// STD Lib
#include <stdio.h>
#include <string.h>

// SDK
#include "esp_log.h"
#include "esp_ota_ops.h"
#include "esp_psram.h"
#include "esp_system.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "nvs.h"
#include "nvs_flash.h"
#include "sdkconfig.h"
#include "soc/gpio_num.h"

// Project headers
#include "appstate.hpp"
#include "types.hpp"

// Project cpp (Unity Build entry)
// clang-format off
#include "led_status.cpp"
#include "connect.cpp"
#include "http_server.cpp"
#include "mdns_service.cpp"
// clang-format on

// Global Application State Definitions
bool g_Ethernet_Initialized = false;
bool g_Wifi_Initialized = false;
uint8_t g_Active_WWW_Partition = 0;

constexpr bool kBlockUntilEthernetEstablished = false;

extern "C" void app_main()
{
  printf("Hello, Calendink OTA! [V1.1]\n");

  printf("PSRAM size: %d bytes\n", esp_psram_get_size());

  httpd_handle_t web_server = NULL;

  esp_err_t err = nvs_flash_init();
  if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND)
  {
    ESP_ERROR_CHECK(nvs_flash_erase());
    err = nvs_flash_init();
  }
  ESP_ERROR_CHECK(err);

  nvs_handle_t my_handle;
  if (nvs_open("storage", NVS_READWRITE, &my_handle) == ESP_OK)
  {
    // Read active www partition from NVS
    err = nvs_get_u8(my_handle, "www_part", &g_Active_WWW_Partition);
    if (err == ESP_OK)
    {
      printf("NVS: Found active www partition: %d\n", g_Active_WWW_Partition);
    }

    if (err == ESP_ERR_NVS_NOT_FOUND)
    {
      // First boot (no NVS key yet): default to www_0
      // This ensures that after a fresh USB flash (which only writes www_0),
      // we start from the correct partition.
      printf("No www_part in NVS, defaulting to 0.\n");
      g_Active_WWW_Partition = 0;
      nvs_set_u8(my_handle, "www_part", 0);
      nvs_commit(my_handle);
    }
    else if (err != ESP_OK)
    {
      printf("Error reading www_part from NVS: %s\n", esp_err_to_name(err));
      g_Active_WWW_Partition = 0;
    }

    if (g_Active_WWW_Partition > 1)
    {
      g_Active_WWW_Partition = 0;
    }
    nvs_close(my_handle);
  }
  else
  {
    printf("Error opening NVS handle!\n");
  }

  // Detect if this is the first boot after a new flash (Firmware or Frontend)
  bool is_new_flash = false;
  if (nvs_open("storage", NVS_READWRITE, &my_handle) == ESP_OK)
  {
    // 1. Check Firmware Compile Time
    char last_time[64] = {0};
    size_t time_size = sizeof(last_time);
    const char *current_time = __DATE__ " " __TIME__;
    if (nvs_get_str(my_handle, "last_fw_time", last_time, &time_size) !=
            ESP_OK ||
        strcmp(last_time, current_time) != 0)
    {
      printf("New firmware detected! (Last: %s, Current: %s)\n",
             last_time[0] ? last_time : "None", current_time);
      is_new_flash = true;
      nvs_set_str(my_handle, "last_fw_time", current_time);
    }

    // 2. Check Frontend Partition Fingerprint (www_0)
    const esp_partition_t *www0_p = esp_partition_find_first(
        ESP_PARTITION_TYPE_DATA, ESP_PARTITION_SUBTYPE_DATA_LITTLEFS, "www_0");
    if (www0_p)
    {
      uint8_t current_sha[32];
      if (esp_partition_get_sha256(www0_p, current_sha) == ESP_OK)
      {
        uint8_t last_sha[32] = {0};
        size_t sha_size = sizeof(last_sha);
        if (nvs_get_blob(my_handle, "www0_sha", last_sha, &sha_size) !=
                ESP_OK ||
            memcmp(last_sha, current_sha, 32) != 0)
        {
          printf("New frontend partition detected via SHA256!\n");
          is_new_flash = true;
          nvs_set_blob(my_handle, "www0_sha", current_sha, 32);
        }
      }
    }

    if (is_new_flash)
    {
      nvs_commit(my_handle);
    }
    nvs_close(my_handle);
  }

