#include <WiFi.h>
#include <PubSubClient.h>
#include <DHT.h>
#include <ArduinoJson.h>
#include <Wire.h>             
#include <LiquidCrystal_I2C.h> 

// --- 硬體定義 ---
#define DHTPIN 2
#define DHTTYPE DHT22
#define LED1_PIN 4
#define LED2_PIN 5
#define LED3_PIN 6
#define LED4_PIN 7
#define I2C_SDA 8    
#define I2C_SCL 9    

DHT dht(DHTPIN, DHTTYPE);
WiFiClient espClient;
PubSubClient client(espClient);
LiquidCrystal_I2C lcd(0x27, 16, 2);

// --- LED 陣列與狀態管理 ---
const int ledPins[4] = {LED1_PIN, LED2_PIN, LED3_PIN, LED4_PIN};

enum Mode { IDLE, FLASHING, TIMER_COUNTDOWN };
Mode ledModes[4] = {IDLE, IDLE, IDLE, IDLE};           
unsigned long targetTimes[4] = {0, 0, 0, 0};           
unsigned long lastFlashTimes[4] = {0, 0, 0, 0};        
const int flashInterval = 300;                         

// 動作定義
enum LedAction { ACT_UNKNOWN, ACT_ON, ACT_OFF, ACT_FLASH, ACT_TIMER };

unsigned long lastMsgTime = 0;

// --- MQTT 設定 ---
const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "mqttgo.io"; 

const char* topics[] = {
  "wokwi/led/control",     // LED 訂閱 (接收控制)
  "wokwi/dht/temperature", // 溫度發布
  "wokwi/dht/humidity"     // 濕度發布
};

// --- 輔助函式：將字串動作轉為 Enum ---
LedAction getActionType(String actionStr) {
  actionStr.toLowerCase();
  if (actionStr == "on" || actionStr == "1")    return ACT_ON;
  if (actionStr == "off" || actionStr == "0")   return ACT_OFF;
  if (actionStr == "flash" || actionStr == "2") return ACT_FLASH;
  if (actionStr == "timer" || actionStr == "3") return ACT_TIMER;
  return ACT_UNKNOWN;
}

// --- 核心邏輯：套用動作到 LED ---
void applyActionToLED(int index, LedAction action, int timerValue) {
  if (index < 0 || index >= 4) return;

  switch (action) {
    case ACT_ON:
      ledModes[index] = IDLE;
      digitalWrite(ledPins[index], HIGH);
      break;
    case ACT_OFF:
      ledModes[index] = IDLE;
      digitalWrite(ledPins[index], LOW);
      break;
    case ACT_FLASH:
      ledModes[index] = FLASHING;
      break;
    case ACT_TIMER:
      digitalWrite(ledPins[index], HIGH);
      targetTimes[index] = millis() + (timerValue * 1000);
      ledModes[index] = TIMER_COUNTDOWN;
      break;
    default:
      break;
  }
}

// 🌟 共用的純字串指令處理器
void handleDirectCommand(String cmd) {
  cmd.toLowerCase();
  LedAction finalAction = ACT_UNKNOWN;
  int targetLed = 0; // 0=全部, 1-4=個別
  int timerVal = 5;  // 預設倒數 5 秒

  if (cmd.startsWith("all")) {
    targetLed = 0;
    finalAction = getActionType(cmd.substring(3));
  } else {
    int splitIndex = 0;
    while (splitIndex < cmd.length() && isDigit(cmd[splitIndex])) {
      splitIndex++;
    }
    if (splitIndex > 0) {
      targetLed = cmd.substring(0, splitIndex).toInt();
      finalAction = getActionType(cmd.substring(splitIndex));
    }
  }

  // 執行動作
  if (finalAction == ACT_UNKNOWN) {
    Serial.println("   ❌ 錯誤: 無法辨識的動作字串");
    return;
  }

  if (targetLed == 0) {
    for (int i = 0; i < 4; i++) applyActionToLED(i, finalAction, timerVal);
    Serial.println("   ➡️ 狀態已更新: 全部 LED");
  } else if (targetLed >= 1 && targetLed <= 4) {
    applyActionToLED(targetLed - 1, finalAction, timerVal);
    Serial.printf("   ➡️ 狀態已更新: LED %d\n", targetLed);
  } else {
    Serial.printf("   ❌ 錯誤: 無效的 LED 編號 %d\n", targetLed);
  }
}

// --- MQTT 訊息回呼 ---
void callback(char* topic, byte* payload, unsigned int length) {
  String rawMsg = "";
  for (int i = 0; i < length; i++) rawMsg += (char)payload[i];
  rawMsg.trim();

  Serial.printf("\n📩 [MQTT 收到指令]: %s\n", rawMsg.c_str());

  StaticJsonDocument<200> doc;
  DeserializationError error = deserializeJson(doc, payload, length);

  if (!error) {
    Serial.println("   📦 解析格式: JSON");
    LedAction finalAction = getActionType(doc["action"] | "");
    int targetLed = doc["led"] | 0;
    int timerVal = doc["value"] | 5;
    
