#include "common/constants.h"
#include "io/nvs_handler.h"
#include "nvs_flash.h"
#include "string.h"

NVSStorageHandler::NVSStorageHandler(
  const char* name_space
) : name_space(name_space) { }

NVSStorageHandler::~NVSStorageHandler() {
  if (this->nvsHandle != 0) {
    nvs_close(this->nvsHandle);
    this->nvsHandle = 0;
  }
}

void NVSStorageHandler::init(const EventGroupHandle_t& system_event_group) {
  esp_err_t err = nvs_flash_init();
  if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
    nvs_flash_erase();
    err = nvs_flash_init();
  }
  ESP_ERROR_CHECK(err);

  err = nvs_open(this->name_space, NVS_READWRITE, &this->nvsHandle);
  if (err != ESP_OK) {
    printf("Error (%s) opening NVS handle!\n", esp_err_to_name(err));
  } else {
    xEventGroupSetBits(system_event_group, STORAGE_READY_BIT);
    printf("NVS Storage initialized.\n");
  }
}

void NVSStorageHandler::put(const char* const& key, const char* const& value) {
  if (this->nvsHandle == 0) {
    printf("NVS handle is not initialized.\n");
    return;
  }

  esp_err_t err = nvs_set_str(this->nvsHandle, key, value);
  if (err != ESP_OK) {
    printf("Error (%s) setting key-value pair in NVS!\n", esp_err_to_name(err));
  } else {
    nvs_commit(this->nvsHandle);
    printf("Key-value pair (%s, %s) stored in NVS.\n", key, value);
  }
}

char* NVSStorageHandler::get(const char* const& key) const {
  if (this->nvsHandle == 0) {
    printf("NVS handle is not initialized.\n");
    return nullptr;
  }

  size_t required_size = 0;
  esp_err_t err = nvs_get_str(this->nvsHandle, key, nullptr, &required_size);
  if (err == ESP_ERR_NVS_NOT_FOUND) {
    printf("Key %s not found in NVS.\n", key);
    return nullptr;
  } else if (err != ESP_OK) {
    printf("Error (%s) getting size for key %s from NVS!\n", esp_err_to_name(err), key);
    return nullptr;
  }

  char* value = (char*)malloc(required_size);
  err = nvs_get_str(this->nvsHandle, key, value, &required_size);
  if (err != ESP_OK) {
    printf("Error (%s) getting value for key %s from NVS!\n", esp_err_to_name(err), key);
    free(value);
    return nullptr;
  }

  return value;
}

NVSIteratorGuard NVSStorageHandler::create_iterator() const {
  nvs_iterator_t it = nullptr;
  esp_err_t err = nvs_entry_find(NVS_DEFAULT_PART_NAME, this->name_space, NVS_TYPE_ANY, &it);
  if (err != ESP_OK) {
    printf("Error (%s) creating NVS iterator!\n", esp_err_to_name(err));
    return NVSIteratorGuard(nullptr, err);
  }

  return NVSIteratorGuard(it, ESP_OK);
}

esp_err_t NVSStorageHandler::process_all(KeyValueProcessor processor, void* arg) const {
  NVSIteratorGuard iterator_guard = this->create_iterator();
  if (!iterator_guard.is_valid()) {
    return iterator_guard.get_error();
  }
  const nvs_iterator_t& it = iterator_guard.get_iterator();

  for (; it != NULL; iterator_guard.advance_iter()) {
    nvs_entry_info_t info;
    esp_err_t err = nvs_entry_info(it, &info);
    if (err != ESP_OK) {
      printf("Error (%s) getting NVS entry info!\n", esp_err_to_name(err));
      return err;
    }
    nvs_handle_t temp_handle;
    err = nvs_open(this->name_space, NVS_READONLY, &temp_handle);
    if (err != ESP_OK) {
      printf("Error (%s) opening NVS handle for reading!\n", esp_err_to_name(err));
      return err;
    }

    // call the processor with the key and value
    processor(arg, info.key, this->get(info.key));
  }
  return ESP_OK;
}
esp_err_t NVSStorageHandler::process_filtered(const char* const& key_prefix, KeyValueProcessor processor, void* arg) const {
  NVSIteratorGuard iterator_guard = this->create_iterator();
  if (!iterator_guard.is_valid()) {
    return iterator_guard.get_error();
  }
  const nvs_iterator_t& it = iterator_guard.get_iterator();

  for (; it != NULL; iterator_guard.advance_iter()) {
    nvs_entry_info_t info;
    esp_err_t err = nvs_entry_info(it, &info);
    if (err != ESP_OK) {
      printf("Error (%s) getting NVS entry info!\n", esp_err_to_name(err));
      return err;
    }
    // check if the key matches the prefix
    if (strncmp(info.key, key_prefix, strlen(key_prefix)) == 0) {
      nvs_handle_t temp_handle;
      err = nvs_open(this->name_space, NVS_READONLY, &temp_handle);
      if (err != ESP_OK) {
        printf("Error (%s) opening NVS handle for reading!\n", esp_err_to_name(err));
        return err;
      }
      // call the processor with the key and value
      processor(arg, info.key, this->get(info.key));
    }
  }
  return ESP_OK;
}

esp_err_t NVSStorageHandler::process_filtered(FilterFunc filter_func, KeyValueProcessor processor, void* arg) const {
  NVSIteratorGuard iterator_guard = this->create_iterator();
  if (!iterator_guard.is_valid()) {
    return iterator_guard.get_error();
  }
  const nvs_iterator_t& it = iterator_guard.get_iterator();

  for (; it != NULL; iterator_guard.advance_iter()) {
    nvs_entry_info_t info;
    esp_err_t err = nvs_entry_info(it, &info);
    if (err != ESP_OK) {
      printf("Error (%s) getting NVS entry info!\n", esp_err_to_name(err));
      return err;
    }
    // check if the key matches the filter function
    if (filter_func(info.key)) {
      nvs_handle_t temp_handle;
      err = nvs_open(this->name_space, NVS_READONLY, &temp_handle);
      if (err != ESP_OK) {
        printf("Error (%s) opening NVS handle for reading!\n", esp_err_to_name(err));
        return err;
      }
      // call the processor with the key and value
      processor(arg, info.key, this->get(info.key));
    }
  }
  return ESP_OK;
}

void NVSStorageHandler::remove(const char* const& key) {
  if (this->nvsHandle == 0) {
    printf("NVS handle is not initialized.\n");
    return;
  }

  esp_err_t err = nvs_erase_key(this->nvsHandle, key);
  if (err != ESP_OK) {
    printf("Error (%s) deleting key %s from NVS!\n", esp_err_to_name(err), key);
  } else {
    nvs_commit(this->nvsHandle);
    printf("Key %s deleted from NVS.\n", key);
  }
}