#include <Wire.h>
#include <RTClib.h>
#include <SPI.h>
#include <SD.h>

// ====== USER SETTINGS ======
const uint8_t PIN_CT      = A0;            // CT on A0
const uint8_t SD_CS       = 10;            // SD CS pin (UNO=10)
const float   ADC_REF     = 5.0;           // UNO 5V
const int     ADC_COUNTS  = 1023;          // 10-bit ADC
const float   MAINS_VRMS  = 220.0;         // power = I_rms * 220
const float   VOLTS_PER_AMP_RMS = (1.0/30.0); // SCT-013-030 (1Vrms @ 30A)
// const float VOLTS_PER_AMP_RMS = 0.5/30.0; // مثال لو عندك SCT-013-000 + burden

const unsigned long MEASURE_WINDOW_MS = 2000;                     // ~2s RMS
const unsigned long LOG_INTERVAL_MS   = 3UL * 60UL * 1000UL;      // كل 3 دقائق
// ===========================

RTC_DS3231 rtc;
File logFile;
bool sdOK = false;

char currentDateStr[11];   // "YYYY-MM-DD"
char currentFileName[13];  // "YYMMDD.CSV"
unsigned long lastLogMs = 0;

// ========== Helpers ==========
void makeDateString(const DateTime& dt, char* out) {
  snprintf(out, 11, "%04d-%02d-%02d", dt.year(), dt.month(), dt.day());
}

// صيغة 8.3: YYMMDD.CSV
void makeFileNameFromDate(const DateTime& dt, char* out) {
  snprintf(out, 13, "%02d%02d%02d.CSV",
           dt.year() % 100, dt.month(), dt.day());
}

bool openTodayFileIfNeeded() {
  DateTime now = rtc.now();
  char dateStr[11], fname[13];
  makeDateString(now, dateStr);
  makeFileNameFromDate(now, fname);

  if (!logFile || strcmp(dateStr, currentDateStr) != 0) {
    if (logFile) { logFile.flush(); logFile.close(); }

    strcpy(currentDateStr, dateStr);
    strcpy(currentFileName, fname);

    bool existed = SD.exists(currentFileName);
    logFile = SD.open(currentFileName, FILE_WRITE);
    if (!logFile) { Serial.println(F("[ERR] open failed!")); return false; }

    if (!existed || logFile.size() == 0) {
      logFile.println("time_h,power_W");
      logFile.flush();
    }
    Serial.print(F("[OK] Logging to ")); Serial.println(currentFileName);
  }
  return true;
}

// حساب RMS للتيار
float measureIrms(unsigned long window_ms) {
  unsigned long t0 = millis();
  double sum = 0.0; uint32_t n = 0;
  while (millis() - t0 < window_ms / 10) { sum += analogRead(PIN_CT); n++; }
  double mid = (n > 0) ? sum / n : 512.0;

  t0 = millis(); n = 0;
  double accumSq = 0.0;
  while (millis() - t0 < window_ms) {
    int raw = analogRead(PIN_CT);
    double centered = raw - mid;
    double volts = centered * (ADC_REF / ADC_COUNTS);
    double inst_I = volts / VOLTS_PER_AMP_RMS;
    accumSq += inst_I * inst_I;
    n++;
  }
  return (n > 0) ? sqrt(accumSq / n) : 0.0;
}

// ========== Setup ==========
void setup() {
  pinMode(PIN_CT, INPUT);
  pinMode(SD_CS, OUTPUT); // مهم مع SD
  Serial.begin(115200);
  delay(300);

  // RTC
  if (!rtc.begin()) {
    Serial.println(F("[ERR] RTC not found!"));
  } else if (rtc.lostPower()) {
    rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));  // set once
    Serial.println(F("[WARN] RTC time set to compile time."));
  }

  // SD
  Serial.print(F("Initializing SD..."));
  sdOK = SD.begin(SD_CS);
  Serial.println(sdOK ? F("OK") : F("FAILED"));
  if (!sdOK) return;

  if (!openTodayFileIfNeeded()) {
    Serial.println(F("[ERR] Failed to open today's CSV."));
  }

  lastLogMs = millis() - LOG_INTERVAL_MS; // أول تسجيل مباشرة
}

// ========== Loop ==========
void loop() {
  if (!sdOK) return;

  if (millis() - lastLogMs >= LOG_INTERVAL_MS) {
    lastLogMs = millis();

    if (!openTodayFileIfNeeded()) return;

    // قياس القدرة
    float Irms  = measureIrms(MEASURE_WINDOW_MS);
    float Power = Irms * MAINS_VRMS;

    // الوقت العشري مع لف عند 24
    DateTime now = rtc.now();
    double time_h = now.hour() + now.minute()/60.0 + now.second()/3600.0;
    if (time_h >= 24.0) time_h = 0.0;

    // عرض
    Serial.print(F("t=")); Serial.print(time_h, 3);
    Serial.print(F(" h | P=")); Serial.print(Power, 2); Serial.println(F(" W"));

    // كتابة في CSV
    if (logFile) {
      logFile.print(time_h, 3); logFile.print(',');
      logFile.println(Power, 2);
      logFile.flush();
    } else {
      Serial.println(F("[ERR] logFile null while writing."));
    }
  }
}