#pragma once

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

#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <ctype.h>
#include <stdio.h>

#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>

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

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

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

#define buffree(s) ((s) ? (free(_bufHdr(s)), (s) = nil) : 0)
#define buffit(s, n) ((n) <= bufcap(s) ? 0 : ((s) = bufgrow((s), (n), sizeof(*(s)))))

#define bufresize(s, n)                                                        \
    do {                                                                       \
        (buffit(s, n));                                                        \
        ((_bufHdr(s)->len) = (n));                                             \
    } while (0)

#define bufpush(s, ...) (buffit((s), 1 + buflen(s)), (s)[_bufHdr(s)->len++] = (__VA_ARGS__))

#define bufpop(s, i) (_bufpop((s), (i), sizeof(*(s))), (s)[_bufHdr(s)->len])

void* bufgrow(void*, vlong, vlong);
void _bufpop(void*, int, vlong);

// -----------------------------------------------------------------------------
// interfaces
// TODO(nnoll): Think about this idea
/*
typedef struct Iface {
    void* impl;
    byte  fcn[];
} Iface;
*/
// -----------------------------------------------------------------------------
// memory allocation

/* allocator interface */
typedef struct mem·Allocator {
    void *(*alloc)(void *iface, uint n, ulong size);
    void  (*free)(void *iface, void *ptr);
} mem·Allocator;

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;

/* system implementation */
extern void  ·free(void* _, void *ptr);
extern void *·alloc(void* _, uint n, ulong size);
extern void *·calloc(void* _, uint n, ulong size);
extern void *·realloc(void* _, void *ptr, uint n, ulong size);

// TODO(nnoll): Allow for nil iterfaces?
static
mem·Allocator mem·sys = {
    .alloc   = ·alloc, 
    .free    = ·free
};

/* 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);

/* 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);

/*
 * UTF-8 functions.
 * Perhaps break into own unit
 * TODO: Add to(upper|lower|title)
 */
typedef uint32 rune;

/* 
 * We have to use the preprocessor to ensure
 * we have unsigned constants. Unfortunate...
 */

#define UTFmax   4
#define RuneSync 0x80u
#define RuneSelf 0x80u
#define RuneErr  0xFFFDu
#define RuneMax  0x10FFFFu
#define RuneMask 0x1FFFFFu

/* utf8 helpers */
int     utf8·fullrune(byte *s, int n);
byte   *utf8·findrune(byte *s, long i);
byte   *utf8·findrrune(byte* s, long c);
int     utf8·bytetorune(rune *r, byte *s);
int     utf8·runetobyte(byte *s, rune *r);
int     utf8·len(byte *s);
int     utf8·runelen(rune r);
int     utf8·isletter(rune r);
int     utf8·isdigit(rune r);
int     utf8·isspace(rune r);
int     utf8·istitle(rune r);

// -----------------------------------------------------------------------------
// I/O

typedef FILE Stream;
typedef struct stat io·Stat;

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

enum
{
    ReadOK  = R_OK,
    WriteOK = W_OK,
    ExecOK  = X_OK,
};

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

/* 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;

typedef struct io·LineReader
{
    int (*readln)(void*, int n, void *buf);
} io·LineReader;

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

typedef struct io·FullReader
{
    io·Reader;
    io·Peeker;
} io·FullReader;

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

typedef struct io·Putter
{
    error (*put)(void*, byte);
    int   (*putstr)(void*, string);
} io·Putter;

typedef struct io·FullWriter
{
    io·Writer;
    io·Putter;
} io·FullWriter;

typedef struct io·ReadWriter
{
    io·Reader;
    io·Writer;
} io·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);
rune  bufio·getrune(io·Buffer *buf);
error bufio·ungetrune(io·Buffer *buf, rune r);
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);

// -----------------------------------------------------------------------------
// 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;

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);
vlong      gz·seek(gz·Stream *s, long off, enum SeekPos whence);

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

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

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();
bool   rng·bernoulli(double f);
uint64 rng·randi(int max);

// -----------------------------------------------------------------------------
// 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;
#define	ARGBEGIN	for((argv0?0:(argv0=*argv)),argv++,argc--;\
			    argv[0] && argv[0][0]=='-' && argv[0][1];\
			    argc--, argv++) {\
				byte *_args, *_argt;\
				rune _argc;\
				_args = &argv[0][1];\
				if(_args[0]=='-' && _args[1]==0){\
					argc--; argv++; break;\
				}\
				_argc = 0;\
				while(*_args && (_args += utf8·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