/*
  Circuit Playground Firmata Firmware

  Special version of the Firmata firmware for Adafruit's Circuit Playground
  physical computing board.  Based on the StandardFirmata firmware but
  with extensions for the components and sensors on the Circuit Playground
  board (NeoPixels, LIS3DH accelerometer, etc).

  Firmata is a generic protocol for communicating with microcontrollers
  from software on a host computer. It is intended to work with
  any host computer software package.

  To download a host software package, please clink on the following link
  to open the list of Firmata client libraries your default browser.

  https://github.com/firmata/arduino#firmata-client-libraries

  Copyright (C) 2006-2008 Hans-Christoph Steiner.  All rights reserved.
  Copyright (C) 2010-2011 Paul Stoffregen.  All rights reserved.
  Copyright (C) 2009 Shigeru Kobayashi.  All rights reserved.
  Copyright (C) 2009-2015 Jeff Hoefs.  All rights reserved.
  Copyright (C) 2016 Tony DiCola.  All rights reservered.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  See file LICENSE.txt for further informations on licensing terms.
*/

#include <SPI.h>
#include <Servo.h>
#include <Wire.h>
#include <Adafruit_CircuitPlayground.h>

// Uncomment below to enable debug output.
//#define DEBUG_MODE

// These defines setup debug output if enabled above (otherwise it
// turns into no-ops that compile out).
#define DEBUG_OUTPUT Serial1
#define DEBUG_BAUD   9600

#ifdef DEBUG_MODE
  #define DEBUG_PRINT(...) { DEBUG_OUTPUT.print(__VA_ARGS__); }
  #define DEBUG_PRINTLN(...) { DEBUG_OUTPUT.println(__VA_ARGS__); }
#else
  #define DEBUG_PRINT(...) {}
  #define DEBUG_PRINTLN(...) {}
#endif

#define I2C_WRITE                   B00000000
#define I2C_READ                    B00001000
#define I2C_READ_CONTINUOUSLY       B00010000
#define I2C_STOP_READING            B00011000
#define I2C_READ_WRITE_MODE_MASK    B00011000
#define I2C_10BIT_ADDRESS_MODE_MASK B00100000
#define I2C_MAX_QUERIES             8
#define I2C_REGISTER_NOT_SPECIFIED  -1

// Circuit playground configuration:
#define PIXEL_COUNT    10     // Number of NeoPixels on the board.
#define PIXEL_PIN      17     // Digital pin connected to the NeoPixel signal line.
#define PIXEL_TYPE     NEO_GRB + NEO_KHZ800  // NeoPixel type.
#define SPEAKER_PIN    5      // Digital pin connected to the speaker.
#define LIS3DH_ADDR    0x18   // LIS3DH I2C address (not used).
#define LIS3DH_CS      8      // LIS3DH chip select line.
#define CAP_COUNT      8      // Number of cap touch inputs.
#define CAP_COMMON     30     // Digital input as the common cap touch pin.
#define CAP_SAMPLES    30     // Number of samples to take for a cap touch input.

// Circuit playground-specific Firmata SysEx commands:
#define CP_COMMAND              0x40  // Byte that identifies all Circuit Playground commands.
#define CP_PIXEL_SET            0x10  // Set NeoPixel, expects the following bytes as data:
                                      //  - Pixel ID (0-9)
                                      //  - Pixel RGB color data as 4 7-bit bytes.  The upper
                                      //    24 bits will be mapped to the R, G, B bytes.
#define CP_PIXEL_SHOW           0x11  // Update NeoPixels with their current color values.
#define CP_PIXEL_CLEAR          0x12  // Clear all NeoPixels to black/off.  Must call show pixels after this to see the change!
#define CP_PIXEL_BRIGHTNESS     0x13  // Set the brightness of the NeoPixels, just like calling the
                                      // NeoPixel library setBrightness function.  Takes one parameter
                                      // which is a single byte with a value 0-100.
#define CP_TONE                 0x20  // Play a tone on the speaker, expects the following bytes as data:
                                      //  - Frequency (hz) as 2 7-bit bytes (up to 2^14 hz, or about 16khz)
                                      //  - Duration (ms) as 2 7-bit bytes.
#define CP_NO_TONE              0x21  // Stop playing anything on the speaker.
#define CP_ACCEL_READ           0x30  // Return the current x, y, z accelerometer values.
#define CP_ACCEL_TAP            0x31  // Return the current accelerometer tap state.
#define CP_ACCEL_READ_REPLY     0x36  // Result of an acceleromete read.  Includes 3 floating point values (4 bytes each) with x, y, z
                                      // acceleration in meters/second^2.
#define CP_ACCEL_TAP_REPLY      0x37  // Result of the tap sensor read.  Includes a byte with the tap register value.
#define CP_ACCEL_TAP_STREAM_ON  0x38  // Turn on continuous streaming of tap data.
#define CP_ACCEL_TAP_STREAM_OFF 0x39  // Turn off streaming of tap data.
#define CP_ACCEL_STREAM_ON      0x3A  // Turn on continuous streaming of accelerometer data.
#define CP_ACCEL_STREAM_OFF     0x3B  // Turn off streaming of accelerometer data.
#define CP_ACCEL_RANGE          0x3C  // Set the range of the accelerometer, takes one byte as a parameter.
                                      // Use a value 0=+/-2G, 1=+/-4G, 2=+/-8G, 3=+/-16G
#define CP_ACCEL_TAP_CONFIG     0x3D  // Set the sensitivity of the tap detection, takes 4 bytes of 7-bit firmata
                                      // data as parameters which expand to 2 unsigned 8-bit bytes value to set:
                                      //   - Type of click: 0 = no click detection, 1 = single click, 2 = single & double click (default)
                                      //   - Click threshold: 0-255, the higher the value the less sensitive.  Depends on the accelerometer
                                      //     range, good values are: +/-16G = 5-10, +/-8G = 10-20, +/-4G = 20-40, +/-2G = 40-80
                                      //     80 is the default value (goes well with default of +/-2G)
#define CP_CAP_READ             0x40  // Read a single capacitive input.  Expects a byte as a parameter with the
                                      // cap touch input to read (0, 1, 2, 3, 6, 9, 10, 12).  Will respond with a
                                      // CP_CAP_REPLY message.
#define CP_CAP_ON               0x41  // Turn on continuous cap touch reads for the specified input (sent as a byte parameter).
#define CP_CAP_OFF              0x42  // Turn off continuous cap touch reads for the specified input (sent as a byte parameter).
#define CP_CAP_REPLY            0x43  // Capacitive input read response.  Includes a byte with the pin # of the cap input, then
                                      // four bytes of data which represent an int32_t value read from the cap input.
#define CP_SENSECOLOR           0x50  // Perform a color sense using the NeoPixel and light sensor.
#define CP_SENSECOLOR_REPLY     0x51  // Result of a color sense, will return the red, green, blue color
                                      // values that were read from the light sensor.  This will return
                                      // 6 bytes of data:
                                      //  - red color (unsigned 8 bit value, split across 2 7-bit bytes)
                                      //  - green color (unsigned 8 bit value, split across 2 7-bit bytes)
                                      //  - blue color (unsigned 8 bit value, split across 2 7-bit bytes)


