#include <PubSubClient.h>
#include <ArduinoJson.h>

// --- Wi-Fi Credentials ---
const char* ssid = "Afrihost Fibre DJ";
const char* password = "0824435505";

// --- MQTT Configuration ---
const char* mqttServer = "mqtt.eclipseprojects.io";
const int mqttPort = 1883;
const char* clientID = "ESP32-FanController";
const char* topicCurve = "esp/fan12/curve/set";
const char* topicTemp = "esp/fan12/temp";
const char* topicStatus = "esp/fan12/status";
const char* topicData = "esp/fan12/data";

// --- Pin Assignments ---
const int pwmPin = 18;
const int tachPin = 19;

// --- PWM Settings ---
const int pwmFreq = 500;
const int pwmPeriod_us = 1000000 / pwmFreq;

// --- Cooling Curve ---
int fanCurve[6] = { 0, 20, 40, 60, 80, 100 };
float currentTemp = 0.0;
int currentDuty = 0;
int lastIndex = -1;

// --- Tachometer Pulse Count ---
volatile unsigned long tachPulses = 0;
unsigned long lastRPMCalc = 0;
int currentRPM = 0;

// --- MQTT Setup ---
WiFiClient espClient;
PubSubClient client(espClient);

// --- Interrupt Handler ---
void IRAM_ATTR onTachPulse() {
  tachPulses++;
}

void connectWiFi() {
  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println(" connected");
}

void mqttCallback(char* topic, byte* payload, unsigned int length) {
  String msg;
  for (unsigned int i = 0; i < length; i++) msg += (char)payload[i];

  if (String(topic) == topicCurve) {
    StaticJsonDocument<128> doc;
    if (!deserializeJson(doc, msg) && doc.containsKey("curve")) {
      JsonArray curve = doc["curve"];
      for (int i = 0; i < 6 && i < curve.size(); i++) {
        fanCurve[i] = curve[i];
      }
      Serial.println("✔️ Fan curve updated.");
    }
  }

  if (String(topic) == topicTemp) {
    currentTemp = msg.toFloat();
  }
}

void reconnectMQTT() {
  while (!client.connected()) {
    Serial.print("Reconnecting MQTT...");
    if (client.connect(clientID)) {
      client.subscribe(topicCurve);
      client.subscribe(topicTemp);
      Serial.println(" connected");
    } else {
      delay(1000);
    }
  }
}

int getCurveIndex(float temp) {
  if (temp <= 30) return 0;
  if (temp <= 35) return 1;
  if (temp <= 40) return 2;
  if (temp <= 45) return 3;
  if (temp <= 50) return 4;
  return 5;
}

void setup() {
  Serial.begin(115200);
  pinMode(pwmPin, OUTPUT);
  pinMode(tachPin, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(tachPin), onTachPulse, FALLING);

  connectWiFi();
  client.setServer(mqttServer, mqttPort);
  client.setCallback(mqttCallback);
}

void loop() {
  if (!client.connected()) reconnectMQTT();
  client.loop();

  // --- Duty Calculation ---
  int index = getCurveIndex(currentTemp);
  int newDuty = fanCurve[index];

  if (index != lastIndex) {
    lastIndex = index;
    Serial.printf("⚠️ Temp range changed → Index: %d → Duty: %d%%\n", index, newDuty);
    // TODO: Beep buzzer here if needed
  }

  currentDuty = newDuty;

  // --- PWM Signal ---
  int highTime = (currentDuty * pwmPeriod_us) / 100;
  int lowTime = pwmPeriod_us - highTime;

  digitalWrite(pwmPin, HIGH);
  delayMicroseconds(highTime);
  digitalWrite(pwmPin, LOW);
  delayMicroseconds(lowTime);

  // --- Every 1 Second: Publish Status ---
  unsigned long now = millis();
  if (now - lastRPMCalc > 1000) {
    noInterrupts();
    unsigned long pulses = tachPulses;
    tachPulses = 0;
    interrupts();

    currentRPM = (pulses / 2) * 60;
    lastRPMCalc = now;

    String status = (currentDuty > 0) ? "ON" : "OFF";

    StaticJsonDocument<128> doc;
    doc["rpm"] = currentRPM;
    doc["duty"] = currentDuty;
    doc["status"] = status;

    char buffer[128];
    serializeJson(doc, buffer);
    client.publish(topicData, buffer);
    client.publish(topicStatus, status.c_str());

    Serial.printf("📤 Published → RPM: %d | Duty: %d%% | Status: %s\n", currentRPM, currentDuty, status.c_str());
  }
}