/*
 * LittleFS block device adapter for W25QXX SPI Flash
 *
 * Maps littlefs read/prog/erase/sync callbacks to the W25QXX driver:
 *   read  -> W25QXX_Read
 *   prog  -> W25QXX_Write_NoCheck  (littleFS guarantees erase-before-prog)
 *   erase -> W25QXX_Erase_Sector   (4 KiB sector)
 *   sync  -> W25QXX_Wait_Busy
 */
#include "lfs_flashbd.h"
#include "../../bspMCU/include/w25qxx.h"
#include <string.h>

int lfs_flashbd_create(const struct lfs_config *cfg,
        const struct lfs_flashbd_config *bdcfg) {
    lfs_flashbd_t *bd = (lfs_flashbd_t *)cfg->context;

    /* 参数校验 */
    if (bdcfg->base_addr % LFS_FLASHBD_SECTOR_SIZE != 0) {
        return LFS_ERR_INVAL;
    }
    if (bdcfg->block_count == 0) {
        return LFS_ERR_INVAL;
    }

    bd->cfg = bdcfg;

    /* 初始化 W25QXX Flash */
    W25QXX_Init();

    return LFS_ERR_OK;
}

int lfs_flashbd_destroy(const struct lfs_config *cfg) {
    (void)cfg;
    return LFS_ERR_OK;
}

int lfs_flashbd_read(const struct lfs_config *cfg, lfs_block_t block,
        lfs_off_t off, void *buffer, lfs_size_t size) {
    lfs_flashbd_t *bd = (lfs_flashbd_t *)cfg->context;

    LFS_ASSERT(block < bd->cfg->block_count);
    LFS_ASSERT(off + size <= cfg->block_size);

    uint32_t addr = bd->cfg->base_addr
                  + (uint32_t)block * cfg->block_size
                  + (uint32_t)off;

    W25QXX_Read((uint8_t *)buffer, addr, (uint16_t)size);

    return LFS_ERR_OK;
}

int lfs_flashbd_prog(const struct lfs_config *cfg, lfs_block_t block,
        lfs_off_t off, const void *buffer, lfs_size_t size) {
    lfs_flashbd_t *bd = (lfs_flashbd_t *)cfg->context;

    LFS_ASSERT(block < bd->cfg->block_count);
    LFS_ASSERT(off + size <= cfg->block_size);

    uint32_t addr = bd->cfg->base_addr
                  + (uint32_t)block * cfg->block_size
                  + (uint32_t)off;

    /*
     * W25QXX_Write_NoCheck 的第一个参数是 uint8_t*（非 const），
     * 但该函数只读取 buffer 内容，不会修改，故安全地去除 const。
     * littleFS 保证写入前块已擦除，因此无需带擦除的 W25QXX_Write。
     */
    W25QXX_Write_NoCheck((uint8_t *)(uintptr_t)buffer, addr, (uint16_t)size);

    return LFS_ERR_OK;
}

int lfs_flashbd_erase(const struct lfs_config *cfg, lfs_block_t block) {
    lfs_flashbd_t *bd = (lfs_flashbd_t *)cfg->context;

    LFS_ASSERT(block < bd->cfg->block_count);

    uint32_t addr = bd->cfg->base_addr
                  + (uint32_t)block * cfg->block_size;

    /*
     * W25QXX_Erase_Sector 的参数是扇区号（内部会乘以 4096），
     * 所以传入字节地址除以扇区大小。
     */
    W25QXX_Erase_Sector(addr / LFS_FLASHBD_SECTOR_SIZE);

    return LFS_ERR_OK;
}

int lfs_flashbd_sync(const struct lfs_config *cfg) {
    (void)cfg;
    W25QXX_Wait_Busy();
    return LFS_ERR_OK;
}

void lfs_flashbd_default_config(
        struct lfs_config *cfg,
        lfs_flashbd_t *bd,
        struct lfs_flashbd_config *bdcfg,
        uint32_t base_addr,
        uint32_t block_count,
        void *read_buffer,
        void *prog_buffer,
        void *lookahead_buffer) {
    memset(cfg, 0, sizeof(*cfg));

    /* flashbd 配置 */
    bdcfg->base_addr   = base_addr;
    bdcfg->block_count = block_count;

    bd->cfg = bdcfg;

    /* 回调函数 */
    cfg->context = bd;
    cfg->read    = lfs_flashbd_read;
    cfg->prog    = lfs_flashbd_prog;
    cfg->erase   = lfs_flashbd_erase;
    cfg->sync    = lfs_flashbd_sync;

    /* 块设备参数 */
    cfg->read_size       = 256;          /* W25QXX 页大小，读取可任意长度 */
    cfg->prog_size       = 256;          /* W25QXX 页编程大小 */
    cfg->block_size      = LFS_FLASHBD_SECTOR_SIZE;  /* 4096 字节扇区 */
    cfg->block_count     = block_count;
    cfg->block_cycles    = 500;          /* 磨损均衡建议值 */
    cfg->cache_size      = 256;          /* 缓存大小 = prog_size */

    /*
     * lookahead 缓存是一个位图，每字节跟踪 8 个块。按块数自动计算，
     * 保证一次分配扫描即可覆盖全部块（块数向上取整到字节）。
     * RAM 消耗 = ceil(block_count / 8) 字节，例如 3072 块 -> 384 字节。
     * 注意：若调用者提供静态 lookahead_buffer，其大小必须 >= 该值。
     */
    cfg->lookahead_size  = (block_count + 7) / 8;
    cfg->compact_thresh  = 0;            /* 使用默认值 */

    /* 静态缓冲区，NULL 则由 littleFS 动态分配 */
    cfg->read_buffer      = read_buffer;
    cfg->prog_buffer      = prog_buffer;
    cfg->lookahead_buffer = lookahead_buffer;

    /* 使用默认值 */
    cfg->name_max = 0;
    cfg->file_max = 0;
    cfg->attr_max = 0;
}