#include <Wire.h>
//#include <Adafruit_GFX.h>
//#include <Adafruit_SSD1306.h>
#include <RotaryEncoder.h>
#include <FlexiTimer2.h>
#include <EEPROM.h>
#include <U8g2lib.h>

#define VERSION "0.9b"

#define SCREEN_ADDRESS 0x3C

#define PPQN 24
#define PULSE_LENGTH 12  //ms (with 12 ms you can't get higher than 208bpm)
#define MAXBPM 200       //250 at 24ppqn with 5ms pulse will be 50/50 square wave
#define MINBPM 20
#define SCREEN_TIMEOUT 600000  //Turn display off after 5 min

/* Rev 1 Config
#define ENC_BTN_PIN 14
#define ENC_D1_PIN 17
#define ENC_D2_PIN 4
#define START_STOP_BTN_PIN 5
#define EXT_INPUT_PIN 2 //needs to be an interrupt pin
#define ANALOGUE_INPUT_1_PIN A2
#define ANALOGUE_INPUT_2_PIN A1
const int outsPins[6] = {6, 11, 7, 10, 8, 9};
*/

// Rev 2 and 3 Config
#define ENC_BTN_PIN 14
#define ENC_D1_PIN 17
#define ENC_D2_PIN 4
#define START_STOP_BTN_PIN 5
#define SHIFT_BTN_PIN 12
#define EXT_INPUT_PIN 2  //needs to be an interrupt pin
#define ANALOGUE_INPUT_1_PIN A7
#define ANALOGUE_INPUT_2_PIN A6
const byte outsPins[6] = { 7, 8, 10, 6, 9, 11 };


const int subDivs[17] = { -24, -12, -8, -6, -4, -3, -2, 1, 2, 3, 4, 5, 6, 7, 8, 16, 32 };  //positive - divide, negative - multiply, 0 - off

byte bpm = 130;
byte bpmModulationChannel = 200;  //0 - CV1, 1 - CV2, 255 - OFF
byte bpmModulationRange = 0;

struct channel {
  byte mode; //0 - CLK, 1 - RND, 2 - SEQ
  byte subDiv;
  byte CV1Target; //0 - Off, 1 - Subdiv, 2 - RND, 3 - SeqPattern
  byte CV1Value;
  byte CV2Target;
  byte CV2Value;
  byte offset;
  byte random;
  byte seqPattern;
};

channel channels[6] = {  //array of channel settings
  { 0, 7, 0, 3, 0, 3, 0, 0, 0 },
  { 0, 7, 0, 3, 0, 3, 0, 0, 0 },
  { 0, 7, 0, 3, 0, 3, 0, 0, 0 },
  { 0, 7, 0, 3, 0, 3, 0, 0, 0 },
  { 0, 7, 0, 3, 0, 3, 0, 0, 0 },
  { 0, 7, 0, 3, 0, 3, 0, 0, 0 }
};

bool seqA1[16] = {1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0};
bool seqA2[16] = {0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0};
bool seqA3[16] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
bool seqA4[16] = {1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0};
bool seqA5[16] = {1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0};
bool seqA6[16] = {0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0};
bool seqA7[16] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
bool seqA8[16] = {1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0};
bool seqB1[16] = {1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0};
bool seqB2[16] = {0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0};
bool seqB3[16] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
bool seqB4[16] = {1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0};
bool seqB5[16] = {1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0};
bool seqB6[16] = {0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0};
bool seqB7[16] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
bool seqB8[16] = {1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0};
bool *currentSeq;
byte currentStep = 0;

byte memCode = 'A'; //Change to different letter if you changed the data structure

unsigned int channelPulseCount[6];
unsigned int channelPulsesPerCycle[6];
byte sixteenthPulseCount = 0;
int playingModes[6];  //actual channel modes array updated from channels object on each beat

unsigned int pulsePeriod;
bool isPlaying = false;

unsigned int tickCount = 0;
unsigned int pulseCount = 0;

byte masterClockMode = 0;  // 0 - internal, 1 - external 24ppqn, 2 - external beat
unsigned long lastExtPulseTime;
unsigned long newExtPulseTime;

bool needPulseReset[6] = { true, true, true, true, true, true };

byte displayTab = 0;
bool insideTab = false;
byte menuItem = 0;
byte lastMenuItem = 3;
bool playBtnPushed = false;
bool shiftBtnPushed = false;

int a1Input = 0;
int a2Input = 0;

int encPositionOld = 0;
unsigned long encPressedTime;
unsigned long encReleasedTime;
bool encPressRegistered;

