#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_NeoPixel.h>
#include <RTClib.h>                 //only for debugging [RTC_DS1307 myRTC;] > [if (!myRTC.begin())]
#include <DS1307RTC.h>

int a = 0;                          //Variable modifiable through the button to make the program change function
int horas;                          //Variable to be displayed on OLED of the hours
int minutos;                        //Variable to display on OLED of the minutes
int segundos;                       //Variable to be displayed on OLED of seconds
int segundostotal;                  //Total time
int segundosrestantes;              //Remaining time
int porcentaje;                     //Percentage of completed time to total time
int visual;                         //Variable that stores the pixel number between 0 and 'NUM_pixels' corresponding to 'percentage'
int sethoras = 0;                   //Variable to store the 'set hours' value
int setminutos = 0;                 //Variable to store the 'set minutes' value
int setsegundos = 0;                //Variable to store the value 'set seconds'
const int PIN_LedDebug = 10;        //Led on the board for debugging
const int PIN_Potenciometro = 4;    //Potentiometer as selector
const int PIN_BotonInicio = 11;     //Start button
const int PIN_Neopixeles = 1;       //NeoPixel Strip RGBW 144L/m 1m SMD5050 SK6812
const int NUM_Pixeles = 144;        //Number of pixels of the strip
int boton = 0;                      //Button status (startup shutdown)
int potenciometroRAW;               //Variable that stores the raw analog reading of the potentiometer
int potenciometro;                  //Variable that stores the average of ten potentiometer measurements (to clean electrical output)
int potenciometro100;               //Variable storing the potentiometer position in percent

//Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
Adafruit_SSD1306 myOLED(128, 64, &Wire, -1); //Reset pin # (or -1 if sharing Arduino reset pin)

//Declaration for an DS1307 RTC connected to I2C (SDA, SCL pins)
RTC_DS1307 myRTC;

//Declaration for Neopixels
Adafruit_NeoPixel pixels(NUM_Pixeles, PIN_Neopixeles, NEO_GRB + NEO_KHZ800);

//---------------------------------------------------------------------------------------------------------------------//

void setup() 
{
    Serial.begin(115200);

    pixels.begin();   //Initialize NeoPixel strip object (REQUIRED)
    pixels.setBrightness(250);   //Set BRIGHTNESS (max = 255)

    if (!myOLED.begin(SSD1306_SWITCHCAPVCC, 0x3C))       //I2C OLED address 0x3C for 128x64
        Serial.println(F("SSD1306 allocation failed"));

    if (!myRTC.begin())
        Serial.println("Couldn't find RTC");

    //myRTC.adjust(DateTime(F(__DATE__), F(__TIME__)));   //Uncomment only to reprogram the RTC time.

    //pinMode(PIN_Neopixeles, OUTPUT);    //It is not necessary to declare it
    pinMode(PIN_BotonInicio, INPUT);
    pinMode(PIN_LedDebug, OUTPUT);
    //pinMode(PIN_Potenciometro, INPUT);    //It is not necessary to declare it
}

//--------------------------------------------------------------------------------------------------------------------//

void loop() {

  //WELCOME FUNCTION
    while (a == 0) {
        //Commands for display of welcome text
        myOLED.clearDisplay();
        myOLED.setTextColor(WHITE);
        myOLED.setTextSize(2);
        myOLED.setCursor(40,0);
        myOLED.println("TIME");
        myOLED.setCursor(46,16);
        myOLED.println("THE");
        myOLED.setCursor(40,34);
        myOLED.println("TIME");
        myOLED.display();

        //Commands to jump to the next stage
        boton = digitalRead(PIN_BotonInicio);
        if (boton == HIGH) {
            delay(300);
            a = 1;
        }

        //Commands to turn off all LEDs
        pixels.clear();
        pixels.show();
        
