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

/*
 * block up paragraphs, possibly with indentation
 */

void	fmt(Biobuf*);
void	outchar(Rune);
void	addrune(Rune);
void	outword(void);
void	puncttest(void);
void	flush(void);

int join=1;		/* can input lines be joined? */
int indent=0;		/* how many spaces to indent */
int length=70;		/* how many columns per output line */
Biobuf bin;
Biobuf bout;

void
main(int argc, char **argv)
{
	int i, f;
	ARGBEGIN{
	case 'i':
		indent = atoi(ARGF());
		break;
	case 'j':
		join = 0;
		break;
	case 'w':
	case 'l':
		length = atoi(ARGF());
		break;
	default:
		fprint(2, "Usage: %s [-j] [-i indent] [-l length] [file ...]\n",
				argv0);
		exits("usage");
	}ARGEND
	if(length<=indent){
		fprint(2, "%s: line length<=indentation\n", argv0);
		exits("length");
	}
	Binit(&bout, 1, OWRITE);
	if(argc<=0){
		Binit(&bin, 0, OREAD);
		fmt(&bin);
	}else{
		for(i=0; i<argc; i++){
			f=open(argv[i], OREAD);
			if(f<0)
				perror(argv[i]);
			else{
				Binit(&bin, f, OREAD);
				fmt(&bin);
				Bclose(&bin);
				if(i!=argc-1)
					Bputc(&bout, '\n');
			}
		}
	}
	exits(0);
}
void
fmt(Biobuf *f)
{
	long c;

	while((c = Bgetrune(f)) >= 0)
		outchar((Rune) c);
	flush();
}

#define TAB 8
#define	NWORD	(TAB*32)

Rune word[NWORD+1];
Rune *wp=word;
int col=0;	/* output column number */
int bol=1;	/* at beginning of output line? */
int punct=0;	/* last character out was punctuation? */
int newline=1;	/* last char read was newline(1) or init space(2) */

void
outchar(Rune c){
	switch(c){
	case '\0':
		break;
	case '\n':
		switch(newline){
		case 0:
			if(join)
				outword();
			else
				flush();
			break;
		case 1:
			flush();
		case 2:
			Bputc(&bout, '\n');
			wp=word;
		}
		newline=1;
		break;
	case ' ':
	case '\t':
		switch(newline) {
		case 0:
			outword();
			break;
		case 1:
			flush();
			newline=2;
		case 2:
			do {
				addrune(L' ');
			} while(c=='\t' && (wp-word)%TAB);
		}
		break;
	default:
		addrune(c);
		newline=0;
	}
}

void
addrune(Rune c)
{
	if(wp==&word[NWORD]) {
		if(utfrune(" \t",wp[-1]))
			wp=word;
		outword();
	}
	*wp++=c;
}

void
outword(void)
{
	int i;

	if(wp==word)
		return;
	if(wp-word+col+(bol?0:punct?2:1)>length){
		Bputc(&bout, '\n');
		col=0;
		bol=1;
	}
	if(col==0){
		for(i=0;i+8<=indent;i+=8)
			Bputc(&bout, '\t');
		while(i++<indent)
			Bputc(&bout, ' ');
		col=indent;
	}
	if(bol)
		bol=0;
	else{
		if(punct){
			Bputc(&bout, ' ');
			col++;
		}
		Bputc(&bout, ' ');
		col++;
	}
	puncttest();
	for (i = 0; word+i < wp; i++)
		Bputrune(&bout, word[i]);
	col+=i;
	wp=word;
}
/* is the word followed by major punctuation, .?:! */
/* disregard short things followed by periods; they are probably
   initials or titles like Mrs. and Dr. */
void
puncttest(void)
{
	Rune *rp;

	punct = 0;
	for(rp=wp; --rp>=word; ) {
		switch(*rp) {
		case ')': case '\'': case '"':
			continue;
		case '.':
			if(isupper(*word)&&rp-word<=3)
				return;
		case '?': case ':': case '!':
			punct = 1;
		default:
			return;
		}
	}
}
void
flush(void){
	outword();
	if(col!=0){
		Bputc(&bout, '\n');
		col=0;
		bol=1;
	}
}