  // If we are running from FACTORY and a new flash was detected, override to
  // www_0
  {
    const esp_partition_t *running = esp_ota_get_running_partition();
    if (running != NULL &&
        running->subtype == ESP_PARTITION_SUBTYPE_APP_FACTORY)
    {
      if (is_new_flash && g_Active_WWW_Partition != 0)
      {
        printf("FACTORY APP + NEW FLASH: Overriding www_part to 0 (was %d)\n",
               g_Active_WWW_Partition);
        g_Active_WWW_Partition = 0;

        // Persist the override
        if (nvs_open("storage", NVS_READWRITE, &my_handle) == ESP_OK)
        {
          nvs_set_u8(my_handle, "www_part", 0);
          nvs_commit(my_handle);
          nvs_close(my_handle);
        }
      }
    }
  }

  ESP_ERROR_CHECK(esp_event_loop_create_default());

  setup_led();

  set_led_status(led_status::ConnectingEthernet);
  g_Ethernet_Initialized = true;
  esp_err_t result = connect_ethernet(kBlockUntilEthernetEstablished);
  if (result != ESP_OK)
  {
    set_led_status(led_status::Failed);
    vTaskDelay(pdMS_TO_TICKS(1000));
    goto shutdown;
  }

  // Check for ethernet connection until its made
  if (!kBlockUntilEthernetEstablished)
  {
    uint8 retries = 1;
    do
    {
      set_led_status(led_status::ConnectingEthernet);
      result = check_ethernet_connection(retries);

      if (result == ESP_ERR_INVALID_STATE)
      {
        printf("Ethernet cable not plugged in, skipping retries.\n");
        break;
      }

      if (result != ESP_OK)
      {
        set_led_status(led_status::Failed);
        vTaskDelay(pdMS_TO_TICKS(1000));
      }

      retries++;
    } while (result == ESP_ERR_TIMEOUT &&
             retries <= CONFIG_CALENDINK_ETH_RETRIES);
  }

  if (result != ESP_OK)
  {
    printf("Ethernet failed, trying wifi\n");
    disconnect_ethernet();
    g_Ethernet_Initialized = false;

    set_led_status(led_status::ConnectingWifi);
    g_Wifi_Initialized = true;
    result =
        connect_wifi(CONFIG_CALENDINK_WIFI_SSID, CONFIG_CALENDINK_WIFI_PASSWORD,
                     kBlockUntilEthernetEstablished);
    if (result != ESP_OK)
    {
      set_led_status(led_status::Failed);
      vTaskDelay(pdMS_TO_TICKS(1000));
      goto shutdown;
    }

    if (!kBlockUntilEthernetEstablished)
    {
      uint8 retries = 1;
      do
      {
        set_led_status(led_status::ConnectingWifi);
        result = check_wifi_connection(retries);

        if (result != ESP_OK)
        {
          set_led_status(led_status::Failed);
          vTaskDelay(pdMS_TO_TICKS(1000));
        }

        retries++;
      } while (result == ESP_ERR_TIMEOUT &&
               retries <= CONFIG_CALENDINK_WIFI_RETRIES);
    }

    if (result != ESP_OK)
    {
      printf("Wifi failed.\n");
      goto shutdown;
    }

    set_led_status(led_status::ReadyWifi);
    printf("Will use Wifi!\n");
  }
  else
  {
    set_led_status(led_status::ReadyEthernet);
    printf("Will use Ethernet!\n");
  }

  printf("Connected! IP acquired.\n");

  // Start the webserver
  web_server = start_webserver();

  // Start mDNS
  start_mdns();

  // Mark the current app as valid to cancel rollback, only if it's an OTA app
  {
    const esp_partition_t *running = esp_ota_get_running_partition();
    if (running != NULL &&
        running->subtype >= ESP_PARTITION_SUBTYPE_APP_OTA_MIN &&
        running->subtype < ESP_PARTITION_SUBTYPE_APP_OTA_MAX)
    {
      esp_ota_mark_app_valid_cancel_rollback();
    }
  }

  // Keep the main task alive indefinitely
  while (true)
  {
    vTaskDelay(pdMS_TO_TICKS(1000));
  }

shutdown:
  printf("Shutting down.\n");

  if (web_server)
  {
    stop_webserver(web_server, g_Active_WWW_Partition);
    web_server = NULL;
  }

  if (g_Ethernet_Initialized)
  {
    disconnect_ethernet();
    g_Ethernet_Initialized = false;
  }
  if (g_Wifi_Initialized)
  {
    disconnect_wifi();
    g_Wifi_Initialized = false;
  }

  destroy_led();

  ESP_ERROR_CHECK(esp_event_loop_delete_default());
  ESP_ERROR_CHECK(nvs_flash_deinit());
}
