/gui/language.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: language.hh
+// Description: Translations API
+
+#ifndef CLIENT_GUI_LANGUAGE_HH
+#define CLIENT_GUI_LANGUAGE_HH
 #pragma once
 
 struct LanguageInfo final {
@@ -37,3 +44,5 @@ namespace language
 std::string_view resolve(std::string_view key);
 std::string resolve_gui(std::string_view key);
 } // namespace language
+
+#endif
diff --git a/src/game/client/gui/main_menu.cc b/src/game/client/gui/main_menu.cc
index d764449..6fa5cc9 100644
--- a/src/game/client/gui/main_menu.cc
+++ b/src/game/client/gui/main_menu.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: main_menu.cc
+// Description: Main menu screen
+
 #include "client/pch.hh"
 
 #include "client/gui/main_menu.hh"
diff --git a/src/game/client/gui/main_menu.hh b/src/game/client/gui/main_menu.hh
index b5333d4..630a10e 100644
--- a/src/game/client/gui/main_menu.hh
+++ b/src/game/client/gui/main_menu.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: main_menu.hh
+// Description: Main menu screen
+
+#ifndef CLIENT_GUI_MAIN_MENU_HH
+#define CLIENT_GUI_MAIN_MENU_HH
 #pragma once
 
 namespace main_menu
@@ -6,3 +13,5 @@ void init(void);
 void shutdown(void);
 void layout(void);
 } // namespace main_menu
+
+#endif
diff --git a/src/game/client/gui/message_box.cc b/src/game/client/gui/message_box.cc
index d97267a..a97d4e3 100644
--- a/src/game/client/gui/message_box.cc
+++ b/src/game/client/gui/message_box.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: message_box.cc
+// Description: A single message screen
+
 #include "client/pch.hh"
 
 #include "client/gui/message_box.hh"
diff --git a/src/game/client/gui/message_box.hh b/src/game/client/gui/message_box.hh
index 9da5358..430b4fb 100644
--- a/src/game/client/gui/message_box.hh
+++ b/src/game/client/gui/message_box.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: message_box.hh
+// Description: A single message screen
+
+#ifndef CLIENT_GUI_MESSAGE_BOX_HH
+#define CLIENT_GUI_MESSAGE_BOX_HH
 #pragma once
 
 using message_box_action = void (*)(void);
@@ -15,3 +22,5 @@ void set_title(std::string_view title);
 void set_subtitle(std::string_view subtitle);
 void add_button(std::string_view text, const message_box_action& action);
 } // namespace message_box
+
+#endif
diff --git a/src/game/client/gui/metrics.cc b/src/game/client/gui/metrics.cc
index f39434a..0c510d9 100644
--- a/src/game/client/gui/metrics.cc
+++ b/src/game/client/gui/metrics.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: metrics.cc
+// Description: Display debug information
+
 #include "client/pch.hh"
 
 #include "client/gui/metrics.hh"
diff --git a/src/game/client/gui/metrics.hh b/src/game/client/gui/metrics.hh
index ab09c34..441a40d 100644
--- a/src/game/client/gui/metrics.hh
+++ b/src/game/client/gui/metrics.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: metrics.hh
+// Description: Display debug information
+
+#ifndef CLIENT_GUI_METRICS_HH
+#define CLIENT_GUI_METRICS_HH
 #pragma once
 
 namespace metrics
@@ -5,3 +12,5 @@ namespace metrics
 void init(void);
 void layout(void);
 } // namespace metrics
+
+#endif
diff --git a/src/game/client/gui/play_menu.cc b/src/game/client/gui/play_menu.cc
index ec263a7..61a99a4 100644
--- a/src/game/client/gui/play_menu.cc
+++ b/src/game/client/gui/play_menu.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: play_menu.cc
+// Description: Server and world list screen
+
 #include "client/pch.hh"
 
 #include "client/gui/play_menu.hh"
diff --git a/src/game/client/gui/play_menu.hh b/src/game/client/gui/play_menu.hh
index 5069592..eeaeca8 100644
--- a/src/game/client/gui/play_menu.hh
+++ b/src/game/client/gui/play_menu.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: play_menu.hh
+// Description: Server and world list screen
+
+#ifndef CLIENT_GUI_PLAY_MENU_HH
+#define CLIENT_GUI_PLAY_MENU_HH
 #pragma once
 
 namespace play_menu
@@ -7,3 +14,5 @@ void shutdown(void);
 void layout(void);
 void update_late(void);
 } // namespace play_menu
+
+#endif
diff --git a/src/game/client/gui/progress_bar.cc b/src/game/client/gui/progress_bar.cc
index 6cc7fae..6b85efe 100644
--- a/src/game/client/gui/progress_bar.cc
+++ b/src/game/client/gui/progress_bar.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: progress_bar.cc
+// Description: Screen with a progress bar
+
 #include "client/pch.hh"
 
 #include "client/gui/progress_bar.hh"
diff --git a/src/game/client/gui/progress_bar.hh b/src/game/client/gui/progress_bar.hh
index 931cad0..e4569e8 100644
--- a/src/game/client/gui/progress_bar.hh
+++ b/src/game/client/gui/progress_bar.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: progress_bar.hh
+// Description: Screen with a progress bar
+
+#ifndef CLIENT_GUI_PROGRESS_BAR_HH
+#define CLIENT_GUI_PROGRESS_BAR_HH
 #pragma once
 
 using progress_bar_action = void (*)(void);
@@ -14,3 +21,5 @@ void reset(void);
 void set_title(std::string_view title);
 void set_button(std::string_view text, const progress_bar_action& action);
 } // namespace progress_bar
+
+#endif
diff --git a/src/game/client/gui/scoreboard.cc b/src/game/client/gui/scoreboard.cc
index 23f3174..1405119 100644
--- a/src/game/client/gui/scoreboard.cc
+++ b/src/game/client/gui/scoreboard.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: scoreboard.cc
+// Description: Display player list
+
 #include "client/pch.hh"
 
