/*
  ESP32-C3 Mini — WiFi NTP Clock on 32x8 WS2812B NeoPixel Matrix
  India Standard Time (UTC+5:30)
  Arvind Patil / AI Centre Nandurbar

  Wiring:
    NeoPixel DIN -> GPIO4 (330ohm resistor inline)
    NeoPixel 5V  -> 5V / VBUS
    NeoPixel GND -> GND (common ground with ESP32-C3)
    1000uF capacitor across matrix 5V/GND recommended.
    DHT22 DATA -> GPIO5 (10k pull-up to 3.3V), VCC -> 3.3V, GND -> GND
    Buzzer (+) -> GPIO6, Buzzer (-) -> GND

  Libraries required (Library Manager):
    - Adafruit NeoMatrix
    - Adafruit NeoPixel
    - Adafruit GFX Library
    - DHT sensor library (Adafruit)
    - Adafruit Unified Sensor
*/

#include <WiFi.h>
#include <time.h>
#include <Adafruit_NeoPixel.h>
#include <Adafruit_GFX.h>
#include <Adafruit_NeoMatrix.h>
#include <DHT.h>

// ---------- USER CONFIG ----------
const char* WIFI_SSID     = "Wokwi-GUEST";  // Wokwi's built-in simulated WiFi network
const char* WIFI_PASSWORD = "";              // Wokwi-GUEST has no password

#define MATRIX_PIN   4
#define MATRIX_W     32
#define MATRIX_H     8
#define BRIGHTNESS   90      // raised for visibility; use a proper 5V/3A+ supply at this level,
                              // not the USB 500mA budget — drop back to ~40 if running off USB only

#define SCROLL_STEP_MS  140   // ms per column of scroll movement (slow, readable pace)

#define DHT_PIN      5
#define DHT_TYPE     DHT22
#define BUZZER_PIN   6

// Default alarm (can later be made configurable over WiFi/web UI)
int alarmHour    = 6;
int alarmMinute  = 30;
bool alarmEnabled = true;

// IST = UTC + 5:30, no daylight saving
const long  GMT_OFFSET_SEC     = 5 * 3600 + 1800;
const int   DAYLIGHT_OFFSET_SEC = 0;
const char* NTP_SERVER = "pool.ntp.org";
// ----------------------------------

DHT dht(DHT_PIN, DHT_TYPE);
float lastTemp = NAN, lastHum = NAN;
unsigned long lastSensorRead = 0;
const unsigned long SENSOR_INTERVAL_MS = 3000;

bool alarmRinging = false;
int lastAlarmMinuteFired = -1;
unsigned long lastBeepToggle = 0;
bool buzzerOn = false;

Adafruit_NeoMatrix matrix = Adafruit_NeoMatrix(
  MATRIX_W, MATRIX_H, MATRIX_PIN,
  NEO_MATRIX_TOP + NEO_MATRIX_LEFT + NEO_MATRIX_ROWS + NEO_MATRIX_ZIGZAG,
  NEO_GRB + NEO_KHZ800
);

uint16_t colorGold, colorGreen, colorCyan, colorRed;
uint16_t currentColor;
int colorCycle = 0;

int scrollX = MATRIX_W;
int secScrollX = MATRIX_W;
unsigned long lastScrollMove = 0;
unsigned long lastColonBlink = 0;
bool colonOn = true;

enum Mode { MODE_TIME, MODE_SECONDS, MODE_SCROLL_DATE, MODE_TEMP_HUM };
Mode mode = MODE_TIME;
unsigned long lastModeSwitch = 0;
const unsigned long MODE_DURATION_MS = 15000; // rotate every 15s
int tempScrollX = MATRIX_W;

void readSensor() {
  if (millis() - lastSensorRead < SENSOR_INTERVAL_MS) return;
  lastSensorRead = millis();
  float h = dht.readHumidity();
  float t = dht.readTemperature();
  if (!isnan(h) && !isnan(t)) {
    lastHum = h;
    lastTemp = t;
  }
}

