#include <u.h>
#include <libc.h>
#include <ctype.h>

#include "git.h"

Reprog *authorpat;
Hash Zhash;

int chattygit;
int interactive = 1;

enum {
	Seed		= 2928213749ULL
};

Object*
emptydir(void)
{
	static Object *e;

	if(e != nil)
		return ref(e);
	e = emalloc(sizeof(Object));
	e->hash = Zhash;
	e->type = GTree;
	e->tree = emalloc(sizeof(Tinfo));
	e->tree->ent = nil;
	e->tree->nent = 0;
	e->flag |= Cloaded|Cparsed;
	e->off = -1;
	ref(e);
	cache(e);
	return e;
}

int
hasheq(Hash *a, Hash *b)
{
	return memcmp(a->h, b->h, sizeof(a->h)) == 0;
}

static int
charval(int c, int *err)
{
	if(c >= '0' && c <= '9')
		return c - '0';
	if(c >= 'a' && c <= 'f')
		return c - 'a' + 10;
	if(c >= 'A' && c <= 'F')
		return c - 'A' + 10;
	*err = 1;
	return -1;
}

void *
emalloc(ulong n)
{
	void *v;
	
	v = mallocz(n, 1);
	if(v == nil)
		sysfatal("malloc: %r");
	setmalloctag(v, getcallerpc(&n));
	return v;
}

void *
eamalloc(ulong n, ulong sz)
{
	uvlong na;
	void *v;

	na = (uvlong)n*(uvlong)sz;
	if(na >= (1ULL<<30))
		sysfatal("alloc: overflow");
	v = mallocz(na, 1);
	if(v == nil)
		sysfatal("malloc: %r");
	setmalloctag(v, getcallerpc(&n));
	return v;
}

void *
erealloc(void *p, ulong n)
{
	void *v;
	
	v = realloc(p, n);
	if(v == nil)
		sysfatal("realloc: %r");
	setmalloctag(v, getcallerpc(&p));
	return v;
}

void *
earealloc(void *p, ulong n, ulong sz)
{
	uvlong na;
	void *v;

	na = (uvlong)n*(uvlong)sz;
	if(na >= (1ULL<<30))
		sysfatal("alloc: overflow");
	v = realloc(p, na);
	if(v == nil)
		sysfatal("realloc: %r");
	setmalloctag(v, getcallerpc(&p));
	return v;
}

char*
estrdup(char *s)
{
	s = strdup(s);
	if(s == nil)
		sysfatal("strdup: %r");
	setmalloctag(s, getcallerpc(&s));
	return s;
}

int
Hfmt(Fmt *fmt)
{
	Hash h;
	int i, n, l;
	char c0, c1;

	l = 0;
	h = va_arg(fmt->args, Hash);
	for(i = 0; i < sizeof h.h; i++){
		n = (h.h[i] >> 4) & 0xf;
		c0 = (n >= 10) ? n-10 + 'a' : n + '0';
		n = h.h[i] & 0xf;
		c1 = (n >= 10) ? n-10 + 'a' : n + '0';
		l += fmtprint(fmt, "%c%c", c0, c1);
	}
	return l;
}

int
Tfmt(Fmt *fmt)
{
	int t;
	int l;

	t = va_arg(fmt->args, int);
	switch(t){
	case GNone:	l = fmtprint(fmt, "none");	break;
	case GCommit:	l = fmtprint(fmt, "commit");	break;
	case GTree:	l = fmtprint(fmt, "tree");	break;
	case GBlob:	l = fmtprint(fmt, "blob");	break;
	case GTag:	l = fmtprint(fmt, "tag");	break;
	case GOdelta:	l = fmtprint(fmt, "odelta");	break;
	case GRdelta:	l = fmtprint(fmt, "gdelta");	break;
	default:	l = fmtprint(fmt, "?%d?", t);	break;
	}
	return l;
}

int
Ofmt(Fmt *fmt)
{
	Object *o;
	int l;

	o = va_arg(fmt->args, Object *);
	print("== %H (%T) ==\n", o->hash, o->type);
	switch(o->type){
	case GTree:
		l = fmtprint(fmt, "tree\n");
		break;
	case GBlob:
		l = fmtprint(fmt, "blob %s\n", o->data);
		break;
	case GCommit:
		l = fmtprint(fmt, "commit\n");
		break;
	case GTag:
		l = fmtprint(fmt, "tag\n");
		break;
	default:
		l = fmtprint(fmt, "invalid: %d\n", o->type);
		break;
	}
	return l;
}

int
Qfmt(Fmt *fmt)
{
	Qid q;

	q = va_arg(fmt->args, Qid);
	return fmtprint(fmt, "Qid{path=0x%llx(dir:%d,obj:%lld), vers=%ld, type=%d}",
	    q.path, QDIR(&q), (q.path >> 8), q.vers, q.type);
}

void
gitinit(void)
{
	fmtinstall('H', Hfmt);
	fmtinstall('T', Tfmt);
	fmtinstall('O', Ofmt);
	fmtinstall('Q', Qfmt);
	inflateinit();
	deflateinit();
	authorpat = regcomp("[\t ]*(.*)[\t ]+([0-9]+)[\t ]+([\\-+]?[0-9]+)");
	osinit(&objcache);
}