    // 如果是 JSON 格式，直接在這裡套用動作
    if (finalAction != ACT_UNKNOWN) {
      if (targetLed == 0) {
        for (int i = 0; i < 4; i++) applyActionToLED(i, finalAction, timerVal);
        Serial.println("   ➡️ 狀態已更新: 全部 LED");
      } else if (targetLed >= 1 && targetLed <= 4) {
        applyActionToLED(targetLed - 1, finalAction, timerVal);
        Serial.printf("   ➡️ 狀態已更新: LED %d\n", targetLed);
      } else {
        Serial.printf("   ❌ 錯誤: 無效的 LED 編號 %d\n", targetLed);
      }
    } else {
      Serial.println("   ❌ 錯誤: 無法辨識的動作字串");
    }
  } else {
    Serial.println("   📝 解析格式: 純字串");
    handleDirectCommand(rawMsg);
  }
}

void setup() {
  Serial.begin(115200);
  
  for (int i = 0; i < 4; i++) {
    pinMode(ledPins[i], OUTPUT);
    digitalWrite(ledPins[i], LOW); // 依據繼電器觸發方式調整 HIGH/LOW
  }

  dht.begin();
  
  Wire.begin(I2C_SDA, I2C_SCL);    
  lcd.init();                       
  lcd.backlight();              
  lcd.setCursor(0, 0);           
  lcd.print("MQTT Connect...");    
  lcd.setCursor(0, 1); 
  lcd.print("NCUT-DB212211");   

  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}

void setup_wifi() {
  delay(10);
  Serial.print("📡 Wi-Fi 連線中: "); Serial.println(ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\n✅ Wi-Fi 已連線");

  configTime(8 * 3600, 0, "pool.ntp.org", "time.nist.gov");
  struct tm timeinfo;
  while (!getLocalTime(&timeinfo)) { delay(500); }
  Serial.println("✅ NTP 時間已同步");
}

void reconnect() {
  while (!client.connected()) {
    String clientId = "ESP32_NCUT_" + String(random(0xffff), HEX);
    if (client.connect(clientId.c_str())) {
      client.subscribe(topics[0]);
      Serial.println("✅ MQTT 已連線");
    } else {
      Serial.print("❌ MQTT 失敗, rc="); Serial.print(client.state());
      delay(5000);
    }
  }
}

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

  unsigned long now = millis();

  // 監聽 Serial 鍵盤輸入指令
  if (Serial.available() > 0) {
    String serialCmd = Serial.readStringUntil('\n'); 
    serialCmd.trim();                                
    
    if (serialCmd.length() > 0) {
      Serial.printf("\n⌨️ [Serial 手動輸入]: %s\n", serialCmd.c_str());
      handleDirectCommand(serialCmd);                
    }
  }

// 1. 每 1 秒執行一次的區塊 (更新 DHT、LCD、以及印出倒數計時)
  if (now - lastMsgTime > 1000) {
    lastMsgTime = now;

    // 印出 LED 倒數計時
    for (int i = 0; i < 4; i++) {
      if (ledModes[i] == TIMER_COUNTDOWN && targetTimes[i] > now) {
        int remainSec = (targetTimes[i] - now) / 1000 + 1; 
        Serial.printf("⏳ LED %d 倒數中: %d 秒\n", i + 1, remainSec);
      }
    }

    struct tm timeinfo;
    if (getLocalTime(&timeinfo)) {
      char dateStr[11], timeStr[9];  
      strftime(dateStr, sizeof(dateStr), "%y/%m/%d", &timeinfo); 
      strftime(timeStr, sizeof(timeStr), "%H:%M:%S", &timeinfo);

      // 讀取溫濕度
      float h = dht.readHumidity();
      float t = dht.readTemperature();

      // 如果讀取成功 (不是 NaN)
      if (!isnan(h) && !isnan(t)) {
        
        static float last_t = -999.0;
        static float last_h = -999.0;
        static unsigned long last_publish_time = 0; // 記錄上次發送 MQTT 的時間

        bool valueChanged = (t != last_t || h != last_h);
        
        // 觸發發送的條件：1. 數值改變了 或 2. 距離上次發送超過 10 秒 (心跳機制)
        if (valueChanged || (now - last_publish_time > 10000)) {
          
          if (valueChanged) {
            Serial.printf("[%s]*檢測到環境變動* 溫度: %.1f °C | 濕度: %.1f %%\n", timeStr, t, h);
            last_t = t;
            last_h = h;
          } else {
            // 這是強制發送的狀態，你可以選擇要不要印出來
            // Serial.println("💓 [MQTT 心跳] 發送當前環境數值"); 
          }

          // 🌟 將發送動作移到這裡，只有符合條件時才發送 MQTT
          client.publish(topics[1], String(t, 1).c_str());
          client.publish(topics[2], String(h, 1).c_str());
          
          last_publish_time = now; // 更新最後發送時間
        }

        // 更新 LCD 畫面 (不管數值有沒有變，LCD 都會維持每秒刷新時間)
        lcd.setCursor(0, 0); lcd.print(dateStr); lcd.print(" T:");
        lcd.print(t, 1); lcd.write((uint8_t)223); 
        
        lcd.setCursor(0, 1); lcd.print(timeStr); lcd.print(" H:");
        lcd.print(h, 1); lcd.print("% ");

      } else {
        Serial.println("⚠️ 無法從 DHT 感測器讀取資料！");
      }
    }
  }

  // 2. LED 非阻塞狀態機
  for (int i = 0; i < 4; i++) {
    switch (ledModes[i]) {
      case FLASHING:
        if (now - lastFlashTimes[i] >= flashInterval) {
          lastFlashTimes[i] = now;
          digitalWrite(ledPins[i], !digitalRead(ledPins[i])); 
        }
        break;
        
      case TIMER_COUNTDOWN:
        if (now >= targetTimes[i]) {
          digitalWrite(ledPins[i], LOW); // 時間到關燈 (視繼電器高低電位調整)
          ledModes[i] = IDLE;
          Serial.printf("✅ LED %d 計時結束，已自動關閉\n", i + 1);
        }
        break;
        
      case IDLE:
        // 無動作
        break;
    }
  }
}