/* lib9660: a simple ISO9660 reader library especially suited to embedded
 *          systems
 *
 * SPDX-License-Identifier: LicenseRef-ISC1
 * SPDX-FileCopyrightText: © 2014 Erin Shepherd
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice appears in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */
#ifndef LIB9660_H
#define LIB9660_H

#include <aux/compiler.h>
#include <libk/std.h>

struct proc;
struct reschedule_ctx;

#define L9660_SEEK_END -1
#define L9660_SEEK_SET 0
#define L9660_SEEK_CUR +1

/* Our error return format */
typedef enum {
  /*! Success! */
  L9660_OK = 0,
  /*! read_sector callback returned false */
  L9660_EIO,
  /*! file system is bad */
  L9660_EBADFS,
  /*! specified name does not exist */
  L9660_ENOENT,
  /*! attempted to open a non-file (e.g. a directory) as a file */
  L9660_ENOTFILE,
  /*! attempted to open a non-directory (e.g. a file) as a directory
   *  may be returned by l9660_openat if e.g. you pass path "a/b" and
   *  "a" is a file
   */
  L9660_ENOTDIR,
} l9660_status;

/* ISO9660 uses big/little/dual endian integers */
typedef struct {
  uint8_t le[2];
} PACKED l9660_luint16;
typedef struct {
  uint8_t be[2];
} PACKED l9660_buint16;
typedef struct {
  uint8_t le[2], be[2];
} PACKED l9660_duint16;
typedef struct {
  uint8_t le[4];
} PACKED l9660_luint32;
typedef struct {
  uint8_t be[4];
} PACKED l9660_buint32;
typedef struct {
  uint8_t le[4], be[4];
} PACKED l9660_duint32;

/* Descriptor time format */
typedef struct {
  char d[17];
} PACKED l9660_desctime;

/* File time format */
typedef struct {
  char d[7];
} PACKED l9660_filetime;

/* Directory entry */
typedef struct {
  uint8_t length;
  uint8_t xattr_length;
  l9660_duint32 sector;
  l9660_duint32 size;
  l9660_filetime time;
  uint8_t flags;
  uint8_t unit_size;
  uint8_t gap_size;
  l9660_duint16 vol_seq_number;
  uint8_t name_len;
  char name[/*name_len*/];
} PACKED l9660_dirent;

typedef struct {
  char sign[2];
  uint8_t len;
  uint8_t version;
  char data[];
} PACKED l9660_su_field;

/* Volume descriptor header */
typedef struct {
  uint8_t type;
  char magic[5];
  uint8_t version;
} PACKED l9660_vdesc_header;

/* Primary volume descriptor */
typedef struct {
  l9660_vdesc_header hdr;
  char pad0[1];
  char system_id[32];
  char volume_id[32];
  char pad1[8];
  l9660_duint32 volume_space_size;
  char pad2[32];
  l9660_duint16 volume_set_size;
  l9660_duint16 volume_seq_number;
  l9660_duint16 logical_block_size;
  l9660_duint32 path_table_size;
  l9660_luint32 path_table_le;
  l9660_luint32 path_table_opt_le;
  l9660_buint32 path_table_be;
  l9660_buint32 path_table_opt_be;
  union {
    l9660_dirent root_dir_ent;
    char pad3[34];
  } PACKED rde;
  char volume_set_id[128];
  char data_preparer_id[128];
  char app_id[128];
  char copyright_file[38];
  char abstract_file[36];
  char bibliography_file[37];
  l9660_desctime volume_created, volume_modified, volume_expires, volume_effective;
  uint8_t file_structure_version;
  char pad4[1];
  char app_reserved[512];
  char reserved[653];
} PACKED l9660_vdesc_primary;

/* A generic volume descriptor (i.e. 2048 bytes) */
typedef union {
  l9660_vdesc_header hdr;
  char _bits[2048];
} PACKED l9660_vdesc;

/* File system structure.
 * Stick this inside your own structure and cast/offset as appropriate to store
 * private data
 */
typedef struct l9660_fs {
  void* udata;
  struct proc* proc;
  struct reschedule_ctx* rctx;
  /* Sector buffer to hold the PVD */
  l9660_vdesc pvd;
  /* read_sector func */
  bool (*read_sector)(struct l9660_fs* fs, void* buf, uint32_t sector);
} l9660_fs;

typedef struct {
  /* single sector buffer */
  char buf[2048];
  l9660_fs* fs;
  uint32_t first_sector;
  uint32_t position;
  uint32_t length;
} l9660_file;

typedef struct {
  /* directories are mostly just files with special accessors, but we like type safetey */
  l9660_file file;
} l9660_dir;

/* Open a file system, initialising *fs. */
l9660_status l9660_openfs(l9660_fs* fs,
                          bool (*read_sector)(l9660_fs* fs, void* buf, uint32_t sector));

/*void l9660_closefs(l9660_fs *fs); (nop) */

/*! Open the root directory */
l9660_status l9660_fs_open_root(l9660_dir* dir, l9660_fs* fs);

/*! Open the subdirectory given by \p path */
l9660_status l9660_opendirat(l9660_dir* dir, l9660_dir* parent, const char* path);
/*! Returns the next directory entry. If end-of-directory is reached, *dirent is
 *  set to NULL. */
l9660_status l9660_readdir(l9660_dir* dir, l9660_dirent** dirent);

#define l9660_seekdir(dir, pos) (l9660_seek(&(dir)->file, L9660_SEEK_SET, (pos)))
#define l9660_telldir(dir)      (l9660_tell(&(dir)->file))

/*! Open the file given by \p path in \p parent */
l9660_status l9660_openat(l9660_file* file, l9660_dir* parent, const char* path);

/*! Read \p size bytes into \p buf. The number of bytes read will be returned in
 *  \p *read. May be less than \p size (but only 0 on EOF)
 */
l9660_status l9660_read(l9660_file* file, void* buf, size_t size, size_t* read);
/*! Seek the file to \p offset from \p whence */
l9660_status l9660_seek(l9660_file* file, int whence, int32_t offset);
/*! Return the current position (suitable for passing to l9660_seek(file, SEEK_SET, ...)) */
uint32_t l9660_tell(l9660_file* file);

const char* l9660_get_rockridge_name(l9660_dirent* dirent, char* out, size_t* out_len);

#endif