#include <WiFi.h>
#include <PubSubClient.h>
#include <ArduinoJson.h> // 用于JSON操作

// ----------- 设备配置 (需要为您自己的设备和环境修改) -----------
// WiFi
const char *ssid = "xxxxx"; // 请输入您的 Wi-Fi 名称
const char *password = "xxxxx";  // 请输入您的 Wi-Fi 密码

// MQTT Broker
const char *mqtt_broker = "broker.emqx.io"; // 您的 MQTT Broker 地址
const char *mqtt_username = "emqx";         // 您的 MQTT 用户名 (如果需要)
const char *mqtt_password = "public";     // 您的 MQTT 密码 (如果需要)
const int mqtt_port = 1883;                 // 您的 MQTT 端口

// 设备唯一标识符 (非常重要, 必须与后端注册的一致)
const char *spotUid = "ESP32_SPOT_001"; // 例如: "SPOT001", "P005-A1" 等

// ----------- MQTT 主题定义 -----------
// 上行 (ESP32 -> 后端)
String topic_status_update; // 状态上报: charging/spot/{spotUid}/status
String topic_command_ack;   // 指令回执: charging/spot/{spotUid}/command/ack
String topic_heartbeat;     // 心跳:   charging/spot/{spotUid}/heartbeat

// 下行 (后端 -> ESP32, ESP32需要订阅这些)
String topic_command_start; // 启动充电: charging/spot/{spotUid}/command/start
String topic_command_stop;  // 停止充电: charging/spot/{spotUid}/command/stop
// String topic_command_query_status; // 查询状态 (可选): charging/spot/{spotUid}/command/query_status

// ----------- 全局变量 -----------
WiFiClient espClient;
PubSubClient client(espClient);

// 模拟硬件状态 (实际项目中需要从传感器或硬件逻辑获取)
const char* currentDeviceStatus = "IDLE"; // 设备当前状态: IDLE, CHARGING, FAULTED 等
float currentVoltage = 220.0;
float currentCurrent = 0.0;
float currentPower = 0.0;
float currentEnergyConsumed = 0.0;
int currentErrorCode = 0;
String currentSessionId = ""; // 当前充电会话ID

// 定时发送相关
unsigned long lastStatusUpdateTime = 0;
unsigned long lastHeartbeatTime = 0;
const long statusUpdateInterval = 30000; // 状态上报间隔 (例如: 30秒)
const long heartbeatInterval = 60000;    // 心跳间隔 (例如: 60秒)

void setup_mqtt_topics() {
    String baseTopic = "charging/spot/" + String(spotUid) + "/";
    topic_status_update = baseTopic + "status";
    topic_command_ack = baseTopic + "command/ack";
    topic_heartbeat = baseTopic + "heartbeat";

    topic_command_start = baseTopic + "command/start";
    topic_command_stop = baseTopic + "command/stop";
    // topic_command_query_status = baseTopic + "command/query_status";
    Serial.println("MQTT 主题初始化完成:");
    Serial.println("  状态上报: " + topic_status_update);
    Serial.println("  指令回执: " + topic_command_ack);
    Serial.println("  心跳:     " + topic_heartbeat);
    Serial.println("  订阅启动指令: " + topic_command_start);
    Serial.println("  订阅停止指令: " + topic_command_stop);
}

void connect_wifi() {
    Serial.println("正在连接 Wi-Fi...");
    WiFi.begin(ssid, password);
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }
    Serial.println("\nWi-Fi 连接成功!");
    Serial.print("IP 地址: ");
    Serial.println(WiFi.localIP());
}

void reconnect_mqtt() {
    while (!client.connected()) {
        Serial.print("尝试连接 MQTT Broker: ");
        Serial.println(mqtt_broker);
        String client_id = "esp32-client-" + String(spotUid) + "-";
        client_id += String(WiFi.macAddress());
        Serial.printf("客户端 ID: %s \n", client_id.c_str());

        if (client.connect(client_id.c_str(), mqtt_username, mqtt_password)) {
            Serial.println("MQTT Broker 连接成功!");
            // 重新订阅主题
            client.subscribe(topic_command_start.c_str());
            Serial.println("已订阅: " + topic_command_start);
            client.subscribe(topic_command_stop.c_str());
            Serial.println("已订阅: " + topic_command_stop);
            // if (topic_command_query_status.length() > 0) client.subscribe(topic_command_query_status.c_str());

            // (可选) 连接成功后立即发送一次状态
            publish_status_update(); 
        } else {
            Serial.print("连接失败, rc=");
            Serial.print(client.state());
            Serial.println(" 2秒后重试...");
            delay(2000);
        }
    }
}

void callback(char *topic, byte *payload, unsigned int length) {
    Serial.println("-----------------------");
    Serial.print("消息抵达, 主题: ");
    Serial.println(topic);

    char message[length + 1];
    memcpy(message, payload, length);
    message[length] = \'\\0\'; // 添加字符串结束符
    Serial.print("消息内容: ");
    Serial.println(message);

