//
// Created by rick on 18-09-21.
//

#ifndef NEW_KERNEL_EXT2_H
#define NEW_KERNEL_EXT2_H

#include <sys/types.h>
#include <attributes.h>

#define EXT2_SIGNATURE 0xEF53

#define EXT2_SB_ADDR 1024
#define EXT2_SB_SIZE 1024
#define EXT2_BGD_START_ADDR (EXT2_SB_ADDR + EXT2_SB_SIZE)

#define EXT2_DEFAULT_RESERVED_INODES 11
#define EXT2_DEFAULT_INODE_SIZE 128

#define EXT2_ROOT_INODE 2

typedef struct ext2_sb {
    uint32_t total_inodes;
    uint32_t total_blocks;
    uint32_t num_reserved_su;
    uint32_t unallocated_blocks;
    uint32_t unallocated_inodes;
    uint32_t no_blocks_with_sb;
    uint32_t block_size;
    uint32_t fragment_size;
    uint32_t no_blocks_per_group;
    uint32_t no_fragments_per_group;
    uint32_t no_inodes_per_group;
    uint32_t last_mounted;
    uint32_t last_written;
    uint16_t no_mounted_since_fschk;
    uint16_t max_no_mounted_since_fschk;
    uint16_t ext2_signature;
    uint16_t fs_state;
    uint16_t error_action;
    uint16_t minor_version;
    uint32_t last_fschk;
    uint32_t interval_fschk;
    uint32_t os_id;
    uint32_t major_version;
    uint16_t uid_reserved;
    uint16_t gid_reserved;

    // below extended fields
    uint32_t first_nor_reserved_inode;
    uint16_t size_inode;
    uint16_t owner_bg;
    uint32_t features_optional;
    uint32_t features_required;
    uint32_t features_ro;
    uint8_t fs_id[16];
    char fs_name[16];
    char last_mounted_path[64];
    uint32_t compression_alg;
    uint8_t preallocate_files;
    uint8_t preallocate_dirs;
    uint16_t: 16; // unused
    uint8_t journal_id[16];
    uint32_t journal_inode;
    uint32_t journal_device;
    uint32_t head_of_orphan_inode_list;
} att_packed ext2_sb_t;

enum {
    EXT2_FS_STATE_CLEAN = 1,
    EXT2_FS_STATE_ERROR = 2,
};

enum {
    EXT2_ERROR_ACTION_IGNORE = 1,
    EXT2_ERROR_ACTION_REMOUNT_RO = 2,
    EXT2_ERROR_ACTION_PANIC = 3,
};

enum {
    EXT2_OS_ID_LINUX = 0,
    EXT2_OS_ID_GNU_HURD = 1,
    EXT2_OS_ID_MASIX = 2,
    EXT2_OS_ID_FREE_BSD = 3,
    EXT2_OS_ID_LITES = 4,
};

enum {
    EXT2_FEATURE_OPTIONAL_PREALLOCATE = 0x01,
    EXT2_FEATURE_OPTIONAL_AFS_SERVER_INODE = 0x02,
    EXT2_FEATURE_OPTIONAL_HAS_JOURNAL = 0x04,
    EXT2_FEATURE_OPTIONAL_EXTENDED_ATTRIBUTES = 0x08,
    EXT2_FEATURE_OPTIONAL_CAN_RESIZE = 0x10,
    EXT2_FEATURE_OPTIONAL_DIR_HASH_INDEX = 0x20,
};
#define EXT2_FEAT_OPT_SUPPORTED ( \
    0 \
    )

enum {
    EXT2_FEATURE_REQUIRED_COMPRESSION = 0x01,
    EXT2_FEATURE_REQUIRED_DIR_HAS_TYPE = 0x02,
    EXT2_FEATURE_REQUIRED_JOURNAL_REPLAY_REQUIRED = 0x04,
    EXT2_FEATURE_REQUIRED_HAS_JOURNAL_DEVICE = 0x08,
};

#define EXT2_FEAT_REQ_SUPPORTED ( \
    EXT2_FEATURE_REQUIRED_DIR_HAS_TYPE | \
    0 \
    )

enum {
    EXT2_FEATURE_RO_SPARSE_SUPERBLOCKS_AND_GROUPS_DESCRIPTOR = 0x01,
    EXT2_FEATURE_RO_64BIT_SIZE = 0x02,
    EXT2_FEATURE_RO_DIR_BTREE = 0X04
};

