#include <rtthread.h>
#include "ffconf.h"
#include "ff.h"

/* ELM FatFs provide a DIR struct */
#define HAVE_DIR_STRUCTURE

#include <dfs_fs.h>
#include <dfs_def.h>

static rt_device_t disk[_VOLUMES] = {0};

static int elm_result_to_dfs(FRESULT result)
{
	int status = DFS_STATUS_OK;

	switch (result)
	{
	case FR_OK:
		break;

	case FR_NO_FILE:
	case FR_NO_PATH:
	case FR_NO_FILESYSTEM:
		status = -DFS_STATUS_ENOENT;
		break;

	case FR_INVALID_NAME:
		status = -DFS_STATUS_EINVAL;
		break;

	case FR_EXIST:
	case FR_INVALID_OBJECT:
		status = -DFS_STATUS_EEXIST;
		break;

	case FR_DISK_ERR:
	case FR_NOT_READY:
	case FR_INT_ERR:
		status = -DFS_STATUS_EIO;
		break;

	case FR_WRITE_PROTECTED:
	case FR_DENIED:
		status = -DFS_STATUS_EROFS;
		break;

	case FR_MKFS_ABORTED:
		status = -DFS_STATUS_EINVAL;
		break;

	default:
		status = -1;
		break;
	}

	return status;
}

int dfs_elm_mount(struct dfs_filesystem* fs, unsigned long rwflag, const void* data)
{
	FATFS *fat;
	FRESULT result;
	rt_uint32_t index;

	/* handle RT-Thread device routine */
	for (index = 0; index < _VOLUMES; index ++)
	{
		if (disk[index] == RT_NULL)
		{
			break;
		}
	}
	if (index == _VOLUMES) return -DFS_STATUS_ENOSPC;

	/* get device */
	disk[index] = fs->dev_id;

	fat = (FATFS *) rt_malloc(sizeof(FATFS));
	if (fat == RT_NULL)
	{
		return -1;
	}

	/* mount fatfs, always 0 logic driver */
	result = f_mount(index, fat);
	if (result == FR_OK)
		fs->data = fat;
	else
	{
		rt_free(fat);
		return elm_result_to_dfs(result);
	}

	return 0;
}

int dfs_elm_unmount(struct dfs_filesystem* fs)
{
	FATFS *fat;
	FRESULT result;
	rt_uint32_t index;

	fat = (FATFS*) fs->data;

	RT_ASSERT(fat != RT_NULL);

	/* find the device index and then umount it */
	for (index = 0; index < _VOLUMES; index ++)
	{
		if (disk[index] == fs->dev_id)
		{
			result = f_mount(index, RT_NULL);

			if (result == FR_OK)
			{
				fs->data = RT_NULL;
				disk[index] = RT_NULL;
				rt_free(fat);
				return DFS_STATUS_OK;
			}
		}
	}

	return -DFS_STATUS_ENOENT;
}

int dfs_elm_mkfs(const char* device_name)
{
	BYTE drv;
	rt_device_t dev;
	FRESULT result;

	/* find device name */
	for (drv = 0; drv < _VOLUMES; drv ++)
	{
		dev = disk[drv];
		if (rt_strncmp(dev->parent.name, device_name, RT_NAME_MAX) == 0)
		{
			/* 1: no partition table */
			/* 0: auto selection of cluster size */
			result = f_mkfs(drv, 1, 0);
			if ( result != FR_OK)
			{
				rt_kprintf("format error\n");
				return elm_result_to_dfs(result);
			}

			return DFS_STATUS_OK;
		}
	}

	/* can't find device driver */
	rt_kprintf("can not find device driver: %s\n", device_name);
	return -DFS_STATUS_EIO;
}

int dfs_elm_statfs(struct dfs_filesystem* fs, struct statfs *buf)
{
	FATFS *f;
	FRESULT res;
	char driver[4];
	DWORD fre_clust, fre_sect, tot_sect;

	RT_ASSERT(fs != RT_NULL);
	RT_ASSERT(buf != RT_NULL);

	f = (FATFS*) fs->data;

	rt_snprintf(driver, sizeof(driver), "%d:", f->drv);
	res = f_getfree(driver, &fre_clust, &f);
	if (res) return elm_result_to_dfs(res);

