Add state machines for recognizing different button presses

For now single, double and long presses are supported.

code/button.h

@@ -0,0 +1,81 @@
+#include "debounce.h"
+
+template<uint16_t SLEEP_TIMEOUT, uint16_t LONGPRESS_TIMEOUT, uint16_t DOUBLEPRESS_TIMEOUT>
+class Button {
+
+    using DResult = Debounce<0>::Result;
+
+    public:
+        enum class State : uint8_t {
+            Sleep,
+            Idle,
+            Pressed,
+            LongPressed,
+            Released,
+            DoublePressed,
+        };
+
+        enum class Result : uint8_t {
+            NoEvent,
+            Press,
+            LongPress,
+            DoublePress,
+        };
+
+        Result event(DResult result) {
+            switch(state) {
+                case State::Sleep :
+                    state = State::Idle;
+                    counter = millis();
+                    break;
+                case State::Idle :
+                    if(result == DResult::Pressed) {
+                        state = State::Pressed;
+                        counter = millis();
+                    } else if(millis() - counter >= SLEEP_TIMEOUT) {
+                        state = State::Sleep;
+                        // Activate Hardware sleep
+                    }
+                    break;
+                case State::Pressed :
+                    if(result == DResult::Released) {
+                        state = State::Released;
+                        counter = millis();
+                    } else if(millis() - counter >= LONGPRESS_TIMEOUT) {
+                        state = State::LongPressed;
+                        return Result::LongPress;
+                    }
+                    break;
+                case State::Released :
+                    if(result == DResult::Pressed) {
+                        state = State::DoublePressed;
+                    } else if(millis() - counter >= DOUBLEPRESS_TIMEOUT) {
+                        state = State::Idle;
+                        counter = millis();
+                        return Result::Press;
+                    }
+                    break;
+                case State::LongPressed :
+                    if(result == DResult::Released) {
+                        state = State::Idle;
+                        counter = millis();
+                    } else {
+                        return Result::LongPress;
+                    }
+                    break;
+                case State::DoublePressed :
+                    if(result == DResult::Released) {
+                        state = State::Idle;
+                        counter = millis();
+                        return Result::DoublePress;
+                    }
+                    break;
+            }
+
+            return Result::NoEvent;
+        }
+
+    private:
+        State state = State::Idle;
+        uint16_t counter = 0;
+};

code/code.ino

@@ -2,6 +2,7 @@
 #undef min
 #undef max
 
+#include "button.h"
 #include "debounce.h"
 #include "lcg_rng.h"
 #include "segment.h"

code/debounce.h

@@ -1,12 +1,57 @@
-enum class State : uint8_t {
-    Unpressed,
-    UnpressedDebounced,
-    Pressed,
-    PressedDebounced,
-};
+#ifndef _DEBOUNCE_H_
+#define _DEBOUNCE_H_
 
 template<uint8_t DEBOUNCE_PRESSED, uint8_t DEBOUNCE_UNPRESSED = DEBOUNCE_PRESSED>
 class Debounce {
+
+    public:
+        enum class State : uint8_t {
+            Unpressed,
+            UnpressedDebounced,
+            Pressed,
+            PressedDebounced,
+        };
+
+        enum class Result : uint8_t {
+            NoEvent,
+            Pressed,
+            Released,
+        };
+
+        Result event(bool pressed) {
+            switch(state) {
+                case State::Unpressed :
+                    if(pressed) {
+                        state = State::PressedDebounced;
+                        counter = millis();
+                        return Result::Pressed;
+                    }
+                    break;
+                case State::PressedDebounced :
+                    if(millis() - counter > DEBOUNCE_PRESSED) {
+                        state = State::Pressed;
+                    }
+                    break;
+                case State::Pressed :
+                    if(!pressed) {
+                        state = State::UnpressedDebounced;
+                        counter = millis();
+                        return Result::Released;
+                    }
+                    break;
+                case State::UnpressedDebounced :
+                    if(millis() - counter > DEBOUNCE_UNPRESSED) {
+                        state = State::Unpressed;
+                    }
+                    break;
+            }
+
+            return Result::NoEvent;
+        }
     
+    private:
+        State state = State::Unpressed;
+        uint8_t counter = 0;
 };
 
+#endif