// the minimum interval for sampling analog input
#define MINIMUM_SAMPLING_INTERVAL   1


/*==============================================================================
 * GLOBAL VARIABLES
 *============================================================================*/

// Circuit playground globals:
bool streamTap = false;
bool streamAccel = false;
// Define type for the cap touch sensor state of each cap touch input.
typedef struct {
  bool streaming;
  uint8_t pin;
} cap_state_type;

cap_state_type cap_state[CAP_COUNT] = {
  { false,  0 },
  { false,  1 },
  { false,  2 },
  { false,  3 },
  { false,  6 },
  { false,  9 },
  { false, 10 },
  { false, 12 }
};


/* analog inputs */
int analogInputsToReport = 0; // bitwise array to store pin reporting

/* digital input ports */
byte reportPINs[TOTAL_PORTS];       // 1 = report this port, 0 = silence
byte previousPINs[TOTAL_PORTS];     // previous 8 bits sent

/* pins configuration */
byte pinConfig[TOTAL_PINS];         // configuration of every pin
byte portConfigInputs[TOTAL_PORTS]; // each bit: 1 = pin in INPUT, 0 = anything else
int pinState[TOTAL_PINS];           // any value that has been written

/* timer variables */
unsigned long currentMillis;        // store the current value from millis()
unsigned long previousMillis;       // for comparison with currentMillis
unsigned int samplingInterval = 19; // how often to run the main loop (in ms)

/* i2c data */
struct i2c_device_info {
  byte addr;
  int reg;
  byte bytes;
};

/* for i2c read continuous more */
i2c_device_info query[I2C_MAX_QUERIES];

byte i2cRxData[64];
boolean isI2CEnabled = false;
signed char queryIndex = -1;
// default delay time between i2c read request and Wire.requestFrom()
unsigned int i2cReadDelayTime = 0;

Servo servos[MAX_SERVOS];
byte servoPinMap[TOTAL_PINS];
byte detachedServos[MAX_SERVOS];
byte detachedServoCount = 0;
byte servoCount = 0;

boolean isResetting = false;

/* utility functions */
void wireWrite(byte data)
{
#if ARDUINO >= 100
  Wire.write((byte)data);
#else
  Wire.send(data);
#endif
}

byte wireRead(void)
{
#if ARDUINO >= 100
  return Wire.read();
#else
  return Wire.receive();
#endif
}

/*==============================================================================
 * FUNCTIONS
 *============================================================================*/

void attachServo(byte pin, int minPulse, int maxPulse)
{
  if (servoCount < MAX_SERVOS) {
    // reuse indexes of detached servos until all have been reallocated
    if (detachedServoCount > 0) {
      servoPinMap[pin] = detachedServos[detachedServoCount - 1];
      if (detachedServoCount > 0) detachedServoCount--;
    } else {
      servoPinMap[pin] = servoCount;
      servoCount++;
    }
    if (minPulse > 0 && maxPulse > 0) {
      servos[servoPinMap[pin]].attach(PIN_TO_DIGITAL(pin), minPulse, maxPulse);
    } else {
      servos[servoPinMap[pin]].attach(PIN_TO_DIGITAL(pin));
    }
  } else {
    Firmata.sendString("Max servos attached");
  }
}

void detachServo(byte pin)
{
  servos[servoPinMap[pin]].detach();
  // if we're detaching the last servo, decrement the count
  // otherwise store the index of the detached servo
  if (servoPinMap[pin] == servoCount && servoCount > 0) {
    servoCount--;
  } else if (servoCount > 0) {
    // keep track of detached servos because we want to reuse their indexes
    // before incrementing the count of attached servos
    detachedServoCount++;
    detachedServos[detachedServoCount - 1] = servoPinMap[pin];
  }

  servoPinMap[pin] = 255;
}

void readAndReportData(byte address, int theRegister, byte numBytes) {
  // allow I2C requests that don't require a register read
  // for example, some devices using an interrupt pin to signify new data available
  // do not always require the register read so upon interrupt you call Wire.requestFrom()
  if (theRegister != I2C_REGISTER_NOT_SPECIFIED) {
    Wire.beginTransmission(address);
    wireWrite((byte)theRegister);
    Wire.endTransmission();
    // do not set a value of 0
    if (i2cReadDelayTime > 0) {
      // delay is necessary for some devices such as WiiNunchuck
      delayMicroseconds(i2cReadDelayTime);
    }
  } else {
    theRegister = 0;  // fill the register with a dummy value
  }