	/* Get total sectors and free sectors */
	tot_sect = (f->n_fatent - 2) * f->csize;
	fre_sect = fre_clust * f->csize;

	buf->f_bfree = fre_sect;
	buf->f_blocks = tot_sect;
	buf->f_bsize = 512;

	return 0;
}

int dfs_elm_open(struct dfs_fd* file)
{
	FIL* fd;
	BYTE mode;
	FRESULT result;
	char *drivers_fn;

#if (_VOLUMES > 1)
	int vol;
	extern int elm_get_vol(FATFS *fat);

	/* add path for ELM FatFS driver support */
	vol = elm_get_vol((FATFS *)file->fs->data);
	if (vol < 0) return -DFS_STATUS_ENOENT;
	drivers_fn = rt_malloc(256);
	if (drivers_fn == RT_NULL) return -DFS_STATUS_ENOMEM;

	rt_snprintf(drivers_fn, 256, "%d:%s", vol, file->path);
#else
	drivers_fn = file->path;
#endif

	if (file->flags & DFS_O_DIRECTORY)
	{
		DIR *dir;

		if (file->flags & DFS_O_CREAT)
		{
			result = f_mkdir(drivers_fn);
			if (result != FR_OK)
			{
#if _VOLUMES > 1
				rt_free(drivers_fn);
#endif
				return elm_result_to_dfs(result);
			}
		}

		/* open directory */
		dir = (DIR *)rt_malloc(sizeof(DIR));
		if (dir == RT_NULL)
		{
#if _VOLUMES > 1
			rt_free(drivers_fn);
#endif
			return -DFS_STATUS_ENOMEM;
		}

		result = f_opendir(dir, drivers_fn);
#if _VOLUMES > 1
		rt_free(drivers_fn);
#endif
		if (result != FR_OK)
		{
			rt_free(dir);
			return elm_result_to_dfs(result);
		}

		file->data = dir;
		return DFS_STATUS_OK;
	}
	else
	{
		mode = FA_READ;

		if (file->flags & DFS_O_WRONLY) mode |= FA_WRITE;
		if ((file->flags & DFS_O_ACCMODE) & DFS_O_RDWR) mode |= FA_WRITE;
		/* Opens the file, if it is existing. If not, a new file is created. */
		if (file->flags & DFS_O_CREAT) mode |= FA_OPEN_ALWAYS;
		/* Creates a new file. If the file is existing, it is truncated and overwritten. */
		if (file->flags & DFS_O_TRUNC) mode |= FA_CREATE_ALWAYS;
		/* Creates a new file. The function fails if the file is already existing. */
		if (file->flags & DFS_O_EXCL) mode |= FA_CREATE_NEW;

		/* allocate a fd */
		fd = (FIL*)rt_malloc(sizeof(FIL));
		if (fd == RT_NULL)
		{
			return -DFS_STATUS_ENOMEM;
		}

		result = f_open(fd, drivers_fn, mode);
#if _VOLUMES > 1
		rt_free(drivers_fn);
#endif
		if (result == FR_OK)
		{
			file->pos  = fd->fptr;
			file->size = fd->fsize;
			file->data = fd;

			if (file->flags & DFS_O_APPEND)
			{
				file->pos = f_lseek(fd, fd->fsize);
			}
		}
		else
		{
			/* open failed, return */
			rt_free(fd);
			return elm_result_to_dfs(result);
		}
	}

	return DFS_STATUS_OK;
}

int dfs_elm_close(struct dfs_fd* file)
{
	FRESULT result;

	result = FR_OK;
	if (file->type == FT_DIRECTORY)
	{
		DIR* dir;

		dir = (DIR*)(file->data);
		RT_ASSERT(dir != RT_NULL);