//unsigned long lastInteractionTime;  // used for display timeout

U8G2_SSD1306_128X64_NONAME_2_HW_I2C u8g2(U8G2_R2, SCL, SDA, U8X8_PIN_NONE); 
RotaryEncoder encoder(ENC_D1_PIN, ENC_D2_PIN, RotaryEncoder::LatchMode::TWO03);

const unsigned char splash_logo[] PROGMEM = {
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
	0x07, 0xf8, 0x03, 0xff, 0xc0, 0x03, 0xf8, 0x1f, 0x00, 0x7c, 0x7c, 0x3f, 0xff, 0xc7, 0xc0, 0x3e, 
	0x0f, 0xfe, 0x03, 0xff, 0xe0, 0x07, 0xf8, 0x0f, 0x00, 0x78, 0x7c, 0x3f, 0xff, 0xc3, 0xe0, 0x7c, 
	0x1f, 0xff, 0x03, 0xff, 0xf0, 0x07, 0xf8, 0x0f, 0x80, 0xf8, 0x7c, 0x3f, 0xff, 0xc3, 0xe0, 0x78, 
	0x3f, 0xff, 0x03, 0xff, 0xf8, 0x07, 0xfc, 0x0f, 0x80, 0xf8, 0x7c, 0x3f, 0xff, 0xc1, 0xf0, 0xf8, 
	0x7e, 0x0f, 0x83, 0xe0, 0xf8, 0x0f, 0x3c, 0x07, 0x80, 0xf0, 0x7c, 0x00, 0xf8, 0x00, 0xf8, 0xf0, 
	0x7c, 0x07, 0x83, 0xe0, 0x78, 0x0f, 0x3c, 0x07, 0xc0, 0xf0, 0x7c, 0x00, 0xf0, 0x00, 0xf9, 0xf0, 
	0x7c, 0x00, 0x03, 0xe0, 0xf8, 0x0f, 0x3e, 0x07, 0xc1, 0xf0, 0x7c, 0x00, 0xf0, 0x00, 0x7d, 0xe0, 
	0x78, 0x00, 0x03, 0xe0, 0xf8, 0x1e, 0x1e, 0x03, 0xc1, 0xe0, 0x7c, 0x00, 0xf0, 0x00, 0x7f, 0xc0, 
	0x78, 0x3f, 0xc3, 0xff, 0xf0, 0x1e, 0x1e, 0x03, 0xe1, 0xe0, 0x7c, 0x00, 0xf0, 0x00, 0x3f, 0xc0, 
	0x78, 0x3f, 0xc3, 0xff, 0xe0, 0x1e, 0x1f, 0x01, 0xe3, 0xe0, 0x7c, 0x00, 0xf0, 0x00, 0x1f, 0x80, 
	0x78, 0x3f, 0xc3, 0xff, 0xc0, 0x3e, 0x1f, 0x01, 0xe3, 0xc0, 0x7c, 0x00, 0xf0, 0x00, 0x1f, 0x80, 
	0x7c, 0x3f, 0xc3, 0xe7, 0xc0, 0x3f, 0xff, 0x01, 0xf3, 0xc0, 0x7c, 0x00, 0xf0, 0x00, 0x0f, 0x00, 
	0x7e, 0x07, 0xc3, 0xe3, 0xe0, 0x3f, 0xff, 0x80, 0xf7, 0xc0, 0x7c, 0x00, 0xf0, 0x00, 0x0f, 0x00, 
	0x3f, 0x1f, 0xc3, 0xe1, 0xe0, 0x7f, 0xff, 0x80, 0xff, 0x80, 0x7c, 0x00, 0xf0, 0x00, 0x0f, 0x00, 
	0x1f, 0xff, 0xc3, 0xe1, 0xf0, 0x78, 0x07, 0x80, 0xff, 0x80, 0x7c, 0x00, 0xf0, 0x00, 0x0f, 0x00, 
	0x0f, 0xff, 0xc3, 0xe0, 0xf8, 0xf8, 0x07, 0xc0, 0x7f, 0x00, 0x7c, 0x00, 0xf0, 0x00, 0x0f, 0x00, 
	0x07, 0xf3, 0xc3, 0xe0, 0xf8, 0xf8, 0x07, 0xc0, 0x7f, 0x00, 0x7c, 0x00, 0xf0, 0x00, 0x0f, 0x00, 
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

