/* Solder Reflow Plate Sketch
 *  H/W - Ver 3.0
 *  S/W - Ver 1.0 */


#include <SPI.h>
#include <LiquidCrystal.h>
#include <EEPROM.h>
#include <Bounce2.h>

//Version Definitions
static const PROGMEM float hw = 3.0;
static const PROGMEM float sw = 1.0;

//Screen Definitions
#define LCD_RS 10
#define LCD_E 9
#define LCD_D4 6
#define LCD_D5 7
#define LCD_D6 3
#define LCD_D7 2
LiquidCrystal lcd(LCD_RS, LCD_E, LCD_D4, LCD_D5, LCD_D6, LCD_D7);


//Pin Definitions
#define mosfet 8
#define upsw 4
#define dnsw 5
#define temp A1
#define vcc A0

Bounce2::Button upButton;
Bounce2::Button downButton;

//Temperature Info
byte maxTempArray[] = { 140, 150, 160, 170, 180 };
byte maxTempIndex = 0;
byte tempIndexAddr = 1;

//Voltage Measurement Info
float vConvert = 52.00;
float vMin = 10.50;

void setup() {
  
  //Pin Direction control
  pinMode(mosfet,OUTPUT);
  digitalWrite(mosfet,LOW);
  pinMode(temp,INPUT);
  pinMode(vcc,INPUT);

  upButton.attach(upsw);
  upButton.setPressedState(LOW);
  upButton.interval(10);

  downButton.attach(dnsw);
  downButton.setPressedState(LOW);
  downButton.interval(10);

  //Pull saved values from EEPROM
  maxTempIndex = EEPROM.read(tempIndexAddr) % sizeof(maxTempArray);

  //Enable Fast PWM with no prescaler
  //TCCR2A = _BV(COM2A1) | _BV(COM2B1) | _BV(WGM21) | _BV(WGM20);
  //TCCR2B = _BV(CS20);

  //Start-up Diplay
  lcd.clear();
  lcd.begin(16, 2);
  lcd.setCursor(0, 0);
  lcd.print("S/W V");
  lcd.print(sw);
  lcd.setCursor(0, 1);
  lcd.print("H/W V");
  lcd.print(hw);

  delay(3000);

  //Go to main menu
  lcd.clear();
  main_menu();
}

void main_menu() {
  
  int x = 0;  //Display change counter
  int y = 100; //Display change max (modulused below)
  while(1) {
    upButton.update();
    downButton.update();
    analogWrite(mosfet,0); //Ensure MOSFET off

    //Button Logic
    if(downButton.pressed() || upButton.pressed()) { //If either button pressed
      delay(100);
      //upButton.update();
      //downButton.update();
      if(downButton.pressed() && upButton.pressed()) { //If both buttons pressed
        if(!heat(maxTempArray[maxTempIndex])) {
          //cancelledPB();
          main_menu();
        }
        else {
          //coolDown();
          //completed();
          main_menu();
        }
      }
      if(upButton.pressed() && maxTempIndex < sizeof(maxTempArray) - 1) { //If upper button pressed
        maxTempIndex++;
        EEPROM.update(tempIndexAddr, maxTempIndex);
      }
      if(downButton.pressed() && maxTempIndex > 0) { //If lower button pressed
        maxTempIndex--;
        EEPROM.update(tempIndexAddr, maxTempIndex);
      }
    }

    //Change Display (left-side)
    if( x == y) {
      lcd.setCursor(0, 0);
      lcd.print("U or D for MAX T");
    }
    else if(x == 0) {
      lcd.setCursor(0, 0);
      lcd.print("U+D for Heating ");
    }
    x = ( x + 1 ) % ( 2 * y ); //Display change increment and modulus
    
    //Update Display (right-side)
    lcd.setCursor(0, 1);
    lcd.print(" ");
    lcd.print(maxTempArray[maxTempIndex]);
    lcd.print(" C | @");
  }
}

bool heat(byte maxTemp) {
  //Heating Display
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Heat to ");
  lcd.print(maxTempArray[maxTempIndex]);
  lcd.print(" C");
  lcd.setCursor(0, 1);
  lcd.print("@");
  lcd.print("   ");
  lcd.print(" C | @");
  delay(3000);
  

  //Heater Control Variables
  /*  Heater follows industry reflow graph. Slow build-up to 'warmUp' temp. Rapid ascent
   *  to 'maxTemp'. Then descent to room temperature. 
   */
  //byte maxTemp; //Declared in function call
  byte maxPWM = 0.70 * maxTemp; //Temperatures (in PWM / 255) influenced by paste temperature
  byte warmUpTemp = 0.75 * maxTemp;
  byte warmUpPWM = 0.72 * warmUpTemp;
  float t; //Used to store current temperature
  float v; //Used to store current voltage
  byte pwmVal = 0; //PWM Value applied to MOSFET
  unsigned long eTime = (millis() / 1000) + (8*60); //Used to store the end time of the heating process, limited to 8 mins
  
  while(1) {

    upButton.update();
    downButton.update();
    
    //Button Control
    if(downButton.pressed() || upButton.pressed()) {
      analogWrite(mosfet, 0);
      return 0;
    }

    //Check Heating not taken more than 8 minutes
    if(millis() / 1000 > eTime) {
      analogWrite(mosfet, 0);
      //cancelledTimer();
    }

    //Measure Values
    t = getTemp();
    v = getVolts();

    //Reflow Profile
    if (t < warmUpTemp) { //Warm Up Section
      if (pwmVal != warmUpPWM) { pwmVal++; } //Slowly ramp to desired PWM Value
      if (v < vMin && pwmVal > 1) { pwmVal = pwmVal - 2; } //Reduce PWM Value if V drops too low but not unless it is still above 1 (avoid overflow/underflow)
    }
    else if (t < maxTemp) { //Push to maximum temp
      if (pwmVal != maxPWM) { pwmVal++; } //Slowly ramp to desired PWM Value
      if (v < vMin && pwmVal > 1) { pwmVal = pwmVal - 2; } //Reduce PWM Value if V drops too low but not unless it is still above 1 (avoid overflow/underflow)
    }
    else { //Heating Complete, return
      analogWrite(mosfet, 0);
      break;
    }
    if (pwmVal > maxPWM ) { pwmVal = maxPWM; } //Catch incase of runaway 

    //MOSFET Control
    analogWrite(mosfet, pwmVal);

    //Update display
    lcd.setCursor(0, 1);
    lcd.print("@");
    lcd.print(t);
    lcd.print(" C | @");
    lcd.print(v);
    lcd.print("V");
  }
}


float getTemp(){
  float t = 0;
  for (byte i = 0; i < 100; i++){ //Poll temp reading 100 times
    t = t + analogRead(temp);
  }
  return ((t / 100) * -1.46) + 434; //Average, convert to C, and return
}

float getVolts(){
  float v = 0;
  for (byte i = 0; i < 20; i++){ //Poll Voltage reading 20 times
    v = v + analogRead(vcc);
  }
  return v / 20 / vConvert; //Average, convert to V, and return
}

void loop() {
  // Not used
}