#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_ILI9341.h>
#include <WiFi.h>
#include <WiFiClientSecure.h>
#include <HTTPClient.h>
#include <ArduinoJson.h>

// GPIOs where the NTC thermistors are connected
const int ntcPins[4] = {32, 33, 34, 35};

// Button pins
const int buttonUpPin = 12;
const int buttonDownPin = 13;
const int buttonOkayPin = 14;

// WiFi credentials
struct WiFiNetwork {
  const char* ssid;
  const char* password;
};

WiFiNetwork wifiNetworks[] = {
  {"Wokwi-GUEST", ""},
  {"Network1", "password1"},
  {"Network2", "password2"},
  {"Network3", "password3"}
};

const int wifiNetworkCount = sizeof(wifiNetworks) / sizeof(WiFiNetwork);
int selectedNetworkIndex = 0;

// Google Sheets API details
const char* google_script_id = "AKfycbzqP-j1L4cLd2TkbbbYWMGUI7_q09IZqja56CQ9RQrjCrRYBax08MNN2u6101fmSKAPSA";

// Constants for the NTC thermistor and resistor
const float nominalResistance = 10000; // 10kΩ resistor
const float nominalTemperature = 25;   // Nominal temperature for the thermistor
const float bCoefficient = 3950;       // Beta coefficient of the thermistor
const float seriesResistor = 10000;    // Value of the series resistor

// ILI9341 display settings
#define TFT_CS     15
#define TFT_RST    4
#define TFT_DC     2
Adafruit_ILI9341 display = Adafruit_ILI9341(TFT_CS, TFT_DC, TFT_RST);

// Timing variables
unsigned long previousMillis = 0;
const long interval = 10000; // Interval for sending data to Google Sheets (10 seconds)

// Menu variables
enum MenuState { MAIN_MENU, TEMPERATURE_MENU, WIFI_SETTINGS_MENU, WIFI_CONNECTING_MENU, WIFI_STATUS_MENU };
MenuState menuState = MAIN_MENU;
int menuIndex = 0;
const int menuItems = 2;

// Track WiFi connection time
unsigned long wifiConnectedTime = 0;

// Logging control
bool loggingEnabled = false;

void setup() {
  // Start the Serial Monitor
  Serial.begin(115200);

  // Initialize ILI9341 display
  display.begin();
  display.setRotation(1);
  display.fillScreen(ILI9341_BLACK);
  display.setTextColor(ILI9341_WHITE);
  display.setTextSize(2);
  delay(2000);

  // Initialize buttons
  pinMode(buttonUpPin, INPUT_PULLUP);
  pinMode(buttonDownPin, INPUT_PULLUP);
  pinMode(buttonOkayPin, INPUT_PULLUP);
}

void loop() {
  // Check button states
  if (digitalRead(buttonUpPin) == LOW) {
    if (menuState == TEMPERATURE_MENU) {
      menuState = MAIN_MENU;
      loggingEnabled = false;  // Stop logging when exiting menu
    } else if (menuState == WIFI_SETTINGS_MENU) {
      selectedNetworkIndex = (selectedNetworkIndex > 0) ? selectedNetworkIndex - 1 : wifiNetworkCount - 1;
    } else {
      menuIndex = (menuIndex > 0) ? menuIndex - 1 : menuItems - 1;
    }
    delay(200); // Debounce delay
  }
  if (digitalRead(buttonDownPin) == LOW) {
    if (menuState == TEMPERATURE_MENU) {
      menuState = MAIN_MENU;
      loggingEnabled = false;  // Stop logging when exiting menu
    } else if (menuState == WIFI_SETTINGS_MENU) {
      selectedNetworkIndex = (selectedNetworkIndex < wifiNetworkCount - 1) ? selectedNetworkIndex + 1 : 0;
    } else {
      menuIndex = (menuIndex < menuItems - 1) ? menuIndex + 1 : 0;
    }
    delay(200); // Debounce delay
  }
  if (digitalRead(buttonOkayPin) == LOW) {
    if (menuState == TEMPERATURE_MENU) {
      loggingEnabled = !loggingEnabled; // Toggle logging state
    } else if (menuState == WIFI_SETTINGS_MENU) {
      menuState = WIFI_CONNECTING_MENU;
      connectToWiFi(wifiNetworks[selectedNetworkIndex].ssid, wifiNetworks[selectedNetworkIndex].password);
    } else {
      switch (menuIndex) {
        case 0:
          menuState = TEMPERATURE_MENU;
          break;
        case 1:
          menuState = WIFI_SETTINGS_MENU;
          break;
      }
    }
    delay(200); // Debounce delay
  }

