#ifndef __LUNAIX_VFS_H
#define __LUNAIX_VFS_H

#include <hal/ahci/hba.h>
#include <lunaix/block.h>
#include <lunaix/ds/hashtable.h>
#include <lunaix/ds/hstr.h>
#include <lunaix/ds/llist.h>

#define VFS_NAME_MAXLEN 128
#define VFS_MAX_FD 32

#define VFS_INODE_TYPE_DIR 0x1
#define VFS_INODE_TYPE_FILE 0x2
#define VFS_INODE_TYPE_DEVICE 0x4

#define VFS_ETOOLONG -1
#define VFS_ENOFS -2
#define VFS_EBADMNT -3
#define VFS_ENODIR -4
#define VFS_EENDOFDIR -5
#define VFS_ENOTFOUND -6
#define VFS_ENOOPS -7
#define VFS_EINVLD -8
#define VFS_EEOF -9

#define VFS_WALK_MKPARENT 0x1
#define VFS_WALK_FSRELATIVE 0x2
#define VFS_WALK_MKDIR 0x4

#define VFS_IOBUF_FDIRTY 0x1

#define VFS_VALID_CHAR(chr)                                                    \
    ('A' <= (chr) && (chr) <= 'Z' || 'a' <= (chr) && (chr) <= 'z' ||           \
     '0' <= (chr) && (chr) <= '9' || (chr) == '.' || (chr) == '_' ||           \
     (chr) == '-')

struct v_dnode;

struct filesystem
{
    struct hlist_node fs_list;
    struct hstr fs_name;
    int (*mount)(struct v_superblock* vsb, struct v_dnode* mount_point);
    int (*unmount)(struct v_superblock* vsb);
};

struct v_superblock
{
    struct llist_header sb_list;
    int fs_id;
    bdev_t dev;
    struct v_dnode* root;
    struct filesystem* fs;
    uint32_t iobuf_size;
    struct
    {
        uint32_t (*read_capacity)(struct v_superblock* vsb);
        uint32_t (*read_usage)(struct v_superblock* vsb);
    } ops;
};

struct dir_context
{
    int index;
    void* cb_data;
    void (*read_complete_callback)(struct dir_context* dctx,
                                   const char* name,
                                   const int dtype);
};

struct v_file_ops
{
    int (*write)(struct v_file* file, void* buffer, size_t len);
    int (*read)(struct v_file* file, void* buffer, size_t len);
    int (*readdir)(struct v_file* file, struct dir_context* dctx);
    int (*seek)(struct v_file* file, size_t offset);
    int (*rename)(struct v_file* file, char* new_name);
    int (*close)(struct v_file* file);
    int (*sync)(struct v_file* file);
};

struct v_file
{
    struct v_inode* inode;
    struct llist_header* f_list;
    uint32_t f_pos;
    void* data; // 允许底层FS绑定他的一些专有数据
    struct v_file_ops ops;
};

struct v_fd
{
    struct v_file* file;
    int pos;
};

struct v_inode
{
    uint32_t itype;
    uint32_t ctime;
    uint32_t mtime;
    uint64_t lb_addr;
    uint32_t ref_count;
    uint32_t lb_usage;
    void* data; // 允许底层FS绑定他的一些专有数据
    struct
    {
        int (*open)(struct v_inode* inode, struct v_file* file);
        int (*sync)(struct v_inode* inode);
        int (*mkdir)(struct v_inode* inode, struct v_dnode* dnode);
        int (*dir_lookup)(struct v_inode* inode, struct v_dnode* dnode);
    } ops;
};

struct v_dnode
{
    struct hstr name;
    struct v_inode* inode;
    struct v_dnode* parent;
    struct hlist_node hash_list;
    struct llist_header children;
    struct llist_header siblings;
    struct v_superblock* super_block;
    struct
    {
        void (*destruct)(struct v_dnode* dnode);
    } ops;
};

struct v_fdtable
{
    struct v_fd* fds[VFS_MAX_FD];
};

/* --- file system manager --- */
void
fsm_init();

void
fsm_register(struct filesystem* fs);

struct filesystem*
fsm_get(const char* fs_name);

struct v_dnode*
vfs_dcache_lookup(struct v_dnode* parent, struct hstr* str);

void
vfs_dcache_add(struct v_dnode* parent, struct v_dnode* dnode);

int
vfs_walk(struct v_dnode* start,
         const char* path,
         struct v_dnode** dentry,
         int walk_options);

int
vfs_mount(const char* fs_name, bdev_t device, struct v_dnode* mnt_point);

int
vfs_unmount(struct v_dnode* mnt_point);

int
vfs_mkdir(const char* parent_path,
          const char* component,
          struct v_dnode** dentry);

int
vfs_open(struct v_dnode* dnode, struct v_file** file);

int
vfs_close(struct v_file* file);

int
vfs_fsync(struct v_file* file);

struct v_superblock*
vfs_sb_alloc();

void
vfs_sb_free(struct v_superblock* sb);

struct v_dnode*
vfs_d_alloc();

void
vfs_d_free(struct v_dnode* dnode);

struct v_inode*
vfs_i_alloc();

void
vfs_i_free(struct v_inode* inode);
#endif /* __LUNAIX_VFS_H */