/*
  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.

  Libraries required (Library Manager):
    - Adafruit NeoMatrix
    - Adafruit NeoPixel
    - Adafruit GFX Library
*/

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

// ---------- USER CONFIG ----------
const char* WIFI_SSID     = "Airtel_aevi_6035";
const char* WIFI_PASSWORD = "air262829";

#define MATRIX_PIN   5
#define MATRIX_W     32
#define MATRIX_H     8
#define BRIGHTNESS   40      // keep low: 256 LEDs on USB power budget

// 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";
// ----------------------------------

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;
unsigned long lastScrollMove = 0;
unsigned long lastColonBlink = 0;
bool colonOn = true;

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

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();
  }
}

void drawClockFace(struct tm &t, bool showSeconds) {
  matrix.fillScreen(0);
  matrix.setTextColor(currentColor);

  char buf[12];
  if (showSeconds) {
    // HH:MM:SS scaled tighter; fallback HH:MM with blinking colon if it overflows 32px
    snprintf(buf, sizeof(buf), "%02d:%02d:%02d", t.tm_hour, t.tm_min, t.tm_sec);
  } else {
    snprintf(buf, sizeof(buf), "%02d%c%02d", t.tm_hour, colonOn ? ':' : ' ', t.tm_min);
  }

  matrix.setCursor(showSeconds ? -8 : 1, 0);
  matrix.print(buf);
  matrix.show();
}

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();

  // rotate display mode
  if (now - lastModeSwitch > MODE_DURATION_MS) {
    lastModeSwitch = now;
    mode = (Mode)((mode + 1) % 3);
    scrollX = MATRIX_W;
  }

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

  switch (mode) {
    case MODE_TIME:
      drawClockFace(timeinfo, false);
      delay(60);
      break;
    case MODE_SECONDS:
      drawClockFace(timeinfo, true);
      delay(200);
      break;
    case MODE_SCROLL_DATE:
      if (now - lastScrollMove > 60) {
        lastScrollMove = now;
        drawScrollDate(timeinfo);
      }
      break;
  }
}