/*
  matrix-scan a set of LEDs

  pins:

  "rows" 12 & 13 go to a 220Ω resistor, then to 2 LEDs each (positive
  / long stem side); also to a 10kΩ resistor then to 2
  phototransistors (collector / long stem side)

  also, from between the 10kΩ and the phototransistors, wire goes to
  A1 & A2

  "columns"
  14 & 15 go to 2 LEDs each (negative / short stem side)

  so that given one of 12|13 and one of 14|15, one LED is identified
 */

#include <driver/dac.h>
#define TSF_IMPLEMENTATION
#define TSF_NO_STDIO
#include "../ESP8266Audio/src/libtinysoundfont/tsf.h"

int currentLed = 0;

#define DEBUG 0

const size_t row_count = 5;
const size_t col_count = 5;

const int rows[row_count] = { 5, 23, 19, 18, 26 };
const int cols[col_count] = { 17, 33, 16, 21, 22 };
const int adc[row_count] = { 2, 4, 12, 27, 14 };
const int ampEnable = 32;

const int octave_shift = 2;

char pressed[row_count*col_count] = { 0 };

hw_timer_t * timer = NULL;
portMUX_TYPE timerMux = portMUX_INITIALIZER_UNLOCKED;
tsf* g_TinySoundFont = 0;
bool playing = false;

//This is a minimal SoundFont with a single loopin saw-wave sample/instrument/preset (484 bytes)
const static unsigned char MinimalSoundFont[] PROGMEM =
{
	#define TEN0 0,0,0,0,0,0,0,0,0,0
	'R','I','F','F',220,1,0,0,'s','f','b','k',
	'L','I','S','T',88,1,0,0,'p','d','t','a',
	'p','h','d','r',76,TEN0,TEN0,TEN0,TEN0,0,0,0,0,TEN0,0,0,0,0,0,0,0,255,0,255,0,1,TEN0,0,0,0,
	'p','b','a','g',8,0,0,0,0,0,0,0,1,0,0,0,'p','m','o','d',10,TEN0,0,0,0,'p','g','e','n',8,0,0,0,41,0,0,0,0,0,0,0,
	'i','n','s','t',44,TEN0,TEN0,0,0,0,0,0,0,0,0,TEN0,0,0,0,0,0,0,0,1,0,
	'i','b','a','g',8,0,0,0,0,0,0,0,2,0,0,0,'i','m','o','d',10,TEN0,0,0,0,
	'i','g','e','n',12,0,0,0,54,0,1,0,53,0,0,0,0,0,0,0,
	's','h','d','r',92,TEN0,TEN0,0,0,0,0,0,0,0,50,0,0,0,0,0,0,0,49,0,0,0,34,86,0,0,60,0,0,0,1,TEN0,TEN0,TEN0,TEN0,0,0,0,0,0,0,0,
	'L','I','S','T',112,0,0,0,'s','d','t','a','s','m','p','l',100,0,0,0,86,0,119,3,31,7,147,10,43,14,169,17,58,21,189,24,73,28,204,31,73,35,249,38,46,42,71,46,250,48,150,53,242,55,126,60,151,63,108,66,126,72,207,
		70,86,83,100,72,74,100,163,39,241,163,59,175,59,179,9,179,134,187,6,186,2,194,5,194,15,200,6,202,96,206,159,209,35,213,213,216,45,220,221,223,76,227,221,230,91,234,242,237,105,241,8,245,118,248,32,252
};

class DblBuffer {
  const static size_t _size = 1000;
  short samples[2][_size];
  size_t readPtr;
  char which;
  bool has_data[2];

 public:
  DblBuffer() :which(0), readPtr(0) {
    has_data[0]=false;
    has_data[1]=false;
  }

  bool needsWriting() {
    return !has_data[1-which];
  }
  size_t size() { return _size; }
  short* ptr() { return samples[1-which]; }
  void writingDone() {
    has_data[1-which]=true;
  }

