#pragma once

// ------------------------------------------------------------------------
// standard library

#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <ctype.h>
#include <stdio.h>
#include <wchar.h>
#include <errno.h>
#include <pwd.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>

typedef wchar_t wchar;

// ----------------------------------------------------------------------------
// dynamic array

typedef struct BufHdr
{
    vlong len;
    vlong cap;
    byte  buf[];
} BufHdr;

#define bufhdr(b)        ((BufHdr*)((uint8*)(b)-offsetof(BufHdr, buf)))
#define buflen(b)        ((b) ? (bufhdr(b)->len) : 0)
#define bufcap(b)        ((b) ? (bufhdr(b)->cap) : 0)
#define bufend(b)        ((b) + buflen(b))
#define bufsize(b)       ((b) ? (buflen(b) * sizeof((b)[0])) : 0)

#define buffree(b)       ((b) ? (free(bufhdr(b)), (b) = nil) : 0)
#define buffit(b, n)     ((n) <= bufcap(b) ? 0 : ((b) = ·bufgrow((b), (n), sizeof(*(b)))))

#define bufpush(b, ...)  (buffit((b), 1 + buflen(b)), (b)[bufhdr(b)->len++] = (__VA_ARGS__))
#define bufaddn(b, n)    (buffit(b, buflen(b)+n), bufhdr(b)->len += n, b+bufhdr(b)->len-n)

#define bufpop(b)         ((b)[--bufhdr(b)->len])
#define bufdel(b, i)      bufdeln((b), (i), 1)
#define bufdeln(b, i, n)  (memmove((b)+(i), (b)+(i)+(n), sizeof(*(b))*(bufhdr(b)->len-(n)-(i)), bufhdr(b)->len -= (n))
#define bufdelswap(b, i)  ((b)[i] = bufend(b)[-1], bufhdr(b)->len-=1)

void* ·bufgrow(void*, vlong, vlong);

// -----------------------------------------------------------------------------
// memory allocation

// TODO(nnoll): Allow for nil iterfaces?
/* allocator interface */
typedef struct mem·Allocator {
    void *(*alloc)(void *heap, uint n, ulong size);
    void  (*free)(void *heap, void *ptr);
} mem·Allocator;

extern mem·Allocator sys·Memory;

typedef struct mem·Reallocator {
    void *(*alloc)(void *iface, uint n, ulong size);
    void *(*realloc)(void *iface, void *ptr, uint n, ulong size);
    void  (*free)(void *iface, void *ptr);
} mem·Reallocator;

extern mem·Reallocator sys·Relocator; 

/* simple memory arena */
typedef struct mem·Arena mem·Arena;

mem·Arena *mem·makearena(mem·Allocator from, void*);
void      *mem·arenaalloc(mem·Arena *A, uint n, ulong size); 
void       mem·freearena(mem·Arena *A);

extern mem·Allocator mem·ArenaAllocator;

/* generalized memxxx functions */
void       memset64(void *dst, uint64 val, uintptr size);

// -----------------------------------------------------------------------------
// coroutines

typedef struct Coro Coro;

Coro*   coro·make(uintptr stk, uintptr (*func)(Coro*, uintptr));
uintptr coro·yield(Coro *c, uintptr arg);
error   coro·free(Coro *c);

// -----------------------------------------------------------------------------
// strings

typedef byte* string;

/* string helpers */
string  str·makecap(const byte *s, vlong len, vlong cap);
string  str·makelen(const byte *s, vlong len);
string  str·make(const byte *s);
string  str·makef(const byte *fmt, ...);
void    str·free(string s);
int     str·len(const string s);
int     str·cap(const string s);
void    str·clear(string *s);
void    str·grow(string *s, vlong delta);
void    str·fit(string *s);
int     str·appendlen(string *s, vlong len, const byte *b);
int     str·append(string *s, const byte* b);
int     str·appendf(string *s, const byte* fmt, ...);
int     str·appendbyte(string *s, const byte b);
bool    str·equals(const string s, const string t);
int     str·find(string s, const byte* substr);
void    str·lower(string s);
void    str·upper(string s);
int     str·read(string s, int size, int n, void *buf);
void    str·replace(string s, const byte* from, const byte* to);
string* str·split(string s, const byte* tok);
string  str·join(vlong len, byte** fields, const byte* sep);

