#include <u.h>
#include <libc.h>
#include <stdio.h>
#include <draw.h>
#include <event.h>
#include <cursor.h>

int checkonly;
char *file, *contents;

typedef struct Slide {
	char *cmd;
	char *arg;
	int linum;
	int nlines;
	char *lines[];
} Slide;

char *
nextline(char **p, int *linum)
{
	char *line;
	while(1){
		(*linum)++;
		line = *p;
		while(**p != '\n' && **p != '\0') (*p)++;
		if(**p == '\0')
			return nil;

		**p = '\0';
		(*p)++;
		return line;
	}
}

Slide *
nextslide(char **p, int *linum)
{
	char *cmd, *arg, *line1, *line, *lineN;
	int nlines, blines, i, slinum;
	Slide *s;

	while(1){
		if((cmd = nextline(p, linum)) == nil)
			return nil;
		if(cmd[0] != '%')
			continue;
		break;
	}
	slinum = *linum;

	cmd++;
	arg = cmd;

	while(*arg != ' ' && *arg != '\t' && *arg != '\0') arg++;
	if(*arg == '\0')
		arg = nil;
	else{
		*(arg++) = '\0';
		while(*arg == ' ' && *arg == '\t' && *arg != '\0') arg++;
		if(*arg == '\0')
			arg = nil;
	}

	line1 = nextline(p, linum);
	if(line1 != nil && *line1 == '%'){
		*p = line1;
		line1[strlen(line1)] = '\n';
		line1 = nil;
	}
	if(line1 == nil){
		s = malloc(sizeof(Slide));
		s->cmd = cmd;
		s->arg = arg;
		s->linum = slinum;
		s->nlines = 0;
		return s;
	}
	lineN = line1;
	nlines = 1;
	blines = 0;

	while((line = nextline(p, linum)) != nil){
		if(*line == '\0'){
			blines++;
			continue;
		}
		if(*line == '%'){
			*p = line;
			line[strlen(line)] = '\n';
			break;
		}

		nlines += blines;
		blines = 0;
		nlines++;
		lineN = line;
	}

	s = malloc(sizeof(Slide) + sizeof(char*) * nlines);

	s->cmd = cmd;
	s->arg = arg;
	s->linum = slinum;
	s->nlines = nlines;

	line = line1;
	for(i = 0; line != lineN; i++){
		s->lines[i] = line;
		line += strlen(line) + 1;
	}
	s->lines[i] = lineN;

	return s;
}

#pragma varargck argpos checkerr 2
void
checkerr(Slide *s, char *msg, ...)
{
	va_list args;

	va_start(args, msg);

	fprint(2,"%s:%d: %s: ", file, s->linum, s->cmd);
	vfprint(2,msg, args);
	fprint(2,"\n");
}
void
checkfile(void)
{
	int waserr, linum;
	char *c2, *p;
	Slide *s;

	waserr = 0;
	linum = 0;

	c2 = strdup(contents);
	p = c2;

	while((s = nextslide(&p, &linum)) != nil){
		if(strcmp(s->cmd, "") == 0)
			continue;
		else if(strcmp(s->cmd, "bullet") == 0)
			continue;
		else if(strcmp(s->cmd, "blank") == 0)
			continue;
		else if(strcmp(s->cmd, "text") == 0)
			continue;
		else if(strcmp(s->cmd, "title") == 0){
			if(s->arg == nil){
				waserr = 1;
				checkerr(s, "missing arg");
			}
		}else{
			waserr = 1;
			checkerr(s, "unknown cmd");
		}
	}

	if(waserr)
		exits("checkfile");
}

void
usage(void)
{
	fprint(2,"usage: %s [ -c ] filename\n", argv0);
	exits("usage");
}

void
main(int argc, char *argv[])
{
	int fd;
	Dir *d;

	ARGBEGIN{
	case 'c':
		checkonly = 1;
		break;
	default:
		usage();
	}ARGEND

	if(argc != 1)
		usage();

	file = argv[0];

	if((fd = open(file, OREAD)) < 0)
		sysfatal("%r");
	if((d = dirfstat(fd)) == nil)
		sysfatal("%r");

	contents = malloc(d->length + 2);
	if(readn(fd, contents, d->length) < 0)
		sysfatal("%r");
	// cursed but makes the handling nicer above
	contents[d->length] = '\n';
	contents[d->length + 1] = '\0';
	free(d);
	close(fd);

	checkfile();

	if(checkonly)
		exits(nil);
}