#include "Arduino.h"
#include "SPI.h"
#include "Adafruit_GFX.h"
#include "Adafruit_ILI9341.h"

// Pin definitions
#define TFT_DC 7
#define TFT_CS 6
#define TFT_MOSI 11
#define TFT_CLK 13
#define TFT_RST 10
#define TFT_MISO 12

#define TRIG_PIN 22
#define ECHO_PIN 23

int prevuis_tankValue = 0;
int current_tankValue = 0;

// Display object
Adafruit_ILI9341 screen(TFT_CS, TFT_DC, TFT_MOSI, TFT_CLK, TFT_RST, TFT_MISO);

// Constants
constexpr uint16_t WARNING_COLOR = ILI9341_RED;
constexpr uint16_t TEXT_COLOR = ILI9341_GREEN;
constexpr uint16_t BG_COLOR = ILI9341_BLACK;
constexpr uint16_t LOADING_COLOR = ILI9341_YELLOW;

// Display positions
struct DisplayPos
{
  uint8_t x;
  uint8_t y;
};

const DisplayPos HEADER_POS = {5, 0};
const DisplayPos BYLINE_POS = {110, 5};
const DisplayPos SALES_POS = {5, 40};
const DisplayPos LITERS_POS = {5, 70};
const DisplayPos PRICE_POS = {5, 100};
const DisplayPos TANK_POS = {5, 130};
const DisplayPos LOADING_POS = {80, 110};

// Variables
int tankValue = 50;
uint16_t tankLabelWidth;

void showLoadingScreen()
{
  screen.fillScreen(BG_COLOR);
  screen.setTextColor(LOADING_COLOR);
  screen.setTextSize(3);
  screen.setCursor(LOADING_POS.x, LOADING_POS.y);
  screen.print("LOADING...");
  delay(1000); // Show loading screen for 1 second
  screen.fillScreen(BG_COLOR);
  screen.setTextColor(TEXT_COLOR);
}

void drawHeader()
{
  screen.setTextSize(4);
  screen.setCursor(HEADER_POS.x, HEADER_POS.y);
  screen.print("AGVM ");

  screen.setTextSize(3);
  screen.setCursor(BYLINE_POS.x, BYLINE_POS.y);
  screen.print("By: Lim Whu");
}

void drawCreditInfo()
{
  screen.setTextSize(3);
  screen.setCursor(SALES_POS.x, SALES_POS.y);
  screen.print("CREDIT:");
}

void drawLitersInfo()
{
  screen.setTextSize(3);
  screen.setCursor(LITERS_POS.x, LITERS_POS.y);
  screen.print("LITERS: 50.5 L");
}

void drawPriceInfo()
{
  screen.setTextSize(3);
  screen.setCursor(PRICE_POS.x, PRICE_POS.y);
  screen.print("PRICE: 75.00 php");
}

void drawTankLabel(uint16_t color = TEXT_COLOR)
{
  screen.setTextSize(3);
  screen.setTextColor(color);
  screen.setCursor(TANK_POS.x, TANK_POS.y);
  screen.print("TANK LEVEL: ");

  // Get label width for future updates
  int16_t x, y;
  screen.getTextBounds("TANK LEVEL: ", TANK_POS.x, TANK_POS.y, &x, &y, &tankLabelWidth, nullptr);
}


void updateTankValue(bool clear = true)
{
  uint16_t color = (tankValue < 20) ? WARNING_COLOR : TEXT_COLOR;

  if (clear)
  {
    char buffer[8];
    sprintf(buffer, "%d%%", prevuis_tankValue); // Format previous value with %
    int16_t x1, y1;
    uint16_t w, h;
    screen.setTextSize(3);
    screen.getTextBounds(buffer, TANK_POS.x + tankLabelWidth, TANK_POS.y, &x1, &y1, &w, &h);
    screen.fillRect(x1, y1, w, h, BG_COLOR); // Clear exact area
  }

  // Redraw the label with the correct color
  drawTankLabel(color);

  screen.setTextSize(3);
  screen.setTextColor(color);
  screen.setCursor(TANK_POS.x + tankLabelWidth, TANK_POS.y);
  screen.print(tankValue);
  screen.print("%");
}


// Change the return type to int (or uint8_t) as you're returning a value
int ultrasonicSensorSetup()
{
  // Set the trigPin to LOW
  digitalWrite(TRIG_PIN, LOW);
  delay(2);

  // Trigger the sensor by sending a HIGH pulse for 10 microseconds
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Read the echoPin, return the sound wave travel time in microseconds
  long duration = pulseIn(ECHO_PIN, HIGH);

  // Calculate the distance (in cm) based on the speed of sound
  int distance = (duration / 2) * 0.0343;
  Serial.println(distance);

  return map(distance, 2, 400, 100, 0); // Map the distance to a percentage
  // Note: This is a placeholder. Actual implementation may vary based on the sensor used.
}

void setup()
{
  Serial.begin(9600); // Initialize serial communication for debugging
  Serial.println("Initializing...");
  // Initialize display
  screen.begin();
  screen.setRotation(3);

  // Show loading screen first
  showLoadingScreen();

  // Draw static elements
  drawHeader();
  drawCreditInfo();
  drawLitersInfo();
  drawPriceInfo();

  // Initialize tank display
  drawTankLabel();
  updateTankValue(false); // Initial draw without clearing

  // Set the trigPin as an output and echoPin as an input
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
}

void loop()
{
  tankValue = ultrasonicSensorSetup(); // Get the tank value from the sensor
  if (tankValue != prevuis_tankValue)
  {
    updateTankValue();
    prevuis_tankValue = tankValue; // Update the previous value
  }
}