// -----------------------------------------------------------------------------
// i/o

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

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

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

/* file handling */
io·Stream *io·open(byte *name, byte *mode);
int        io·fd(io·Stream *s);
error      io·stat(io·Stream *s, io·Stat *buf);
error      io·close(io·Stream *s);
byte       io·getbyte(io·Stream *s);
error      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);
error      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);

/* basic os helpers */
int     os·exists(byte *path, int flag);
byte   *os·basename(byte *path);
int     os·sep(void);

/* io interfaces */
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*);
    error (*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
{
    error (*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;

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

enum
{
    bufio·size   = 2*4096,
    bufio·ungets = 8,
    bufio·eof    = -1,
    bufio·err    = -2,

    bufio·nil = 1 << 0,
    bufio·rdr = 1 << 1,
    bufio·wtr = 1 << 2,
    bufio·end = 1 << 3,
};

struct io·Buffer
{
    int state;
    int runesize;
    void *h;
    union {
        io·Reader rdr;
        io·Writer wtr;
    };
    vlong size;
    byte *beg, *pos, *end;
    byte  buf[bufio·size + bufio·ungets];
};

error bufio·initreader(io·Buffer *buf, io·Reader rdr, void *h);
void  bufio·finireader(io·Buffer *buf);
int   bufio·getbyte(io·Buffer *buf);
error bufio·ungetbyte(io·Buffer *buf, byte c);
int   bufio·read(io·Buffer *buf, int sz, int n, void *out);

// -----------------------------------------------------------------------------
// memory mapped files

typedef struct mmap·Reader 
{
    vlong len;
    union {
        byte   *buf;
        ubyte *ubuf;
    };
} mmap·Reader;

mmap·Reader mmap·open(byte *name);
error       mmap·close(mmap·Reader rdr);

// -----------------------------------------------------------------------------
// filesystem

#define iota(x) 1 << (x)
enum
{
    fs·preorder = iota(0),
    fs·nolinks  = iota(1),
    fs·verbose  = iota(2),
};
#undef iota

typedef struct fs·Walker  fs·Walker;
typedef struct fs·History fs·History;

struct fs·Walker
{
    int fd, lev, max, err;
    uchar  flags : 4;
    fs·History *hist;
    struct {
        void  *data;
        int  (*func)(void *data, char *relp, char *absp, io·Stat* info);
    };
    char *base, *end, path[4096];
};

int  fs·init(fs·Walker *, char *path);
void fs·fini(fs·Walker *);
void fs·walk(fs·Walker *);

// -----------------------------------------------------------------------------
// libflate
// NOTE: Experimental!

typedef struct flate·Reader flate·Reader;
typedef struct flate·Writer flate·Writer;

flate·Reader *flate·openreader(io·Reader rdr, void* r, mem·Allocator mem, void* m);
int           flate·read(flate·Reader *rdr, int sz, int n, void *buf);
error         flate·closereader(flate·Reader *rdr);

flate·Writer *flate·openwriter(io·Writer wtr, void* w, mem·Allocator mem, void* m);
int           flate·write(flate·Writer *wtr, int sz, int n, void *buf);
error         flate·closewriter(flate·Writer *wtr);

// -----------------------------------------------------------------------------
// libgz

typedef void gz·Stream;

