//
// flash: nonvolatile k/v storage
//

#include <esp_event.h>
#include <esp_log.h>
#include "nvs_flash.h"
#include "flash.h"
#include <inttypes.h>


// Private variables
static nvs_handle_t my_handle;
static const char *TAG = "flash";


// Initialize flash storage
void flash_init(void)
{
     // Initialize NVS
    esp_err_t ret = nvs_flash_init();
    if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
        ESP_ERROR_CHECK(nvs_flash_erase());
        ret = nvs_flash_init();
    }
    ESP_ERROR_CHECK(ret);

}


// Write k/v to flash
void flash_write(char* key, int32_t val)
{
    ESP_LOGI(TAG, "Writing keyval %s => %ld", key, val);

    // Open handle
    esp_err_t err = nvs_open("storage", NVS_READWRITE, &my_handle);

    if (err != ESP_OK) 
    {
        ESP_LOGI(TAG, "Error (%s) opening NVS handle!\n", esp_err_to_name(err));
    } 
    else 
    {
        // Write
        err = nvs_set_i32(my_handle, key, val);

        if(err != ESP_OK)
            ESP_LOGI(TAG, "Failed!\n");

        err = nvs_commit(my_handle);
        if(err != ESP_OK)
            ESP_LOGI(TAG, "Failed!\n");

        // Close
        nvs_close(my_handle);
    }
}


// Read k/v from flash
int32_t flash_read(char* key)
{
    int32_t val = -1; // value will default to -1 if not set

    // Open
    ESP_LOGI(TAG, "Reading keyval %s", key);
    esp_err_t err = nvs_open("storage", NVS_READONLY, &my_handle);
    
    if (err != ESP_OK) 
    {
        ESP_LOGI(TAG, "Error (%s) opening NVS handle!\n", esp_err_to_name(err));
    } 
    else
    {
        // Read
        err = nvs_get_i32(my_handle, key, &val);
        switch (err) {
            case ESP_OK:
                ESP_LOGI(TAG, "Read value %ld\n", val);
                break;
            case ESP_ERR_NVS_NOT_FOUND:
                ESP_LOGI(TAG, "The value is not initialized yet!\n");
                break;
            default :
                ESP_LOGI(TAG, "Error (%s) reading!\n", esp_err_to_name(err));
        }
        // Close
        nvs_close(my_handle);
    }
    return val;
}