// ============================================================
// ESP32 Serial Logger
// Hardware: ESP-WROOM-32D DevKitC V4 + DS3231 RTC
//
// Arduino IDE Settings:
//   Board: "ESP32 Dev Module"
//   Upload Speed: 921600
//   CPU Frequency: 240MHz (WiFi/BT)
//   Flash Frequency: 80MHz
//   Flash Mode: QIO
//   Flash Size: 4MB (32Mb)
//   Partition Scheme: "Huge APP (3MB No OTA/1MB SPIFFS)"
//   PSRAM: Disabled
//
// Required Libraries:
//   1. WebSockets by Links2004
//   2. ArduinoJson v6.x
//   3. SoftWire by Steve Marple (+ AsyncDelay)
//   4. SD, SPI (built-in)
//
// Pin Assignments:
//   UART2 TX: GPIO17 | UART2 RX: GPIO16
//   SD MISO: GPIO19 | SD MOSI: GPIO23 | SD SCLK: GPIO18 | SD CS: GPIO5 (VSPI)
//   RTC SDA: GPIO25 | RTC SCL: GPIO26 (DS3231 @ 0x68, SoftWire)
//
// WiFi:
//   Boot → AP mode (always available)
//   Settings → STA mode enable (AP+STA dual mode)
// ============================================================

#include <Arduino.h>
#include <WiFi.h>
#include <esp_wifi.h>
#include <WebServer.h>
#include <WebSocketsServer.h>
#include <ArduinoJson.h>
#include <SPI.h>
#include <SD.h>
#include <SoftWire.h>
#include <freertos/FreeRTOS.h>
#include <freertos/task.h>
#include <freertos/queue.h>
#include <freertos/semphr.h>
#include <sys/time.h>
#include <time.h>

#include "config.h"
#include "serial_task.h"
#include "sdcard_task.h"
#include "web_task.h"
#include "rtc_task.h"

// --- WiFi STA state (controlled from web UI) ---
volatile bool staEnabled = false;
volatile bool staConnected = false;
char staSSID[64] = "";
char staPW[64] = "";

// ============================================================
// Enable STA mode (AP+STA dual) - called from web_task
// ============================================================
bool wifiEnableSTA(const char *ssid, const char *password) {
  if (!ssid || strlen(ssid) == 0) return false;

  strncpy(staSSID, ssid, sizeof(staSSID) - 1);
  strncpy(staPW, password, sizeof(staPW) - 1);

  Serial.printf("[WiFi] Enabling STA: SSID='%s'\n", staSSID);

  // Switch to AP+STA dual mode
  WiFi.mode(WIFI_AP_STA);
  WiFi.softAP(WIFI_AP_SSID, WIFI_AP_PASSWORD);
  WiFi.begin(staSSID, staPW);
  WiFi.setSleep(false);

  staEnabled = true;

  // Wait for connection (non-blocking, with timeout)
  unsigned long start = millis();
  while (WiFi.status() != WL_CONNECTED && millis() - start < 10000) {
    delay(500);
    Serial.print(".");
  }
  Serial.println();

  if (WiFi.status() == WL_CONNECTED) {
    staConnected = true;
    Serial.printf("[WiFi] STA connected! IP: %s (RSSI: %d)\n",
      WiFi.localIP().toString().c_str(), WiFi.RSSI());
    Serial.printf("[WiFi] AP still active: %s (%s)\n",
      WIFI_AP_SSID, WiFi.softAPIP().toString().c_str());

    // STA 연결 성공 → NTP 시도
    configTime(NTP_GMT_OFFSET, NTP_DAYLIGHT_OFFSET, NTP_SERVER);

    return true;
  } else {
    staConnected = false;
    Serial.println("[WiFi] STA connection failed (will keep retrying)");
    return false;
  }
}

// ============================================================
// Disable STA mode - return to AP only
// ============================================================
void wifiDisableSTA() {
  Serial.println("[WiFi] Disabling STA, AP-only mode");
  WiFi.disconnect(true);
  delay(100);
  WiFi.mode(WIFI_AP);
  WiFi.softAP(WIFI_AP_SSID, WIFI_AP_PASSWORD);

  staEnabled = false;
  staConnected = false;
  staSSID[0] = '\0';
  staPW[0] = '\0';

  Serial.printf("[WiFi] AP mode: %s (%s)\n",
    WIFI_AP_SSID, WiFi.softAPIP().toString().c_str());
}

// ============================================================
// NTP + STA Monitor Task
// Periodically checks STA status, retries connection, syncs NTP
// ============================================================
void ntpSyncTask(void *param) {
  Serial.println("[Task] NTP/WiFi monitor started");
  vTaskDelay(pdMS_TO_TICKS(3000));

  while (true) {
    // If STA is enabled, monitor connection
    if (staEnabled) {
      if (WiFi.status() == WL_CONNECTED) {
        if (!staConnected) {
          staConnected = true;
          Serial.printf("[WiFi] STA reconnected: %s\n",
            WiFi.localIP().toString().c_str());
        }