int
hparse(Hash *h, char *b)
{
	int i, err;

	err = 0;
	for(i = 0; i < sizeof(h->h); i++){
		err = 0;
		h->h[i] = 0;
		h->h[i] |= ((charval(b[2*i], &err) & 0xf) << 4);
		h->h[i] |= ((charval(b[2*i+1], &err)& 0xf) << 0);
		if(err){
			werrstr("invalid hash");
			return -1;
		}
	}
	return 0;
}

int
slurpdir(char *p, Dir **d)
{
	int r, f;

	if((f = open(p, OREAD)) == -1)
		return -1;
	r = dirreadall(f, d);
	close(f);
	return r;
}	

int
hassuffix(char *base, char *suf)
{
	int nb, ns;

	nb = strlen(base);
	ns = strlen(suf);
	if(ns <= nb && strcmp(base + (nb - ns), suf) == 0)
		return 1;
	return 0;
}

int
swapsuffix(char *dst, int dstsz, char *base, char *oldsuf, char *suf)
{
	int bl, ol, sl, l;

	bl = strlen(base);
	ol = strlen(oldsuf);
	sl = strlen(suf);
	l = bl + sl - ol;
	if(l + 1 > dstsz || ol > bl)
		return -1;
	memmove(dst, base, bl - ol);
	memmove(dst + bl - ol, suf, sl);
	dst[l] = 0;
	return l;
}

char *
strip(char *s)
{
	char *e;

	while(isspace(*s))
		s++;
	e = s + strlen(s);
	while(e > s && isspace(*--e))
		*e = 0;
	return s;
}

void
_dprint(char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	vfprint(2, fmt, ap);
	va_end(ap);
}

/* Finds the directory containing the git repo. */
int
findrepo(char *buf, int nbuf)
{
	char *p, *suff;

	suff = "/.git/HEAD";
	if(getwd(buf, nbuf - strlen(suff) - 1) == nil)
		return -1;

	for(p = buf + strlen(buf); p != nil; p = strrchr(buf, '/')){
		strcpy(p, suff);
		if(access(buf, AEXIST) == 0){
			p[p == buf] = '\0';
			return 0;
		}
		*p = '\0';
	}
	werrstr("not a git repository");
	return -1;
}

int
showprogress(int x, int pct)
{
	if(!interactive)
		return 0;
	if(x > pct){
		pct = x;
		fprint(2, "\b\b\b\b%3d%%", pct);
	}
	return pct;
}

void
qinit(Objq *q)
{
	memset(q, 0, sizeof(Objq));
	q->nheap = 0;
	q->heapsz = 8;
	q->heap = eamalloc(q->heapsz, sizeof(Qelt));
}

void
qclear(Objq *q)
{
	free(q->heap);
}

void
qput(Objq *q, Object *o, int color)
{
	Qelt t;
	int i;

	if(q->nheap == q->heapsz){
		q->heapsz *= 2;
		q->heap = earealloc(q->heap, q->heapsz, sizeof(Qelt));
	}
	q->heap[q->nheap].o = o;
	q->heap[q->nheap].color = color;
	q->heap[q->nheap].ctime = o->commit->ctime;
	for(i = q->nheap; i > 0; i = (i-1)/2){
		if(q->heap[i].ctime < q->heap[(i-1)/2].ctime)
			break;
		t = q->heap[i];
		q->heap[i] = q->heap[(i-1)/2];
		q->heap[(i-1)/2] = t;
	}
	q->nheap++;
}

int
qpop(Objq *q, Qelt *e)
{
	int i, l, r, m;
	Qelt t;

	if(q->nheap == 0)
		return 0;
	*e = q->heap[0];
	if(--q->nheap == 0)
		return 1;

	i = 0;
	q->heap[0] = q->heap[q->nheap];
	while(1){
		m = i;
		l = 2*i+1;
		r = 2*i+2;
		if(l < q->nheap && q->heap[m].ctime < q->heap[l].ctime)
			m = l;
		if(r < q->nheap && q->heap[m].ctime < q->heap[r].ctime)
			m = r;
		if(m == i)
			break;
		t = q->heap[m];
		q->heap[m] = q->heap[i];
		q->heap[i] = t;
		i = m;
	}
	return 1;
}

u64int
murmurhash2(void *pp, usize n)
{
	u32int m = 0x5bd1e995;
	u32int r = 24;
	u32int h, k;
	u32int *w, *e;
	uchar *p;
	
	h = Seed ^ n;
	e = pp;
	e += (n / 4);
	for (w = pp; w != e; w++) {
		/*
		 * NB: this is endian dependent.
		 * This is fine for use in git, since the
		 * hashes computed here are only ever used
		 * for in memory data structures.
		 *
		 * Pack files will differ when packed on
		 * machines with different endianness,
		 * but the results will still be correct.
		 */
		k = *w;
		k *= m;
		k ^= k >> r;
		k *= m;

		h *= m;
		h ^= k;
	}

	p = (uchar*)w;
	switch (n & 0x3) {
	case 3:	h ^= p[2] << 16;
	case 2:	h ^= p[1] << 8;
	case 1:	h ^= p[0] << 0;
		h *= m;
	}

	h ^= h >> 13;
	h *= m;
	h ^= h >> 15;

	return h;
}