/*
 ╔═══════════════════════════════════════════════════════════╗
 ║  ESP32-C3 MINI  ×  MAX7219 32×8  —  WiFi INDIA CLOCK    ║
 ║  IST — Indian Standard Time  (UTC + 5:30)                ║
 ║  By: Arvind Patil | AI Centre Nandurbar                  ║
 ╚═══════════════════════════════════════════════════════════╝

 ─── ARDUINO IDE BOARD SETTINGS ─────────────────────────────
   Board          : ESP32C3 Dev Module
   USB CDC on Boot: ENABLED   ← Serial Monitor जरूरी
   Flash Mode     : QIO
   Flash Size     : 4MB
   CPU Freq       : 160 MHz
   Upload Speed   : 921600

 ─── LIBRARIES (Library Manager में install करें) ────────────
   1. MD_Parola   by MajicDesigns  ≥ 3.7.0
   2. MD_MAX72XX  by MajicDesigns  ≥ 3.4.0
   (SPI.h और WiFi.h — built-in हैं, install नहीं चाहिए)

 ─── WIRING — ESP32-C3 Mini → MAX7219 ──────────────────────
   ESP32-C3       MAX7219 Module
   ──────────     ─────────────
   GPIO  6   →   DIN   (Data In / MOSI)
   GPIO  4   →   CLK   (Clock)
   GPIO  5   →   CS    (Chip Select / LOAD)
   5V        →   VCC   (5V power)
   GND       →   GND

   ⚠️ Cascade: CLK/DIN shared, CS shared across all modules
   ⚠️ 4 modules cascaded = 32×8 display

 ─── FEATURES ────────────────────────────────────────────────
   ✅ WiFi NTP sync (auto-reconnect)
   ✅ IST = UTC + 5:30 (19800 sec offset)
   ✅ Time: HH:MM:SS with blinking colon
   ✅ Date scroll every 30 sec
   ✅ Day name scroll (Mon, Tue...)
   ✅ WiFi connect animation on startup
   ✅ Brightness: auto dim at night (22:00–06:00)
   ✅ NTP resync every hour
*/

#include <SPI.h>
#include <MD_Parola.h>
#include <MD_MAX72xx.h>
#include <WiFi.h>
#include <time.h>

// ─── YOUR WiFi CREDENTIALS ─────────────────────────────────
#define WIFI_SSID   "Airtel_arvi_3035"      // ← अपना WiFi नाम
#define WIFI_PASS   "air26289"       // ← अपना Password

// ─── SPI PINS (ESP32-C3 safe pins) ─────────────────────────
#define PIN_MOSI    6     // DIN
#define PIN_CLK     4     // CLK
#define PIN_CS      5     // CS/LOAD

// ─── MAX7219 CONFIG ─────────────────────────────────────────
#define HARDWARE_TYPE  MD_MAX72XX::FC16_HW  // FC-16 module type
#define NUM_DEVICES    4                    // 4 modules = 32 cols

// ─── NTP CONFIG ─────────────────────────────────────────────
#define NTP_SERVER1    "pool.ntp.org"
#define NTP_SERVER2    "time.google.com"
#define NTP_SERVER3    "in.pool.ntp.org"
#define TZ_OFFSET_SEC  19800   // IST = UTC + 5:30 = 5*3600 + 30*60
#define DST_SEC        0       // India has no DST

// ─── TIMING ─────────────────────────────────────────────────
#define DATE_SCROLL_EVERY_SEC  30   // Show date every N seconds
#define NTP_RESYNC_MIN         60   // Re-sync NTP every N minutes
#define SCROLL_SPEED_MS        40   // Scroll text speed (ms/frame)

// ─── BRIGHTNESS ─────────────────────────────────────────────
#define BRIGHT_DAY    5    // 0–15 (daytime:  06:00–21:59)
#define BRIGHT_NIGHT  1    // 0–15 (night:    22:00–05:59)

// ════════════════════════════════════════════════════════════
MD_Parola display = MD_Parola(HARDWARE_TYPE, PIN_MOSI, PIN_CLK, PIN_CS, NUM_DEVICES);

// State
bool     timeSynced      = false;
bool     colonVisible    = true;
uint32_t lastColonToggle = 0;
uint32_t lastDateScroll  = 0;
uint32_t lastNTPSync     = 0;
uint32_t lastSecond      = 0;

bool     scrolling       = false;
char     scrollBuf[64];

const char* dayNames[]   = {"Sun","Mon","Tue","Wed","Thu","Fri","Sat"};
const char* monthNames[] = {"Jan","Feb","Mar","Apr","May","Jun",
                             "Jul","Aug","Sep","Oct","Nov","Dec"};

// ─── HELPERS ────────────────────────────────────────────────
void setAutoBrightness(int hour) {
  if (hour >= 6 && hour < 22)
    display.setIntensity(BRIGHT_DAY);
  else
    display.setIntensity(BRIGHT_NIGHT);
}

void showStatic(const char* txt) {
  display.setTextAlignment(PA_CENTER);
  display.print(txt);
}

void startScroll(const char* txt) {
  strncpy(scrollBuf, txt, sizeof(scrollBuf) - 1);
  scrollBuf[sizeof(scrollBuf) - 1] = '\0';
  display.displayScroll(scrollBuf, PA_LEFT, PA_SCROLL_LEFT, SCROLL_SPEED_MS);
  scrolling = true;
}

