#include <string.h>

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"

#include "esp_event_loop.h"
#include "esp_heap_caps.h"
#include "esp_log.h"
#include "esp_wifi.h"
#include "nvs_flash.h"

#include "driver/gpio.h"
#include "driver/uart.h"
#include "driver/spi_common.h"
#include "driver/spi_master.h"

#include "lwip/err.h"
#include "lwip/sys.h"

#include "esp32-wifi-manager.h"

#define MAX_ESSID (32)
#define MAX_PASSWORD (64)

static const char *TAG = "WM";
nvs_handle nvs;

typedef struct wifi_manager_ap_info {
  char ssid[MAX_ESSID];
  char password[MAX_PASSWORD];
} wifi_manager_ap_info_t;

typedef struct ap_store_base {
  int8_t last;
  uint8_t count;
  uint32_t magic;

  wifi_manager_ap_info_t aps[CONFIG_WIFI_MANAGER_MAX_AP];
} ap_store_t;

ap_store_t ap_store;
static EventGroupHandle_t wm_event_group;

void wifi_manager_connect();

uint8_t wifi_manager_ap_count() {
  return ap_store.count;
};

static esp_err_t wifi_event_handler(void *ctx, system_event_t *event) {
  ESP_LOGI(TAG, "wifi event: %d", event->event_id);

  switch (event->event_id) {
    case SYSTEM_EVENT_STA_START:
      ESP_LOGI(TAG, "SYSTEM_EVENT_STA_START");
      ESP_ERROR_CHECK(esp_wifi_connect());
      break;
    case SYSTEM_EVENT_STA_GOT_IP:
      ESP_LOGI(TAG, "SYSTEM_EVENT_STA_GOT_IP");
      ESP_LOGI(TAG, "Got IP: %s\n",
          ip4addr_ntoa(&event->event_info.got_ip.ip_info.ip));

      xEventGroupSetBits(wm_event_group, WIFI_CONNECTED);
      break;
    case SYSTEM_EVENT_STA_DISCONNECTED:
      ESP_LOGI(TAG, "SYSTEM_EVENT_STA_DISCONNECTED");
      ESP_ERROR_CHECK(esp_wifi_connect());

      xEventGroupClearBits(wm_event_group, WIFI_CONNECTED);
      break;
    default:
      break;
  }
  return ESP_OK;

  return ESP_OK;
}

uint8_t wifi_manager_add_ap(char *ssid, char *password) {
  strcpy(ap_store.aps[ap_store.count].ssid, (char *)ssid);
  strcpy(ap_store.aps[ap_store.count].password, (char *)password);

  ++ap_store.count;

  wifi_manager_save_config();

  return ap_store.count;
};

void wifi_manager_connect() {
  tcpip_adapter_init();
  ESP_ERROR_CHECK(esp_event_loop_init(wifi_event_handler, NULL) );

  wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
  ESP_ERROR_CHECK(esp_wifi_init(&cfg));
  wifi_config_t wifi_config = {
    .sta = {
    }
  };

  memcpy((char *)&wifi_config.sta.ssid, ap_store.aps[ap_store.last].ssid, strlen(ap_store.aps[ap_store.last].ssid) + 1);
  memcpy((char *)&wifi_config.sta.password, ap_store.aps[ap_store.last].password, strlen(ap_store.aps[ap_store.last].password) + 1);

  ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA) );
  ESP_ERROR_CHECK(esp_wifi_set_config(ESP_IF_WIFI_STA, &wifi_config) );
  ESP_ERROR_CHECK(esp_wifi_start());

  ESP_LOGI(TAG, "wifi_init_sta finished.");
  ESP_LOGI(TAG, "connect to ap SSID:%s password:%s",
      wifi_config.sta.ssid, wifi_config.sta.password);
};

void wifi_manager_main_loop() {
  while(true) {
    EventBits_t ev_bits = xEventGroupGetBits(wm_event_group);

    if(ev_bits & AP_AVAILABLE && (ev_bits & WIFI_CONNECTING) == 0) {
      ESP_LOGI(TAG, "AP Available, starting WiFi connect");

      xEventGroupSetBits(wm_event_group, WIFI_CONNECTING);

      ap_store.last = 0;

      wifi_manager_connect();
    }

    vTaskDelay(3000 / portTICK_PERIOD_MS);
  }
}

void wifi_manager_save_config() {
  ESP_LOGI(TAG, "writing %d byte config", sizeof(ap_store));
  ESP_LOGI(TAG, "ap_store.magic = 0x%4X", ap_store.magic);
  ESP_LOGI(TAG, "ap_store.count = %d", ap_store.count);
  ESP_LOGI(TAG, "ap_store.last = %d", ap_store.last);

  uint8_t i = 0;

  for(; i < ap_store.count; i++) {
    ESP_LOGI(TAG, "AP: %s", ap_store.aps[i].ssid);
  }

  if(ap_store.count > 0) {
    ESP_LOGI(TAG, "setting AP_AVAILABLE");

    xEventGroupSetBits(wm_event_group, AP_AVAILABLE);
  }

  ESP_ERROR_CHECK(nvs_set_blob(nvs, "config", &ap_store, (size_t)sizeof(ap_store)));
  nvs_commit(nvs);
};

void wifi_manager_reset_store() {
  memset(&ap_store, 0, sizeof(ap_store));

  ap_store.magic = WIFI_MANAGER_MAGIC;
  ap_store.last = -1;

  wifi_manager_save_config();
};

void wifi_manager_load_config() {
  size_t store_size = 0;
  esp_err_t err;

  err = nvs_get_blob(nvs, "config", NULL, &store_size);
  if (err != ESP_OK && err != ESP_ERR_NVS_NOT_FOUND) ESP_ERROR_CHECK(err);

  err = nvs_get_blob(nvs, "config", &ap_store, &store_size);
  if (err != ESP_OK && err != ESP_ERR_NVS_NOT_FOUND) ESP_ERROR_CHECK(err);

  if(ap_store.magic != WIFI_MANAGER_MAGIC) {
    ESP_LOGI(TAG, "load_config got bad magic: 0x%8X", ap_store.magic);

    wifi_manager_reset_store();

    return wifi_manager_save_config();
  }

  if(ap_store.count > 0) {
    xEventGroupSetBits(wm_event_group, AP_AVAILABLE);
  }

  uint8_t i = 0;
  for(; i < ap_store.count; i++)
    ESP_LOGI(TAG, "AP: %s", ap_store.aps[i].ssid);

  ESP_LOGI(TAG, "load_config found %d APs", ap_store.count);
};

EventGroupHandle_t wifi_manager_start() {
  ESP_ERROR_CHECK(nvs_open("wm-config", NVS_READWRITE, &nvs));

  wm_event_group = xEventGroupCreate();

  wifi_manager_load_config();

  xTaskCreate(&wifi_manager_main_loop, "wm_main_loop",  4096, NULL, 6, NULL);

  return wm_event_group;
};