NFC Jukebox Player

#include <Arduino.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <Adafruit_GFX.h>
#include <Adafruit_ILI9341.h>
#include <Adafruit_PN532.h>
#include <SparkFun_MAX1704x_Fuel_Gauge_Arduino_Library.h>
#include <Audio.h>

constexpr uint8_t I2C_SDA_PIN = 8;
constexpr uint8_t I2C_SCL_PIN = 9;
constexpr uint8_t SPI_MOSI_PIN = 11;
constexpr uint8_t SPI_MISO_PIN = 13;
constexpr uint8_t SPI_SCK_PIN = 12;
constexpr uint8_t TFT_CS_PIN = 10;
constexpr uint8_t TFT_DC_PIN = 15;
constexpr uint8_t TFT_RST_PIN = 16;
constexpr uint8_t SD_CS_PIN = 14;
constexpr uint8_t I2S_BCLK_PIN = 38;
constexpr uint8_t I2S_LRC_PIN = 39;
constexpr uint8_t I2S_DIN_PIN = 40;
constexpr uint8_t SONG_CLK_PIN = 1;
constexpr uint8_t SONG_DT_PIN = 2;
constexpr uint8_t SONG_SW_PIN = 3;
constexpr uint8_t SOUND_CLK_PIN = 4;
constexpr uint8_t SOUND_DT_PIN = 5;
constexpr uint8_t SOUND_SW_PIN = 6;

struct Track {
  const char *title;
  const char *artist;
  const char *file;
  uint16_t artColor;
};

const Track tracks[] = {
  {"Midnight Ride", "Jukebox Demo", "/01.mp3", ILI9341_MAGENTA},
  {"Sunrise", "Jukebox Demo", "/02.mp3", ILI9341_ORANGE},
  {"Neon City", "Jukebox Demo", "/03.mp3", ILI9341_CYAN}
};
constexpr uint8_t TRACK_COUNT = sizeof(tracks) / sizeof(tracks[0]);

Adafruit_ILI9341 screen(TFT_CS_PIN, TFT_DC_PIN, TFT_RST_PIN);
Adafruit_PN532 nfc(Wire);
SFE_MAX1704X fuelGauge;
Audio audio;

uint8_t selectedTrack = 0;
uint8_t playingTrack = 0;
uint8_t volumeLevel = 14;
int8_t bassLevel = 0;
bool bassMode = false;
bool sdReady = false;
bool nfcReady = false;
bool gaugeReady = false;
bool playing = false;
uint32_t playStartedAt = 0;
uint32_t lastClockDraw = 0;
uint32_t lastBatteryDraw = 0;
int lastSongClk;
int lastSoundClk;
int lastSongButton = HIGH;
int lastSoundButton = HIGH;
uint32_t lastSongButtonAt = 0;
uint32_t lastSoundButtonAt = 0;

void drawStaticScreen() {
  screen.fillScreen(ILI9341_BLACK);
  screen.fillRect(0, 0, 320, 28, ILI9341_NAVY);
  screen.setTextColor(ILI9341_WHITE, ILI9341_NAVY);
  screen.setTextSize(2);
  screen.setCursor(8, 6);
  screen.print("NFC JUKEBOX");
  screen.drawRect(235, 5, 58, 16, ILI9341_WHITE);
  screen.fillRect(294, 10, 3, 7, ILI9341_WHITE);
  screen.setTextColor(ILI9341_DARKGREY, ILI9341_BLACK);
  screen.setTextSize(1);
  screen.setCursor(10, 220);
  screen.print("Turn left knob: select   Press: play");
  screen.setCursor(10, 232);
  screen.print("Turn right: volume   Press: bass mode");
}

void drawTrack() {
  const Track &track = tracks[selectedTrack];
  screen.fillRect(12, 42, 112, 112, track.artColor);
  screen.fillRect(20, 50, 96, 96, ILI9341_BLACK);
  screen.fillCircle(68, 98, 41, track.artColor);
  screen.fillCircle(68, 98, 14, ILI9341_BLACK);
  screen.fillCircle(68, 98, 4, ILI9341_WHITE);

  screen.fillRect(135, 42, 178, 100, ILI9341_BLACK);
  screen.setTextColor(ILI9341_WHITE, ILI9341_BLACK);
  screen.setTextSize(2);
  screen.setCursor(135, 49);
  screen.print(track.title);
  screen.setTextColor(ILI9341_LIGHTGREY, ILI9341_BLACK);
  screen.setTextSize(1);
  screen.setCursor(135, 77);
  screen.print(track.artist);
  screen.setCursor(135, 95);
  screen.print(playing && playingTrack == selectedTrack ? "PLAYING" : "SELECTED");
  screen.fillRect(135, 116, 175, 30, ILI9341_BLACK);
  screen.setTextColor(ILI9341_GREEN, ILI9341_BLACK);
  screen.setTextSize(2);
  screen.setCursor(135, 119);
  screen.print("00:00");
}

void drawControls() {
  screen.fillRect(12, 166, 296, 44, ILI9341_BLACK);
  screen.setTextColor(ILI9341_WHITE, ILI9341_BLACK);
  screen.setTextSize(1);
  screen.setCursor(12, 169);
  screen.print("VOLUME");
  screen.setCursor(164, 169);
  screen.print(bassMode ? "BASS (ACTIVE)" : "BASS");
  screen.drawRect(12, 184, 130, 12, ILI9341_WHITE);
  screen.drawRect(164, 184, 130, 12, ILI9341_WHITE);
  screen.fillRect(14, 186, map(volumeLevel, 0, 21, 0, 126), 8, ILI9341_GREEN);
  screen.fillRect(166, 186, map(bassLevel + 12, 0, 18, 0, 126), 8, bassMode ? ILI9341_YELLOW : ILI9341_BLUE);
}

