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

// A simple data logger for the Arduino analog pins

// how many milliseconds between grabbing data and logging it. 1000 ms is once a second
#define LOG_INTERVAL  5000// mills between entries (reduce to take more/faster data)

#define ECHO_TO_SERIAL   1 // echo data to serial port

// The analog pins that connect to the sensors
const int analogInPinBat = A0; // Analog pin the battery voltage divider is attached to
const int analogInPinPanNeg = A1; //Analog pin the panel negative to ground voltage divider is attached to
//const int analogInPinPanPos = A2; //Analog pin the panel positive to ground voltage divider  is attached to
//Ground is provided by the negative battery
const float Vcc = 4.91; // µC Vcc (V)
/*Voltage divider positive panel (Ohm)
const float R1 = 37000; 
const float R2 = 13000; */
//Voltage divider negative panel (Ohm)
const float R3 = 37000;
const float R4 = 13000;
//Voltage divider battery (Ohm)
const float R5 = 27000;
const float R6 = 13000;

// the digital pins that connect to the LEDs
#define redLEDpin 2
#define greenLEDpin 3

RTC_DS1307 RTC; // define the Real Time Clock object

// for the data logging shield, we use digital pin 10 for the SD cs line
const int chipSelect = 10;

// the logging file
File logfile;

//the statistics
Statistic PanStats;
Statistic BatStats;

void error(char *str)
{
  Serial.print("Erreur: ");
  Serial.println(str);
  
  // red LED indicates error
  digitalWrite(redLEDpin, HIGH);
  
  while(1);
}

void setup(void)
{
  Serial.begin(9600);
  Serial.println();
  
  PanStats.clear(); //explicitly start clean
  BatStats.clear();
  // use debugging LEDs
  pinMode(redLEDpin, OUTPUT);
  pinMode(greenLEDpin, OUTPUT);
  
/*#if WAIT_TO_START
  Serial.println("Type any character to start");
  while (!Serial.available());
#endif //WAIT_TO_START
*/  
  // initialize the SD card
  Serial.print("Initializing SD card...");
  // make sure that the default chip select pin is set to
  // output, even if you don't use it:
  pinMode(10, OUTPUT);
  
  // see if the card is present and can be initialized:
  if (!SD.begin(chipSelect)) {
    error("Card failed, or not present");
  }
  Serial.println("card initialized.");
  
 //create a new file
  char filename[] = "BATPAN00.CSV";
  logfile = SD.open(filename, FILE_WRITE);
  
  
  if (! logfile) {
    error("couldnt create file");
  }
  
  Serial.print("Logging to: ");
  Serial.println(filename);

  // connect to RTC
  Wire.begin();  
  if (!RTC.begin()) {
    logfile.println("RTC failed");
#if ECHO_TO_SERIAL
    Serial.println("RTC failed");
#endif  //ECHO_TO_SERIAL
  }
  
  logfile.println("millis; date; VPan; VBAt");
  logfile.println();
#if ECHO_TO_SERIAL
  Serial.println("millis; date; VPan; VBAt");
  Serial.println();
#endif //ECHO_TO_SERIAL
 
  // If you want to set the aref to something other than 5v
  //analogReference(EXTERNAL);
}

void loop(void)
{
  DateTime now;

  // delay for the amount of time we want between readings
  delay((LOG_INTERVAL -1) - (millis() % LOG_INTERVAL));
  
  digitalWrite(greenLEDpin, HIGH);
  
  // log milliseconds since starting
  uint32_t m = millis();
   
  #if ECHO_TO_SERIAL
  Serial.print(m);         // milliseconds since start
  Serial.print("; ");  
#endif

  // fetch the time
  now = RTC.now();
  
