#pragma once

enum SeekPos
{
    seek·cur = SEEK_CUR,
    seek·set = SEEK_SET,
    seek·end = SEEK_END
};

typedef struct io·Reader
{
    int (*read)(void*, int sz, int n, void *buf);
} io·Reader;
extern io·Reader sys·Reader;

typedef struct io·Peeker
{
    byte  (*get)(void*);
    int   (*unget)(void*, byte);
} io·Peeker;
extern io·Peeker sys·Peeker;

typedef struct io·Seeker
{
    int        (*seek)(void *skr, long off, enum SeekPos whence);
    long       (*tell)(void *skr);
} io·Seeker;
extern io·Seeker sys·Seeker;

typedef struct io·SeekReader
{
    io·Seeker;
    io·Reader;
} io·SeekReader;
extern io·SeekReader sys·SeekReader;

typedef struct io·PeekReader
{
    io·Reader;
    io·Peeker;
} io·PeekReader;
extern io·PeekReader sys·PeekReader;

typedef struct io·Writer
{
    int (*write)(void*, int sz, int n, void *buf);
} io·Writer;
extern io·Writer sys·Writer;

typedef struct io·Putter
{
    int (*put) (void*, byte);
    int (*puts)(void*, string);
} io·Putter;
extern io·Putter sys·Putter;

typedef struct io·PutWriter
{
    io·Writer;
    io·Putter;
} io·PutWriter;
extern io·PutWriter sys·PutWriter;

typedef struct io·ReadWriter
{
    io·Reader;
    io·Writer;
} io·ReadWriter;
extern io·ReadWriter sys·ReadWriter;

/* XXX: change casing */
enum
{
    ReadOK  = R_OK,
    WriteOK = W_OK,
    ExecOK  = X_OK,
};

/* XXX(deprecated): file handling */

typedef FILE io·Stream;
typedef struct stat io·Stat;

io·Stream *io·open(byte *name, byte *mode);
int        io·fd(io·Stream *s);
int        io·stat(io·Stream *s, io·Stat *buf);
int        io·close(io·Stream *s);
byte       io·getbyte(io·Stream *s);
int        io·ungetbyte(io·Stream *s, byte c);
int        io·read(io·Stream *s, int sz, int n, void *buf);
int        io·readln(io·Stream *s, int n, byte *buf);
int        io·putbyte(io·Stream *s, byte c);
int        io·putstring(io·Stream *s, string str);
int        io·write(io·Stream *s, int sz, int n, void *buf);
int        io·flush(io·Stream *s);
int        io·seek(io·Stream *s, long off, enum SeekPos whence);
long       io·tell(io·Stream *s);

/* buffered i/o */
typedef struct io·Buffer io·Buffer;

#define iota(x) (1 << (x))
enum
{
    io·BufEof    = -1,
    io·BufErr    = -2,
    io·BufUngets = 8,
    io·BufMagic  = 0x314159,
    io·BufLen    = 2*4096,

    /* state */
    io·BufNil = iota(0),
    io·BufRdr = iota(1),
    io·BufWtr = iota(2),
    io·BufEnd = iota(3)
};
#undef iota

struct io·Buffer
{
    int state, id, flag;
    struct{
        int in;      /* negative number of bytes at end */
        int out;     /* number of bytes at start */
        int line;    /* number of bytes after last readline */
    } off;
    intptr pos, cap; /* position in file, capacity of buffer */
    uchar *b,*g,*e;  /* start, good bytes, end of byte pointers */
    uchar bytes[];
};

int     bio·init(io·Buffer *io, int fd, int mode);
int     bio·initcap(io·Buffer *io, int fd, int mode, int cap);

/* basic os helpers */
/* XXX: find a better location for this */
int     os·exists(byte *path, int flag);
byte   *os·dirname(byte *path);
byte   *os·basename(byte *path);
int     os·sep(void);