#define EXT2_FEAT_RO_64BIT_SIZE (SIZE_MAX > UINT32_MAX)
#define EXT2_FEAT_RO_SUPPORTED ( \
    (EXT2_FEAT_RO_64BIT_SIZE ? EXT2_FEATURE_RO_64BIT_SIZE : 0) | \
    0 \
    )

typedef struct ext2_bg_descriptor {
    uint32_t block_usage_bm;
    uint32_t inode_usage_bm;
    uint32_t start_block_inode;
    uint16_t no_unallocated_blocks;
    uint16_t no_unallocated_inodes;
    uint16_t no_dirs;
    uint8_t unused[14];
} ext2_bg_descriptor_t;

typedef struct ext2_inode {
    union {
        uint16_t type_permission;
        struct {
            uint8_t permission_o: 3;
            uint8_t permission_g: 3;
            uint8_t permission_u: 3;
            bool permission_sticky: 1;
            bool permission_setgid: 1;
            bool permission_setuid: 1;
            uint8_t type: 4;
        } att_packed;
    };
    uint16_t uid;
    uint32_t size_l;
    uint32_t last_access;
    uint32_t created;
    uint32_t last_mod;
    uint32_t deleted;
    uint16_t gid;
    uint16_t no_hard_links;
    uint32_t no_sectors;
    uint32_t flags;
    uint32_t os_val1;
    uint32_t dbp[12]; // fist 12 direct block pointers
    uint32_t sibp;
    uint32_t dibp;
    uint32_t tibp;
    uint32_t generation;
    uint32_t extended_attr;
    union {
        uint32_t size_h;
        uint32_t dir_acl;
    };
    uint32_t fragment_addr;
    uint8_t os_val2[12];
} att_packed ext2_inode_t;

enum {
    EXT2_INODE_FLAG_SECURE_DELETE = 0x00000001,
    EXT2_INODE_FLAG_KEEP_COPY_ON_DELETE = 0x00000002,
    EXT2_INODE_FLAG_FILE_COMPRESSION = 0x00000004,
    EXT2_INODE_FLAG_SYNC_UPDATE = 0x00000008,
    EXT2_INODE_FLAG_IMMUTABLE = 0x00000010,
    EXT2_INODE_FLAG_APPEND_ONLY = 0x00000020,
    EXT2_INODE_FLAG_NO_DUMP = 0x00000040,
    EXT2_INODE_FLAG_LAST_ACCESS_IGNORE = 0x00000080,
    EXT2_INODE_FLAG_HASH_INDEXED_DIR = 0x00010000,
    EXT2_INODE_FLAG_AFS_DIRECTORY = 0x00020000,
    EXT2_INODE_FLAG_JOURNAL_FILE_DATA = 0x00040000,
};

typedef struct ext2_dir_entry {
    uint32_t inode;
    uint16_t ent_size;
    uint8_t name_size;
    uint8_t type_or_name_size_h;
    char name;
} ext2_dir_entry_t;

enum {
    EXT2_INODE_TYPE_FIFO = 0x1,
    EXT2_INODE_TYPE_CHAR_DEV = 0x2,
    EXT2_INODE_TYPE_DIR = 0x4,
    EXT2_INODE_TYPE_BLOCK_DEV = 0x6,
    EXT2_INODE_TYPE_FILE = 0x8,
    EXT2_INODE_TYPE_SYM_LINK = 0xA,
    EXT2_INODE_TYPE_UNIX_SOCK = 0xC,
};

enum {
    EXT2_DIR_TYPE_UNKNOWN = 0,
    EXT2_DIR_TYPE_FILE = 1,
    EXT2_DIR_TYPE_DIR = 2,
    EXT2_DIR_TYPE_CHAR_DEV = 3,
    EXT2_DIR_TYPE_BLOCK_DEV = 4,
    EXT2_DIR_TYPE_FIFO = 5,
    EXT2_DIR_TYPE_SOCKET = 6,
    EXT2_DIR_TYPE_SOFT_LINK = 7,
};

typedef struct ext2_mount_info {
    ext2_sb_t sb;
    uint32_t no_block_groups;
    uint64_t block_size;
    uint64_t fragment_size;
    void *block_dev;
} ext2_mount_info_t;

#endif //NEW_KERNEL_EXT2_H