  Wire.requestFrom(address, numBytes);  // all bytes are returned in requestFrom

  // check to be sure correct number of bytes were returned by slave
  if (numBytes < Wire.available()) {
    Firmata.sendString("I2C: Too many bytes received");
  } else if (numBytes > Wire.available()) {
    Firmata.sendString("I2C: Too few bytes received");
  }

  i2cRxData[0] = address;
  i2cRxData[1] = theRegister;

  for (int i = 0; i < numBytes && Wire.available(); i++) {
    i2cRxData[2 + i] = wireRead();
  }

  // send slave address, register and received bytes
  Firmata.sendSysex(SYSEX_I2C_REPLY, numBytes + 2, i2cRxData);
}

void outputPort(byte portNumber, byte portValue, byte forceSend)
{
  // pins not configured as INPUT are cleared to zeros
  portValue = portValue & portConfigInputs[portNumber];
  // only send if the value is different than previously sent
  if (forceSend || previousPINs[portNumber] != portValue) {
    Firmata.sendDigitalPort(portNumber, portValue);
    previousPINs[portNumber] = portValue;
  }
}

/* -----------------------------------------------------------------------------
 * check all the active digital inputs for change of state, then add any events
 * to the Serial output queue using Serial.print() */
void checkDigitalInputs(void)
{
  /* Using non-looping code allows constants to be given to readPort().
   * The compiler will apply substantial optimizations if the inputs
   * to readPort() are compile-time constants. */
  if (TOTAL_PORTS > 0 && reportPINs[0]) outputPort(0, readPort(0, portConfigInputs[0]), false);
  if (TOTAL_PORTS > 1 && reportPINs[1]) outputPort(1, readPort(1, portConfigInputs[1]), false);
  if (TOTAL_PORTS > 2 && reportPINs[2]) outputPort(2, readPort(2, portConfigInputs[2]), false);
  if (TOTAL_PORTS > 3 && reportPINs[3]) outputPort(3, readPort(3, portConfigInputs[3]), false);
  if (TOTAL_PORTS > 4 && reportPINs[4]) outputPort(4, readPort(4, portConfigInputs[4]), false);
  if (TOTAL_PORTS > 5 && reportPINs[5]) outputPort(5, readPort(5, portConfigInputs[5]), false);
  if (TOTAL_PORTS > 6 && reportPINs[6]) outputPort(6, readPort(6, portConfigInputs[6]), false);
  if (TOTAL_PORTS > 7 && reportPINs[7]) outputPort(7, readPort(7, portConfigInputs[7]), false);
  if (TOTAL_PORTS > 8 && reportPINs[8]) outputPort(8, readPort(8, portConfigInputs[8]), false);
  if (TOTAL_PORTS > 9 && reportPINs[9]) outputPort(9, readPort(9, portConfigInputs[9]), false);
  if (TOTAL_PORTS > 10 && reportPINs[10]) outputPort(10, readPort(10, portConfigInputs[10]), false);
  if (TOTAL_PORTS > 11 && reportPINs[11]) outputPort(11, readPort(11, portConfigInputs[11]), false);
  if (TOTAL_PORTS > 12 && reportPINs[12]) outputPort(12, readPort(12, portConfigInputs[12]), false);
  if (TOTAL_PORTS > 13 && reportPINs[13]) outputPort(13, readPort(13, portConfigInputs[13]), false);
  if (TOTAL_PORTS > 14 && reportPINs[14]) outputPort(14, readPort(14, portConfigInputs[14]), false);
  if (TOTAL_PORTS > 15 && reportPINs[15]) outputPort(15, readPort(15, portConfigInputs[15]), false);
}

// -----------------------------------------------------------------------------
/* sets the pin mode to the correct state and sets the relevant bits in the
 * two bit-arrays that track Digital I/O and PWM status
 */
void setPinModeCallback(byte pin, int mode)
{
  if (pinConfig[pin] == PIN_MODE_IGNORE)
    return;

  if (pinConfig[pin] == PIN_MODE_I2C && isI2CEnabled && mode != PIN_MODE_I2C) {
    // disable i2c so pins can be used for other functions
    // the following if statements should reconfigure the pins properly
    disableI2CPins();
  }
  if (IS_PIN_DIGITAL(pin) && mode != PIN_MODE_SERVO) {
    if (servoPinMap[pin] < MAX_SERVOS && servos[servoPinMap[pin]].attached()) {
      detachServo(pin);
    }
  }
  if (IS_PIN_ANALOG(pin)) {
    reportAnalogCallback(PIN_TO_ANALOG(pin), mode == PIN_MODE_ANALOG ? 1 : 0); // turn on/off reporting
  }
  if (IS_PIN_DIGITAL(pin)) {
    if (mode == INPUT || mode == PIN_MODE_PULLUP) {
      portConfigInputs[pin / 8] |= (1 << (pin & 7));
    } else {
      portConfigInputs[pin / 8] &= ~(1 << (pin & 7));
    }
  }
  pinState[pin] = 0;
  switch (mode) {
    case PIN_MODE_ANALOG:
      if (IS_PIN_ANALOG(pin)) {
        if (IS_PIN_DIGITAL(pin)) {
          pinMode(PIN_TO_DIGITAL(pin), INPUT);    // disable output driver
#if ARDUINO <= 100
          // deprecated since Arduino 1.0.1 - TODO: drop support in Firmata 2.6
          digitalWrite(PIN_TO_DIGITAL(pin), LOW); // disable internal pull-ups
#endif
        }
        pinConfig[pin] = PIN_MODE_ANALOG;
      }
      break;
    case INPUT:
      if (IS_PIN_DIGITAL(pin)) {
        pinMode(PIN_TO_DIGITAL(pin), INPUT);    // disable output driver
#if ARDUINO <= 100
        // deprecated since Arduino 1.0.1 - TODO: drop support in Firmata 2.6
        digitalWrite(PIN_TO_DIGITAL(pin), LOW); // disable internal pull-ups
#endif
        pinConfig[pin] = INPUT;
      }
      break;
    case PIN_MODE_PULLUP:
      if (IS_PIN_DIGITAL(pin)) {
        pinMode(PIN_TO_DIGITAL(pin), INPUT_PULLUP);
        pinConfig[pin] = PIN_MODE_PULLUP;
        pinState[pin] = 1;
      }
      break;
    case OUTPUT:
      if (IS_PIN_DIGITAL(pin)) {
        digitalWrite(PIN_TO_DIGITAL(pin), LOW); // disable PWM
        pinMode(PIN_TO_DIGITAL(pin), OUTPUT);
        pinConfig[pin] = OUTPUT;
      }
      break;
    case PIN_MODE_PWM:
      if (IS_PIN_PWM(pin)) {
        pinMode(PIN_TO_PWM(pin), OUTPUT);
        analogWrite(PIN_TO_PWM(pin), 0);
        pinConfig[pin] = PIN_MODE_PWM;
      }
      break;
    case PIN_MODE_SERVO:
      if (IS_PIN_DIGITAL(pin)) {
        pinConfig[pin] = PIN_MODE_SERVO;
        if (servoPinMap[pin] == 255 || !servos[servoPinMap[pin]].attached()) {
          // pass -1 for min and max pulse values to use default values set
          // by Servo library
          attachServo(pin, -1, -1);
        }
      }
      break;
    case PIN_MODE_I2C:
      if (IS_PIN_I2C(pin)) {
        // mark the pin as i2c
        // the user must call I2C_CONFIG to enable I2C for a device
        pinConfig[pin] = PIN_MODE_I2C;
      }
      break;
    default:
      Firmata.sendString("Unknown pin mode"); // TODO: put error msgs in EEPROM
  }
  // TODO: save status to EEPROM here, if changed
}