  // Update the display based on the current menu state
  switch (menuState) {
    case MAIN_MENU:
      displayMainMenu();
      break;
    case TEMPERATURE_MENU:
      displayTemperatureMenu();
      break;
    case WIFI_SETTINGS_MENU:
      displayWiFiSettingsMenu();
      break;
    case WIFI_CONNECTING_MENU:
      displayWiFiConnectingMenu();
      break;
    case WIFI_STATUS_MENU:
      displayWiFiStatusMenu();
      break;
  }

  // Handle timing for sending data to Google Sheets
  if (loggingEnabled) {
    unsigned long currentMillis = millis();
    if (currentMillis - previousMillis >= interval) {
      previousMillis = currentMillis;

      // Prepare the data to be sent
      String data = prepareData();

      // Send data to Google Sheets
      sendToGoogleSheets(data);
    }
  }

  // Update WiFi status indicator
  updateWiFiStatus();
}

void connectToWiFi(const char* ssid, const char* password) {
  WiFi.begin(ssid, password);
  unsigned long startAttemptTime = millis();

  // Attempt to connect for 10 seconds
  while (WiFi.status() != WL_CONNECTED && millis() - startAttemptTime < 10000) {
    delay(500);
    Serial.print(".");
  }

  display.fillScreen(ILI9341_BLACK);
  display.setTextSize(2);
  display.setCursor(0, 0);
  if (WiFi.status() == WL_CONNECTED) {
    wifiConnectedTime = millis();
    Serial.println("Connected to WiFi");
    display.println("Connected to WiFi");
  } else {
    Serial.println("Failed to connect to WiFi");
    display.println("Failed to connect to WiFi");
  }
  delay(2000); // Show the connection status for 2 seconds
  menuState = MAIN_MENU; // Return to main menu after showing connection status
}

String prepareData() {
  String data = "timestamp=" + String(millis()) + "&";

  for (int i = 0; i < 4; i++) {
    float temperatureC = readTemperature(ntcPins[i]);
    if (isnan(temperatureC)) {
      Serial.print("Error: Could not read temperature data from sensor ");
      Serial.println(i + 1);
      data += "sensor" + String(i + 1) + "=Error&";
    } else {
      data += "sensor" + String(i + 1) + "=" + String(temperatureC) + "&";
    }
  }

  // Remove the last '&'
  data.remove(data.length() - 1);

  return data;
}

float readTemperature(int pin) {
  int adcValue = analogRead(pin);
  float resistance = seriesResistor / ((4095.0 / adcValue) - 1);
  float steinhart;
  steinhart = resistance / nominalResistance;           // (R/Ro)
  steinhart = log(steinhart);                           // ln(R/Ro)
  steinhart /= bCoefficient;                            // 1/B * ln(R/Ro)
  steinhart += 1.0 / (nominalTemperature + 273.15);     // + (1/To)
  steinhart = 1.0 / steinhart;                          // Invert
  steinhart -= 273.15;                                  // Convert to Celsius

  return steinhart;
}

void displayMainMenu() {
  display.fillScreen(ILI9341_BLACK);
  display.setTextSize(2);
  display.setCursor(0, 0);
  display.println("Main Menu");