const uint8_t velvetscreen[597] U8G2_FONT_SECTION("velvetscreen") = 
  "I\0\2\2\3\3\3\3\4\5\5\0\0\5\0\5\0\0\363\0\0\2\70!\6)\251\254\0\42\6\23"
  "\317$\25#\12-\351UC\345\241*\0$\11,\331\215\24e\32\11%\12-\351\250\244r\245\222\0"
  "&\11-\351\351*\311\250\2'\5\21\257\10(\6*\271\251\62)\10*\271\304\224\24\0*\11-\351"
  "V\325jF\0+\7\33\313\245\225\0,\5\21\251\10-\5\13\315\14.\5\11\251\4/\7$\331\307"
  "\66\0\60\10,\331\251h&\5\61\7+\311\310\326\0\62\11,\331l\224T\36\1\63\11,\331l\224"
  "\64\32\11\64\10,\331D\71t\1\65\11,\331\14\275\321H\0\66\11,\331\251\274bR\0\67\10,"
  "\331\214\34\353\10\70\11,\331\251\230TL\12\71\11,\331\251\230vR\0:\6\31\253\244\0;\6!"
  "\251$\1<\7+\311\246\272\0=\6\33\313\354\1>\7+\311\344\252\4\77\11,\331l\224\64\216\0"
  "@\12-\351\255J\215\14\27\0A\10,\331\251\70\246\14B\11,\331\254\70R\34\2C\11,\331\251"
  "\250cR\0D\10,\331\254h\216\4E\10,\331\14=\364\10F\10,\331\14\275r\6G\10,\331"
  "\215\234f\32H\10,\331D\71\246\14I\6)\251\14\1J\10,\331\327\62)\0K\11,\331D\225"
  "d*\3L\7,\331\344\366\10M\11-\351\344\265\222\326\1N\11-\351\344\251\222\334\1O\10,\331"
  "\251h&\5P\11,\331\254\70R\316\0Q\10,\331\251h\305\24R\10,\331\254\70R\63S\11,"
  "\331\215\214\64\32\11T\7+\311\254\330\2U\10,\331DgR\0V\12-\351d\235\312\224#\0W"
  "\12-\351d\225TR]\0X\11,\331D\231T\224\1Y\12-\351\344Tg\224Q\4Z\7+\311"
  "\314T\16[\6*\271\254J\134\11$\331d\224QF\1]\6*\271\250j^\5\23\317\65_\6\14"
  "\331\214\0o\7[\333\214\64\2p\11-\351-\265\227Z\0q\7-\351\35_\13r\10+\311D\65"
  "T\4s\7-\351\334\366\30t\7-\351\374G\0u\10-\351\334*\351\61v\5\211\335\4w\12-"
  "\351\255J\215\234\26\0x\6\33\311\244\16\0\0\0\4\377\377\0";


void setup() {
  Serial.begin(9600);

  //check last bit in eeprom to know if the correct settings were stored
  if (EEPROM.read(1023) == memCode) {
    int addr = 0;
    EEPROM.get(addr, bpm);
    addr = addr + sizeof(bpm);
    EEPROM.get(addr, bpmModulationChannel);
    addr = addr + sizeof(bpmModulationChannel);
    EEPROM.get(addr, bpmModulationRange);
    addr = addr + sizeof(bpmModulationRange);
    EEPROM.get(addr, masterClockMode);
    addr = addr + sizeof(masterClockMode);
    EEPROM.get(addr, channels);
  } else {
    saveState();
    EEPROM.write(1023, memCode);
  }

  pinMode(ENC_BTN_PIN, INPUT_PULLUP);
  pinMode(START_STOP_BTN_PIN, INPUT_PULLUP);
  pinMode(SHIFT_BTN_PIN, INPUT_PULLUP);
  pinMode(EXT_INPUT_PIN, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(EXT_INPUT_PIN), externalClock, FALLING);

  for (byte i = 0; i < 6; i++) {
    pinMode(outsPins[i], OUTPUT);
  }

  /*display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS);
  display.setRotation(2);
  display.clearDisplay();