        // Try NTP sync
        struct tm timeinfo;
        configTime(NTP_GMT_OFFSET, NTP_DAYLIGHT_OFFSET, NTP_SERVER);
        if (getLocalTime(&timeinfo, 3000)) {
          rtcSyncFromSystem();
          static uint32_t ntpCount = 0;
          if (++ntpCount % 60 == 1) {  // Log every ~60 cycles
            Serial.printf("[NTP] Synced: %04d-%02d-%02d %02d:%02d:%02d\n",
              timeinfo.tm_year + 1900, timeinfo.tm_mon + 1, timeinfo.tm_mday,
              timeinfo.tm_hour, timeinfo.tm_min, timeinfo.tm_sec);
          }
        }
      } else {
        staConnected = false;
        // Auto-retry connection
        if (strlen(staSSID) > 0) {
          WiFi.begin(staSSID, staPW);
        }
      }
    }

    vTaskDelay(pdMS_TO_TICKS(60000));  // Check every 60s
  }
}

// ============================================================
// Setup
// ============================================================
void setup() {
  Serial.begin(115200);
  delay(1000);

  Serial.println("============================================");
  Serial.println("  ESP32 Serial Logger v2.1");
  Serial.println("  ESP-WROOM-32D DevKitC V4 + DS3231");
  Serial.println("============================================");
  Serial.printf("  Free Heap: %d bytes\n", ESP.getFreeHeap());
  Serial.printf("  CPU Freq: %d MHz\n", getCpuFrequencyMhz());
  Serial.println("============================================\n");

  // 1. DS3231 RTC
  Serial.println("--- Step 1: RTC ---");
  bool hasRTC = rtcInit();

  // 2. WiFi - Always start AP mode (immediate access)
  Serial.println("\n--- Step 2: WiFi (AP mode) ---");
  WiFi.mode(WIFI_AP);
  WiFi.softAP(WIFI_AP_SSID, WIFI_AP_PASSWORD);
  Serial.printf("[WiFi] AP SSID: %s\n", WIFI_AP_SSID);
  Serial.printf("[WiFi] AP IP: %s\n", WiFi.softAPIP().toString().c_str());
  Serial.println("[WiFi] STA: disabled (enable via Settings page)");

  // 3. Time status
  Serial.println("\n--- Step 3: Time ---");
  if (hasRTC && rtcStatus.timeSynced) {
    Serial.println("[Time] Using RTC time");
  } else {
    Serial.println("[Time] Waiting for browser sync");
  }

  // 4. SD Card
  Serial.println("\n--- Step 4: SD Card ---");
  sdTaskInit();

  // 5. Serial2 UART
  Serial.println("\n--- Step 5: Serial2 ---");
  serialTaskInit();

  // 6. Web Server + WebSocket
  Serial.println("\n--- Step 6: Web Server ---");
  webTaskInit();

  // 7. RTC periodic sync task
  rtcTaskInit();

  // 8. NTP + WiFi monitor task (always running)
  xTaskCreatePinnedToCore(ntpSyncTask, "NTP", TASK_STACK_NTP,
    NULL, TASK_PRIORITY_NTP, NULL, 0);

  // Status summary
  Serial.println("\n============================================");
  Serial.println("  All systems initialized!");
  Serial.printf("  Free Heap: %d bytes\n", ESP.getFreeHeap());
  Serial.printf("  AP URL: http://%s\n", WiFi.softAPIP().toString().c_str());
  Serial.println("============================================");
  Serial.println("  Core 1: SerialRX(5), SerialTX(4)");
  Serial.println("  Core 0: SDLog(3), WebBC(2), RTC(1), NTP(1)");
  Serial.println("  Loop  : server.handleClient()");
  Serial.printf("  RTC: %s | Time: %s\n",
    rtcStatus.available ? "OK" : "NO",
    rtcStatus.timeSynced ? "Valid" : "Pending");
  Serial.printf("  AutoStart: %s\n",
    sdAutoStart ? "ON (logging started)" : "OFF");
  Serial.println("============================================\n");
}

// ============================================================
// Loop
// ============================================================
void loop() {
  server.handleClient();
  vTaskDelay(pdMS_TO_TICKS(2));

  static unsigned long lastReport = 0;
  if (millis() - lastReport > 30000) {
    lastReport = millis();
    char timeBuf[24];
    getTimestamp(timeBuf, sizeof(timeBuf));
    Serial.printf("[SYS] %s | Heap:%d | SD:%s | WS:%d | RTC:%s | STA:%s | Auto:%s\n",
      timeBuf,
      ESP.getFreeHeap(),
      sdCardPresent() ? "OK" : "FAIL",
      webSocket.connectedClients(),
      rtcStatus.available ? "OK" : "NO",
      staConnected ? "ON" : "OFF",
      sdAutoStart ? "ON" : "OFF");
  }
}