/*
 * Sets the value of an individual pin. Useful if you want to set a pin value but
 * are not tracking the digital port state.
 * Can only be used on pins configured as OUTPUT.
 * Cannot be used to enable pull-ups on Digital INPUT pins.
 */
void setPinValueCallback(byte pin, int value)
{
  if (pin < TOTAL_PINS && IS_PIN_DIGITAL(pin)) {
    if (pinConfig[pin] == OUTPUT) {
      pinState[pin] = value;
      digitalWrite(PIN_TO_DIGITAL(pin), value);
    }
  }
}

void analogWriteCallback(byte pin, int value)
{
  if (pin < TOTAL_PINS) {
    switch (pinConfig[pin]) {
      case PIN_MODE_SERVO:
        if (IS_PIN_DIGITAL(pin))
          servos[servoPinMap[pin]].write(value);
        pinState[pin] = value;
        break;
      case PIN_MODE_PWM:
        if (IS_PIN_PWM(pin))
          analogWrite(PIN_TO_PWM(pin), value);
        pinState[pin] = value;
        break;
    }
  }
}

void digitalWriteCallback(byte port, int value)
{
  byte pin, lastPin, pinValue, mask = 1, pinWriteMask = 0;

  if (port < TOTAL_PORTS) {
    // create a mask of the pins on this port that are writable.
    lastPin = port * 8 + 8;
    if (lastPin > TOTAL_PINS) lastPin = TOTAL_PINS;
    for (pin = port * 8; pin < lastPin; pin++) {
      // do not disturb non-digital pins (eg, Rx & Tx)
      if (IS_PIN_DIGITAL(pin)) {
        // do not touch pins in PWM, ANALOG, SERVO or other modes
        if (pinConfig[pin] == OUTPUT || pinConfig[pin] == INPUT) {
          pinValue = ((byte)value & mask) ? 1 : 0;
          if (pinConfig[pin] == OUTPUT) {
            pinWriteMask |= mask;
          } else if (pinConfig[pin] == INPUT && pinValue == 1 && pinState[pin] != 1) {
            // only handle INPUT here for backwards compatibility
#if ARDUINO > 100
            pinMode(pin, INPUT_PULLUP);
#else
            // only write to the INPUT pin to enable pullups if Arduino v1.0.0 or earlier
            pinWriteMask |= mask;
#endif
          }
          pinState[pin] = pinValue;
        }
      }
      mask = mask << 1;
    }
    writePort(port, (byte)value, pinWriteMask);
  }
}


// -----------------------------------------------------------------------------
/* sets bits in a bit array (int) to toggle the reporting of the analogIns
 */
//void FirmataClass::setAnalogPinReporting(byte pin, byte state) {
//}
void reportAnalogCallback(byte analogPin, int value)
{
  if (analogPin < TOTAL_ANALOG_PINS) {
    if (value == 0) {
      analogInputsToReport = analogInputsToReport & ~ (1 << analogPin);
    } else {
      analogInputsToReport = analogInputsToReport | (1 << analogPin);
      // prevent during system reset or all analog pin values will be reported
      // which may report noise for unconnected analog pins
      if (!isResetting) {
        // Send pin value immediately. This is helpful when connected via
        // ethernet, wi-fi or bluetooth so pin states can be known upon
        // reconnecting.
        Firmata.sendAnalog(analogPin, analogRead(analogPin));
      }
    }
  }
  // TODO: save status to EEPROM here, if changed
}

void reportDigitalCallback(byte port, int value)
{
  if (port < TOTAL_PORTS) {
    reportPINs[port] = (byte)value;
    // Send port value immediately. This is helpful when connected via
    // ethernet, wi-fi or bluetooth so pin states can be known upon
    // reconnecting.
    if (value) outputPort(port, readPort(port, portConfigInputs[port]), true);
  }
  // do not disable analog reporting on these 8 pins, to allow some
  // pins used for digital, others analog.  Instead, allow both types
  // of reporting to be enabled, but check if the pin is configured
  // as analog when sampling the analog inputs.  Likewise, while
  // scanning digital pins, portConfigInputs will mask off values from any
  // pins configured as analog
}