void drawTempHumidity() {
  matrix.fillScreen(0);
  matrix.setTextColor(currentColor);
  char buf[24];
  if (isnan(lastTemp) || isnan(lastHum)) {
    snprintf(buf, sizeof(buf), "SENSOR ERR   ");
  } else {
    snprintf(buf, sizeof(buf), "TEMP %.1fC  HUM %.0f%%   ", lastTemp, lastHum);
  }
  matrix.setCursor(tempScrollX, 0);
  matrix.print(buf);
  matrix.show();

  int w = strlen(buf) * 6;
  if (--tempScrollX < -w) tempScrollX = MATRIX_W;
}

void checkAlarm(struct tm &t) {
  if (alarmEnabled && !alarmRinging &&
      t.tm_hour == alarmHour && t.tm_min == alarmMinute) {
    if (lastAlarmMinuteFired != t.tm_min) {
      lastAlarmMinuteFired = t.tm_min;
      alarmRinging = true;
    }
  }
  if (t.tm_min != alarmMinute) lastAlarmMinuteFired = -1;
}

void drawAlarmRinging(struct tm &t) {
  unsigned long now = millis();
  // toggle buzzer tone on/off every 500ms
  if (now - lastBeepToggle > 500) {
    lastBeepToggle = now;
    buzzerOn = !buzzerOn;
    if (buzzerOn) tone(BUZZER_PIN, 1500);
    else noTone(BUZZER_PIN);
  }
  // flash "ALARM HH:MM" on the matrix
  bool flashOn = (now / 300) % 2 == 0;
  matrix.fillScreen(0);
  if (flashOn) {
    matrix.setTextColor(colorRed);
    matrix.setCursor(tempScrollX, 0);
    char buf[16];
    snprintf(buf, sizeof(buf), "ALARM %02d:%02d   ", t.tm_hour, t.tm_min);
    matrix.print(buf);
    if (--tempScrollX < -(int)(strlen(buf) * 6)) tempScrollX = MATRIX_W;
  }
  matrix.show();
}

// Call from loop(), e.g. on a button press or web request, to silence the alarm
void stopAlarm() {
  alarmRinging = false;
  noTone(BUZZER_PIN);
  digitalWrite(BUZZER_PIN, LOW);
}

void connectWiFi() {
  matrix.fillScreen(0);
  matrix.setCursor(0, 0);
  matrix.setTextColor(colorGold);
  matrix.print("WIFI");
  matrix.show();

  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);

  unsigned long start = millis();
  while (WiFi.status() != WL_CONNECTED && millis() - start < 20000) {
    delay(300);
  }

  if (WiFi.status() == WL_CONNECTED) {
    Serial.print("Connected. IP: ");
    Serial.println(WiFi.localIP());
  } else {
    Serial.println("WiFi connection failed, will retry in loop().");
  }
}

void syncTime() {
  configTime(GMT_OFFSET_SEC, DAYLIGHT_OFFSET_SEC, NTP_SERVER);
  struct tm timeinfo;
  int attempts = 0;
  while (!getLocalTime(&timeinfo) && attempts < 10) {
    delay(500);
    attempts++;
  }
}

void setup() {
  Serial.begin(115200);
  matrix.begin();
  matrix.setTextWrap(false);
  matrix.setBrightness(BRIGHTNESS);
  matrix.setTextSize(1);

  colorGold  = matrix.Color(224, 184, 74);
  colorGreen = matrix.Color(56, 255, 106);
  colorCyan  = matrix.Color(77, 224, 255);
  colorRed   = matrix.Color(255, 59, 59);
  currentColor = colorGold;

