/**
 * @file    bsp_flash.c
 * @brief   Flash storage driver implementation
 */

#include "bsp_flash.h"
#include "main.h"

/* Default settings */
static const system_settings_t default_settings = {
    .fan_threshold = 30.0f,
    .fan_mode = 1,      // AUTO
    .light_state = 0,   // OFF
    .valid = SETTINGS_VALID_FLAG
};

/**
 * @brief  Get Flash page address
 */
static uint32_t get_page_address(uint32_t addr)
{
    return addr & 0xFFFFF800;  // 2KB page alignment
}

/**
 * @brief  Erase Flash page
 */
static HAL_StatusTypeDef erase_page(uint32_t page_address)
{
    FLASH_EraseInitTypeDef erase_init;
    uint32_t page_error = 0;
    
    HAL_FLASH_Unlock();
    
    erase_init.TypeErase = FLASH_TYPEERASE_PAGES;
    erase_init.PageAddress = page_address;
    erase_init.NbPages = 1;
    
    HAL_StatusTypeDef status = HAL_FLASHEx_Erase(&erase_init, &page_error);
    
    HAL_FLASH_Lock();
    
    return status;
}

/**
 * @brief  Load settings from Flash
 */
bool BSP_Flash_LoadSettings(system_settings_t *settings)
{
    if (settings == NULL) return false;
    
    /* Read from Flash */
    system_settings_t *flash_data = (system_settings_t *)SETTINGS_ADDR;
    
    /* Check valid flag */
    if (flash_data->valid == SETTINGS_VALID_FLAG)
    {
        settings->fan_threshold = flash_data->fan_threshold;
        settings->fan_mode = flash_data->fan_mode;
        settings->light_state = flash_data->light_state;
        settings->valid = flash_data->valid;
        return true;
    }
    
    /* No valid settings, use defaults */
    *settings = default_settings;
    return false;
}

/**
 * @brief  Save settings to Flash
 */
bool BSP_Flash_SaveSettings(const system_settings_t *settings)
{
    if (settings == NULL) return false;
    
    uint32_t page_addr = get_page_address(SETTINGS_ADDR);
    
    /* Erase page first */
    if (erase_page(page_addr) != HAL_OK)
    {
        return false;
    }
    
    HAL_FLASH_Unlock();
    
    /* Write data halfword by halfword */
    uint16_t *src = (uint16_t *)settings;
    uint32_t dst = SETTINGS_ADDR;
    
    for (uint32_t i = 0; i < sizeof(system_settings_t) / 2; i++)
    {
        if (HAL_FLASH_Program(FLASH_TYPEPROGRAM_HALFWORD, dst, *src) != HAL_OK)
        {
            HAL_FLASH_Lock();
            return false;
        }
        dst += 2;
        src++;
    }
    
    HAL_FLASH_Lock();
    
    return true;
}

/**
 * @brief  Reset settings to default
 */
void BSP_Flash_ResetSettings(void)
{
    BSP_Flash_SaveSettings(&default_settings);
}