#include <WiFi.h>
#include <PubSubClient.h>
#include <esp_system.h>

// ========================
// WiFi配置
// ========================

const char* ssid = "Wokwi-GUEST";
const char* password = "";

// ========================
// MQTT配置
// ========================

const char* mqtt_server = "broker.hivemq.com";
const int mqtt_port = 1883;

const char* mqtt_topic =
  "scuec/ue-demo/7f3a9c/sensor";

// ========================
// MQTT客户端
// ========================

WiFiClient espClient;
PubSubClient client(espClient);

unsigned long lastSend = 0;


// ========================
// 生成一位小数随机数
// ========================

float randomFloat(float minValue, float maxValue)
{
  int minInt = (int)(minValue * 10);
  int maxInt = (int)(maxValue * 10);

  return random(minInt, maxInt + 1) / 10.0f;
}


// ========================
// 温度三档随机
//
// SAFE:
// 20.0 ~ 30.0
//
// WARNING:
// 30.1 ~ 40.0
//
// ERROR:
// 40.1 ~ 50.0
// ========================

float generateTemperature()
{
  // 0 = SAFE
  // 1 = WARNING
  // 2 = ERROR
  int level = random(0, 3);

  switch (level)
  {
    case 0:
      return randomFloat(20.0f, 30.0f);

    case 1:
      return randomFloat(30.1f, 40.0f);

    case 2:
      return randomFloat(40.1f, 50.0f);
  }

  return 25.0f;
}


// ========================
// 湿度三档随机
//
// SAFE:
// 40.0 ~ 60.0
//
// WARNING:
// 30.0 ~ 39.9
// 或
// 60.1 ~ 70.0
//
// ERROR:
// 20.0 ~ 29.9
// 或
// 70.1 ~ 90.0
// ========================

float generateHumidity()
{
  // 0 = SAFE
  // 1 = WARNING
  // 2 = ERROR
  int level = random(0, 3);

  switch (level)
  {
    case 0:
    {
      return randomFloat(40.0f, 60.0f);
    }

    case 1:
    {
      // 随机选择偏低或偏高
      if (random(0, 2) == 0)
      {
        return randomFloat(30.0f, 39.9f);
      }
      else
      {
        return randomFloat(60.1f, 70.0f);
      }
    }

    case 2:
    {
      // 随机选择严重偏低或严重偏高
      if (random(0, 2) == 0)
      {
        return randomFloat(20.0f, 29.9f);
      }
      else
      {
        return randomFloat(70.1f, 90.0f);
      }
    }
  }

  return 50.0f;
}


// ========================
// 连接WiFi
// ========================

void setup_wifi()
{
  Serial.print("Connecting WiFi");

  WiFi.begin(
    ssid,
    password,
    6
  );

  while (WiFi.status() != WL_CONNECTED)
  {
    delay(500);
    Serial.print(".");
  }

  Serial.println();
  Serial.println("WiFi connected");
}


// ========================
// 连接MQTT
// ========================

void reconnect()
{
  while (!client.connected())
  {
    Serial.print("Connecting MQTT...");

    // 创建随机客户端ID
    // 防止多人连接公共Broker时互相顶掉
    String clientId =
      "ESP32-UE-Demo-";

    clientId +=
      String(random(0xffff), HEX);

    if (client.connect(clientId.c_str()))
    {
      Serial.println("connected");
    }
    else
    {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(
        ", retry in 2 seconds"
      );

      delay(2000);
    }
  }
}


// ========================
// 初始化
// ========================

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

  // 初始化随机种子
  randomSeed(esp_random());

  setup_wifi();

  client.setServer(
    mqtt_server,
    mqtt_port
  );
}


// ========================
// 主循环
// ========================

void loop()
{
  // MQTT断开后自动重连
  if (!client.connected())
  {
    reconnect();
  }

  client.loop();

  // 每1秒发送一次数据
  if (millis() - lastSend >= 1000)
  {
    lastSend = millis();

    // 生成随机温度
    float temperature =
      generateTemperature();

    // 生成随机湿度
    float humidity =
      generateHumidity();

    // ========================
    // 构造JSON
    // ========================

    String data = "{";

    data += "\"temperature\":";
    data += String(
      temperature,
      1
    );

    data += ",";

    data += "\"humidity\":";
    data += String(
      humidity,
      1
    );

    data += "}";

    // ========================
    // 发布MQTT消息
    // ========================

    bool success =
      client.publish(
        mqtt_topic,
        data.c_str()
      );

    if (success)
    {
      Serial.print("Publish: ");
      Serial.println(data);
    }
    else
    {
      Serial.println(
        "Publish failed"
      );
    }
  }
}