/* interfaces */
extern io·Reader     gz·Reader;
extern io·Peeker     gz·Peeker;
extern io·Seeker     gz·Seeker;
extern io·SeekReader gz·SeekReader;
extern io·PeekReader gz·PeekReader;

extern io·Writer     gz·Writer;
extern io·Putter     gz·Putter;
extern io·PutWriter  gz·PutWriter;
extern io·ReadWriter gz·ReadWriter;

gz·Stream *gz·open(byte *path, byte *mode);
error      gz·close(gz·Stream* s);
int        gz·read(gz·Stream *s, int sz, int n, void* buf);
int        gz·readln(gz·Stream *s, int n, byte *buf);
byte       gz·getbyte(gz·Stream *s);
error      gz·ungetbyte(gz·Stream *s, byte c);
int        gz·write(gz·Stream *s, int sz, int n, void* buf);
error      gz·putbyte(gz·Stream *s, byte str);
error      gz·putstring(gz·Stream *s, byte *str);
int        gz·printf(gz·Stream *s, byte *fmt, ...);
error      gz·flush(gz·Stream *s);
int        gz·seek(gz·Stream *s, long off, enum SeekPos whence);
long       gz·tell(gz·Stream *s);

// -----------------------------------------------------------------------------
// libjson
// NOTE: Experimental!

// -----------------------------------------------------------------------------
// error handling functions

void exits(char *s);
void errorf(byte* fmt, ...);
void verrorf(byte* fmt, va_list args); 
void panicf(byte *fmt, ...);
void vpanicf(byte *fmt, va_list args); 

// -----------------------------------------------------------------------------
// sorting

void sort·ints(uintptr n, int arr[]);
void sort·int8s(uintptr n, int8 arr[]);
void sort·int16s(uintptr n, int16 arr[]);
void sort·int32s(uintptr n, int32 arr[]);
void sort·int64s(uintptr n, int64 arr[]);

void sort·uints(uintptr n, uint arr[]);
void sort·uint8s(uintptr n, uint8 arr[]);
void sort·uint16s(uintptr n, uint16 arr[]);
void sort·uint32s(uintptr n, uint32 arr[]);
void sort·uint64s(uintptr n, uint64 arr[]);

void sort·floats(uintptr n, float arr[]);
void sort·doubles(uintptr n, double arr[]);

void sort·strings(uintptr n, byte* arr[]);

// -----------------------------------------------------------------------------
// fast random number generation

error  rng·init(uint64 seed);
double rng·random(void);
double rng·exponential(double lambda);
bool   rng·bernoulli(double f);
uint64 rng·randi(int max);
uint64 rng·poisson(double mean);

// -----------------------------------------------------------------------------
// variable arguments

/* from plan9 libc */

#define	ERRMAX	128 /* max length of error string */

#define	SET(x)	((x)=0)
#define	USED(x)	if(x){}else{}
#ifdef __GNUC__
#	if __GNUC__ >= 3
#		undef USED
#		define USED(x) ((void)(x))
#	endif
#endif

extern char *argv0;
int arg·bytetorune(uint32*, byte *);
#define	ARGBEGIN	for((argv0?0:(argv0=*argv)),argv++,argc--;            \
			    argv[0] && argv[0][0]=='-' && argv[0][1];                 \
			    argc--, argv++) {                                         \
				byte *_args, *_argt;                                      \
				uint32 _argc;                                             \
				_args = &argv[0][1];                                      \
				if(_args[0]=='-' && _args[1]==0){                         \
					argc--; argv++; break;                                \
				}                                                         \
				_argc = 0;                                                \
				while(*_args && (_args += arg·bytetorune(&_argc, _args)))\
				switch(_argc)
#define	ARGEND		SET(_argt);USED(_argt);USED(_argc);USED(_args);}USED(argv);USED(argc);
#define	ARGF()		(_argt=_args, _args="",\
				(*_argt? _argt: argv[1]? (argc--, *++argv): 0))
#define	EARGF(x)	(_argt=_args, _args="",\
				(*_argt? _argt: argv[1]? (argc--, *++argv): ((x), abort(), (char*)0)))

#define	ARGC()		_argc