/*==============================================================================
 * Circuit Playground commands
 *============================================================================*/

void circuitPlaygroundCommand(byte command, byte argc, byte* argv) {
  switch (command) {
    case CP_PIXEL_SET:
      // Set a NeoPixel to the specified RGB color.
      // Expect: 1 byte pixel number, 4 bytes pixel RGB value (as 7-bit bytes)
      if (argc >= 5) {
        // Parse out the pixel number and R, G, B bytes.
        uint8_t pixel = argv[0] & 0x7F;
        uint8_t r = (argv[1] << 1) | ((argv[2] & 0x7F) >> 6);  // Red = 7 bits from byte 4 and 1 bit from byte 5
        uint8_t g = ((argv[2] & 0x3F) << 2) | (((argv[3]) & 0x7F) >> 5);  // Green = 6 bits from byte 5 and 2 bits from byte 6
        uint8_t b = ((argv[3] & 0x1F) << 3) | (((argv[4]) & 0x7F) >> 4);  // Blue = 5 bits from byte 6 and 3 bits from byte 7
        CircuitPlayground.strip.setPixelColor(pixel, r, g, b);
      }
      break;
    case CP_PIXEL_SHOW:
      // Light up the neopixels with their current buffer values.
      CircuitPlayground.strip.show();
      break;
    case CP_PIXEL_CLEAR:
      // Clear all the pixel color values.
      CircuitPlayground.strip.clear();
      break;
    case CP_PIXEL_BRIGHTNESS:
      // Set pixel brightness.
      // Expects 1 byte with the brightness as a value 0-100.
      if (argc >= 1) {
        uint8_t brightness = argv[0];
        if (brightness > 100) {
          return;
        }
        CircuitPlayground.strip.setBrightness(brightness);
      }
    case CP_TONE:
      // Play a tone on the speaker.
      // Expect: 2 bytes tone frequency, 2 bytes tone duration
      if (argc >= 4) {
        uint16_t frequency = ((argv[1] & 0x7F) << 7) | (argv[0] & 0x7F);
        uint16_t duration = ((argv[3] & 0x7F) << 7) | (argv[2] & 0x7F);
        // If duration is zero then interpret that as continuous tone playback.
        if (duration == 0) {
          tone(SPEAKER_PIN, frequency);
        }
        else {
          tone(SPEAKER_PIN, frequency, duration);
        }
      }
      break;
    case CP_NO_TONE:
      // Stop tone playback.
      noTone(SPEAKER_PIN);
      break;
    case CP_ACCEL_READ:
      sendAccelResponse();
      break;
    case CP_ACCEL_TAP:
      sendTapResponse();
      break;
    case CP_ACCEL_TAP_STREAM_ON:
      streamTap = true;
      break;
    case CP_ACCEL_TAP_STREAM_OFF:
      streamTap = false;
      break;
    case CP_ACCEL_STREAM_ON:
      streamAccel = true;
      break;
    case CP_ACCEL_STREAM_OFF:
      streamAccel = false;
      break;
    case CP_CAP_READ:
      // Flip the streaming bool on for the specified input.
      // First check we have enough parameters and grab the input from the first byte.
      if (argc >= 1) {
        uint8_t input = argv[0] & 0x7F;
        // Now find the specified cap input and send a response with its current cap touch value.
        for (int i=0; i<CAP_COUNT; ++i) {
          if (cap_state[i].pin == input) {
            sendCapResponse(input);
          }
        }
      }
      break;
    case CP_CAP_ON:
      // Flip the streaming bool on for the specified input.
      // First check we have enough parameters and grab the input from the first byte.
      if (argc >= 1) {
        uint8_t input = argv[0] & 0x7F;
        // Now find the specified cap input and flip on its streaming bit.
        for (int i=0; i<CAP_COUNT; ++i) {
          if (cap_state[i].pin == input) {
            cap_state[i].streaming = true;
          }
        }
      }
      break;
    case CP_CAP_OFF:
      // Flip the streaming bool off for the specified input.
      // First check we have enough parameters and grab the input from the first byte.
      if (argc >= 1) {
        uint8_t input = argv[0] & 0x7F;
        // Now find the specified cap input and flip on its streaming bit.
        for (int i=0; i<CAP_COUNT; ++i) {
          if (cap_state[i].pin == input) {
            cap_state[i].streaming = false;
          }
        }
      }
      break;
    case CP_ACCEL_RANGE:
      // Set the range of the accelerometer based on the passed in value.
      // First check we have enough parameters and grab the input from the first byte.
      if (argc >= 1) {
        uint8_t range = argv[0] & 0x7F;
        // Check the range is an allowed value (0, 1, 2, 3).
        if (range > 3) {
          // Unknown range value, stop processing!
          return;
        }
        // Set the range of the accelerometer.
        CircuitPlayground.lis.setRange((lis3dh_range_t)range);
      }
      break;
    case CP_ACCEL_TAP_CONFIG:
      // Set the sensitivity of tap detection.
      // Expects 4 7-bit firmata bytes as input, which expand to 2 bytes of 8-bit unsigned data.
      // First check we have enough parameters.
      if (argc >= 4) {
        // Parse out paramemters.
        uint8_t type = ((argv[1] & 0x01) << 7) | (argv[0] & 0x7F);
        uint8_t threshold = ((argv[3] & 0x01) << 7) | (argv[2] & 0x7F);
        // Set the click threshold values.
        CircuitPlayground.lis.setClick(type, threshold);
      }
    case CP_SENSECOLOR:
      // Sense the color of an object over the light sensor and send back
      // a CP_SENSECOLOR_REPLY response.
      sendColorSenseResponse();
  }
}

