#include <LiquidCrystal_I2C.h>
#include <SoftwareSerial.h>
//temp sensor
#include <OneWire.h>
#include <DallasTemperature.h>

LiquidCrystal_I2C lcd(0x3F, 20, 4); //https://github.com/marcoschwartz/LiquidCrystal_I2C

OneWire oneWire(4);             //OneWire Library (with Tim Stud)
DallasTemperature tsensor(&oneWire); //DallasTempratureSensor Library
SoftwareSerial wlan(6, 5); //RX, TX

long lastLCDupdate = millis();
boolean lcdchanged = true;
int temp = 0;
byte cancelcause = 0; //why is the heater off? -> 0= None, 1 = canceled (btn), 2= temp, 3=to long on, 4=tempmovement, 5=abort(inet)
byte state = 0; //current satate -> 0 = idle, 1 = heating, 2 = cooking
long heating = -1;//millis() value when heater started
int starttemp = 0;
char status[21] = "--------------------";//dont forget \0 at the end
const byte padd = 6;//used in updateLCD(), used to determine how far left the right part of the screen should be
const byte cookingtemp = 98; //desired start temp

void setup() {
  pinMode(2, OUTPUT);
  pinMode(3, INPUT_PULLUP);

  digitalWrite(2, LOW);

  lcd.init();                      // initialize the lcd
  // Print a message to the LCD.
  lcd.backlight();
  lcd.setCursor(6, 0);
  lcd.print("Autokocher");
  lcd.setCursor(3, 1);
  lcd.print("Yannis Gerlach");

  delay(1000);
  tsensor.begin();

  Serial.begin(115200);//DEBUG
  wlan.begin(9600);

  updateLCD();
}

int getTemp() {
  tsensor.requestTemperatures();
  return (tsensor.getTempCByIndex(0) * 100);
}

void updateLCD() {
  if (lcdchanged || heating > 0) {
    lcd.clear();
    lcd.clear();
    lcd.backlight();
    lcd.setCursor(0, 0);
    lcd.print("Herd:");
    lcd.setCursor(padd, 0);
    lcd.print(heating > 0 ? "An" : "Aus");
    lcd.setCursor(0, 1);
    lcd.print("Temp:");
    lcd.setCursor(padd, 1);
    lcd.print(temp);
    lcd.print("C");
    lcd.setCursor(0, 2);
    if (cancelcause != 0) {
      lcd.print("Err :");
      lcd.setCursor(padd, 2);
      switch (cancelcause) {
        case 1: lcd.print("Abbr-Btn."); break;
        case 2: lcd.print("Tempzuhoch"); break;
        case 3: lcd.print("Zeit"); break;
        case 4: lcd.print("TempSensor"); break;
        case 5: lcd.print("Abbr-INet."); break;
        default: lcd.print("undef.");
      }
    } else if (heating > 0) {
      lcd.print("An  :");
      lcd.setCursor(padd, 2);
      lcd.print((millis() - heating) / 1000);
      lcd.print("s");
    }

    lcd.setCursor(0, 3);
    lcd.print(status);
    lastLCDupdate = millis();
    lcdchanged = false;
  } else if (millis() - lastLCDupdate > 10000) {
    lcd.noBacklight();
  }
}

void sendStatus() {
  wlan.print('r');//msg type
  wlan.print(heating);//heater status
  wlan.print('.');//delimiter
  wlan.print(cancelcause);//error?
  wlan.print('.');//delimiter
  wlan.print(temp);//temp
  wlan.print('.');//delimiter
  wlan.print(state);
  wlan.print('\0');//EOT
}

//handle the conenction to the esp
void handleWLAN() {
  if (status[0] == '-' || status[0] == ' ') { //TODO: this line does not work as intended???
    /*Serial.print("requeststatus: ");
      Serial.print(status[0]);
      Serial.print(status[1]);
      Serial.print(status[2]);
      Serial.print(" ");
      Serial.println(status);*/
    wlan.write('s');
    wlan.flush();
  }

  if (wlan.available()) {
    char first = wlan.read();
    if (first == 's') {
      //status update
      bool ava = true;
      for (unsigned char i = 0; i < 20; i++) { //does somehow not exit this loop???
        char old = status[i];
        char new_ = ' ';
        if (wlan.available() && ava) {
          new_ = wlan.read();
          Serial.print(new_);
          Serial.print(new_, DEC);
          Serial.println(new_, HEX);
          if (new_ == '\0') {
            ava = false;
            new_ = ' ';
          }
        }

        if (old != new_) {
          lcdchanged = true;
          status[i] = new_;
        }
      }

      //status[2] = (rand()%10)+'a';//DEBUG
    } else if (first == 'r') { //report
      sendStatus();
    } else if (first == 'a') { //abort!
      setheater(false);
      wlan.print('a');
    } else if (first == 'g') { //go
      if (heating < 0) { //heater off?
        setheater(true);
      }
    }
  }
}

//security checks
void checkHeater() {
  if (temp > 105) { //overtemp
    cancelcause = 2;
    setheater(false);
  }

  if (millis() - heating > 600000) { //longer than 10min on
    cancelcause = 3;
    setheater(false);
  }

  if (millis() - heating > 60000 && starttemp >= temp - 1) { //on for 60s and temp did not change
    cancelcause = 4;
    setheater(false);
  }
}

bool presed = false;
void loop() {
  delay(5);

  handleWLAN();

  {
    int old = temp;
    temp = getTemp() / 100;
    /* if(old != temp)
       lcdchanged = true;*/ //cause random lcd turn on
  }

  if ((millis() - lastLCDupdate) > 500) { //reprint LCD every 1/2 seconds
    updateLCD();
  }

  //button pressed
  if (digitalRead(3) == LOW) {
    if (!presed) {
      presed = true;
      //toggle
      if (heating > 0) {
        cancelcause = 1;
      }
      setheater(heating < 0);//toggle heater
      updateLCD();
    }
  } else {
    presed = false;
  }

  if (heating > 0)
    checkHeater();

  if(temp >= cookingtemp && state == 1) {
    //coocking temp reached!
    //go !
    state = 2;
    sendStatus();
    //TODO: trigger servo
  }
}

void setheater(bool on) {
  heating = on ? millis() : -1;
  if (on) {
    cancelcause = 0;
    starttemp = temp; 
  }
  digitalWrite(2, on);
  digitalWrite(13, on);
  lcdchanged = true;
  state = on; // on = true -> state = 1 (heating); on = false -> state = 0 (idle)
  sendStatus();
}