#include <Arduino.h>

const uint8_t LIGHT_PINS[3] = {2, 4, 5};        // LIGHT1..3
const uint8_t TUBE_PINS[4]  = {12, 13, 14, 15}; // TUBE1..4
const uint8_t FAN_PINS[4]   = {18, 19, 21, 22}; // FAN_S1..4

struct SystemState {
  bool lights[3] = {false, false, false};
  bool tubes[4] = {false, false, false, false};
  uint8_t fanSpeed = 0; // 0=OFF, 1..4
  bool fault = false;
};

SystemState state;
String rxLine = "";
unsigned long lastHeartbeatMs = 0;
const unsigned long HEARTBEAT_MS = 10000;

void trimAndUpper(String &s) {
  s.trim();
  s.toUpperCase();
}

void fanAllOff() {
  for (int i = 0; i < 4; i++) {
    digitalWrite(FAN_PINS[i], LOW);
  }
}

void applyOutputs() {
  for (int i = 0; i < 3; i++) {
    digitalWrite(LIGHT_PINS[i], state.lights[i] ? HIGH : LOW);
  }

  for (int i = 0; i < 4; i++) {
    digitalWrite(TUBE_PINS[i], state.tubes[i] ? HIGH : LOW);
  }

  fanAllOff();
  if (state.fanSpeed >= 1 && state.fanSpeed <= 4) {
    digitalWrite(FAN_PINS[state.fanSpeed - 1], HIGH);
  }
}

void sendStatus() {
  Serial.print("STATUS FAN=");
  Serial.print(state.fanSpeed);

  for (int i = 0; i < 3; i++) {
    Serial.print(" LIGHT");
    Serial.print(i + 1);
    Serial.print("=");
    Serial.print(state.lights[i] ? 1 : 0);
  }

  for (int i = 0; i < 4; i++) {
    Serial.print(" TUBE");
    Serial.print(i + 1);
    Serial.print("=");
    Serial.print(state.tubes[i] ? 1 : 0);
  }

  Serial.print(" FAULT=");
  Serial.println(state.fault ? 1 : 0);
}

void printHelp() {
  Serial.println("AVAILABLE COMMANDS:");
  Serial.println("GET STATUS");
  Serial.println("SET LIGHT1 ON|OFF");
  Serial.println("SET LIGHT2 ON|OFF");
  Serial.println("SET LIGHT3 ON|OFF");
  Serial.println("SET TUBE1 ON|OFF");
  Serial.println("SET TUBE2 ON|OFF");
  Serial.println("SET TUBE3 ON|OFF");
  Serial.println("SET TUBE4 ON|OFF");
  Serial.println("SET FAN OFF");
  Serial.println("SET FAN SPEED 1");
  Serial.println("SET FAN SPEED 2");
  Serial.println("SET FAN SPEED 3");
  Serial.println("SET FAN SPEED 4");
  Serial.println("RESET");
  Serial.println("HELP");
}

void clearAll() {
  for (int i = 0; i < 3; i++) state.lights[i] = false;
  for (int i = 0; i < 4; i++) state.tubes[i] = false;
  state.fanSpeed = 0;
  state.fault = false;
  applyOutputs();
}

bool setLight(int idx, bool on) {
  if (idx < 0 || idx >= 3) return false;
  state.lights[idx] = on;
  applyOutputs();
  Serial.print("OK LIGHT");
  Serial.print(idx + 1);
  Serial.print(" ");
  Serial.println(on ? "ON" : "OFF");
  return true;
}

bool setTube(int idx, bool on) {
  if (idx < 0 || idx >= 4) return false;
  state.tubes[idx] = on;
  applyOutputs();
  Serial.print("OK TUBE");
  Serial.print(idx + 1);
  Serial.print(" ");
  Serial.println(on ? "ON" : "OFF");
  return true;
}

bool setFan(uint8_t speed) {
  if (speed > 4) {
    Serial.println("ERR FAN_SPEED_RANGE");
    return false;
  }

  fanAllOff();
  state.fanSpeed = speed;
  applyOutputs();

