Smart Monitor Audio Hub

#include <Arduino.h>
#include <SPI.h>
#include <ArduinoJson.h>
#include <Adafruit_GFX.h>
#include <Adafruit_ST7789.h>


struct PlayerState {
  String title = "Esperando Windows";
  String artist = "Conecte la aplicacion auxiliar";
  String album;
  uint32_t positionMs = 0;
  uint32_t durationMs = 0;
  uint8_t volume = 0;
  bool playing = false;
  bool connected = false;
  bool muted = false;
};


// Forward declarations
void sendCommand(const char *command);
String clipped(const String &text, uint8_t maxChars);
String timeText(uint32_t milliseconds);
void drawStaticUi();
void drawMetadata();
void drawMetadataSafe();
void drawStatus();
void drawProgress();
void refreshUi(bool force);
void parseState(const String &line);
void readSerial();
bool pressedEvent(uint8_t index, int pin);
void readControls();

constexpr int TFT_SCK = 12;
constexpr int TFT_MOSI = 11;
constexpr int TFT_CS = 10;
constexpr int TFT_DC = 14;
constexpr int TFT_RST = 15;
constexpr int TFT_BL = 16;
constexpr int ENC_CLK = 4;
constexpr int ENC_DT = 5;
constexpr int ENC_SW = 6;
constexpr int PREV_BUTTON = 7;
constexpr int NEXT_BUTTON = 17;

Adafruit_ST7789 tft(TFT_CS, TFT_DC, TFT_RST);



PlayerState player;
String inputLine;
uint32_t lastPacketMs = 0;
uint32_t lastUiMs = 0;
uint32_t lastControlMs = 0;
int lastEncoderClk = HIGH;
bool lastButtonLevel[3] = {HIGH, HIGH, HIGH};
bool stableButtonLevel[3] = {HIGH, HIGH, HIGH};
uint32_t lastButtonChange[3] = {0, 0, 0};
uint32_t pressStartMs = 0;
bool encoderPressed = false;
String shownTitle, shownArtist, shownAlbum;
int shownVolume = -1;
bool shownConnected = false, shownPlaying = false, shownMuted = false;
uint32_t shownPosition = UINT32_MAX, shownDuration = UINT32_MAX;

const uint16_t C_BG = 0x0861;
const uint16_t C_PANEL = 0x18C3;
const uint16_t C_TEXT = ST77XX_WHITE;
const uint16_t C_MUTED = 0x8410;
const uint16_t C_ACCENT = 0x2E9F;
const uint16_t C_GREEN = 0x3ECA;
const uint16_t C_RED = 0xF945;

void sendCommand(const char *command) {
  StaticJsonDocument<64> doc;
  doc["cmd"] = command;
  serializeJson(doc, Serial);
  Serial.println();
}

String clipped(const String &text, uint8_t maxChars) {
  if (text.length() <= maxChars) return text;
  return text.substring(0, maxChars - 3) + "...";
}

String timeText(uint32_t milliseconds) {
  uint32_t seconds = milliseconds / 1000;
  char out[12];
  snprintf(out, sizeof(out), "%lu:%02lu", (unsigned long)(seconds / 60), (unsigned long)(seconds % 60));
  return String(out);
}

void drawStaticUi() {
  tft.fillScreen(C_BG);
  tft.fillRoundRect(8, 8, 304, 42, 8, C_PANEL);
  tft.setTextColor(C_TEXT, C_PANEL);
  tft.setTextSize(2);
  tft.setCursor(18, 20);
  tft.print("SMART MONITOR SPEAKER");
  tft.drawRoundRect(8, 62, 304, 116, 8, C_PANEL);
  tft.drawRoundRect(8, 190, 304, 42, 8, C_PANEL);
}

void drawMetadataSafe() {
  // Separate helper keeps the display update localized when text changes.
  tft.fillRect(18, 78, 284, 88, C_PANEL);
  tft.setTextWrap(false);
  tft.setTextColor(C_TEXT, C_PANEL);
  tft.setTextSize(2);
  tft.setCursor(18, 82);
  tft.print(clipped(player.title, 27));
  tft.setTextColor(C_ACCENT, C_PANEL);
  tft.setCursor(18, 111);
  tft.print(clipped(player.artist, 31));
  tft.setTextColor(C_MUTED, C_PANEL);
  tft.setCursor(18, 140);
  tft.print(clipped(player.album, 31));
}

void drawStatus() {
  const bool link = player.connected && (millis() - lastPacketMs < 2500);
  tft.fillCircle(288, 29, 7, link ? C_GREEN : C_RED);
  tft.fillRect(18, 198, 284, 26, C_PANEL);
  tft.setTextSize(2);
  tft.setTextColor(C_TEXT, C_PANEL);
  tft.setCursor(18, 202);
  tft.print(player.playing ? ">" : "||");
  tft.setCursor(55, 202);
  if (player.muted) tft.print("MUTE ");
  tft.print("VOL ");
  tft.print(player.volume);
  tft.print("%");
  tft.setTextColor(link ? C_GREEN : C_RED, C_PANEL);
  tft.setCursor(188, 202);
  tft.print(link ? "PC OK" : "SIN PC");
}

