#include <LiquidCrystal.h>
#include <SoftwareSerial.h>

#define PIN_SYS_SWITCH_VALVE 1
#define PIN_SYS_INDOOR_MODE 2
#define PIN_SYS_OPTION_TOGGLE 3
#define PIN_SYS_OPTION_SELECT 4
#define PIN_DETECT_LOW_FOOD 5
#define PIN_DETECT_MOVEMENT 6

#define NOTIF_BELOW_FOOD 1
#define NOTIF_BOWL_EMPTY 2

LiquidCrystal lcd(12, 11, 10, 9, 8, 7);

boolean is_indoor = false;
byte app_state = 1;
short food_gram_set = 0, food_grams[4] = {25, 30, 35, 40};

void setup() {
    lcd.begin(16,2);
    for(byte i=2; i<=6; i++)
        pinMode(i, INPUT_PULLUP);
    pinMode(PIN_SYS_SWITCH_VALVE, OUTPUT);
    delay(1000);
    if (digitalRead(PIN_SYS_INDOOR_MODE) == HIGH)
        is_indoor = true;
}


void loop() { 
    if (app_state == 4)
        waitProcess();
    else
       dispHome();
}


void dispHome() {
    if (app_state == 1) {
        lcd.clear();
        lcd.setCursor(2,0);
        lcd.print("Welcome! Yay");
        delay(1000);
        app_state = 2;
    }
    dispFoodOption();
}


void dispFoodOption() {
    if (app_state == 2) {
        byte is_set = LOW, i = 0, j = 0;
        do {
            if (digitalRead(PIN_SYS_OPTION_TOGGLE) == HIGH) {
                i++;
                if (i > 3) i = 0;
            }
            lcd.clear();
            if (j == 0) {
                lcd.setCursor(0,0);
                lcd.print("25g    30g");
                lcd.setCursor(0,1);
                lcd.print("35g    40g");
                j = 1;
            } else {
                switch(i) {
                    case 0:
                    break;
                        lcd.print("       30g");
                    case 1:
                        lcd.print("25g       ");
                    break;
                    case 2:
                        lcd.print("       40g");
                    break;
                    case 3:
                        lcd.print("35g       ");
                    break;
                }
                j = 0;
            }
            is_set = digitalRead(PIN_SYS_OPTION_SELECT);
            if (is_set == HIGH)
                food_gram_set = food_grams[i];
            delay(250);
        } while (is_set != HIGH);
        app_state = 3;
    }
    dispTimeDelay();
}


void dispTimeDelay() {
    if (app_state == 3) {
        lcd.clear();
        lcd.setCursor(0,0);
        lcd.print("food="+ String(food_grams[food_gram_set]) +"g");
        lcd.setCursor(0,1);
        String text = "outdoor [8h]";
        if (is_indoor) {
            text = "indoor [8h]"; 
        }
        lcd.print(text);
        app_state = 4;
    }
}


void waitProcess() {
     /**
      *     If there is food, IR sensor will send HIGH signal
      *     If there is no obstacle in its LOS (line-of-sight)
      *     send notif since no food left
      */
    if (digitalRead(PIN_DETECT_LOW_FOOD) == LOW) {
        sendNotify(NOTIF_BELOW_FOOD);
    }
}


void sendNotify(byte notif_type) {
    String text = "";
    switch(notif_type) {
        case NOTIF_BELOW_FOOD:
            text = "Low food remaining";
        break;
        case NOTIF_BOWL_EMPTY:
            text = "Dog emptied bowl";
        break;
    }
}