/*
 * Ain El Aql — ESP32 Gate Controller
 * 
 * Two operation modes:
 *   1. WiFi Mode: Polls the cloud backend every 1 second for gate commands.
 *      Works from anywhere in the world (real hardware + Wokwi simulation).
 *   2. USB Serial Mode: Receives '1' from the browser's Web Serial API.
 *      Works when ESP32 is plugged into the security PC via USB.
 *
 * Both modes work simultaneously — whichever signal arrives first opens the gate.
 */

#include <ESP32Servo.h>
#include <WiFi.h>
#include <HTTPClient.h>
#include <ArduinoJson.h>

// ── Configuration ─────────────────────────────────────────
// Change these to match your setup:
const char* WIFI_SSID     = "YOUR_WIFI_SSID";
const char* WIFI_PASSWORD = "YOUR_WIFI_PASSWORD";

// Your backend URL (Railway deployment)
const char* BACKEND_URL   = "https://ain-el-aql-backend-production.up.railway.app";
const char* GATE_LOCATION = "OPERA";

// ── Hardware ──────────────────────────────────────────────
Servo gateServo;
const int servoPin = 18;       // GPIO 18 on ESP32
const int LED_PIN  = 2;        // Built-in LED for status

// ── State ─────────────────────────────────────────────────
bool gateIsOpen = false;
unsigned long lastPollTime = 0;
const unsigned long POLL_INTERVAL_MS = 1000;  // Poll every 1 second

void setup() {
  Serial.begin(115200);
  Serial.println("\n╔══════════════════════════════════════╗");
  Serial.println("║   Ain El Aql — Gate Controller v2   ║");
  Serial.println("╚══════════════════════════════════════╝");
  
  // Setup servo
  ESP32PWM::allocateTimer(0);
  gateServo.setPeriodHertz(50);
  gateServo.attach(servoPin, 500, 2400);
  gateServo.write(0);  // Start closed
  
  // Setup LED
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW);
  
  // Connect to WiFi
  Serial.print("[WiFi] Connecting to ");
  Serial.print(WIFI_SSID);
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  
  int attempts = 0;
  while (WiFi.status() != WL_CONNECTED && attempts < 30) {
    delay(500);
    Serial.print(".");
    attempts++;
  }
  
  if (WiFi.status() == WL_CONNECTED) {
    Serial.println(" ✅ Connected!");
    Serial.print("[WiFi] IP: ");
    Serial.println(WiFi.localIP());
    digitalWrite(LED_PIN, HIGH);  // LED on = WiFi connected
  } else {
    Serial.println(" ❌ WiFi failed. USB Serial mode only.");
  }
  
  Serial.println("[READY] Listening for commands (WiFi + USB Serial)");
  Serial.println("[USB]   Send '1' via Serial to open gate");
}

void openGate(int durationSeconds) {
  if (gateIsOpen) return;  // Prevent double-open
  
  gateIsOpen = true;
  Serial.println("🟢 GATE OPENING...");
  gateServo.write(90);
  
  // Blink LED while gate is open
  for (int i = 0; i < durationSeconds * 2; i++) {
    digitalWrite(LED_PIN, (i % 2 == 0) ? HIGH : LOW);
    delay(500);
    
    // Check for early close via serial
    if (Serial.available() > 0) {
      char cmd = Serial.read();
      if (cmd == '0') {
        Serial.println("⚡ Manual close command received");
        break;
      }
    }
  }
  
  Serial.println("🔴 GATE CLOSING...");
  gateServo.write(0);
  digitalWrite(LED_PIN, WiFi.status() == WL_CONNECTED ? HIGH : LOW);
  gateIsOpen = false;
}

HTTPClient http;
bool httpInitialized = false;

void pollBackend() {
  if (WiFi.status() != WL_CONNECTED) return;
  if (gateIsOpen) return;
  
  if (!httpInitialized) {
    http.setReuse(true);
    httpInitialized = true;
  }
  
  String url = String(BACKEND_URL) + "/gate/poll?location=" + GATE_LOCATION;
  
  http.begin(url);
  http.setTimeout(2000);
  int httpCode = http.GET();
  
  if (httpCode == 200) {
    String response = http.getString();
    
    // Parse JSON
    StaticJsonDocument<512> doc;
    DeserializationError error = deserializeJson(doc, response);
    
    if (!error) {
      const char* status = doc["status"];
      
      if (strcmp(status, "command") == 0) {
        const char* action = doc["command"]["action"];
        int duration = doc["command"]["duration_seconds"] | 10;
        const char* plate = doc["command"]["plate"] | "Unknown";
        
        Serial.print("📡 Cloud command: ");
        Serial.print(action);
        Serial.println("s");
        
        if (strcmp(action, "open") == 0) {
          openGate(duration);
        }
      }
    }
  } else if (httpCode < 0) {
    // If error (e.g. timeout), end and re-init next time
    http.end();
    httpInitialized = false;
  }
  // If 200 OK, we DO NOT call http.end() so the TLS socket stays alive!
}

void loop() {
  // ── Mode 1: USB Serial Commands ───────────────────────
  if (Serial.available() > 0) {
    char cmd = Serial.read();
    if (cmd == '1') {
      Serial.println("🔌 USB command received!");
      openGate(10);
    }
  }
  
  // ── Mode 2: WiFi Cloud Polling ────────────────────────
  unsigned long now = millis();
  if (now - lastPollTime >= POLL_INTERVAL_MS) {
    lastPollTime = now;
    pollBackend();
  }
  
  // Small delay to prevent busy-waiting
  delay(10);
}