#include <Arduino.h>
#include <WiFi.h>
#include <ArduinoJson.h>
#include <esp_ota_ops.h>
#include <esp_task_wdt.h>
#include <esp_system.h>
#include <Preferences.h>
#include "pin_config.h"
#include "config_manager.h"
#include "wifi_manager.h"
#include "gsm_manager.h"
#include "transport_manager.h"
#include "mqtt_client.h"
#include "acuvim_reader.h"
#include "sd_manager.h"
#include "web_server.h"
#include "ota_manager.h"
#include "heartbeat_manager.h"
#include "health_monitor.h"
#include "command_handler.h"

ConfigManager configMgr;
WifiManager wifiMgr;
HardwareSerial modemSerial(1);
GsmManager gsmMgr(modemSerial);
TransportManager transportMgr;
MqttClient mqttClient;
AcuvimReader acuvim;
SdManager sdMgr;
OtaManager otaMgr;
HeartbeatManager heartbeatMgr;
HealthMonitor healthMon;
CommandHandler cmdHandler;
WebPortal webPortal;
WiFiClient wifiNetClient;

unsigned long lastPollMs = 0;
bool sleepScheduled = false;

void checkCrashLoop() {
    esp_reset_reason_t reason = esp_reset_reason();
    bool wasCrash = (reason == ESP_RST_PANIC || reason == ESP_RST_INT_WDT ||
                     reason == ESP_RST_TASK_WDT || reason == ESP_RST_WDT);

    Preferences prefs;
    prefs.begin("acuvim_sys", false);
    if (wasCrash) {
        uint8_t crashes = prefs.getUChar("crash_count", 0) + 1;
        prefs.putUChar("crash_count", crashes);
        Serial.printf("[Main] Crash detected (count: %d)\n", crashes);
        if (crashes >= 5) {
            Serial.println("[Main] Crash loop detected, performing factory reset");
            prefs.putUChar("crash_count", 0);
            prefs.end();
            configMgr.reset();
            configMgr.save();
            ESP.restart();
        }
    } else {
        prefs.putUChar("crash_count", 0);
    }
    prefs.end();
}

void printAcuvimData(const AcuvimData& d) {
    Serial.println("========================================");
    Serial.println("        Acuvim II Readings");
    Serial.println("========================================");

    Serial.printf("  Va: %7.1f V   Vb: %7.1f V   Vc: %7.1f V\n", d.voltage_a, d.voltage_b, d.voltage_c);
    Serial.printf("  Ia: %7.2f A   Ib: %7.2f A   Ic: %7.2f A\n", d.current_a, d.current_b, d.current_c);
    Serial.printf("  P:  %7.3f kW  Q:  %7.3f kVAR  S: %7.3f kVA\n", d.active_power, d.reactive_power, d.apparent_power);
    Serial.printf("  PF: %7.3f     F:  %7.2f Hz\n", d.power_factor, d.frequency);
    Serial.printf("  Import: %.1f kWh   Export: %.1f kWh\n", d.import_active_energy, d.export_active_energy);
    Serial.printf("  Read: %lu ms  Success: %lu  Errors: %lu  Heap: %lu\n",
                  acuvim.getLastReadDurationMs(), acuvim.getSuccessCount(),
                  acuvim.getErrorCount(), (unsigned long)ESP.getFreeHeap());
    Serial.println("========================================\n");
}

void setup() {
    Serial.begin(115200);
    while (!Serial && millis() < 3000) {
        ;
    }

    Serial.println();
    Serial.println("========================================");
    Serial.println("  Tau Acuvim II Monitor");
    Serial.printf("  Firmware: %s\n", FW_VERSION);
    Serial.printf("  Build: %s %s\n", __DATE__, __TIME__);
    Serial.println("========================================");
    Serial.println();

    pinMode(LED_PIN, OUTPUT);
    digitalWrite(LED_PIN, LOW);

    // --- OTA self-test validation ---
    {
        const esp_partition_t* running = esp_ota_get_running_partition();
        esp_ota_img_states_t ota_state;
        if (esp_ota_get_state_partition(running, &ota_state) == ESP_OK) {
            if (ota_state == ESP_OTA_IMG_PENDING_VERIFY) {
                Serial.println("[OTA] New firmware pending validation - marking valid after successful boot");
                esp_ota_mark_app_valid_cancel_rollback();
            }
        }
    }

    // --- Crash loop detection ---
    checkCrashLoop();

    // --- Watchdog (30s timeout, panic on expiry) ---
    esp_task_wdt_init(30, true);
    esp_task_wdt_add(NULL);

    // --- Config ---
    configMgr.begin();
    DeviceConfig& cfg = configMgr.get();

    // --- Modbus ---
    acuvim.begin(cfg.modbus_slave_addr, cfg.modbus_baud_rate);

    // --- SD Card ---
    sdMgr.begin(cfg.device_id);
    sdMgr.setRetentionDays(cfg.sd_retention_days);

    // --- GSM ---
    gsmMgr.begin();

    // --- Transport ---
    transportMgr.begin(wifiMgr, gsmMgr, configMgr, &wifiNetClient);

    // --- Health Monitor ---
    healthMon.begin(configMgr, mqttClient, acuvim);

    // --- Command Handler ---
    cmdHandler.begin(configMgr, wifiMgr, gsmMgr, transportMgr,
                     mqttClient, acuvim, otaMgr, sdMgr, healthMon);