  // log time in serial console
  #if ECHO_TO_SERIAL
  Serial.print(now.day(), DEC);
  Serial.print("/");
  Serial.print(now.month(), DEC);
  Serial.print("/");
  Serial.print(now.year(), DEC);
  Serial.print(" ");
  Serial.print(now.hour(), DEC);
  Serial.print(":");
  Serial.print(now.minute(), DEC);
  Serial.print(":");
  Serial.print(now.second(), DEC);
  #endif //ECHO_TO_SERIAL

   // read the analog in value:
 /* analogRead(analogInPinPanPos);
  delay(10);
  int sensorValuePanPos = analogRead(analogInPinPanPos);*/
  
  analogRead(analogInPinPanNeg);
  delay(10);
  int sensorValuePanNeg = analogRead(analogInPinPanNeg);
  
  analogRead(analogInPinBat);
  delay(10);
  int sensorValueBat = analogRead(analogInPinBat);
   
  /*float v_pinPanPos = Vcc*sensorValuePanPos/1023;
  float v_PanPos = v_pinPanPos/(R2/(R1+R2));*/
  float v_pinPanNeg = Vcc*sensorValuePanNeg/1023;
  float v_PanNeg =  v_pinPanNeg/(R4/(R3+R4));
  float v_pinBat = Vcc*sensorValueBat/1023;
  float v_Bat = v_pinBat/(R6/(R5+R6));
  float v_Pan = (v_Bat - v_PanNeg) * ;
  
  #if ECHO_TO_SERIAL
  //for debugging
  Serial.print("; ");
  Serial.print(sensorValuePanPos);
  Serial.print("; ");
  Serial.print(sensorValuePanNeg);
  Serial.print("; ");
  Serial.print(sensorValueBat);
  /*Serial.print("; ");
  Serial.print(v_PanPos);*/
  Serial.print("; ");
  Serial.print(v_PanNeg);
  
  Serial.print("; ");
  Serial.print(v_Pan);
  Serial.print("; ");
  Serial.println(v_Bat);
  #endif //ECHO_TO_SERIAL
  delay(100);  
  digitalWrite(greenLEDpin, LOW);
  
  PanStats.add(v_Pan);
  BatStats.add(v_Bat);
 
  if ((PanStats.count() == 120) && (BatStats.count() == 120))
  {
    // log time
    logfile.print(now.day(), DEC);
    logfile.print("/");
    logfile.print(now.month(), DEC);
    logfile.print("/");
    logfile.print(now.year(), DEC);
    logfile.print(" ");
    logfile.print(now.hour(), DEC);
    logfile.print(":");
    logfile.print(now.minute(), DEC);
    logfile.print(":");
    logfile.print(now.second(), DEC);
        
    //log data
    logfile.print("; ");    
    logfile.print(PanStats.average(), 2);
    logfile.print("; ");    
    logfile.println(BatStats.average(), 2);
  
    logfile.println();
    
    #if ECHO_TO_SERIAL
    Serial.println("=====================================");
    Serial.print("  Count: ");
    Serial.println(PanStats.count());
    Serial.print("  v_Pan Min: ");
    Serial.println(PanStats.minimum(),2);
    Serial.print("  v_Bat Min: ");
    Serial.println(BatStats.minimum(),2);
    Serial.print("  v_Pan Max: ");
    Serial.println(PanStats.maximum(),2);
    Serial.print("  v_Bat Max: ");
    Serial.println(BatStats.maximum(),2);
    Serial.print("  v_Pan Moyenne: ");
    Serial.println(PanStats.average(), 2);
    Serial.print("  v_Bat Moyenne: ");
    Serial.println(BatStats.average(), 2);
    Serial.println("=====================================");
    Serial.println();
    #endif // ECHO_TO_SERIAL
      
    PanStats.clear();
    BatStats.clear();
    delay(10);
  
  // blink LED to show we are syncing data to the card & updating FAT!
  digitalWrite(redLEDpin, HIGH);
  logfile.flush();
  delay(500);
  digitalWrite(redLEDpin, LOW);
  }
  
}