// Send a color sense response back to the host computer.
void sendColorSenseResponse() {
  // Perform a color sense with NeoPixel #1 and the light sensor.
  uint8_t red, green, blue;
  CircuitPlayground.senseColor(red, green, blue);
  // Construct a response data packet and send it.
  uint8_t data[4] = {0};
  data[0] = CP_SENSECOLOR_REPLY;
  data[1] = red;
  data[2] = green;
  data[3] = blue;
  // Send the response.
  Firmata.sendSysex(CP_COMMAND, 4, data);
}

// Read the accelerometer and send a response packet.
void sendAccelResponse() {
  // Get an accelerometer X, Y, Z reading.
  sensors_event_t event;
  CircuitPlayground.lis.getEvent(&event);
  // Construct a response data packet.
  uint8_t data[13] = {0};
  data[0] = CP_ACCEL_READ_REPLY;
  // Put the three 32-bit float X,Y,Z reading into the packet.
  // Note that Firmata.sendSysex will automatically convert bytes into
  // two 7-bit bytes that are Firmata/MIDI compatible.
  // Use a union to easily grab the bytes of the float.
  union {
    float value;
    uint8_t bytes[4];
  } reading;
  // Grab each X, Y, Z float byte value and copy it into the response.
  reading.value = event.acceleration.x;
  memcpy(data+1, reading.bytes, 4);
  reading.value = event.acceleration.y;
  memcpy(data+5, reading.bytes, 4);
  reading.value = event.acceleration.z;
  memcpy(data+9, reading.bytes, 4);
  // Send the response.
  Firmata.sendSysex(CP_COMMAND, 13, data);
}

// Read the accelerometer tap detection and send a response packet.
void sendTapResponse() {
  // Get the accelerometer tap detection state.
  uint8_t click = CircuitPlayground.lis.getClick();
  // Construct a response data packet and send it.
  uint8_t data[2] = {0};
  data[0] = CP_ACCEL_TAP_REPLY;
  data[1] = click;
  // Send the response.
  Firmata.sendSysex(CP_COMMAND, 2, data);
}

// Read the capacitive sensor state and send a response packet.
void sendCapResponse(uint8_t pin) {
  // Get the cap sense value for the provided input pin.
  int32_t value = CircuitPlayground.readCap(pin, CAP_SAMPLES);
  // Build a response data packet and send it.  The response includes:
  // - uint8_t: CP_CAP_REPLY value
  // - uint8_t: pin number of the read input
  // - int32_t: cap sensor value, large values mean the input was touched
  union {
    struct {
      uint8_t type;
      uint8_t pin;
      int32_t value;
    } data;
    uint8_t bytes[6];
  } response;
  response.data.type = CP_CAP_REPLY;
  response.data.pin = pin;
  response.data.value = value;
  // Send the response, this will expand each byte into 2 bytes of 7-bit data.
  Firmata.sendSysex(CP_COMMAND, 6, response.bytes);
}

/*==============================================================================
 * SYSEX-BASED commands
 *============================================================================*/

void sysexCallback(byte command, byte argc, byte *argv)
{
  byte mode;
  byte slaveAddress;
  byte data;
  int slaveRegister;
  unsigned int delayTime;

  switch (command) {
    // Circuit playground command processing:
    case CP_COMMAND:
      if (argc < 1) return;
      circuitPlaygroundCommand(argv[0], argc-1, argv+1);
      break;
    case I2C_REQUEST:
      mode = argv[1] & I2C_READ_WRITE_MODE_MASK;
      if (argv[1] & I2C_10BIT_ADDRESS_MODE_MASK) {
        Firmata.sendString("10-bit addressing not supported");
        return;
      }
      else {
        slaveAddress = argv[0];
      }

      switch (mode) {
        case I2C_WRITE:
          Wire.beginTransmission(slaveAddress);
          for (byte i = 2; i < argc; i += 2) {
            data = argv[i] + (argv[i + 1] << 7);
            wireWrite(data);
          }
          Wire.endTransmission();
          delayMicroseconds(70);
          break;
        case I2C_READ:
          if (argc == 6) {
            // a slave register is specified
            slaveRegister = argv[2] + (argv[3] << 7);
            data = argv[4] + (argv[5] << 7);  // bytes to read
          }
          else {
            // a slave register is NOT specified
            slaveRegister = I2C_REGISTER_NOT_SPECIFIED;
            data = argv[2] + (argv[3] << 7);  // bytes to read
          }
          readAndReportData(slaveAddress, (int)slaveRegister, data);
          break;
        case I2C_READ_CONTINUOUSLY:
          if ((queryIndex + 1) >= I2C_MAX_QUERIES) {
            // too many queries, just ignore
            Firmata.sendString("too many queries");
            break;
          }
          if (argc == 6) {
            // a slave register is specified
            slaveRegister = argv[2] + (argv[3] << 7);
            data = argv[4] + (argv[5] << 7);  // bytes to read
          }
          else {
            // a slave register is NOT specified
            slaveRegister = (int)I2C_REGISTER_NOT_SPECIFIED;
            data = argv[2] + (argv[3] << 7);  // bytes to read
          }
          queryIndex++;
          query[queryIndex].addr = slaveAddress;
          query[queryIndex].reg = slaveRegister;
          query[queryIndex].bytes = data;
          break;
        case I2C_STOP_READING:
          byte queryIndexToSkip;
          // if read continuous mode is enabled for only 1 i2c device, disable
          // read continuous reporting for that device
          if (queryIndex <= 0) {
            queryIndex = -1;
          } else {
            // if read continuous mode is enabled for multiple devices,
            // determine which device to stop reading and remove it's data from
            // the array, shifiting other array data to fill the space
            for (byte i = 0; i < queryIndex + 1; i++) {
              if (query[i].addr == slaveAddress) {
                queryIndexToSkip = i;
                break;
              }
            }