void drawProgress() {
  const uint16_t x = 18, y = 165, w = 284;
  uint32_t duration = player.durationMs;
  uint32_t position = duration ? min(player.positionMs, duration) : 0;
  uint16_t filled = duration ? (uint32_t)w * position / duration : 0;
  tft.fillRoundRect(x, y, w, 8, 4, C_MUTED);
  if (filled) tft.fillRoundRect(x, y, filled, 8, 4, C_ACCENT);
  tft.fillRect(18, 176, 284, 11, C_BG);
  tft.setTextSize(1);
  tft.setTextColor(C_TEXT, C_BG);
  tft.setCursor(18, 178);
  tft.print(timeText(position));
  tft.setCursor(270, 178);
  tft.print(timeText(duration));
}

void refreshUi(bool force = false) {
  const bool link = player.connected && (millis() - lastPacketMs < 2500);
  if (force || player.title != shownTitle || player.artist != shownArtist || player.album != shownAlbum) {
    drawMetadataSafe();
    shownTitle = player.title; shownArtist = player.artist; shownAlbum = player.album;
  }
  if (force || player.positionMs != shownPosition || player.durationMs != shownDuration) {
    drawProgress(); shownPosition = player.positionMs; shownDuration = player.durationMs;
  }
  if (force || player.volume != shownVolume || link != shownConnected || player.playing != shownPlaying || player.muted != shownMuted) {
    drawStatus(); shownVolume = player.volume; shownConnected = link; shownPlaying = player.playing; shownMuted = player.muted;
  }
}

void parseState(const String &line) {
  StaticJsonDocument<768> doc;
  DeserializationError error = deserializeJson(doc, line);
  if (error || String((const char *)(doc["type"] | "")) != "state") return;
  player.connected = doc["connected"] | true;
  player.title = String((const char *)(doc["title"] | "Sin titulo"));
  player.artist = String((const char *)(doc["artist"] | ""));
  player.album = String((const char *)(doc["album"] | ""));
  player.positionMs = doc["position_ms"] | 0;
  player.durationMs = doc["duration_ms"] | 0;
  player.playing = doc["playing"] | false;
  player.volume = constrain(doc["volume"] | 0, 0, 100);
  player.muted = doc["muted"] | false;
  lastPacketMs = millis();
}

void readSerial() {
  while (Serial.available()) {
    char c = (char)Serial.read();
    if (c == '\n') {
      parseState(inputLine);
      inputLine = "";
    } else if (c != '\r' && inputLine.length() < 700) {
      inputLine += c;
    } else if (inputLine.length() >= 700) {
      inputLine = "";
    }
  }
}

bool pressedEvent(uint8_t index, int pin) {
  const bool rawLevel = digitalRead(pin);
  const uint32_t now = millis();
  if (rawLevel != lastButtonLevel[index]) {
    lastButtonLevel[index] = rawLevel;
    lastButtonChange[index] = now;
  }
  if (rawLevel != stableButtonLevel[index] && now - lastButtonChange[index] >= 35) {
    stableButtonLevel[index] = rawLevel;
    return stableButtonLevel[index] == LOW;
  }
  return false;
}

void readControls() {
  int clk = digitalRead(ENC_CLK);
  if (clk != lastEncoderClk && clk == LOW) {
    sendCommand(digitalRead(ENC_DT) == HIGH ? "volume_up" : "volume_down");
  }
  lastEncoderClk = clk;

  bool encoderLevel = digitalRead(ENC_SW);
  if (!encoderPressed && encoderLevel == LOW && millis() - lastButtonChange[0] > 35) {
    encoderPressed = true;
    pressStartMs = millis();
  }
  if (encoderPressed && encoderLevel == HIGH) {
    sendCommand(millis() - pressStartMs >= 700 ? "mute" : "play_pause");
    encoderPressed = false;
    lastButtonChange[0] = millis();
  }
  if (pressedEvent(1, PREV_BUTTON)) sendCommand("previous");
  if (pressedEvent(2, NEXT_BUTTON)) sendCommand("next");
}

void setup() {
  Serial.begin(115200);
  pinMode(TFT_BL, OUTPUT); digitalWrite(TFT_BL, HIGH);
  pinMode(ENC_CLK, INPUT_PULLUP); pinMode(ENC_DT, INPUT_PULLUP); pinMode(ENC_SW, INPUT_PULLUP);
  pinMode(PREV_BUTTON, INPUT_PULLUP); pinMode(NEXT_BUTTON, INPUT_PULLUP);
  lastEncoderClk = digitalRead(ENC_CLK);
  SPI.begin(TFT_SCK, -1, TFT_MOSI, TFT_CS);
  tft.init(240, 320);
  tft.setRotation(1);
  drawStaticUi();
  refreshUi(true);
}

void loop() {
  readSerial();
  readControls();
  uint32_t now = millis();
  if (player.connected && now - lastPacketMs > 2500) player.connected = false;
  if (now - lastUiMs >= 250) {
    lastUiMs = now;
    refreshUi();
  }
}