#include <Adafruit_GFX.h>
#include <Adafruit_ILI9341.h>

#define TFT_CS 10
#define TFT_DC 9
#define TFT_RST 8

Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC, TFT_RST);

int up = 7;
int ok = 6;
int down = 5;

int sum = 0;


String actualItems[][2] = {
  {"Item 1", "100"},
  {"Item 2", "200"},
  {"Item 3", "300"},
  {"Item 4", "400"}
};

int itemCount = 0;

int cursorItem = 0;

String currentItems[20][3];

bool isChanged = true;

void setup() {
  Serial.begin(9600);
  tft.begin();
  Serial.println("~~ AutoCart Presents ~~ ");
  Serial.println("Height :- " + String(tft.height()) + " , Width :- " + String(tft.width()));
  tft.setRotation(1);
  tft.fillScreen(ILI9341_WHITE);

  tft.fillRect(0, 0, tft.width(), 30, ILI9341_RED);
  tft.setTextSize(3);
  tft.setCursor(90, 5);
  tft.setTextColor(ILI9341_WHITE);
  tft.println("AutoCart");

  tft.fillRect(0, 30, tft.width(), 30, ILI9341_BLUE);
  tft.setTextSize(2);
  tft.setCursor(40, 40);
  tft.setTextColor(ILI9341_WHITE);
  tft.println("Total amount :- ");
  tft.setCursor(tft.width() - 70, 40);
  tft.println(sum);

  tft.fillRect(0, 60, tft.width(), 35, ILI9341_BLACK);
  tft.drawRect(0, 60, tft.width(), 35, ILI9341_DARKGREY);
  tft.setTextSize(2);
  tft.setTextColor(ILI9341_WHITE);
  tft.setCursor(20, 70);
  tft.println("Name");
  tft.setCursor(170, 70);
  tft.println("Qty.");
  tft.setCursor(250, 70);
  tft.println("Price");


  pinMode(up, INPUT_PULLUP);
  pinMode(ok, INPUT_PULLUP);
  pinMode(down, INPUT_PULLUP);

}

void loop() {
  checkButtons(currentItems, actualItems, isChanged);
  printList(currentItems, isChanged);
}


void checkButtons(String currentItems[20][3], String actualItems[][2], bool& isChanged) {
  if (digitalRead(down) == LOW) {
    if (cursorItem < itemCount-1) {
      cursorItem++;
      isChanged = true;
    }
    delay(100);
  }
  if (digitalRead(up) == LOW) {
    if (cursorItem > 0) {
      cursorItem--;
      isChanged = true;
    }
    delay(100);
  }
  if (digitalRead(ok) == LOW) {

    int index = random(0, 4);
    String newItem[2] = actualItems[index];
    bool isNewAdded = true;
    for (int i = 0; i < itemCount; i++) {
      if (currentItems[i][0] == newItem[0]) {
        int lastQty = currentItems[i][1].toInt() + 1;
        currentItems[i][1] = String(lastQty);
        isNewAdded = false;
        break;
      }
    }
    if (isNewAdded) {
      currentItems[itemCount][0] = newItem[0];
      currentItems[itemCount][1] = "1";
      currentItems[itemCount][2] = newItem[1];
      itemCount++;
    }

    isChanged = true;

    delay(200);
  }
}


void printList(String currentItems[20][3], bool& isChanged) {
  if (isChanged) {
    sum = 0;
    tft.setTextColor(ILI9341_BLACK);

    for (int i = 0; i < itemCount  ; i++) {
      if ( i == cursorItem) {
        tft.fillRect(0, 100 + i * 23, tft.width(), 23, 0xef7d);
        tft.fillCircle(10, 110 + i * 23, 5, ILI9341_BLACK);
      } else {
        tft.fillRect(0, 100 + i * 23, tft.width(), 23, ILI9341_WHITE);
      }
      tft.setCursor(30, 105 + i * 23);
      tft.println(currentItems[i][0]);
      tft.setCursor(180, 105 + i * 23);
      tft.println(currentItems[i][1]);
      tft.setCursor(250, 105 + i * 23);
      tft.println(currentItems[i][2]);
      sum += (currentItems[i][1].toInt() * currentItems[i][2].toInt());
    }
    tft.fillRect(tft.width() - 70, 30, tft.width(), 30, ILI9341_BLUE);
    tft.setCursor(tft.width() - 70, 40);
    tft.setTextColor(ILI9341_WHITE);
    tft.println(String(sum));
    isChanged = false;
  }
}