  connectWiFi();
  if (WiFi.status() == WL_CONNECTED) {
    syncTime();
  }

  dht.begin();
  pinMode(BUZZER_PIN, OUTPUT);
  digitalWrite(BUZZER_PIN, LOW);
}

void drawClockFace(struct tm &t) {
  matrix.fillScreen(0);
  matrix.setTextColor(currentColor);
  char buf[8];
  snprintf(buf, sizeof(buf), "%02d%c%02d", t.tm_hour, colonOn ? ':' : ' ', t.tm_min);
  matrix.setCursor(1, 0);
  matrix.print(buf);
  matrix.show();
}

void drawClockWithSeconds(struct tm &t) {
  // HH:MM:SS is wider than the 32px matrix, so scroll it slowly instead of truncating
  char buf[16];
  snprintf(buf, sizeof(buf), "%02d:%02d:%02d   ", t.tm_hour, t.tm_min, t.tm_sec);

  matrix.fillScreen(0);
  matrix.setTextColor(currentColor);
  matrix.setCursor(secScrollX, 0);
  matrix.print(buf);
  matrix.show();

  int textWidthPx = strlen(buf) * 6;
  if (--secScrollX < -textWidthPx) secScrollX = MATRIX_W;
}

void drawScrollDate(struct tm &t) {
  static const char* days[] = {"SUN","MON","TUE","WED","THU","FRI","SAT"};
  static const char* mons[] = {"JAN","FEB","MAR","APR","MAY","JUN","JUL","AUG","SEP","OCT","NOV","DEC"};

  char buf[40];
  snprintf(buf, sizeof(buf), "%s %d %s IST   ",
           days[t.tm_wday], t.tm_mday, mons[t.tm_mon]);

  matrix.fillScreen(0);
  matrix.setTextColor(currentColor);
  matrix.setCursor(scrollX, 0);
  matrix.print(buf);
  matrix.show();

  int textWidthPx = strlen(buf) * 6;
  if (--scrollX < -textWidthPx) scrollX = MATRIX_W;
}

void loop() {
  // reconnect handling
  if (WiFi.status() != WL_CONNECTED) {
    connectWiFi();
    if (WiFi.status() == WL_CONNECTED) syncTime();
  }

  struct tm timeinfo;
  if (!getLocalTime(&timeinfo)) {
    delay(500);
    return;
  }

  unsigned long now = millis();

  readSensor();
  checkAlarm(timeinfo);

  // alarm takes over the display until stopped (e.g. by a physical button on an interrupt pin)
  if (alarmRinging) {
    drawAlarmRinging(timeinfo);
    delay(50);
    return;
  }

  // rotate display mode
  if (now - lastModeSwitch > MODE_DURATION_MS) {
    lastModeSwitch = now;
    mode = (Mode)((mode + 1) % 4);
    scrollX = MATRIX_W;
    tempScrollX = MATRIX_W;
    secScrollX = MATRIX_W;
  }

  // blink colon every 500ms in MODE_TIME
  if (now - lastColonBlink > 500) {
    lastColonBlink = now;
    colonOn = !colonOn;
  }

  switch (mode) {
    case MODE_TIME:
      drawClockFace(timeinfo);
      delay(60);
      break;
    case MODE_SECONDS:
      if (now - lastScrollMove > SCROLL_STEP_MS) {
        lastScrollMove = now;
        drawClockWithSeconds(timeinfo);
      }
      break;
    case MODE_SCROLL_DATE:
      if (now - lastScrollMove > SCROLL_STEP_MS) {
        lastScrollMove = now;
        drawScrollDate(timeinfo);
      }
      break;
    case MODE_TEMP_HUM:
      if (now - lastScrollMove > SCROLL_STEP_MS) {
        lastScrollMove = now;
        drawTempHumidity();
      }
      break;
  }
}

/*
  NOTE: to physically silence the alarm, wire a push button to an interrupt-capable
  GPIO (e.g. GPIO7) with INPUT_PULLUP, and call stopAlarm() from its ISR/flag check
  at the top of loop(). Omitted here to keep the sketch focused on the core features.
*/