  short pop() {
    if (readPtr >= _size) {
      has_data[which]=false;
      which=1-which;readPtr=0;
    }
    if (!has_data[which]) return 0;

    return samples[which][readPtr++];
  }
} buffer;

void IRAM_ATTR onTimer() {
  return;
  if (!g_TinySoundFont) return;

  portENTER_CRITICAL_ISR(&timerMux);

  dac_output_voltage(DAC_CHANNEL_1, buffer.pop() >> 8);

  portEXIT_CRITICAL_ISR(&timerMux);
}

void setup() {
  Serial.begin(115200);

  pinMode(ampEnable, OUTPUT);
  digitalWrite(ampEnable, LOW);

  dac_i2s_disable();
  dac_output_enable(DAC_CHANNEL_1);

  for (int i=0;i<row_count;++i) {
    pinMode(rows[i], OUTPUT|PULLUP);
    pinMode(adc[i], INPUT);
  }
  for (int i=0;i<col_count;++i) {
    pinMode(cols[i], OUTPUT|PULLDOWN);
  }

  currentLed = 0;
  playing = false;

  g_TinySoundFont = tsf_load_memory(MinimalSoundFont, sizeof(MinimalSoundFont));
  if (g_TinySoundFont) {
    // render at 20kHz
    tsf_set_output(g_TinySoundFont, TSF_MONO, 20000, 0);

    // pre-scaling by 4k, then calling on every 1 tick, should give us 20kHz
    timer = timerBegin(0, 1000, true);
    timerAttachInterrupt(timer, &onTimer, true);
    timerAlarmWrite(timer, 4, true);
    timerAlarmEnable(timer);
  }
  else {
    Serial.println("failed to start tsf");
  }
}

void tristate(int pin) {
  pinMode(pin,OUTPUT|PULLDOWN);
  digitalWrite(pin,LOW);
  pinMode(pin,INPUT);
}

void power(int pin) {
  pinMode(pin,OUTPUT|PULLUP);
  digitalWrite(pin,HIGH);
}

void ground(int pin) {
  pinMode(pin,OUTPUT|PULLDOWN);
  digitalWrite(pin,LOW);
}

void enableLed(int led) {
  int row = (led/col_count) % row_count ;
  int col = led%col_count;

#if DEBUG & 0x02
  Serial.print("enabling ");
  Serial.print(row);
  Serial.print(" ");
  Serial.println(col);
#endif

  for (int i=0;i<row_count;++i) {
    if (i==row) { power(rows[i]); }
    else { ground(rows[i]); }
  }
  for (int i=0;i<col_count;++i) {
    if (i==col) { ground(cols[i]); }
    else { tristate(cols[i]); }
  }
}

int sense(int led) {
  int row = (led/col_count)%row_count;

  int value = analogRead(adc[row]);

#if DEBUG & 0x04
  Serial.println(value);
#endif

  return value < 500;
}

void loop() {
#if DEBUG & 0x01
  Serial.print("current led ");
  Serial.println(currentLed);
#endif

  enableLed(currentLed);
  delay(5);
  if (sense(currentLed)) {
    if (!pressed[currentLed]) {
      Serial.print(currentLed);
      Serial.println(" proximity!");

      pressed[currentLed]=1;
      if (g_TinySoundFont) {
        portENTER_CRITICAL_ISR(&timerMux);
        tsf_note_on(g_TinySoundFont, 0, 60 + currentLed, 1.0f);
        portEXIT_CRITICAL_ISR(&timerMux);
      }
    }
  }
  else if (pressed[currentLed]) {
    pressed[currentLed]=0;
    if (g_TinySoundFont) {
      portENTER_CRITICAL_ISR(&timerMux);
      tsf_note_off(g_TinySoundFont, 0, 60 + currentLed);
      portEXIT_CRITICAL_ISR(&timerMux);
    }
  }

  currentLed = (currentLed+1)%(row_count*col_count);

  if (buffer.needsWriting()) {
    tsf_render_short(g_TinySoundFont, buffer.ptr(), buffer.size(), 0);
    buffer.writingDone();
  }
}