/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : usbd_storage_if.c
  * @version        : v1.0_Cube
  * @brief          : Memory management layer.
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2026 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */

/* Includes ------------------------------------------------------------------*/
#include "usbd_storage_if.h"

/* USER CODE BEGIN INCLUDE */
#include "fatfs.h"
#include "ff.h"
/* USER CODE END INCLUDE */

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/

/* USER CODE BEGIN PV */
/* Private variables ---------------------------------------------------------*/
extern SD_HandleTypeDef hsd;
extern FATFS SDFatFS;
extern char SDPath[4];

static uint8_t sd_initialized = 0;
/* USER CODE END PV */

/** @addtogroup STM32_USB_OTG_DEVICE_LIBRARY
  * @brief Usb device.
  * @{
  */

/** @defgroup USBD_STORAGE
  * @brief Usb mass storage device module
  * @{
  */

/** @defgroup USBD_STORAGE_Private_TypesDefinitions
  * @brief Private types.
  * @{
  */

/* USER CODE BEGIN PRIVATE_TYPES */

/* USER CODE END PRIVATE_TYPES */

/**
  * @}
  */

/** @defgroup USBD_STORAGE_Private_Defines
  * @brief Private defines.
  * @{
  */

#define STORAGE_LUN_NBR                  1
#define STORAGE_BLK_NBR                  0x10000
#define STORAGE_BLK_SIZ                  0x200

/* USER CODE BEGIN PRIVATE_DEFINES */

/* USER CODE END PRIVATE_DEFINES */

/**
  * @}
  */

/** @defgroup USBD_STORAGE_Private_Macros
  * @brief Private macros.
  * @{
  */

/* USER CODE BEGIN PRIVATE_MACRO */

/* USER CODE END PRIVATE_MACRO */

/**
  * @}
  */

/** @defgroup USBD_STORAGE_Private_Variables
  * @brief Private variables.
  * @{
  */

/* USER CODE BEGIN INQUIRY_DATA_FS */
/** USB Mass storage Standard Inquiry Data. */
const int8_t STORAGE_Inquirydata_FS[] = {/* 36 */

  /* LUN 0 */
  0x00,
  0x80,
  0x02,
  0x02,
  (STANDARD_INQUIRY_DATA_LEN - 5),
  0x00,
  0x00,
  0x00,
  'S', 'T', 'M', ' ', ' ', ' ', ' ', ' ', /* Manufacturer : 8 bytes */
  'P', 'r', 'o', 'd', 'u', 'c', 't', ' ', /* Product      : 16 Bytes */
  ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ',
  '0', '.', '0' ,'1'                      /* Version      : 4 Bytes */
};
/* USER CODE END INQUIRY_DATA_FS */

/* USER CODE BEGIN PRIVATE_VARIABLES */

/* USER CODE END PRIVATE_VARIABLES */

/**
  * @}
  */

/** @defgroup USBD_STORAGE_Exported_Variables
  * @brief Public variables.
  * @{
  */

extern USBD_HandleTypeDef hUsbDeviceFS;

/* USER CODE BEGIN EXPORTED_VARIABLES */

/* USER CODE END EXPORTED_VARIABLES */

/**
  * @}
  */

/** @defgroup USBD_STORAGE_Private_FunctionPrototypes
  * @brief Private functions declaration.
  * @{
  */

static int8_t STORAGE_Init_FS(uint8_t lun);
static int8_t STORAGE_GetCapacity_FS(uint8_t lun, uint32_t *block_num, uint16_t *block_size);
static int8_t STORAGE_IsReady_FS(uint8_t lun);
static int8_t STORAGE_IsWriteProtected_FS(uint8_t lun);
static int8_t STORAGE_Read_FS(uint8_t lun, uint8_t *buf, uint32_t blk_addr, uint16_t blk_len);
static int8_t STORAGE_Write_FS(uint8_t lun, uint8_t *buf, uint32_t blk_addr, uint16_t blk_len);
static int8_t STORAGE_GetMaxLun_FS(void);

/* USER CODE BEGIN PRIVATE_FUNCTIONS_DECLARATION */

/* USER CODE END PRIVATE_FUNCTIONS_DECLARATION */

/**
  * @}
  */

USBD_StorageTypeDef USBD_Storage_Interface_fops_FS =
{
  STORAGE_Init_FS,
  STORAGE_GetCapacity_FS,
  STORAGE_IsReady_FS,
  STORAGE_IsWriteProtected_FS,
  STORAGE_Read_FS,
  STORAGE_Write_FS,
  STORAGE_GetMaxLun_FS,
  (int8_t *)STORAGE_Inquirydata_FS
};

/* Private functions ---------------------------------------------------------*/
/**
  * @brief  Initializes the storage unit (medium) over USB FS IP
  * @param  lun: Logical unit number.
  * @retval USBD_OK if all operations are OK else USBD_FAIL
  */
int8_t STORAGE_Init_FS(uint8_t lun)
{
  /* USER CODE BEGIN 2 */
  UNUSED(lun);

  // 1. 检查 SD 句柄状态
  // 如果之前在 main.c 里已经 HAL_SD_Init 过了，这里只要确认状态即可
  HAL_SD_StateTypeDef state = HAL_SD_GetState(&hsd);
  
  if(state == HAL_SD_STATE_RESET)
  {
      // 只有在从未初始化的情况下才初始化
      if (HAL_SD_Init(&hsd) != HAL_OK) {
          return (USBD_FAIL);
      }
  }