		/* release memory */
		rt_free(dir);
	}
	else if (file->type == FT_REGULAR)
	{
		FIL* fd;
		fd = (FIL*)(file->data);
		RT_ASSERT(fd != RT_NULL);

		result = f_close(fd);
		if (result == FR_OK)
		{
			/* release memory */
			rt_free(fd);
		}
	}

	return elm_result_to_dfs(result);
}

int dfs_elm_ioctl(struct dfs_fd* file, int cmd,	void* args)
{
	return -DFS_STATUS_ENOSYS;
}

int dfs_elm_read(struct dfs_fd* file, void* buf, rt_size_t len)
{
	FIL* fd;
	FRESULT result;
	UINT byte_read;

	if (file->type == FT_DIRECTORY)
	{
		return -DFS_STATUS_EISDIR;
	}

	fd = (FIL*)(file->data);
	RT_ASSERT(fd != RT_NULL);

	result = f_read(fd, buf, len, &byte_read);
	/* update position */
	file->pos  = fd->fptr;
	if (result == FR_OK) return byte_read;

	return elm_result_to_dfs(result);
}

int dfs_elm_write(struct dfs_fd* file, const void* buf, rt_size_t len)
{
	FIL* fd;
	FRESULT result;
	UINT byte_write;

	if (file->type == FT_DIRECTORY)
	{
		return -DFS_STATUS_EISDIR;
	}

	fd = (FIL*)(file->data);
	RT_ASSERT(fd != RT_NULL);

	result = f_write(fd, buf, len, &byte_write);
	/* update position and file size */
	file->pos  = fd->fptr;
	file->size = fd->fsize;
	if (result == FR_OK) return byte_write;

	return elm_result_to_dfs(result);
}

int dfs_elm_flush(struct dfs_fd* file)
{
	FIL* fd;
	FRESULT result;

	fd = (FIL*)(file->data);
	RT_ASSERT(fd != RT_NULL);

	result = f_sync(fd);
	return elm_result_to_dfs(result);
}

int dfs_elm_lseek(struct dfs_fd* file, rt_off_t offset)
{
	FRESULT result;
	if (file->type == FT_REGULAR)
	{
		FIL* fd;

		/* regular file type */
		fd = (FIL*)(file->data);
		RT_ASSERT(fd != RT_NULL);
		
		result = f_lseek(fd, offset);
		if (result == FR_OK)
		{
			/* return current position */
			return fd->fptr;
		}
	}
	else if (file->type == FT_DIRECTORY)
	{
		/* which is a directory */
		DIR* dir;

		dir = (DIR*)(file->data);
		RT_ASSERT(dir != RT_NULL);

		result = f_seekdir(dir, offset / sizeof(struct dirent));
		if (result == FR_OK)
		{
			/* update file position */
			file->pos = offset;
			return file->pos;
		}
	}

	return elm_result_to_dfs(result);
}

int dfs_elm_getdents(struct dfs_fd* file, struct dirent* dirp, rt_uint32_t count)
{
	DIR* dir;
	FILINFO fno;
	FRESULT result;
	rt_uint32_t index;
	struct dirent* d;

	dir = (DIR*)(file->data);
	RT_ASSERT(dir != RT_NULL);

	/* make integer count */
	count = (count / sizeof(struct dirent)) * sizeof(struct dirent);
	if ( count == 0 ) return -DFS_STATUS_EINVAL;

#if _USE_LFN
	/* allocate long file name */
	fno.lfname = rt_malloc(256);
	fno.lfsize = 256;
#endif

	index = 0;
	while (1)
	{
		char *fn;

		d = dirp + index;

		result = f_readdir(dir, &fno);
		if (result != FR_OK || fno.fname[0] == 0) break;

#if _USE_LFN
		fn = *fno.lfname? fno.lfname : fno.fname;
#else
		fn = fno.fname;
#endif

		d->d_type = DFS_DT_UNKNOWN;
		if (fno.fattrib & AM_DIR) d->d_type = DFS_DT_DIR;
		else d->d_type = DFS_DT_REG;

		d->d_namlen = rt_strlen(fn);
		d->d_reclen = (rt_uint16_t)sizeof(struct dirent);
		rt_strncpy(d->d_name, fn, rt_strlen(fn) + 1);

		index ++;
		if ( index * sizeof(struct dirent) >= count )
			break;
	}

#if _USE_LFN
	rt_free(fno.lfname);
#endif

	if (index == 0)
		return elm_result_to_dfs(result);

	file->pos += index * sizeof(struct dirent);

	return index * sizeof(struct dirent);
}

int dfs_elm_unlink(struct dfs_filesystem* fs, const char* path)
{
	FRESULT result;