void drawBattery() {
  if (!gaugeReady) return;
  float percent = fuelGauge.getSOC();
  percent = constrain(percent, 0.0f, 100.0f);
  screen.fillRect(237, 7, 54, 12, ILI9341_NAVY);
  screen.fillRect(238, 8, (int)(percent * 0.52f), 10, percent < 20 ? ILI9341_RED : ILI9341_GREEN);
  screen.setTextColor(ILI9341_WHITE, ILI9341_NAVY);
  screen.setTextSize(1);
  screen.setCursor(252, 9);
  screen.print((int)percent);
  screen.print('%');
}

void drawElapsedTime() {
  screen.fillRect(135, 116, 175, 30, ILI9341_BLACK);
  screen.setTextColor(ILI9341_GREEN, ILI9341_BLACK);
  screen.setTextSize(2);
  screen.setCursor(135, 119);
  uint32_t elapsed = playing ? (millis() - playStartedAt) / 1000 : 0;
  char timeText[6];
  snprintf(timeText, sizeof(timeText), "%02lu:%02lu", elapsed / 60, elapsed % 60);
  screen.print(timeText);
}

void startSelectedTrack() {
  if (!sdReady) return;
  audio.stopSong();
  playingTrack = selectedTrack;
  playing = audio.connecttoFS(SD, tracks[selectedTrack].file);
  if (playing) playStartedAt = millis();
  drawTrack();
}

void applyTone() {
  audio.setTone(bassLevel, 0, 0);
  drawControls();
}

void updateEncoder(uint8_t clkPin, uint8_t dtPin, int &lastClk, bool isSongKnob) {
  int clkNow = digitalRead(clkPin);
  if (clkNow != lastClk && clkNow == LOW) {
    int direction = digitalRead(dtPin) != clkNow ? 1 : -1;
    if (isSongKnob) {
      selectedTrack = (selectedTrack + direction + TRACK_COUNT) % TRACK_COUNT;
      drawTrack();
    } else if (bassMode) {
      bassLevel = constrain(bassLevel + direction, -12, 6);
      applyTone();
    } else {
      volumeLevel = constrain(volumeLevel + direction, 0, 21);
      audio.setVolume(volumeLevel);
      drawControls();
    }
  }
  lastClk = clkNow;
}

void checkButtons() {
  int songNow = digitalRead(SONG_SW_PIN);
  if (lastSongButton == HIGH && songNow == LOW && millis() - lastSongButtonAt > 180) {
    lastSongButtonAt = millis();
    startSelectedTrack();
  }
  lastSongButton = songNow;

  int soundNow = digitalRead(SOUND_SW_PIN);
  if (lastSoundButton == HIGH && soundNow == LOW && millis() - lastSoundButtonAt > 180) {
    lastSoundButtonAt = millis();
    bassMode = !bassMode;
    drawControls();
  }
  lastSoundButton = soundNow;
}

void checkNfc() {
  if (!nfcReady) return;
  uint8_t uid[7];
  uint8_t uidLength = 0;
  if (nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uidLength, 40)) {
    uint32_t hash = 0;
    for (uint8_t i = 0; i < uidLength; i++) hash = hash * 33 + uid[i];
    selectedTrack = hash % TRACK_COUNT;
    startSelectedTrack();
    delay(450);
  }
}

void setup() {
  Serial.begin(115200);
  pinMode(SONG_CLK_PIN, INPUT_PULLUP);
  pinMode(SONG_DT_PIN, INPUT_PULLUP);
  pinMode(SONG_SW_PIN, INPUT_PULLUP);
  pinMode(SOUND_CLK_PIN, INPUT_PULLUP);
  pinMode(SOUND_DT_PIN, INPUT_PULLUP);
  pinMode(SOUND_SW_PIN, INPUT_PULLUP);
  lastSongClk = digitalRead(SONG_CLK_PIN);
  lastSoundClk = digitalRead(SOUND_CLK_PIN);

  Wire.begin(I2C_SDA_PIN, I2C_SCL_PIN);
  screen.begin();
  screen.setRotation(1);
  drawStaticScreen();

  SPI.begin(SPI_SCK_PIN, SPI_MISO_PIN, SPI_MOSI_PIN, SD_CS_PIN);
  sdReady = SD.begin(SD_CS_PIN, SPI);

  nfc.begin();
  uint32_t version = nfc.getFirmwareVersion();
  nfcReady = version != 0;
  if (nfcReady) nfc.SAMConfig();

  gaugeReady = fuelGauge.begin();
  audio.setPinout(I2S_BCLK_PIN, I2S_LRC_PIN, I2S_DIN_PIN);
  audio.setVolume(volumeLevel);
  applyTone();
  drawTrack();
  drawBattery();
}

void loop() {
  audio.loop();
  updateEncoder(SONG_CLK_PIN, SONG_DT_PIN, lastSongClk, true);
  updateEncoder(SOUND_CLK_PIN, SOUND_DT_PIN, lastSoundClk, false);
  checkButtons();
  checkNfc();

  if (millis() - lastClockDraw >= 1000) {
    lastClockDraw = millis();
    drawElapsedTime();
  }
  if (millis() - lastBatteryDraw >= 30000) {
    lastBatteryDraw = millis();
    drawBattery();
  }
}