  // 2. 绝对不要在这里 f_mount 或 f_mkfs !!!
  // USB 只是搬运工，文件系统由电脑端管理。
  
  sd_initialized = 1;
  return (USBD_OK);
  /* USER CODE END 2 */
}

/**
  * @brief  Returns the medium capacity.
  * @param  lun: Logical unit number.
  * @param  block_num: Number of total block number.
  * @param  block_size: Block size.
  * @retval USBD_OK if all operations are OK else USBD_FAIL
  */
int8_t STORAGE_GetCapacity_FS(uint8_t lun, uint32_t *block_num, uint16_t *block_size)
{
  /* USER CODE BEGIN 3 */
  UNUSED(lun);
  
  HAL_SD_CardInfoTypeDef cardinfo;
  
  if (HAL_SD_GetCardInfo(&hsd, &cardinfo) == HAL_OK)
  {
    // 修正 2: 欺骗电脑，强制报告 512 字节扇区
    *block_size = 512;

    if (cardinfo.LogBlockSize == 512) {
        *block_num = cardinfo.LogBlockNbr - 1;
    }
    else {
        // 如果 SD NAND 是 2048/4096 字节页，需要转换块数量
        // 例如：实际 4096，那 USB 看到的块数就是 实际块数 * 8
        uint32_t ratio = cardinfo.LogBlockSize / 512;
        *block_num = (cardinfo.LogBlockNbr * ratio) - 1;
    }
    return (USBD_OK);
  }
  
  return (USBD_FAIL);
  /* USER CODE END 3 */
}

/**
  * @brief   Checks whether the medium is ready.
  * @param  lun:  Logical unit number.
  * @retval USBD_OK if all operations are OK else USBD_FAIL
  */
int8_t STORAGE_IsReady_FS(uint8_t lun)
{
  /* USER CODE BEGIN 4 */
  UNUSED(lun);
  
  // 简单检查硬件状态
  if (hsd.State == HAL_SD_STATE_RESET) {
      return (USBD_FAIL);
  }
  
  // 对于 SD NAND，即使内部 BUSY，为了不让 USB 掉线，通常也返回 OK
  // 实际的等待放到 Read/Write 函数里去做
  return (USBD_OK);
  /* USER CODE END 4 */
}

/**
  * @brief  Checks whether the medium is write protected.
  * @param  lun: Logical unit number.
  * @retval USBD_OK if all operations are OK else USBD_FAIL
  */
int8_t STORAGE_IsWriteProtected_FS(uint8_t lun)
{
  /* USER CODE BEGIN 5 */
  UNUSED(lun);

  return (USBD_OK);
  /* USER CODE END 5 */
}

/**
  * @brief  Reads data from the medium.
  * @param  lun: Logical unit number.
  * @param  buf: data buffer.
  * @param  blk_addr: Logical block address.
  * @param  blk_len: Blocks number.
  * @retval USBD_OK if all operations are OK else USBD_FAIL
  */
int8_t STORAGE_Read_FS(uint8_t lun, uint8_t *buf, uint32_t blk_addr, uint16_t blk_len)
{
  /* USER CODE BEGIN 6 */
  UNUSED(lun);
  
  // 使用较长的超时时间 (SD NAND 读写较慢)
  uint32_t timeout = 2000;

  if (HAL_SD_ReadBlocks(&hsd, buf, blk_addr, blk_len, 0xffff) != HAL_OK) {
    return (USBD_FAIL);
  }
  
  // 等待传输完成 (重要: 确保 DMA/中断搬运完毕)
  uint32_t tickstart = HAL_GetTick();
  while(HAL_SD_GetCardState(&hsd) != HAL_SD_CARD_TRANSFER)
  {
      if((HAL_GetTick() - tickstart) > timeout) return USBD_FAIL;
  }
  
  return (USBD_OK);
  /* USER CODE END 6 */
}

/**
  * @brief  Writes data into the medium.
  * @param  lun: Logical unit number.
  * @param  buf: data buffer.
  * @param  blk_addr: Logical block address.
  * @param  blk_len: Blocks number.
  * @retval USBD_OK if all operations are OK else USBD_FAIL
  */
int8_t STORAGE_Write_FS(uint8_t lun, uint8_t *buf, uint32_t blk_addr, uint16_t blk_len)
{
  /* USER CODE BEGIN 7 */
  UNUSED(lun);
  
  // 修正 3: 增加超时时间，并等待 Busy 结束
  uint32_t timeout = 5000; // 给 5秒，SD NAND 写入由于要擦除/编程，很慢

  if (HAL_SD_WriteBlocks(&hsd, buf, blk_addr, blk_len, 0xffff) != HAL_OK) {
    return (USBD_FAIL);
  }

  // 【最关键的一步】等待 SD NAND 内部编程结束
  // 如果没有这一步，文件就会丢失！
  uint32_t tickstart = HAL_GetTick();
  while(HAL_SD_GetCardState(&hsd) != HAL_SD_CARD_TRANSFER)
  {
      if((HAL_GetTick() - tickstart) > timeout) return USBD_FAIL;
  }

  return (USBD_OK);
  /* USER CODE END 7 */
}

/**
  * @brief  Returns the Max Supported LUNs.
  * @param  None
  * @retval Lun(s) number.
  */
int8_t STORAGE_GetMaxLun_FS(void)
{
  /* USER CODE BEGIN 8 */
  return (STORAGE_LUN_NBR - 1);
  /* USER CODE END 8 */
}

/* USER CODE BEGIN PRIVATE_FUNCTIONS_IMPLEMENTATION */

/* USER CODE END PRIVATE_FUNCTIONS_IMPLEMENTATION */

/**
  * @}
  */

/**
  * @}
  */