  if (speed == 0) {
    Serial.println("OK FAN OFF");
  } else {
    Serial.print("OK FAN SPEED ");
    Serial.println(speed);
  }
  return true;
}

void processSetDevice(const String &device, const String &value) {
  for (int i = 0; i < 3; i++) {
    String name = "LIGHT" + String(i + 1);
    if (device == name) {
      if (value == "ON") setLight(i, true);
      else if (value == "OFF") setLight(i, false);
      else Serial.println("ERR INVALID_VALUE");
      return;
    }
  }

  for (int i = 0; i < 4; i++) {
    String name = "TUBE" + String(i + 1);
    if (device == name) {
      if (value == "ON") setTube(i, true);
      else if (value == "OFF") setTube(i, false);
      else Serial.println("ERR INVALID_VALUE");
      return;
    }
  }

  if (device == "FAN") {
    if (value == "OFF") setFan(0);
    else Serial.println("ERR USE SET FAN SPEED <1..4> OR SET FAN OFF");
    return;
  }

  Serial.println("ERR INVALID_DEVICE");
}

void processCommand(String line) {
  trimAndUpper(line);
  if (line.length() == 0) return;

  if (line == "GET STATUS") {
    sendStatus();
    return;
  }

  if (line == "HELP") {
    printHelp();
    return;
  }

  if (line == "RESET") {
    clearAll();
    Serial.println("OK RESET");
    sendStatus();
    return;
  }

  if (line.startsWith("SET FAN SPEED ")) {
    String speedStr = line.substring(String("SET FAN SPEED ").length());
    speedStr.trim();
    int speed = speedStr.toInt();

    if (speed < 1 || speed > 4) {
      Serial.println("ERR FAN_SPEED_RANGE");
      return;
    }

    setFan((uint8_t)speed);
    return;
  }

  if (line.startsWith("SET ")) {
    String rest = line.substring(4);
    rest.trim();

    int sp = rest.indexOf(' ');
    if (sp < 0) {
      Serial.println("ERR INVALID_FORMAT");
      return;
    }

    String device = rest.substring(0, sp);
    String value = rest.substring(sp + 1);
    trimAndUpper(device);
    trimAndUpper(value);

    processSetDevice(device, value);
    return;
  }

  Serial.println("ERR UNKNOWN_COMMAND");
}

void serialRxTask() {
  while (Serial.available()) {
    char c = (char)Serial.read();

    if (c == '\n' || c == '\r') {
      if (rxLine.length() > 0) {
        processCommand(rxLine);
        rxLine = "";
      }
    } else {
      if (rxLine.length() < 120) {
        rxLine += c;
      } else {
        rxLine = "";
        Serial.println("ERR LINE_TOO_LONG");
      }
    }
  }
}

void faultMonitorTask() {
  int active = 0;
  for (int i = 0; i < 4; i++) {
    if (digitalRead(FAN_PINS[i]) == HIGH) active++;
  }

  if (active > 1) {
    state.fault = true;
    fanAllOff();
    state.fanSpeed = 0;
    Serial.println("ERR FAN_INTERLOCK_FAULT");
  }
}

void heartbeatTask() {
  unsigned long now = millis();
  if (now - lastHeartbeatMs >= HEARTBEAT_MS) {
    lastHeartbeatMs = now;
    sendStatus();
  }
}

void setup() {
  Serial.begin(115200);

  for (int i = 0; i < 3; i++) {
    pinMode(LIGHT_PINS[i], OUTPUT);
    digitalWrite(LIGHT_PINS[i], LOW);
  }

  for (int i = 0; i < 4; i++) {
    pinMode(TUBE_PINS[i], OUTPUT);
    digitalWrite(TUBE_PINS[i], LOW);
  }

  for (int i = 0; i < 4; i++) {
    pinMode(FAN_PINS[i], OUTPUT);
    digitalWrite(FAN_PINS[i], LOW);
  }

  clearAll();

  Serial.println("====================================");
  Serial.println("ESP32 SMART ROOM POWER CONTROLLER");
  Serial.println("READY - Type HELP");
  Serial.println("====================================");
  sendStatus();
}

void loop() {
  serialRxTask();
  faultMonitorTask();
  heartbeatTask();
}