Implement I2C communication with STM

include/App.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include "AppState.h"
 #include "MissionSelect.h"
 #include "defines.h"
 
@@ -7,8 +8,6 @@
 
 #include <memory>
 
-enum class AppView { MISSION_SELECT, AMI, DRIVER, TESTING };
-
 class SDLManager {
 public:
   SDLManager();
@@ -24,6 +23,7 @@ public:
 
 private:
   void init_sdl();
+  void init_state();
 
   void handle_events();
   void render();
@@ -33,10 +33,10 @@ private:
   // others and its destructor is called after the others.
   SDLManager sdl_manager;
 
+  std::unique_ptr<AppState> state;
   std::unique_ptr<MissionSelect> mission_select;
 
   bool running;
-  AppView view;
 
   SDL_Window* window;
   SDL_Renderer* renderer;

include/AppState.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <fmt/ostream.h>
+
+#include <optional>
+#include <ostream>
+#include <string>
+
+constexpr int I2C_SLAVE_ADDR = 0x20;
+constexpr int I2C_POLL_COMMAND = 0x00;
+
+enum class AppView { MISSION_SELECT, AMI, DRIVER, TESTING };
+std::ostream& operator<<(std::ostream& os, AppView view);
+
+class AppState {
+public:
+  AppState(const std::string& i2c_dev_path);
+  ~AppState();
+
+  void poll();
+
+  AppView get_view();
+
+private:
+  // This is optional so that we can still run the code on a PC without I2C
+  std::optional<int> i2c_dev_file;
+
+  AppView view;
+};