#if _VOLUMES > 1
	int vol;
	char *drivers_fn;
	extern int elm_get_vol(FATFS *fat);

	/* add path for ELM FatFS driver support */
	vol = elm_get_vol((FATFS *)fs->data);
	if (vol < 0) return -DFS_STATUS_ENOENT;
	drivers_fn = rt_malloc(256);
	if (drivers_fn == RT_NULL) return -DFS_STATUS_ENOMEM;

	rt_snprintf(drivers_fn, 256, "%d:%s", vol, path);
#else
	const char *drivers_fn;
	drivers_fn = path;
#endif

	result = f_unlink(drivers_fn);
#if _VOLUMES > 1
	rt_free(drivers_fn);
#endif
	return elm_result_to_dfs(result);
}

int dfs_elm_rename(struct dfs_filesystem* fs, const char* oldpath, const char* newpath)
{
	FRESULT result;

#if _VOLUMES > 1
	char *drivers_oldfn, *drivers_newfn;
	int vol;
	extern int elm_get_vol(FATFS *fat);

	/* add path for ELM FatFS driver support */
	vol = elm_get_vol((FATFS *)fs->data);
	if (vol < 0) return -DFS_STATUS_ENOENT;

	drivers_oldfn = rt_malloc(256);
	if (drivers_oldfn == RT_NULL) return -DFS_STATUS_ENOMEM;
	drivers_newfn = rt_malloc(256);
	if (drivers_newfn == RT_NULL)
	{
		rt_free(drivers_oldfn);
		return -DFS_STATUS_ENOMEM;
	}

	rt_snprintf(drivers_oldfn, 256, "%d:%s", vol, oldpath);
	rt_snprintf(drivers_newfn, 256, "%d:%s", vol, newpath);
#else
	const char *drivers_oldfn, *drivers_newfn;

	drivers_oldfn = oldpath;
	drivers_newfn = newpath;
#endif

	result = f_rename(drivers_oldfn, drivers_newfn);
#if _VOLUMES > 1
	rt_free(drivers_oldfn);
	rt_free(drivers_newfn);
#endif
	return elm_result_to_dfs(result);
}

int dfs_elm_stat(struct dfs_filesystem* fs, const char *path, struct stat *st)
{
	FILINFO file_info;
	FRESULT result;


#if _VOLUMES > 1
	int vol;
	char *drivers_fn;
	extern int elm_get_vol(FATFS *fat);

	/* add path for ELM FatFS driver support */
	vol = elm_get_vol((FATFS *)fs->data);
	if (vol < 0) return -DFS_STATUS_ENOENT;
	drivers_fn = rt_malloc(256);
	if (drivers_fn == RT_NULL) return -DFS_STATUS_ENOMEM;

	rt_snprintf(drivers_fn, 256, "%d:%s", vol, path);
#else
	const char *drivers_fn;
	drivers_fn = path;
#endif

#if _USE_LFN
	/* allocate long file name */
	file_info.lfname = rt_malloc(256);
	file_info.lfsize = 256;
#endif

	result = f_stat(drivers_fn, &file_info);
#if _VOLUMES > 1
	rt_free(drivers_fn);
#endif
	if (result == FR_OK)
	{
		/* convert to dfs stat structure */
		st->st_dev   = 0;

		st->st_mode = DFS_S_IFREG | DFS_S_IRUSR | DFS_S_IRGRP | DFS_S_IROTH |
		DFS_S_IWUSR | DFS_S_IWGRP | DFS_S_IWOTH;
		if (file_info.fattrib & AM_DIR)
		{
			st->st_mode &= ~DFS_S_IFREG;
			st->st_mode |= DFS_S_IFDIR | DFS_S_IXUSR | DFS_S_IXGRP | DFS_S_IXOTH;
		}
		if (file_info.fattrib & AM_RDO)
			st->st_mode &= ~(DFS_S_IWUSR | DFS_S_IWGRP | DFS_S_IWOTH);

		st->st_size  = file_info.fsize;
		st->st_mtime = file_info.ftime;
		st->st_blksize = 512;
	}

