// oled screen
#include <Tiny4kOLED.h>
// SD card
#include <SD.h>
#define CS_PIN 9 // sd card pin
File root;

// temp & humidity sensor
#include <dht.h>
#define DHT22_PIN 2
dht DHT;

// Light sensor Characteristics
const float GAMMA = 0.7;
const float RL10 = 50;

// Clock
#include "RTClib.h"
RTC_DS1307 rtc;
char daysOfTheWeek[7][12] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};


// Soil moisture sensor
const int soil_pin = A1;

//led 
int water_led = 4;
int light_led = 3;

// relay modules
const int relay_water = 7; // water pump
const int relay_light = 8; // light bulb
//@@@@@@@@@@@@@@@@@@@@@@@@@@@

// parameters -----
int update_time = int(30 *1000); // update loop time in ms

int cont1 = 0; 
int soil_data_save_rate = 40; // number of loops before saving data
// it corresponds to 20min since 20min* 60sec/min =1200 sec / 30sec/loop =40 loop

void setup() {
  oled.begin(128, 64, sizeof(tiny4koled_init_128x64br), tiny4koled_init_128x64br);
  oled.setFont(FONT6X8);  // Two fonts are supplied with this library, FONT8X16 and FONT6X8
  oled.clear();
  oled.on();
  rtc.begin();
  SD.begin(CS_PIN);
  pinMode(water_led, OUTPUT);
  pinMode(light_led, OUTPUT);
  pinMode(relay_water, OUTPUT);
  pinMode(relay_light, OUTPUT);
}

void loop() {
  oled.clear();
  digitalWrite(water_led, LOW);
  digitalWrite(light_led, LOW);

  // Temp & Humidity sensor ==================
    int chk = DHT.read22(DHT22_PIN);
    oled.setCursor(1, 10);
    oled.print(F("Room Temp.: "));
    oled.print(DHT.temperature, 1);
    oled.println(" C");
    oled.setCursor(1,11);
    oled.print(F("Room Humidity: "));
    oled.print(DHT.humidity, 1);
    oled.println(" %");
  // Light sensor ============================
  int analog_light_read = analogRead(A0);
  float voltage = analog_light_read / 1024. * 5;
  float resistance = 2000 * voltage / (1 - voltage / 5);
  float lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));

  oled.setCursor(1,12);
  oled.print("Room Light: ");
  if (lux > 50) {
    oled.print("-ok-");
    digitalWrite(relay_light,LOW); // deactivate light 
  } else {
    oled.print("Dark  ");
    digitalWrite(light_led, HIGH);   // turn light alert led on 
    digitalWrite(relay_light,HIGH); // activate light 
  }
  // Clock  ============================
  DateTime now = rtc.now();
  oled.setCursor(1, 8);
  oled.print(now.month(), DEC);
  oled.print('/');
  oled.print(now.day(), DEC);
  oled.print(' ');
  oled.print(daysOfTheWeek[now.dayOfTheWeek()]);
  oled.print(' ');
  oled.print(now.hour(), DEC);
  oled.print(':');
  oled.print(now.minute(), DEC);
  // oled.print(':');
  // oled.print(now.second(), DEC);

  // Soil moisture  =================
  float soil_H  = analogRead(soil_pin)/10; // value 0-1000 convert to %
  oled.setCursor(1,14);
  oled.print("Soil moist.:");
  oled.print(soil_H); 
  oled.print(" %");
  if(soil_H<30){
    digitalWrite(water_led, HIGH);   // turn water alert led on 
    digitalWrite(relay_water,HIGH); // activate water pump for 5sec
    delay(5000);
    digitalWrite(relay_water,LOW); // deactivate water
  }
  //--- saving data on soil moist to SD
  if(cont1==soil_data_save_rate){
  File data_soil = SD.open("soil_moist_data.txt", FILE_WRITE);
  if (data_soil) {
    data_soil.print(now.hour());data_soil.print("\t");
    data_soil.print(now.minute());data_soil.print("\t");
    data_soil.print(soil_H);
    data_soil.close();
    cont1=0;
  }}
  cont1 += 1;
 //=============================================
  delay(update_time); 
}