AceButton.h

/*
   Copyright 2018 Brian T. Park

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

#ifndef ACE_BUTTON_H
#define ACE_BUTTON_H

#include <Arduino.h>
#include "ButtonConfig.h"

namespace ace_button {

class AceButton {
  public:
    // The supported event types.

    static const uint8_t kEventPressed = 0;

    static const uint8_t kEventReleased = 1;

    static const uint8_t kEventClicked = 2;

    static const uint8_t kEventDoubleClicked = 3;

    static const uint8_t kEventLongPressed = 4;

    static const uint8_t kEventRepeatPressed = 5;

    static const uint8_t kButtonStateUnknown = 2;

    explicit AceButton(uint8_t pin = 0, uint8_t defaultReleasedState = HIGH,
        uint8_t id = 0);

    void init(uint8_t pin = 0, uint8_t defaultReleasedState = HIGH,
        uint8_t id = 0);

    ButtonConfig* getButtonConfig() ACE_BUTTON_INLINE {
      return mButtonConfig;
    }

    void setButtonConfig(ButtonConfig* buttonConfig) ACE_BUTTON_INLINE {
      mButtonConfig = buttonConfig;
    }

    void setEventHandler(ButtonConfig::EventHandler eventHandler)
        ACE_BUTTON_INLINE {
      mButtonConfig->setEventHandler(eventHandler);
    }

    uint8_t getPin() ACE_BUTTON_INLINE { return mPin; }

    uint8_t getId() ACE_BUTTON_INLINE { return mId; }

    uint8_t getDefaultReleasedState();

    uint8_t getLastButtonState() ACE_BUTTON_INLINE {
      return mLastButtonState;
    }

    void check();

    bool isReleased(uint8_t buttonState) ACE_BUTTON_INLINE {
      return buttonState == getDefaultReleasedState();
    }

  // Some of these protected methods may be useful to the calling client but I
  // don't want to release them to the public because I want to keep the API as
  // small as possible for easier long term maintenance. (Once a method is
  // released to the public, it must be supported forever to ensure backwards
  // compatibility with older client code.)

  private:
    // Disable copy-constructor and assignment operator
    AceButton(const AceButton&) = delete;
    AceButton& operator=(const AceButton&) = delete;

    void setPin(uint8_t pin) ACE_BUTTON_INLINE { mPin = pin; }

    void setDefaultReleasedState(uint8_t state);

    void setId(uint8_t id) ACE_BUTTON_INLINE { mId = id; }

    // Various bit masks to store a boolean flag in the 'mFlags' field.
    // We use bit masks to save static RAM. If we had used a 'bool' type, each
    // of these would consume one byte.
    static const uint8_t kFlagDefaultReleasedState = 0x01;
    static const uint8_t kFlagDebouncing = 0x02;
    static const uint8_t kFlagPressed = 0x04;
    static const uint8_t kFlagClicked = 0x08;
    static const uint8_t kFlagDoubleClicked = 0x10;
    static const uint8_t kFlagLongPressed = 0x20;
    static const uint8_t kFlagRepeatPressed = 0x40;

    // Methods for accessing the button's internal states.
    // I don't expect these to be useful to the outside world.

    // If this is set, then mLastDebounceTime is valid.
    bool isDebouncing() ACE_BUTTON_INLINE {
      return mFlags & kFlagDebouncing;
    }

    void setDebouncing() ACE_BUTTON_INLINE {
      mFlags |= kFlagDebouncing;
    }

    void clearDebouncing() ACE_BUTTON_INLINE {
      mFlags &= ~kFlagDebouncing;
    }

    // If this is set, then mLastPressTime is valid.
    bool isPressed() ACE_BUTTON_INLINE {
      return mFlags & kFlagPressed;
    }

    void setPressed() ACE_BUTTON_INLINE {
      mFlags |= kFlagPressed;
    }

    void clearPressed() ACE_BUTTON_INLINE {
      mFlags &= ~kFlagPressed;
    }

    // If this is set, then mLastClickTime is valid.
    bool isClicked() ACE_BUTTON_INLINE {
      return mFlags & kFlagClicked;
    }

    void setClicked() ACE_BUTTON_INLINE {
      mFlags |= kFlagClicked;
    }

    void clearClicked() ACE_BUTTON_INLINE {
      mFlags &= ~kFlagClicked;
    }

    // A double click was detected. No need to store the last double-clicked
    // time because we don't support a triple-click event (yet).
    bool isDoubleClicked() ACE_BUTTON_INLINE {
      return mFlags & kFlagDoubleClicked;
    }

    void setDoubleClicked() ACE_BUTTON_INLINE {
      mFlags |= kFlagDoubleClicked;
    }

    void clearDoubleClicked() ACE_BUTTON_INLINE {
      mFlags &= ~kFlagDoubleClicked;
    }

    // If this is set, then mLastPressTime can be treated as the start
    // of a long press.
    bool isLongPressed() ACE_BUTTON_INLINE {
      return mFlags & kFlagLongPressed;
    }

    void setLongPressed() ACE_BUTTON_INLINE {
      mFlags |= kFlagLongPressed;
    }

    void clearLongPressed() ACE_BUTTON_INLINE {
      mFlags &= ~kFlagLongPressed;
    }

    // If this is set, then mLastRepeatPressTime is valid.
    bool isRepeatPressed() ACE_BUTTON_INLINE {
      return mFlags & kFlagRepeatPressed;
    }

    void setRepeatPressed() ACE_BUTTON_INLINE {
      mFlags |= kFlagRepeatPressed;
    }

    void clearRepeatPressed() ACE_BUTTON_INLINE {
      mFlags &= ~kFlagRepeatPressed;
    }

    bool checkDebounced(uint16_t now, uint8_t buttonState);

    bool checkInitialized(uint16_t now, uint16_t buttonState);

    void checkLongPress(uint16_t now, uint8_t buttonState);

    void checkRepeatPress(uint16_t now, uint8_t buttonState);

    void checkChanged(uint16_t now, uint8_t buttonState);

    void checkReleased(uint16_t now, uint8_t buttonState);

    void checkPressed(uint16_t now, uint8_t buttonState);

    void checkClicked(uint16_t now, uint8_t buttonState);

    void checkDoubleClicked(uint16_t now, uint8_t buttonState);

    void checkOrphanedClick(uint16_t now, uint8_t buttonState);

    void handleEvent(uint8_t eventType);

    uint8_t mPin; // button pin number
    uint8_t mId; // identifier, e.g. an index into an array

    // Internal states of the button debouncing and event handling.
    // NOTE: We don't keep track of the lastDoubleClickTime, because we
    // don't support a TripleClicked event. That may change in the future.
    uint16_t mLastDebounceTime; // ms
    uint16_t mLastClickTime; // ms
    uint16_t mLastPressTime; // ms
    uint16_t mLastRepeatPressTime; // ms

    uint8_t mFlags;

    uint8_t mLastButtonState;

    ButtonConfig* mButtonConfig;
};

}
#endif