 #include "client/gui/scoreboard.hh"
diff --git a/src/game/client/gui/scoreboard.hh b/src/game/client/gui/scoreboard.hh
index 86f8088..fd4bf32 100644
--- a/src/game/client/gui/scoreboard.hh
+++ b/src/game/client/gui/scoreboard.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: scoreboard.hh
+// Description: Display player list
+
+#ifndef CLIENT_GUI_SCOREBOARD_HH
+#define CLIENT_GUI_SCOREBOARD_HH
 #pragma once
 
 namespace scoreboard
@@ -5,3 +12,5 @@ namespace scoreboard
 void init(void);
 void layout(void);
 } // namespace scoreboard
+
+#endif
diff --git a/src/game/client/gui/settings.cc b/src/game/client/gui/settings.cc
index b456909..65e91aa 100644
--- a/src/game/client/gui/settings.cc
+++ b/src/game/client/gui/settings.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: settings.cc
+// Description: Visual config value editing
+
 #include "client/pch.hh"
 
 #include "client/gui/settings.hh"
diff --git a/src/game/client/gui/settings.hh b/src/game/client/gui/settings.hh
index efb8ca4..1a3a1f8 100644
--- a/src/game/client/gui/settings.hh
+++ b/src/game/client/gui/settings.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: settings.hh
+// Description: Visual config value editing
+
+#ifndef CLIENT_GUI_SETTINGS_HH
+#define CLIENT_GUI_SETTINGS_HH
 #pragma once
 
 namespace config
@@ -88,3 +95,5 @@ namespace settings
 {
 void add_language_select(int priority, settings_location location, std::string_view name);
 } // namespace settings
+
+#endif
diff --git a/src/game/client/gui/splash.cc b/src/game/client/gui/splash.cc
index 84ecb8b..7d7b86c 100644
--- a/src/game/client/gui/splash.cc
+++ b/src/game/client/gui/splash.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: splash.cc
+// Description: Startup splash screen
+
 #include "client/pch.hh"
 
 #include "client/gui/splash.hh"
diff --git a/src/game/client/gui/splash.hh b/src/game/client/gui/splash.hh
index ca612fe..abdeb5a 100644
--- a/src/game/client/gui/splash.hh
+++ b/src/game/client/gui/splash.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: splash.hh
+// Description: Startup splash screen
+
+#ifndef CLIENT_GUI_SPLASH_HH
+#define CLIENT_GUI_SPLASH_HH
 #pragma once
 
 namespace client_splash
@@ -6,3 +13,5 @@ void init(void);
 void init_late(void);
 void render(void);
 } // namespace client_splash
+
+#endif
diff --git a/src/game/client/gui/status_lines.cc b/src/game/client/gui/status_lines.cc
index ce661a3..39421b2 100644
--- a/src/game/client/gui/status_lines.cc
+++ b/src/game/client/gui/status_lines.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: status_lines.cc
+// Description: Display lines of text in-game
+
 #include "client/pch.hh"
 
 #include "client/gui/status_lines.hh"
diff --git a/src/game/client/gui/status_lines.hh b/src/game/client/gui/status_lines.hh
index b921947..706b4ad 100644
--- a/src/game/client/gui/status_lines.hh
+++ b/src/game/client/gui/status_lines.hh
@@ -1,3 +1,10 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: status_lines.hh
+// Description: Display lines of text in-game
+
+#ifndef CLIENT_GUI_STATUS_LINES_HH
+#define CLIENT_GUI_STATUS_LINES_HH
 #pragma once
 
 constexpr static unsigned int STATUS_DEBUG = 0x0000;  // generic debug line
@@ -16,3 +23,5 @@ namespace status_lines
 void set(unsigned int line, std::string_view text, const ImVec4& color, float fadeout);
 void unset(unsigned int line);
 } // namespace status_lines
+
+#endif
diff --git a/src/game/client/gui/window_title.cc b/src/game/client/gui/window_title.cc
index b15f2c5..ea65b64 100644
--- a/src/game/client/gui/window_title.cc
+++ b/src/game/client/gui/window_title.cc
@@ -1,3 +1,8 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: window_title.cc
+// Description: Random MOTD in the window title
+
 #include "client/pch.hh"
 
 #include "client/gui/window_title.hh"
diff --git a/src/game/client/gui/window_title.hh b/src/game/client/gui/window_title.hh
index 544ed44..78f7326 100644
--- a/src/game/client/gui/window_title.hh
+++ b/src/game/client/gui/window_title.hh
@@ -1,6 +1,15 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright (c) 2025 Kirill Dmitrievich
+// File: window_title.hh
+// Description: Random MOTD in the window title
+
+#ifndef CLIENT_GUI_WINDOW_TITLE_HH
+#define CLIENT_GUI_WINDOW_TITLE_HH
 #pragma once
 
 namespace window_title
 {
 void update(void);
 } // namespace window_title
+
+#endif