    StaticJsonDocument<256> doc; // 适当调整JSON文档大小
    DeserializationError error = deserializeJson(doc, message);

    if (error) {
        Serial.print("JSON 解析失败: ");
        Serial.println(error.f_str());
        return;
    }

    const char* commandId = doc["commandId"]; // 提取 commandId 用于回执

    // 根据主题处理指令
    if (String(topic) == topic_command_start) {
        Serial.println("接收到 [启动充电] 指令");
        // 实际硬件操作: 启动充电
        // 例如: digitalWrite(RELAY_PIN, HIGH);
        currentDeviceStatus = "CHARGING";
        if (doc.containsKey("sessionId")) {
             currentSessionId = String(doc["sessionId"].as<const char*>());
        }
        Serial.println("模拟: 充电已启动。会话ID: " + currentSessionId);
        publish_command_ack(commandId, true, "Charging started successfully");
        publish_status_update(); // 立即更新状态

    } else if (String(topic) == topic_command_stop) {
        Serial.println("接收到 [停止充电] 指令");
        // 实际硬件操作: 停止充电
        // 例如: digitalWrite(RELAY_PIN, LOW);
        currentDeviceStatus = "COMPLETED"; // 或者 "IDLE"，取决于逻辑
        Serial.println("模拟: 充电已停止。");
        publish_command_ack(commandId, true, "Charging stopped successfully");
        currentSessionId = ""; // 清除会话ID
        publish_status_update(); // 立即更新状态
    }
    // else if (String(topic) == topic_command_query_status) {
    //     Serial.println("接收到 [查询状态] 指令");
    //     publish_status_update(); // 回复当前状态
    //     publish_command_ack(commandId, true, "Status reported");
    // }
     else {
        Serial.println("未知指令主题");
    }
    Serial.println("-----------------------");
}

void publish_message(const String& topic, const JsonDocument& doc, const char* message_type) {
    String jsonBuffer;
    serializeJson(doc, jsonBuffer);
    Serial.print("发送 ");
    Serial.print(message_type);
    Serial.print(" 到主题 [");
    Serial.print(topic);
    Serial.print("]: ");
    Serial.println(jsonBuffer);

    if (client.publish(topic.c_str(), jsonBuffer.c_str())) {
        Serial.println(String(message_type) + " 发送成功");
    } else {
        Serial.println(String(message_type) + " 发送失败");
    }
}

void publish_status_update() {
    StaticJsonDocument<512> doc; // 适当调整JSON文档大小
    doc["spotUid"] = spotUid;
    doc["timestamp"] = String(WiFi.getTime()); // 需要NTP同步时间才能获取正确UTC时间，此处仅为示例
    doc["status"] = currentDeviceStatus;
    doc["voltage"] = currentVoltage;
    doc["current"] = currentCurrent;
    doc["power"] = currentPower;
    doc["energyConsumed"] = currentEnergyConsumed;
    doc["errorCode"] = currentErrorCode;
    if (currentSessionId.length() > 0) {
        doc["sessionId"] = currentSessionId;
    } else {
        doc["sessionId"] = nullptr; // 或者不包含此字段
    }
    
    publish_message(topic_status_update, doc, "状态更新");
    lastStatusUpdateTime = millis();
}

void publish_heartbeat() {
    StaticJsonDocument<256> doc; // 适当调整JSON文档大小
    doc["spotUid"] = spotUid;
    doc["timestamp"] = String(WiFi.getTime()); // 同上，NTP时间问题
    doc["status"] = currentDeviceStatus; // 心跳中也带上当前状态

    publish_message(topic_heartbeat, doc, "心跳");
    lastHeartbeatTime = millis();
}

void publish_command_ack(const char* commandId, bool success, const char* message) {
    if (!commandId || strlen(commandId) == 0) {
        Serial.println("无法发送ACK: commandId 为空");
        return;
    }
    StaticJsonDocument<256> doc; // 适当调整JSON文档大小
    doc["commandId"] = commandId;
    doc["spotUid"] = spotUid;
    doc["status"] = success ? "SUCCESS" : "FAILURE";
    doc["message"] = message;

    publish_message(topic_command_ack, doc, "指令回执");
}

void setup() {
    Serial.begin(115200);
    Serial.println("\nESP32 充电桩模拟客户端启动...");

    setup_mqtt_topics(); // 初始化MQTT主题
    connect_wifi();      // 连接Wi-Fi

    client.setServer(mqtt_broker, mqtt_port);
    client.setCallback(callback); // 设置消息回调函数
}

void loop() {
    if (!client.connected()) {
        reconnect_mqtt(); // 如果MQTT未连接，则重连
    }
    client.loop(); // 维持MQTT连接和处理消息

    unsigned long currentTime = millis();

    // 定时发送状态更新
    if (currentTime - lastStatusUpdateTime > statusUpdateInterval) {
        // 在实际项目中，这里应该先更新 currentVoltage, currentCurrent 等状态值
        // 例如: currentVoltage = readVoltageSensor();
        publish_status_update();
    }

    // 定时发送心跳
    if (currentTime - lastHeartbeatTime > heartbeatInterval) {
        publish_heartbeat();
    }

    // 模拟充电过程中的电量和功率变化 (仅为演示)
    if (String(currentDeviceStatus) == "CHARGING") {
        currentEnergyConsumed += 0.01; // 假设每秒消耗0.01kWh (不精确，仅为演示)
        currentCurrent = 5.0; // 假设充电电流5A
        currentPower = (currentVoltage * currentCurrent) / 1000.0; // kW
        // 注意：实际项目中这些值应来自传感器或充电控制器
        // 这里为了演示，每隔一段时间简单更新一下
    } else {
        currentCurrent = 0.0;
        currentPower = 0.0;
    }
     delay(100); // 短暂延时，避免loop过于频繁，给其他任务一点时间 (可选)
}