  //Splash screen
  display.drawBitmap(0, 16, splash_logo, 128, 19, 1);

  display.setCursor(0, 56);
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.print(F("V:"));
  display.print(F(VERSION));
  display.display();
  delay(800);*/
  //u8g2.setI2CAddress(SCREEN_ADDRESS);
  u8g2.begin();

  updateScreen();
  calculateCycles();
  calculateBPMTiming();

  FlexiTimer2::set(1, 1.0 / 1000, clock);  // 1.0/1000 = 1ms period. If other than 1ms calculateBPMTiming() might need tweaking
  FlexiTimer2::start();
}

void loop() {
  checkInputs();
  /*if ((millis() - lastInteractionTime) > SCREEN_TIMEOUT) {
    display.clearDisplay();
    display.display();
  if (masterClockMode == 2 || masterClockMode == 3) {
    calculateBPMTiming();
  }}*/
}

void clock() {
  if (isPlaying) {

    // Action on each pulse
    if (tickCount == 0) {
      sendTriggers();
    }

    //this part gets the Pulse and Ticks ticking
    //it's placed after the triggers to avoid problems on the start (when pulseCount==0)
    tickCount++;
    if (masterClockMode == 0) {
      if (tickCount >= pulsePeriod) {
        tickCount = 0;
        if (pulseCount < (PPQN - 1)) {  //-1 is here to avoid extra IF to reset to 0
          pulseCount++;
        } else {
          pulseCount = 0;
        }
        if (bpmModulationRange != 0) {
          calculateBPMTiming();
        }
      }
    }

    // pull low all outputs after set pulse length
    if (tickCount >= PULSE_LENGTH) {
      for (byte i = 0; i < 6; i++) {
        digitalWrite(outsPins[i], LOW);
      }
    }
  }
}

void externalClock() {
  lastExtPulseTime = newExtPulseTime;
  newExtPulseTime = millis();

  if (masterClockMode == 1) {  // EXT-24
    //reset cycles if there was no pulses for a while
    if ((newExtPulseTime - lastExtPulseTime) > 125) {  //125ms is 20bpm
      for (byte i = 0; i < 6; i++) {
        channelPulseCount[i] = 0;
      }
    }

    if (!isPlaying) {
      isPlaying = true;
    }
    tickCount = 0;  //to make things happen in the main clock function
    if (pulseCount < (PPQN - 1)) {
      pulseCount++;
    } else {
      pulseCount = 0;
    }

  }
}

void sendTriggers() {

  for (byte i = 0; i < 6; i++) {
    if (playingModes[i] != subDivs[channels[i].subDiv]) {
      needPulseReset[i] = true;
    }
  }

  //16th notes for sequencer
  if (sixteenthPulseCount == 0) {
    for (byte i = 0; i < 6; i++) {
      if (channels[i].mode == 2 && channelPulseCount[i] == 0 && currentSeq[currentStep]) {
        digitalWrite(outsPins[i], HIGH);
      }
    }
  }
  if (sixteenthPulseCount < (PPQN / 4) - 1) {
    sixteenthPulseCount++;
  } else {
    sixteenthPulseCount = 0;
    if (currentStep < 15) {
      currentStep ++;
    } else {
      currentStep = 0;
    }
  }

  //switching modes on the beat and resetting channel clock
  if (pulseCount == 0) {
    calculateCycles();
    for (byte i = 0; i < 6; i++) {
      if (needPulseReset[i] == true) {
        channelPulseCount[i] = 0;
        needPulseReset[i] = false;
      }
    }
  }

