#ifndef EMBPART_FAT32_H
#define EMBPART_FAT32_H

#include <stdint.h>

#ifdef __linux
#include <stdio.h>
#include "../../MassStorage.h"

#define MSG(...) printf(__VA_ARGS__)
#endif

typedef struct {
    uint8_t boot_jump[3]; // jump instruction used for bootable volume
    uint8_t formatter_name[8]; // identification of application or OS formatted this device
    uint16_t bytes_per_sector; // number of bytes per sector
    uint8_t sectors_per_cluster; // number of sectors per cluster
    uint16_t n_reserved_sectors; // number of reserved sectors
    uint8_t n_fats; // number of FAT copies
    uint8_t _unused0[2];
    uint8_t _unused1[2];
    uint8_t media_descriptor; // media descriptor differentiating between removable and non-removable devices
    uint8_t _unused2[2];
    uint16_t sectors_per_track; // number of sectors per track
    uint16_t n_heads; // number of heads
    uint32_t n_hidden_sectors; // number of hidden sectors preceding this volume
    uint32_t n_total_sectors; // total number of sectors in this volume
    uint32_t n_sectors_per_fat; // number of sectors per FAT
    uint16_t flags; // flags, see docs.
    uint16_t version; // FAT version number
    uint32_t root_first_cluster; // first cluster of the root directory
    uint16_t fsinfo_sector; // sector of the FSINFO structure
    uint16_t boot_backup_sector; // sector of backup boot code in the reserved region
    uint8_t _reserved0[12];
    uint8_t logical_driver_number; // logical drive number of the partition
    uint8_t _reserved1;
    uint8_t extended_boot_signature; // extended boot signature
    uint32_t volume_serial_number; // volume serial number
    uint8_t volume_label[11]; // volume label string
    uint8_t fs_type[8]; // file system type ("FAT32")
} __attribute__((packed)) Bpb_Fat32;

typedef struct {
    const MassStorage * mstg; // mass storage holding the partition
    uint32_t bpb_s; // sector of bios parameter block
    uint32_t fat_s; // first sector of the FAT area
    uint32_t root_s; // first sector of root directory
    uint32_t data_s; // first sector of the data area (~volume)
    uint32_t serial_number; // serial number of the volume
    uint32_t sectors_per_fat; // sectors per FAT table
    uint16_t bytes_per_sector; // number of bytes creating a sector
    uint16_t sectors_per_cluster; // number of sectors creating a cluster
    uint16_t fat_entries_per_sector; // number of FAT entries per sector
    uint8_t fat_copies; // number of FAT table copies
    uint8_t volume_label[11]; // pointer to volume label
} Fat32_CtrlBlock;

typedef uint32_t Fat32_FatTableEntry;

#define FAT32_FATT_READ_ONLY (1)
#define FAT32_FATT_HIDDEN (1 << 1)
#define FAT32_FATT_SYSTEM (1 << 2)
#define FAT32_FATT_VOLUME (1 << 3)
#define FAT32_FATT_DIRECTORY (1 << 4)
#define FAT32_FATT_ARCHIVE (1 << 5)

typedef struct {
    uint8_t short_fname[8]; // short filename
    uint8_t extension[3]; // file extension
    uint8_t attributes; // entry attributes
    uint8_t _reserved0;
    uint8_t creat_time_hs; // file creation time, hundredth of a second (0-199)
    uint16_t creat_time_hms; // file creation time, hour, minute, second
    uint16_t create_date_ymd; // file creation date year, month, day
    uint16_t lastacc_data_ymd; // ...
    uint16_t first_cluster_high; // high word of first cluster
    uint16_t lastmod_time_hms; // ...
    uint16_t lastmod_date_ymd; // ...
    uint16_t first_cluster_low; // high word of first cluster
    uint32_t size; // file size in bytes
} __attribute__((packed)) Fat32_FileEntry;

typedef struct {
    uint8_t index; // order of this entry in the series of LFN entries
    uint16_t ustr04[5]; // characters 0-4
    uint8_t attributes; // must have bits 0-3 set
    uint8_t type; // should be zero
    uint8_t checksum; // string checksum
    uint16_t ustr5A[6]; // characters 5-10
    uint16_t cluster; // should be zero
    uint16_t ustrBC[2]; // characters 11-12
} __attribute__((packed)) Fat32_LongFileNameEntry;

typedef struct {
    uint32_t pos; // byte position
    uint32_t cluster; // cluster corresponding to the position
    uint32_t sector; // sector of the last read
    uint32_t sector_begin_pos; // byte position of the sector's begin
} Fat32_SeekHint;

typedef struct {
    Fat32_CtrlBlock * ctrl; // pointer FAT32 control block
    Fat32_SeekHint last_pos; // last read position
    uint32_t entry_pos; // FileEntry byte position
} Fat32_FileHelper;

int fat32_load(Fat32_CtrlBlock *ctrl, uint32_t bpb_s, const MassStorage * mstg);

int fat32_list_dir(const Fat32_CtrlBlock *ctrl, const char * dir);

uint32_t fat32_read_file(const Fat32_CtrlBlock * ctrl, const Fat32_FileEntry * entry, uint32_t pos, uint32_t len, uint8_t * p);

const Fat32_FileEntry * fat32_locate_file(const Fat32_CtrlBlock *ctrl, const char *path);

#endif //EMBPART_FAT32_H