#include "heartbeat_manager.h"
#include <ArduinoJson.h>
#include <Preferences.h>
#include <esp_system.h>
#include <time.h>

static String getResetReasonString() {
    esp_reset_reason_t reason = esp_reset_reason();
    switch (reason) {
        case ESP_RST_POWERON:   return "POWER_ON";
        case ESP_RST_EXT:       return "EXTERNAL";
        case ESP_RST_SW:        return "SW_RESET";
        case ESP_RST_PANIC:     return "PANIC";
        case ESP_RST_INT_WDT:   return "INT_WDT";
        case ESP_RST_TASK_WDT:  return "TASK_WDT";
        case ESP_RST_WDT:       return "WDT";
        case ESP_RST_DEEPSLEEP: return "DEEP_SLEEP";
        case ESP_RST_BROWNOUT:  return "BROWNOUT";
        default:                return "UNKNOWN";
    }
}

static uint32_t getEpochTime() {
    time_t now;
    time(&now);
    return (now < 1700000000) ? millis() / 1000 : (uint32_t)now;
}

void HeartbeatManager::begin(ConfigManager& config, TransportManager& transport,
                              MqttClient& mqtt, AcuvimReader& acuvim,
                              WifiManager& wifi, GsmManager& gsm,
                              SdManager& sd, OtaManager& ota) {
    _config = &config;
    _transport = &transport;
    _mqtt = &mqtt;
    _acuvim = &acuvim;
    _wifi = &wifi;
    _gsm = &gsm;
    _sd = &sd;
    _ota = &ota;

    _lastHeartbeatMs = 0;
    _heartbeatCount = 0;
    _sentInitial = false;

    loadBootCount();

    Serial.printf("[HB] Boot count: %lu, last reset: %s\n",
                  _bootCount, getResetReasonString().c_str());
}

void HeartbeatManager::loadBootCount() {
    Preferences prefs;
    prefs.begin("acuvim_sys", false);
    _bootCount = prefs.getUInt("boot_count", 0) + 1;
    prefs.putUInt("boot_count", _bootCount);
    prefs.end();
}

void HeartbeatManager::loop() {
    if (!_mqtt->isConnected()) return;

    if (!_sentInitial) {
        _sentInitial = true;
        sendNow();
        return;
    }

    DeviceConfig& cfg = _config->get();
    unsigned long intervalMs = (unsigned long)cfg.heartbeat_interval_sec * 1000;
    if (millis() - _lastHeartbeatMs >= intervalMs) {
        sendNow();
    }
}

void HeartbeatManager::sendNow() {
    if (!_mqtt->isConnected()) return;

    String payload = buildPayload();

    DeviceConfig& cfg = _config->get();
    char topic[128];
    snprintf(topic, sizeof(topic), "%s/%s/heartbeat",
             cfg.mqtt_topic_prefix, cfg.device_id);

    if (_mqtt->publish(topic, payload.c_str())) {
        _heartbeatCount++;
        _lastHeartbeatMs = millis();
    } else {
        Serial.println("[HB] Publish failed");
    }
}

String HeartbeatManager::buildPayload() {
    JsonDocument doc;
    DeviceConfig& cfg = _config->get();

    doc["ts"] = getEpochTime();
    doc["dev"] = cfg.device_id;
    doc["fw"] = FW_VERSION;
    doc["up"] = millis() / 1000;
    doc["boot"] = _bootCount;
    doc["hb"] = _heartbeatCount + 1;

    // Connection info
    JsonObject conn = doc["conn"].to<JsonObject>();
    const char* transportName = TransportManager::transportTypeName(_transport->getActiveTransport());
    conn["type"] = transportName;

    JsonObject wifiObj = conn["wifi"].to<JsonObject>();
    wifiObj["ssid"] = _wifi->getSSID();
    wifiObj["rssi"] = _wifi->getRSSI();
    wifiObj["ip"] = _wifi->getIPAddress();

    JsonObject gsmObj = conn["gsm"].to<JsonObject>();
    gsmObj["enabled"] = cfg.gsm_enabled;
    gsmObj["connected"] = _gsm->isConnected();
    gsmObj["signal"] = _gsm->getSignalPercent();
    gsmObj["operator"] = _gsm->getOperator();

    conn["mqtt"] = _mqtt->isConnected();

    // Health
    JsonObject health = doc["health"].to<JsonObject>();
    health["heap_free"] = ESP.getFreeHeap();
    health["heap_min"] = ESP.getMinFreeHeap();
    health["psram_free"] = ESP.getFreePsram();
    health["reset_reason"] = getResetReasonString();
    health["uptime_sec"] = millis() / 1000;

    if (ESP.getMinFreeHeap() < 30000) {
        Serial.printf("[HB] WARNING: Low min free heap: %lu bytes\n",
                      (unsigned long)ESP.getMinFreeHeap());
    }

    // Modbus
    JsonObject modbus = doc["modbus"].to<JsonObject>();
    uint32_t total = _acuvim->getSuccessCount() + _acuvim->getErrorCount();
    modbus["connected"] = _acuvim->getConsecutiveErrors() == 0 && _acuvim->getSuccessCount() > 0;
    modbus["success"] = _acuvim->getSuccessCount();
    modbus["errors"] = _acuvim->getErrorCount();
    modbus["error_rate"] = (total > 0) ?
        serialized(String((float)_acuvim->getErrorCount() * 100.0f / total, 1)) :
        serialized("0.0");
    modbus["last_error"] = _acuvim->getLastError();
    modbus["last_read_ms"] = _acuvim->getLastReadDurationMs();

    // SD
    JsonObject sd = doc["sd"].to<JsonObject>();
    sd["available"] = _sd->isAvailable();
    sd["queued"] = _sd->getQueuedCount();
    if (_sd->isAvailable()) {
        sd["free_mb"] = (uint32_t)(_sd->getFreeSpace() / 1048576);
    }

    // OTA
    JsonObject ota = doc["ota"].to<JsonObject>();
    ota["version"] = FW_VERSION;
    ota["partition"] = _ota->getRunningPartition();
    ota["update_available"] = _ota->isUpdateAvailable();

    String output;
    serializeJson(doc, output);
    return output;
}