        //Commands to make a visual welcome animation
        //pixels.clear();   //Set all pixel colors to 'off'
        //for(int i=0; i<NUM_Pixeles; i++) {    //The first NeoPixel in a strand is #0, second is 1, all the way up to the count of pixels minus one.
        //    pixels.setPixelColor(i, pixels.Color(255, 255, 255));   //pixels.Color() takes RGB values, from 0,0,0 up to 255,255,255
        //    pixels.show();    //Send the updated pixel colors to the hardware.
        //    delay(100);  //Pause before next pass through loop
        //    pixels.setPixelColor(i, pixels.Color(0, 0, 0, 0));
        //    pixels.show();
        //}
        //Provokes a malfunction of the button, although it gives a more attractive visual appearance
    }

  //FUNCTION TO CHOOSE THE TIME
    while (a == 1) {
        //Function to jump to the next phase()
        boton = digitalRead(PIN_BotonInicio);   //Button reading
        if (boton == HIGH) {    //If the button has been pressed
            delay(300);   //Delay to avoid debounce of the button, which causes a double jump of functions (from a1 to a3)
            a = 2;    //Changes the value of a by jumping to the next function
        }
        
        //Function to clean the electrical output of the potentiometer and mitigate erroneous values
        potenciometroRAW = 0;    //To not carry over any previous measurement we set the value to 0
        for (int i=0; i<10; i++)    //Function that loops 'i' times (10) the potentiometer reading, accumulating them in a sum
            potenciometroRAW = (potenciometroRAW + analogRead(PIN_Potenciometro));    //Re-read analog raw (one after the other is added up)
        potenciometro = (potenciometroRAW / 10);    //Obtain the average by dividing the total sum by the number of measurements taken (10).
        
        potenciometro100 = map(potenciometro, 0, 1024, 0, 100);   //Convert to percentage (map from 0 to 100) the potentiometer value (960 and 600 are the calculated limit values of the pot).

        if ((potenciometro100 < 15) && (sethoras > 0)) {    //If the potentiometer is in range, we decrease the minutes by one unit.
            sethoras--;
            delay(200);
        }

        if ((potenciometro100 < 30) && (potenciometro100 >= 15) && (setminutos > 0)) {    //If the potentiometer is in range, we decrease the minutes by one unit
            setminutos--;
            delay(200);
        }

        //if ((potenciometro100 <= 20) && (setminutos = 0) && (sethoras > 0)) {    //Special case
        //    setminutos = 59;
        //    sethoras--;
        //}
        // Make the minutes jump to 0, I don't know why (before it was as an if inside the previous one)

        if ((potenciometro100 <= 45) && (potenciometro100 >= 30) && (setsegundos > 0)) {    //If the potentiometer is in range, we decrease the seconds by one unit
            setsegundos--;
            delay(200);
        }

        //if ((potenciometro100 < 45) && (potenciometro100 > 20) && (setsegundos = 0) && (setminutos > 0)) {    //Special case
        //    setsegundos = 59;
        //    setminutos--;
        //}
        //Makes the seconds jump to 0, I don't know why (before it was as an if inside the previous one)

        //Range between 45 and 55 without action.

        if ((potenciometro100 >= 55) && (potenciometro100 <= 70))    //If the potentiometer is in range, we increase the seconds by one unit
            setsegundos++;
            if (setsegundos == 60) {
                setsegundos = 0;
                setminutos++;
            delay(200);
            }

        if ((potenciometro100 > 70) && (potenciometro100 <= 85))    //If the potentiometer is in range, we increase the minutes by one unit
            setminutos++;
            if (setminutos == 60) {
                setminutos = 0;
                sethoras++;
            delay(200);
            }

        if (potenciometro100 > 85) {    //If the potentiometer is in range, we decrease the minutes by one unit
            sethoras++;
            delay(200);
        }