// ─── WiFi CONNECT ───────────────────────────────────────────
void connectWiFi() {
  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_SSID, WIFI_PASS);

  Serial.print("WiFi connecting");
  startScroll("WiFi...");

  uint8_t dots = 0;
  uint32_t start = millis();

  while (WiFi.status() != WL_CONNECTED) {
    // Animate dots on display while connecting
    if (display.displayAnimate()) {
      display.displayReset();
    }
    if (millis() - start > 15000) {
      Serial.println("\nWiFi timeout — will retry");
      showStatic("ERR");
      delay(2000);
      return;
    }
    Serial.print(".");
    delay(200);
  }

  Serial.println();
  Serial.print("Connected! IP: ");
  Serial.println(WiFi.localIP());

  startScroll("WiFi OK!");
  delay(1500);
}

// ─── NTP SYNC ───────────────────────────────────────────────
void syncNTP() {
  if (WiFi.status() != WL_CONNECTED) return;

  showStatic("SYNC");
  Serial.println("NTP syncing...");

  configTime(TZ_OFFSET_SEC, DST_SEC,
             NTP_SERVER1, NTP_SERVER2, NTP_SERVER3);

  // Wait for valid time (up to 10 sec)
  struct tm ti;
  uint32_t t0 = millis();
  while (!getLocalTime(&ti)) {
    if (millis() - t0 > 10000) {
      Serial.println("NTP sync failed");
      showStatic("Err");
      delay(2000);
      return;
    }
    delay(200);
  }

  timeSynced = true;
  lastNTPSync = millis();
  Serial.printf("NTP OK: %02d:%02d:%02d IST\n",
                ti.tm_hour, ti.tm_min, ti.tm_sec);

  // Show "IST OK" briefly
  char msg[32];
  sprintf(msg, "IST %02d:%02d", ti.tm_hour, ti.tm_min);
  startScroll(msg);
  delay(2000);
}

// ─── DRAW CLOCK FACE ────────────────────────────────────────
void drawTime(struct tm* ti) {
  char buf[16];
  // HH:MM — colon blinks every 500ms
  if (colonVisible)
    sprintf(buf, "%02d:%02d", ti->tm_hour, ti->tm_min);
  else
    sprintf(buf, "%02d %02d", ti->tm_hour, ti->tm_min);

  display.setTextAlignment(PA_CENTER);
  display.print(buf);
}

// ─── SCROLL DATE ────────────────────────────────────────────
void scrollDate(struct tm* ti) {
  char msg[48];
  sprintf(msg, " %s %02d %s %04d  IST",
          dayNames[ti->tm_wday],
          ti->tm_mday,
          monthNames[ti->tm_mon],
          ti->tm_year + 1900);
  startScroll(msg);
}

// ════════════════════════════════════════════════════════════
//  SETUP
// ════════════════════════════════════════════════════════════
void setup() {
  Serial.begin(115200);
  delay(500);

  // Init display
  display.begin();
  display.setIntensity(BRIGHT_DAY);
  display.displayClear();
  display.setTextAlignment(PA_CENTER);
  display.print("INIT");
  delay(800);

  Serial.println("ESP32-C3 WiFi IST Clock | AI Centre Nandurbar");

  // Show welcome scroll
  startScroll("India Clock  IST");
  uint32_t t0 = millis();
  while (millis() - t0 < 2000) {
    if (display.displayAnimate()) display.displayReset();
  }

  // Connect WiFi + sync NTP
  connectWiFi();
  syncNTP();

  lastDateScroll  = millis();
  lastColonToggle = millis();
  lastSecond      = millis();
}

// ════════════════════════════════════════════════════════════
//  LOOP
// ════════════════════════════════════════════════════════════
void loop() {
  uint32_t now = millis();

  // ── If scrolling, handle animation ──
  if (scrolling) {
    if (display.displayAnimate()) {
      display.displayReset();
      scrolling = false;
    }
    return;  // Don't update clock while scrolling
  }

  // ── WiFi watchdog ──
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("WiFi lost — reconnecting...");
    showStatic("WiFi");
    delay(500);
    connectWiFi();
    syncNTP();
    return;
  }

  // ── NTP hourly resync ──
  if (timeSynced && (now - lastNTPSync > (uint32_t)NTP_RESYNC_MIN * 60000UL)) {
    syncNTP();
    return;
  }

  // ── Get current IST time ──
  struct tm ti;
  if (!getLocalTime(&ti)) {
    showStatic("--:--");
    return;
  }

  // ── Auto brightness ──
  setAutoBrightness(ti.tm_hour);

  // ── Blink colon every 500ms ──
  if (now - lastColonToggle >= 500) {
    colonVisible = !colonVisible;
    lastColonToggle = now;
  }

  // ── Scroll date every N seconds ──
  if (now - lastDateScroll >= (uint32_t)DATE_SCROLL_EVERY_SEC * 1000UL) {
    lastDateScroll = now;
    scrollDate(&ti);
    return;
  }

  // ── Draw time ──
  drawTime(&ti);

  // ── Serial debug every second ──
  if (now - lastSecond >= 1000) {
    lastSecond = now;
    Serial.printf("IST: %02d:%02d:%02d | %s %02d %s | WiFi: %ddBm\n",
                  ti.tm_hour, ti.tm_min, ti.tm_sec,
                  dayNames[ti.tm_wday], ti.tm_mday,
                  monthNames[ti.tm_mon],
                  WiFi.RSSI());
  }

  delay(50);
}