    // --- MQTT ---
    mqttClient.begin(transportMgr.getClient());
    mqttClient.setConfig(cfg);
    mqttClient.onCommand([](const String& topic, const String& payload) {
        cmdHandler.handleCommand(topic, payload);
    });

    // --- Transport change callback ---
    transportMgr.onTransportChange([](TransportType type) {
        if (type == TransportType::NONE) {
            Serial.println("[Main] No transport available");
            mqttClient.disconnect();
            return;
        }
        Serial.printf("[Main] Transport changed to %s, reconnecting MQTT...\n",
                      TransportManager::transportTypeName(type));
        mqttClient.disconnect();
        mqttClient.begin(transportMgr.getClient());
        mqttClient.setConfig(configMgr.get());
        mqttClient.connect();
        heartbeatMgr.sendNow();
    });

    // --- WiFi: start AP first (always available for configuration) ---
    wifiMgr.startAP(cfg.device_id);

    // --- WiFi: STA connection ---
    if (cfg.wifi_enabled && cfg.wifi_ssid[0] != '\0') {
        wifiMgr.onConnect([]() {
            Serial.println("[Main] WiFi connected");
            transportMgr.forceEvaluate();
        });
        wifiMgr.onDisconnect([]() {
            Serial.println("[Main] WiFi lost");
            transportMgr.forceEvaluate();
        });
        wifiMgr.begin(cfg.wifi_ssid, cfg.wifi_password);
    } else {
        Serial.println("[Main] WiFi STA disabled or not configured");
    }

    // --- GSM: connect if enabled and modem available ---
    if (gsmMgr.isModemAvailable() && cfg.gsm_enabled && cfg.gsm_apn[0] != '\0') {
        gsmMgr.connect(cfg.gsm_apn, cfg.gsm_user, cfg.gsm_pass);
        transportMgr.forceEvaluate();
    }

    // --- OTA Manager ---
    otaMgr.begin(configMgr, transportMgr, gsmMgr);

    // --- Heartbeat Manager ---
    heartbeatMgr.begin(configMgr, transportMgr, mqttClient, acuvim,
                       wifiMgr, gsmMgr, sdMgr, otaMgr);

    // --- Web Portal ---
    webPortal.begin(configMgr, wifiMgr, mqttClient, acuvim, gsmMgr, transportMgr, sdMgr, otaMgr);

    Serial.printf("[Main] Poll interval: %d s (GSM: %d s)\n",
                  cfg.poll_interval_sec, cfg.gsm_poll_interval_sec);
    Serial.println("[Main] Setup complete\n");
}

void loop() {
    esp_task_wdt_reset();

    wifiMgr.loop();
    transportMgr.loop();
    mqttClient.loop();
    sdMgr.loop();
    otaMgr.loop();
    heartbeatMgr.loop();
    webPortal.loop();

    // Device registration on first MQTT connect
    if (mqttClient.isConnected() && !cmdHandler.isRegistered()) {
        cmdHandler.sendRegistration();
    }

    if (mqttClient.isConnected() && sdMgr.hasQueuedData()) {
        sdMgr.drainBatch(mqttClient, 5);
    }

    DeviceConfig& cfg = configMgr.get();
    unsigned long intervalMs;
    if (transportMgr.getActiveTransport() == TransportType::GSM) {
        intervalMs = (unsigned long)cfg.gsm_poll_interval_sec * 1000;
    } else {
        intervalMs = (unsigned long)cfg.poll_interval_sec * 1000;
    }

    unsigned long now = millis();
    if (now - lastPollMs < intervalMs) {
        return;
    }
    lastPollMs = now;

    digitalWrite(LED_PIN, HIGH);

    AcuvimData data;
    if (acuvim.readAll(data)) {
        printAcuvimData(data);
        webPortal.setLatestData(data);
        cmdHandler.setLatestData(data);
        healthMon.evaluate(data);

        if (mqttClient.isConnected()) {
            const char* connType = TransportManager::transportTypeName(
                transportMgr.getActiveTransport());
            int signal = transportMgr.getSignalStrength();
            const char* opName = nullptr;
            String opStr;
            if (transportMgr.getActiveTransport() == TransportType::GSM) {
                opStr = gsmMgr.getOperator();
                opName = opStr.c_str();
            }
            mqttClient.publishTelemetry(data, connType, signal, opName);
        } else if (sdMgr.isAvailable()) {
            sdMgr.bufferTelemetry(data);
        }
    } else {
        Serial.printf("[Main] Read failed - error: 0x%02X, consecutive: %lu, total: %lu\n",
                      acuvim.getLastError(),
                      acuvim.getConsecutiveErrors(),
                      acuvim.getErrorCount());
        healthMon.evaluate(data);
    }

    digitalWrite(LED_PIN, LOW);

    // Deep sleep support
    if (cfg.sleep_duration_min > 0 && !sleepScheduled) {
        unsigned long wakeMs = (unsigned long)cfg.wake_duration_sec * 1000;
        if (millis() > wakeMs) {
            sleepScheduled = true;
            Serial.printf("[Main] Entering deep sleep for %d minutes\n", cfg.sleep_duration_min);
            heartbeatMgr.sendNow();
            delay(500);
            mqttClient.disconnect();
            wifiMgr.disconnect();
            gsmMgr.powerOff();
            esp_task_wdt_delete(NULL);
            uint64_t sleepMicros = (uint64_t)cfg.sleep_duration_min * 60 * 1000000;
            esp_sleep_enable_timer_wakeup(sleepMicros);
            esp_deep_sleep_start();
        }
    }
}