        //Commands to display the HH:MM:SS we are selecting for the timer
        myOLED.clearDisplay();
        myOLED.setTextColor(WHITE);
        myOLED.setTextSize(2);
        myOLED.setCursor(0,0);
        myOLED.print("SET TIMER:");
        myOLED.setCursor(0,16);
        myOLED.print("HH:MM:SS");
        myOLED.setCursor(0,34);
        print2digits(sethoras);
        myOLED.print(":");
        print2digits(setminutos);
        myOLED.print(":");
        print2digits(setsegundos);
        myOLED.display();

        //DEBUGGING (to check if it is reading the potentiometer, the button and if the counter is incremented accordingly)
        //Serial.write("Potenciometro(%):");
        //Serial.println(position);
        //Serial.write("Estado del boton:");
        //Serial.println(a);
        //Serial.write("Variable setsegundos(s):");
        //Serial.println(setsegundos);
        //delay(1000);
    }

  //FUNCTION TO REPRESENT THE REMAINING TIME
    while (a == 2) {
        segundostotal = setsegundos + (setminutos * 60) + (sethoras * 60 * 60);   //Convert the selected time to seconds
        segundosrestantes = segundostotal;    //Gives as initial value to seconds remaining the total value of the time
        
        while (segundosrestantes > 0) {
            porcentaje = map(segundosrestantes, segundostotal, 0, 0, 100);   //Convert to range from 0 to 100 (%) the percentage of time completed
            visual = map(segundosrestantes, segundostotal, 0, 0, NUM_Pixeles);   //Convert to range from 0 to 'NUM_Pixels' the percentage of time completed
            delay (1000);   //Discounting in 1-second periods
            segundosrestantes--;
       
            horas = ((segundosrestantes / 60)/ 60);   //Convert remaining seconds to hours
            minutos = (segundosrestantes / 60) % 60;  //Convert remaining seconds to minutes
            segundos = segundosrestantes % 60;        //Convert remaining seconds to 60-second periods
    
            //Display the remaining HH:MM:SS of the timer
            myOLED.clearDisplay();
            myOLED.setTextColor(WHITE);
            myOLED.setTextSize(2);
            myOLED.setCursor(0,0);
            myOLED.print("TIME LEFT:");
            myOLED.setCursor(0,16);
            myOLED.print("HH:MM:SS");
            myOLED.setCursor(0,34);
            print2digits(horas);
            myOLED.print(":");
            print2digits(minutos);
            myOLED.print(":");
            print2digits(segundos);
            myOLED.setTextSize(1);
            myOLED.setCursor(0,52);
            myOLED.print("COMPLETADO:");
            myOLED.print(porcentaje);
            myOLED.print("%");
            myOLED.display();

            //Commands to turn on the leds according to the percentage completed
            pixels.setPixelColor(visual, pixels.Color(255, 255, 255, 255));    //It lights the LEDs corresponding to the percentage of time completed.
            pixels.show();
        }
    
        while (segundosrestantes == 0) {
            myOLED.clearDisplay();
            myOLED.setTextColor(WHITE);
            myOLED.setTextSize(2);
            myOLED.setCursor(40,0);
            myOLED.println("TIME");
            myOLED.setCursor(51,16);
            myOLED.println("IS");
            myOLED.setCursor(40,34);
            myOLED.println("OVER");
            myOLED.display();
            
            for(int i=0; i<144; i++) {
                pixels.setPixelColor(i, pixels.Color(255, 255, 255, 255));
                pixels.show();
                delay(50);
            }
            for(int i=0; i<144; i++) {
                pixels.setPixelColor(i, pixels.Color(0, 0, 0, 0));
                pixels.show();
                delay(50);
            }

            //boton = digitalRead(PIN_BotonInicio);
            //if (boton == HIGH) {
            //    delay(300);
            //    a = 0;
            //}
            //Does not work because it does not exit the while (this while does not evaluate 'a')
        }
    }
}

//Function to write two digits in the time counter even if the time to be represented is only one digit
void print2digits(int number) {
    if (number >= 0 && number < 10) {
        myOLED.write('0');
    }
    myOLED.print(number);
}