  //multiplier
  for (byte i = 0; i < 6; i++) {
    
    //RND modulation
    byte randMod = 0;
    if (channels[i].CV1Target == 2) {
      randMod = randMod + a1Input;
    }
    if (channels[i].CV2Target == 2) {
      randMod = randMod + a2Input;
    }
    if (channels[i].CV1Target == 2 || channels[i].CV2Target == 2) {
      randMod = map(randMod, 0, 1023, -5, +5);
    }
    byte randAmount = channels[i].random + randMod;
    if (randAmount > 100) {
      randAmount = 0;
    } else if (randAmount > 10) {
      randAmount = 10;
    }


    if ((channels[i].mode == 0 && channelPulseCount[i] == channels[i].offset) //CLK with offset
     || (channels[i].mode == 1 && channelPulseCount[i] == 0 && (random(10) + 1) > randAmount) //RND
     //|| (channels[i].mode == 2 && channelPulseCount[i] == 0 && currentSeq[currentStep])
       ) {
        digitalWrite(outsPins[i], HIGH);
    }
    if (channelPulseCount[i] < channelPulsesPerCycle[i]) {
      channelPulseCount[i]++;
    } else {
      channelPulseCount[i] = 0;
    }
  }

}

void calculateCycles() {

  for (byte i = 0; i < 6; i++) {
    if (channels[i].CV1Target != 1 && channels[i].CV2Target != 1)  {
      playingModes[i] = subDivs[channels[i].subDiv];
    } else if (channels[i].CV1Target == 1) { //subdiv modulation happens here
      int mod;
      mod = a1Input;
      mod = map(mod, 0, 1023, (channels[i].CV1Value * -1), channels[i].CV1Value);
      playingModes[i] = subDivs[channels[i].subDiv - mod];  //subtracting because the innitial array is backwards
    } else if (channels[i].CV2Target == 1) {
      int mod;
      mod = a2Input;
      mod = map(mod, 0, 1023, (channels[i].CV2Value * -1), channels[i].CV2Value);
      playingModes[i] = subDivs[channels[i].subDiv - mod];
    }

    if (playingModes[i] > 0 && channels[i].mode != 2) {
      channelPulsesPerCycle[i] = (playingModes[i] * PPQN) - 1;
    } else if (playingModes[i] <= 0 && channels[i].mode != 2) {
      channelPulsesPerCycle[i] = (PPQN / abs(playingModes[i])) - 1;
    } else if (channels[i].mode == 2) { //Sequencer plays 1/16th
      channelPulsesPerCycle[i] = (PPQN / 4) - 1;
    }
    if (channels[i].offset > channelPulsesPerCycle[i]) {
      channels[i].offset = channelPulsesPerCycle[i];
    }
  }
}

void calculateBPMTiming() {
  int mod = 0;
  if (masterClockMode == 0) {  //Internal clock
    if (bpmModulationRange != 0 && bpmModulationChannel == 0) {
      mod = map(a1Input, 0, 1023, bpmModulationRange * -10, bpmModulationRange * 10);
    } else if (bpmModulationRange != 0 && bpmModulationChannel == 1) {
      mod = map(a2Input, 0, 1023, bpmModulationRange * -10, bpmModulationRange * 10);
    }
    pulsePeriod = 60000 / ((bpm + mod) * PPQN);

  } else if (masterClockMode == 2) {  //for external beat clock
    pulsePeriod = (newExtPulseTime - lastExtPulseTime) / PPQN;

  } else if (masterClockMode == 3) {  //for ext 1/16 clock (hardcoded)
    pulsePeriod = (newExtPulseTime - lastExtPulseTime) / 6;
  }
}

void resetClocks() {
  for (byte i = 0; i < 6; i++) {
    channelPulseCount[i] = 0;
    digitalWrite(outsPins[i], LOW);  //to avoid stuck leds
  }
  pulseCount = 0;
  tickCount = 0;
}

void saveState() {
  int addr = 0;
  EEPROM.put(addr, bpm);
  addr = addr + sizeof(bpm);
  EEPROM.put(addr, bpmModulationChannel);
  addr = addr + sizeof(bpmModulationChannel);
  EEPROM.put(addr, bpmModulationRange);
  addr = addr + sizeof(bpmModulationRange);
  EEPROM.put(addr, masterClockMode);
  addr = addr + sizeof(masterClockMode);
  EEPROM.put(addr, channels);
}