            for (byte i = queryIndexToSkip; i < queryIndex + 1; i++) {
              if (i < I2C_MAX_QUERIES) {
                query[i].addr = query[i + 1].addr;
                query[i].reg = query[i + 1].reg;
                query[i].bytes = query[i + 1].bytes;
              }
            }
            queryIndex--;
          }
          break;
        default:
          break;
      }
      break;
    case I2C_CONFIG:
      delayTime = (argv[0] + (argv[1] << 7));

      if (delayTime > 0) {
        i2cReadDelayTime = delayTime;
      }

      if (!isI2CEnabled) {
        enableI2CPins();
      }

      break;
    case SERVO_CONFIG:
      if (argc > 4) {
        // these vars are here for clarity, they'll optimized away by the compiler
        byte pin = argv[0];
        int minPulse = argv[1] + (argv[2] << 7);
        int maxPulse = argv[3] + (argv[4] << 7);

        if (IS_PIN_DIGITAL(pin)) {
          if (servoPinMap[pin] < MAX_SERVOS && servos[servoPinMap[pin]].attached()) {
            detachServo(pin);
          }
          attachServo(pin, minPulse, maxPulse);
          setPinModeCallback(pin, PIN_MODE_SERVO);
        }
      }
      break;
    case SAMPLING_INTERVAL:
      if (argc > 1) {
        samplingInterval = argv[0] + (argv[1] << 7);
        if (samplingInterval < MINIMUM_SAMPLING_INTERVAL) {
          samplingInterval = MINIMUM_SAMPLING_INTERVAL;
        }
      } else {
        //Firmata.sendString("Not enough data");
      }
      break;
    case EXTENDED_ANALOG:
      if (argc > 1) {
        int val = argv[1];
        if (argc > 2) val |= (argv[2] << 7);
        if (argc > 3) val |= (argv[3] << 14);
        analogWriteCallback(argv[0], val);
      }
      break;
    case CAPABILITY_QUERY:
      Firmata.write(START_SYSEX);
      Firmata.write(CAPABILITY_RESPONSE);
      for (byte pin = 0; pin < TOTAL_PINS; pin++) {
        if (IS_PIN_DIGITAL(pin)) {
          Firmata.write((byte)INPUT);
          Firmata.write(1);
          Firmata.write((byte)PIN_MODE_PULLUP);
          Firmata.write(1);
          Firmata.write((byte)OUTPUT);
          Firmata.write(1);
        }
        if (IS_PIN_ANALOG(pin)) {
          Firmata.write(PIN_MODE_ANALOG);
          Firmata.write(10); // 10 = 10-bit resolution
        }
        if (IS_PIN_PWM(pin)) {
          Firmata.write(PIN_MODE_PWM);
          Firmata.write(8); // 8 = 8-bit resolution
        }
        if (IS_PIN_DIGITAL(pin)) {
          Firmata.write(PIN_MODE_SERVO);
          Firmata.write(14);
        }
        if (IS_PIN_I2C(pin)) {
          Firmata.write(PIN_MODE_I2C);
          Firmata.write(1);  // TODO: could assign a number to map to SCL or SDA
        }
        Firmata.write(127);
      }
      Firmata.write(END_SYSEX);
      break;
    case PIN_STATE_QUERY:
      if (argc > 0) {
        byte pin = argv[0];
        Firmata.write(START_SYSEX);
        Firmata.write(PIN_STATE_RESPONSE);
        Firmata.write(pin);
        if (pin < TOTAL_PINS) {
          Firmata.write((byte)pinConfig[pin]);
          Firmata.write((byte)pinState[pin] & 0x7F);
          if (pinState[pin] & 0xFF80) Firmata.write((byte)(pinState[pin] >> 7) & 0x7F);
          if (pinState[pin] & 0xC000) Firmata.write((byte)(pinState[pin] >> 14) & 0x7F);
        }
        Firmata.write(END_SYSEX);
      }
      break;
    case ANALOG_MAPPING_QUERY:
      Firmata.write(START_SYSEX);
      Firmata.write(ANALOG_MAPPING_RESPONSE);
      for (byte pin = 0; pin < TOTAL_PINS; pin++) {
        Firmata.write(IS_PIN_ANALOG(pin) ? PIN_TO_ANALOG(pin) : 127);
      }
      Firmata.write(END_SYSEX);
      break;
  }
}

void enableI2CPins()
{
  byte i;
  // is there a faster way to do this? would probaby require importing
  // Arduino.h to get SCL and SDA pins
  for (i = 0; i < TOTAL_PINS; i++) {
    if (IS_PIN_I2C(i)) {
      // mark pins as i2c so they are ignore in non i2c data requests
      setPinModeCallback(i, PIN_MODE_I2C);
    }
  }

  isI2CEnabled = true;

  Wire.begin();
}

/* disable the i2c pins so they can be used for other functions */
void disableI2CPins() {
  isI2CEnabled = false;
  // disable read continuous mode for all devices
  queryIndex = -1;
}

/*==============================================================================
 * SETUP()
 *============================================================================*/

void systemResetCallback()
{
  isResetting = true;

  // initialize a defalt state
  // TODO: option to load config from EEPROM instead of default

  // Reset circuit playground components to a default state with nothing running.
  // (i.e. no pixels lit, no sound, no data streaming back)
  circuitPlaygroundReset();

  if (isI2CEnabled) {
    disableI2CPins();
  }

  for (byte i = 0; i < TOTAL_PORTS; i++) {
    reportPINs[i] = false;    // by default, reporting off
    portConfigInputs[i] = 0;  // until activated
    previousPINs[i] = 0;
  }

  for (byte i = 0; i < TOTAL_PINS; i++) {
    // pins with analog capability default to analog input
    // otherwise, pins default to digital output
    if (IS_PIN_ANALOG(i)) {
      // turns off pullup, configures everything
      setPinModeCallback(i, PIN_MODE_ANALOG);
    } else if (IS_PIN_DIGITAL(i)) {
      // sets the output to 0, configures portConfigInputs
      setPinModeCallback(i, OUTPUT);
    }

    servoPinMap[i] = 255;
  }
  // by default, do not report any analog inputs
  analogInputsToReport = 0;

  detachedServoCount = 0;
  servoCount = 0;

  /* send digital inputs to set the initial state on the host computer,
   * since once in the loop(), this firmware will only send on change */
  /*
  TODO: this can never execute, since no pins default to digital input
        but it will be needed when/if we support EEPROM stored config
  for (byte i=0; i < TOTAL_PORTS; i++) {
    outputPort(i, readPort(i, portConfigInputs[i]), true);
  }
  */
  isResetting = false;
}

void circuitPlaygroundReset() {
  // Reset the circuit playground components into a default state
  // with none of the pixels lit, no tones playing, and no cap touch
  // or accelerometer data streaming back.