  display.setCursor(0, 40);
  display.setTextColor(menuIndex == 0 ? ILI9341_BLACK : ILI9341_WHITE, menuIndex == 0 ? ILI9341_WHITE : ILI9341_BLACK);
  display.println("1. Temperatures");

  display.setCursor(0, 80);
  display.setTextColor(menuIndex == 1 ? ILI9341_BLACK : ILI9341_WHITE, menuIndex == 1 ? ILI9341_WHITE : ILI9341_BLACK);
  display.println("2. WiFi Settings");
}

void displayTemperatureMenu() {
  display.fillScreen(ILI9341_BLACK);
  display.setTextSize(2);
  display.setCursor(0, 0);
  display.println("Temperatures");

  display.setTextSize(1);
  for (int i = 0; i < 4; i++) {
    float temperatureC = readTemperature(ntcPins[i]);
    display.setCursor(0, 30 + (i * 20));
    display.print("Sensor ");
    display.print(i + 1);
    display.print(": ");
    if (isnan(temperatureC)) {
      display.println("Error");
    } else {
      display.print(temperatureC);
      display.println(" C");
    }
  }

  // Indicate logging status
  display.setCursor(0, 120);
  display.setTextSize(2);
  display.setTextColor(loggingEnabled ? ILI9341_WHITE : ILI9341_BLACK, loggingEnabled ? ILI9341_BLACK : ILI9341_WHITE);
  display.print(loggingEnabled ? "Logging: ON" : "Logging: OFF");
}

void displayWiFiSettingsMenu() {
  display.fillScreen(ILI9341_BLACK);
  display.setTextSize(2);
  display.setCursor(0, 0);
  display.println("WiFi Settings");

  display.setTextSize(1);
  for (int i = 0; i < wifiNetworkCount; i++) {
    display.setCursor(0, 30 + (i * 20));
    display.setTextColor(i == selectedNetworkIndex ? ILI9341_BLACK : ILI9341_WHITE, i == selectedNetworkIndex ? ILI9341_WHITE : ILI9341_BLACK);
    display.println(wifiNetworks[i].ssid);
  }
}

void displayWiFiConnectingMenu() {
  display.fillScreen(ILI9341_BLACK);
  display.setTextSize(2);
  display.setCursor(0, 0);
  display.print("Connecting to ");
  display.println(wifiNetworks[selectedNetworkIndex].ssid);
}

void displayWiFiStatusMenu() {
  display.fillScreen(ILI9341_BLACK);
  display.setTextSize(2);
  display.setCursor(0, 0);
  display.println("WiFi Status");

  display.setTextSize(1);
  display.setCursor(0, 30);
  display.print("SSID: ");
  display.println(WiFi.SSID());

  display.setCursor(0, 50);
  display.print("Signal: ");
  int32_t rssi = WiFi.RSSI();
  display.print(rssi);
  display.println(" dBm");

  unsigned long connectedTime = (millis() - wifiConnectedTime) / 1000;
  display.setCursor(0, 70);
  display.print("Connected for: ");
  display.print(connectedTime);
  display.println(" s");

  // Check for back button
  if (digitalRead(buttonOkayPin) == LOW) {
    menuState = MAIN_MENU;
    delay(200); // Debounce delay
  }
}

void updateWiFiStatus() {
  // Draw a small dot indicator for WiFi status
  display.fillCircle(300, 10, 5, (WiFi.status() == WL_CONNECTED) ? ILI9341_GREEN : ILI9341_RED);
}

void sendToGoogleSheets(const String& data) {
  WiFiClientSecure client;
  HTTPClient http;

  client.setInsecure();
  String url = String("https://script.google.com/macros/s/") + google_script_id + "/exec?" + data;

  http.begin(client, url);
  int httpCode = http.GET();

  if (httpCode > 0) {
    Serial.println("Data sent successfully");
  } else {
    Serial.println("Error in sending data: " + String(httpCode));
  }

  http.end();
}