#ifndef __FAT_H__
#define __FAT_H__

#define NULL 0

struct BPB {
	unsigned char BS_jmpBoot[3];
	char BS_OEMName[8];
	unsigned short BPB_BytesPerSec;
	unsigned char BPB_SecPerClus;
	unsigned short BPB_RsvdSecCnt;
	unsigned char BPB_NumFATs;
	unsigned short BPB_RootEntCnt;
	unsigned short BPB_TotSec16;
	unsigned char BPB_Media;
	unsigned short BPB_FATSz16;
	unsigned short BPB_SecPerTrk;
	unsigned short BPB_NumHeads;
	unsigned int BPB_HiddSec;
	unsigned int BPB_TotSec32;
	union FatType {
		struct Fat16 {
			unsigned char BS_DrvNum;
			unsigned char BS_Reserved1;
			unsigned char BS_BootSig;
			unsigned int BS_VolID;
			char BS_VolLab[11];
			char BS_FilSysType[8];
		} Fat16;
		struct Fat32 {
			unsigned int BPB_FATSz32;
			unsigned short BPB_ExtFlags;
			unsigned short BPB_FSVer;
			unsigned int BPB_RootClus;
			unsigned short BPB_FSInfo;
			unsigned short BPB_BkBootSec;
			char BPB_Reserved[12];
			unsigned char BS_DrvNum;
			unsigned char BS_Reserved1;
			unsigned char BS_BootSig;
			unsigned int BS_VolID;
			char BS_VolLab[11];
			char BS_FilSysType[8];
		} Fat32;
	} FatType;
}__attribute__((packed));

struct fat_fsinfo {
	unsigned int FSI_LeadSig;
	unsigned char FSI_Reserved1[480];
	unsigned int FSI_StructSig;
	unsigned int FSI_Free_Count;
	unsigned int FSI_Nxt_Free;
	unsigned char FSI_Reserved2[12];
	unsigned int FSI_TailSig;
} __attribute__((packed));

struct fat_dir {
	char DIR_Name[11];
	unsigned char DIR_Attribute;
	unsigned char DIR_NTRes;
	unsigned char DIR_CrtTimeTenth;
	char DIR_Res[6];
	unsigned short DIR_FirstClustHi;
	unsigned short DIR_WrtTime;
	unsigned short DIR_WrtDate;
	unsigned short DIR_FirstClustLo;
	unsigned int DIR_FileSize;
}__attribute__((packed));

struct fat_long_dir {
	unsigned char LDIR_Ord;
	short LDIR_Name1[5];
	unsigned char LDIR_Attrib;
	unsigned char LDIR_Type;
	unsigned char LDIR_Chksum;
	short LDIR_Name2[6];
	unsigned short LDIR_FirstClustLo;
	short LDIR_Name3[2];
}__attribute__((packed));

struct fat_data {
	struct BPB superblock;
	unsigned char fat;
	unsigned int fat_size;
	unsigned int root_dir_sectors;
	unsigned int totsec;
	unsigned int first_data_sec;
	unsigned int data_sec;
	unsigned int count_of_clusters;
};

struct fat_file_info {
	unsigned int start_cluster;
	unsigned int *clusterchain;
	unsigned int file_size;
	unsigned char type;
	unsigned int atime;
	unsigned int ctime;
	unsigned int mtime;
	unsigned char dirty;
};

#define ATTR_READ_ONLY 0x01
#define ATTR_HIDDEN 0x02
#define ATTR_SYSTEM 0x04
#define ATTR_VOLUME_ID 0x08
#define ATTR_DIRECTORY 0x10
#define ATTR_ARCHIVE 0x20
#define ATTR_LONG_NAME (ATTR_READ_ONLY | ATTR_HIDDEN | ATTR_SYSTEM | ATTR_VOLUME_ID)
#define ATTR_LONG_NAME_MASK (ATTR_READ_ONLY | ATTR_HIDDEN | ATTR_SYSTEM | ATTR_VOLUME_ID  | ATTR_DIRECTORY | ATTR_ARCHIVE)

extern int fat_load_superblock(struct vfs_device_t *device);
extern unsigned int fat_read_entire_file(struct vfs_device_t *device, unsigned int start_cluster, char **buffer);
extern struct fat_file_info  *fat_check_if_exists(struct vfs_device_t *device, char *path, int type);
extern int fat_get_dents(struct vfs_device_t *device, struct fat_file_info *info, char *buffer, int len, unsigned long long offset, unsigned long long *newoffset);
extern int fat_create_directory(struct vfs_device_t *device, char *path);
extern int fat_write_data(struct vfs_device_t *device, struct fat_file_info *info, char *filename, char *buffer, int len, unsigned long long offset);
extern int fat_trunc_file(struct vfs_device_t *device, struct fat_file_info *info, char *filename);
extern int fat_create_file(struct vfs_device_t *device, char *path);
extern int fat_read_data(struct vfs_device_t *device, struct fat_file_info *info, char *buffer, int len, unsigned long long offset);
extern int fat_change_directory(struct vfs_device_t *device, char *path);
#endif