  // Turn off all the NeoPixels.
  CircuitPlayground.strip.clear();
  CircuitPlayground.strip.show();

  // Reset the accelerometer to a default range.
  CircuitPlayground.lis.setRange(LIS3DH_RANGE_2_G);
  delay(100);
  CircuitPlayground.lis.setClick(2, 80);
  delay(100);

  // Turn off streaming of tap, accel, and cap touch data.
  streamTap = false;
  streamAccel = false;
  for (int i=0; i<CAP_COUNT; ++i) {
    cap_state[i].streaming = false;
  }

  // Stop any tones on the speaker.
  noTone(SPEAKER_PIN);
}

void setup()
{
  // Circuit playground debug setup
  #ifdef DEBUG_MODE
    DEBUG_OUTPUT.begin(DEBUG_BAUD);
    DEBUG_PRINTLN("Circuit Playground Firmata starting up!");
  #endif

  // Circuit playground setup:
  if (!CircuitPlayground.begin()) {
    // Failed to initialize circuit playground, fast blink the red LED on the board.
    DEBUG_PRINTLN("Failed to initialize circuit playground!");
    pinMode(13, OUTPUT);
    while (1) {
      digitalWrite(13, LOW);
      delay(100);
      digitalWrite(13, HIGH);
      delay(100);
    }
  }

  Firmata.setFirmwareVersion(FIRMATA_MAJOR_VERSION, FIRMATA_MINOR_VERSION);

  Firmata.attach(ANALOG_MESSAGE, analogWriteCallback);
  Firmata.attach(DIGITAL_MESSAGE, digitalWriteCallback);
  Firmata.attach(REPORT_ANALOG, reportAnalogCallback);
  Firmata.attach(REPORT_DIGITAL, reportDigitalCallback);
  Firmata.attach(SET_PIN_MODE, setPinModeCallback);
  Firmata.attach(SET_DIGITAL_PIN_VALUE, setPinValueCallback);
  Firmata.attach(START_SYSEX, sysexCallback);
  Firmata.attach(SYSTEM_RESET, systemResetCallback);

  // to use a port other than Serial, such as Serial1 on an Arduino Leonardo or Mega,
  // Call begin(baud) on the alternate serial port and pass it to Firmata to begin like this:
  // Serial1.begin(57600);
  // Firmata.begin(Serial1);
  // then comment out or remove lines 701 - 704 below
  Firmata.begin(57600);

  // Tell Firmata to ignore pins that are used by the Circuit Playground hardware.
  // This MUST be called or else Firmata will 'clobber' pins like the SPI CS!
  pinConfig[1]  = PIN_MODE_IGNORE;   // Pin 1 = LIS3DH interrupt
  pinConfig[11] = PIN_MODE_IGNORE;   // Pin 11 = SPI
  pinConfig[10] = PIN_MODE_IGNORE;   // Pin 10 = SPI
  pinConfig[9]  = PIN_MODE_IGNORE;   // Pin 9  = SPI
  pinConfig[28] = PIN_MODE_IGNORE;   // Pin 28 = D8 = LIS3DH CS
  pinConfig[26] = PIN_MODE_IGNORE;   // Messes with CS too?

  //while (!Serial) {
  //  ; // wait for serial port to connect. Only needed for ATmega32u4-based boards (Leonardo, etc).
  //}
  systemResetCallback();  // reset to default config
}

/*==============================================================================
 * LOOP()
 *============================================================================*/
void loop()
{
  byte pin, analogPin;

  /* DIGITALREAD - as fast as possible, check for changes and output them to the
   * FTDI buffer using Serial.print()  */
  checkDigitalInputs();

  /* STREAMREAD - processing incoming messagse as soon as possible, while still
   * checking digital inputs.  */
  while (Firmata.available())
    Firmata.processInput();

  // TODO - ensure that Stream buffer doesn't go over 60 bytes

  currentMillis = millis();
  if (currentMillis - previousMillis > samplingInterval) {
    previousMillis += samplingInterval;
    /* ANALOGREAD - do all analogReads() at the configured sampling interval */
    for (pin = 0; pin < TOTAL_PINS; pin++) {
      if (IS_PIN_ANALOG(pin) && pinConfig[pin] == PIN_MODE_ANALOG) {
        analogPin = PIN_TO_ANALOG(pin);
        if (analogInputsToReport & (1 << analogPin)) {
          Firmata.sendAnalog(analogPin, analogRead(analogPin));
        }
      }
    }
    // report i2c data for all device with read continuous mode enabled
    if (queryIndex > -1) {
      for (byte i = 0; i < queryIndex + 1; i++) {
        readAndReportData(query[i].addr, query[i].reg, query[i].bytes);
      }
    }
    // Check if a tap event should be streamed to the firmata client.
    if (streamTap) {
      sendTapResponse();
    }
    // Check if an accelerometer event should be streamed to the firmata client.
    if (streamAccel) {
      sendAccelResponse();
    }
    // Check if any cap touch inputs should be streamed to the firmata client.
    for (int i=0; i<CAP_COUNT; ++i) {
      if (cap_state[i].streaming) {
        sendCapResponse(cap_state[i].pin);
      }
    }
  }
}
