#include <WiFi.h>
#include <HTTPClient.h>

// ---------------- WiFi Configuration ----------------
const char* wifiSsid = "Wokwi-GUEST";
const char* wifiPassword = "";

// ---------------- Server Configuration ----------------
const char* baseApiUrl = "https://energymeter.pythonanywhere.com/addlog";
const char* deviceId = "dev123";

// ---------------- ADC Pins ----------------
const int voltagePotPin = 34;
const int currentPotPin = 35;
const int powerPotPin   = 32;
const int energyPotPin  = 33;

// ---------------- Button Pin ----------------
const int uploadButtonPin = 25; // LOW = upload

// ---------------- Function Declarations ----------------
float readScaledValue(int pin, float minValue, float maxValue);
void connectToWiFi();
void uploadEnergyData(float voltage, float current, float power, float energy);
void printValuesToSerial(float voltage, float current, float power, float energy);

// ---------------- Setup ----------------
void setup() {
  Serial.begin(115200);

  pinMode(voltagePotPin, INPUT);
  pinMode(currentPotPin, INPUT);
  pinMode(powerPotPin, INPUT);
  pinMode(energyPotPin, INPUT);
  pinMode(uploadButtonPin, INPUT_PULLUP);

  connectToWiFi();
}

// ---------------- Loop ----------------
void loop() {
  float voltage = readScaledValue(voltagePotPin, 0.0, 260.0);
  float current = readScaledValue(currentPotPin, 0.0, 3.0);
  float power   = readScaledValue(powerPotPin,   0.0, 1000.0);
  float energy  = readScaledValue(energyPotPin,  0.0, 100.0);

  if (digitalRead(uploadButtonPin) == LOW) {
    uploadEnergyData(voltage, current, power, energy);
    delay(10000); // wait 10 sec after upload
  } else {
    printValuesToSerial(voltage, current, power, energy);
    delay(500);
  }
}

// ------------------------------------------------------
// Reads ADC value and scales it to required range
// ------------------------------------------------------
float readScaledValue(int pin, float minValue, float maxValue) {
  int rawValue = analogRead(pin);
  if (rawValue < 0) {
    Serial.println("ADC read error");
    return minValue;
  }
  return ((float)rawValue / 4095.0) * (maxValue - minValue) + minValue;
}

// ------------------------------------------------------
// Connects ESP32 to WiFi
// ------------------------------------------------------
void connectToWiFi() {
  WiFi.begin(wifiSsid, wifiPassword);
  Serial.print("Connecting to WiFi");

  int retryCount = 0;
  while (WiFi.status() != WL_CONNECTED && retryCount < 20) {
    delay(500);
    Serial.print(".");
    retryCount++;
  }

  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("\nWiFi Connected");
  } else {
    Serial.println("\nWiFi Connection Failed");
  }
}

// ------------------------------------------------------
// Uploads data using HTTP GET
// ------------------------------------------------------
void uploadEnergyData(float voltage, float current, float power, float energy) {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("WiFi not connected, upload skipped");
    return;
  }

  HTTPClient http;

  String fullUrl = String(baseApiUrl) +
    "?deviceid=" + deviceId +
    "&voltage=" + String(voltage, 2) +
    "&current=" + String(current, 2) +
    "&power="   + String(power, 2) +
    "&energy="  + String(energy, 2);

  Serial.println("Uploading Data:");
  Serial.println(fullUrl);

  http.begin(fullUrl);
  int httpCode = http.GET();

  if (httpCode > 0) {
    Serial.println("Server Response: " + http.getString());
  } else {
    Serial.print("HTTP Error: ");
    Serial.println(http.errorToString(httpCode));
  }

  http.end();
}

// ------------------------------------------------------
// Prints values to Serial Monitor
// ------------------------------------------------------
void printValuesToSerial(float voltage, float current, float power, float energy) {
  Serial.print("Voltage: "); Serial.print(voltage, 2); Serial.print(" V | ");
  Serial.print("Current: "); Serial.print(current, 2); Serial.print(" A | ");
  Serial.print("Power: ");   Serial.print(power, 2);   Serial.print(" W | ");
  Serial.print("Energy: ");  Serial.print(energy, 2);  Serial.println(" units");
}