#if _USE_LFN
	rt_free(file_info.lfname);
#endif

	return elm_result_to_dfs(result);
}

static const struct dfs_filesystem_operation dfs_elm =
{
	"elm",
	dfs_elm_mount,
	dfs_elm_unmount,
	dfs_elm_mkfs,
	dfs_elm_statfs,

	dfs_elm_open,
	dfs_elm_close,
	dfs_elm_ioctl,
	dfs_elm_read,
	dfs_elm_write,
	dfs_elm_flush,
	dfs_elm_lseek,
	dfs_elm_getdents,
	dfs_elm_unlink,
	dfs_elm_stat,
	dfs_elm_rename,
};

int elm_init(void)
{
    /* register fatfs file system */
    dfs_register(&dfs_elm);

	return 0;
}

/*
 * RT-Thread Device Interface for ELM FatFs
 */
#include "diskio.h"

/* Inidialize a Drive */
DSTATUS disk_initialize (BYTE drv)
{
	return 0;
}

/* Return Disk Status */
DSTATUS disk_status (BYTE drv)
{
	return 0;
}

/* Read Sector(s) */
DRESULT disk_read (BYTE drv, BYTE *buff, DWORD sector, BYTE count)
{
	rt_size_t result;
	rt_device_t device = disk[drv];

	result = rt_device_read(device, sector, buff, count);
	if (result == count)
	{
		return RES_OK;
	}

	return RES_ERROR;
}

/* Write Sector(s) */
DRESULT disk_write (BYTE drv, const BYTE *buff, DWORD sector, BYTE count)
{
	rt_size_t result;
	rt_device_t device = disk[drv];

	result = rt_device_write(device, sector, buff, count);
	if (result == count)
	{
		return RES_OK;
	}

	return RES_ERROR;
}

/* Miscellaneous Functions */
DRESULT disk_ioctl (BYTE drv, BYTE ctrl, void *buff)
{
	rt_device_t device = disk[drv];

	if (device == RT_NULL) return RES_ERROR;

	if (ctrl == GET_SECTOR_COUNT)
	{
		struct rt_device_blk_geometry geometry;

		rt_memset(&geometry, 0, sizeof(geometry));
		rt_device_control(device, RT_DEVICE_CTRL_BLK_GETGEOME, &geometry);

		*(DWORD*)buff = geometry.sector_count;
		if (geometry.sector_count == 0) return RES_ERROR;
	}
	else if (ctrl == GET_SECTOR_SIZE)
	{
		struct rt_device_blk_geometry geometry;

		rt_memset(&geometry, 0, sizeof(geometry));
		rt_device_control(device, RT_DEVICE_CTRL_BLK_GETGEOME, &geometry);

		*(WORD*)buff = geometry.bytes_per_sector;
	}
	else if (ctrl == GET_BLOCK_SIZE) /* Get erase block size in unit of sectors (DWORD) */
	{
		struct rt_device_blk_geometry geometry;

		rt_memset(&geometry, 0, sizeof(geometry));
		rt_device_control(device, RT_DEVICE_CTRL_BLK_GETGEOME, &geometry);

		*(DWORD*)buff = geometry.block_size/geometry.bytes_per_sector;
	}

	return RES_OK;
}

rt_time_t get_fattime()
{
	return 0;
}

#if _FS_REENTRANT
int ff_cre_syncobj(BYTE drv, _SYNC_t* m)
{
    char name[8];
    rt_mutex_t mutex;

    rt_snprintf(name, sizeof(name), "fat%d", drv);
    mutex = rt_mutex_create(name, RT_IPC_FLAG_FIFO);
    if (mutex != RT_NULL)
    {
        *m = mutex;
        return RT_TRUE;
    }

    return RT_FALSE;
}

int ff_del_syncobj(_SYNC_t m)
{
    rt_mutex_delete(m);

    return RT_TRUE;
}

int ff_req_grant(_SYNC_t m)
{
    if (rt_mutex_take(m, _FS_TIMEOUT) == RT_EOK) return RT_TRUE;

    return RT_FALSE;
}

void ff_rel_grant(_SYNC_t m)
{
	rt_mutex_release(m);
}

#endif