Enable buttons and the display.

Kind-of-sort-of usable-ish.

Time.h

@@ -79,4 +79,145 @@ public:
     }
 };
 
+class WallClockTime {
+
+    // TODO: Implement a saturating counter?
+
+public:
+    WallClockTime()
+        : m_hours(0)
+        , m_minutes(0)
+        , m_seconds(0)
+    {}
+
+    WallClockTime(uint8_t hours, uint8_t minutes, uint8_t seconds)
+        : m_hours(hours)
+        , m_minutes(minutes)
+        , m_seconds(seconds)
+    {}
+
+    static inline uint8_t hour24_to_hour12(uint8_t hour24) {
+        if (hour24 == 0) {
+            return 12;
+        } else if (hour24 > 12) {
+            return hour24 - 12;
+        } else {
+            return hour24;
+        }
+    }
+
+    static inline uint8_t hour24_is_am(uint8_t hour24) {
+        return hour24 >= 12;
+    }
+
+    inline uint8_t get_hours_12() const {
+        return hour24_to_hour12(m_hours);
+    }
+
+    inline uint8_t get_hours_12_tens() const {
+        return get_hours_12() / 10;
+    }
+
+    inline uint8_t get_hours_12_ones() const {
+        return get_hours_12() % 10;
+    }
+
+    inline bool get_is_pm() const {
+        return m_hours >= 12;
+    }
+
+    inline uint8_t get_hours_24() const {
+        return m_hours;
+    }
+
+    inline uint8_t get_hours_24_ones() const {
+        return m_hours % 10;
+    }
+
+    inline uint8_t get_hours_24_tens() const {
+        return m_hours / 10;
+    }
+
+    inline uint8_t get_minutes() const {
+        return m_minutes;
+    }
+
+    inline uint8_t get_minutes_ones() const {
+        return m_minutes % 10;
+    }
+
+    inline uint8_t get_minutes_tens() const {
+        return m_minutes / 10;
+    }
+
+    inline uint8_t get_seconds() const {
+        return m_seconds;
+    }
+
+    inline uint8_t get_seconds_ones() const {
+        return m_seconds % 10;
+    }
+
+    inline uint8_t get_seconds_tens() const {
+        return m_seconds / 10;
+    }
+
+    inline void increment_hours() {
+        m_hours++;
+        if (m_hours >= 24) {
+            m_hours = 0;
+        }
+    }
+
+    inline void increment_minutes() {
+        m_minutes++;
+        if (m_minutes >= 60) {
+            m_minutes = 0;
+        }
+    }
+
+    inline void increment_seconds() {
+        m_seconds++;
+        if (m_seconds >= 60) {
+            m_seconds = 0;
+        }
+    }
+
+    inline void decrement_hours() {
+        if (m_hours == 0) {
+            m_hours = 23;
+        } else {
+            m_hours--;
+        }
+    }
+
+    inline void decrement_minutes() {
+        if (m_minutes == 0) {
+            m_minutes = 59;
+        } else {
+            m_minutes--;
+        }
+    }
+
+    inline void decrement_seconds() {
+        if (m_seconds == 0) {
+            m_seconds = 59;
+        } else {
+            m_seconds--;
+        }
+    }
+
+    inline void toggle_am_pm() {
+        if (m_hours < 12) {
+            m_hours += 12;
+        } else {
+            m_hours -= 12;
+        }
+    }
+
+private:
+    uint8_t m_hours;
+    uint8_t m_minutes;
+    uint8_t m_seconds;
+};
 }