/* $Id$ */
/*
 * Copyright (c) 2008 Kristaps Dzonsons <kristaps@kth.se>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the
 * above copyright notice and this permission notice appear in all
 * copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
 * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */
#include <assert.h>
#include <ctype.h>
#include <err.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "libmdocml.h"
#include "private.h"
#include "ml.h"

/* TODO: literal tokens. */

#define	COLUMNS		  72
#define	INDENT		  4
#define	MAXINDENT	  10

enum	md_tok {
	MD_TEXT,
	MD_INLINE_IN,
	MD_INLINE_OUT,
	MD_BLK_IN,
	MD_BLK_OUT,
};

struct	md_mlg {
	const struct md_args	*args;
	const struct md_rbuf	*rbuf;

	struct md_mbuf	 *mbuf;
	struct rofftree	 *tree;
	size_t		  indent;
	size_t		  pos;
	enum md_tok	  last;
	void		 *arg;
	struct ml_cbs	  cbs;
	int		  flags;
#define	ML_OVERRIDE_ONE	 (1 << 0)
#define	ML_OVERRIDE_ALL	 (1 << 1)
	void		 *data;
};


static	void		 mlg_roffmsg(void *arg, enum roffmsg, 
				const char *, const char *, char *);
static	int		 mlg_roffhead(void *, const struct tm *, 
				const char *, const char *, 
				const char *, const char *);
static	int		 mlg_rofftail(void *);
static	int		 mlg_roffin(void *, int, int *, char **);
static	int		 mlg_roffdata(void *, int, 
				const char *, char *);
static	int		 mlg_roffout(void *, int);
static	int		 mlg_roffblkin(void *, int, int *, char **);
static	int		 mlg_roffblkout(void *, int);
static	int		 mlg_roffspecial(void *, int, 
				const char *, char **);
static	int		 mlg_roffblkheadin(void *, int, 
				int *, char **);
static	int		 mlg_roffblkheadout(void *, int);
static	int		 mlg_roffblkbodyin(void *, int, 
				int *, char **);
static	int		 mlg_roffblkbodyout(void *, int);

static	int		 mlg_begintag(struct md_mlg *, enum md_ns, 
				int, int *, char **);
static	int		 mlg_endtag(struct md_mlg *, enum md_ns, int);
static	int	  	 mlg_indent(struct md_mlg *);
static	int		 mlg_newline(struct md_mlg *);
static	void		 mlg_mode(struct md_mlg *, enum md_tok);
static	int		 mlg_data(struct md_mlg *, int, 
				const char *, char *);
static	void		 mlg_err(struct md_mlg *, const char *, 
				const char *, const char *, ...);
static	void		 mlg_warn(struct md_mlg *, const char *, 
				const char *, const char *, ...);
static	void		 mlg_msg(struct md_mlg *, enum roffmsg, 
				const char *, const char *, char *);
static	void		 mlg_vmsg(struct md_mlg *, enum roffmsg, 
				const char *, const char *, 
				const char *, va_list);

#ifdef __linux__
extern	size_t		 strlcat(char *, const char *, size_t);
extern	size_t		 strlcpy(char *, const char *, size_t);
#endif


static int
mlg_begintag(struct md_mlg *p, enum md_ns ns, int tok,
		int *argc, char **argv)
{
	ssize_t		 res;

	assert(MD_NS_DEFAULT != ns);

	switch (ns) {
	case (MD_NS_INLINE):
		if ( ! (ML_OVERRIDE_ONE & p->flags) && 
				! (ML_OVERRIDE_ALL & p->flags) && 
				p->pos + 11 >= COLUMNS)
			if ( ! mlg_newline(p))
				return(0);
		if (0 != p->pos && (MD_TEXT == p->last || 
					MD_INLINE_OUT == p->last)
				&& ! (ML_OVERRIDE_ONE & p->flags)
				&& ! (ML_OVERRIDE_ALL & p->flags))
			if ( ! ml_nputs(p->mbuf, " ", 1, &p->pos))
				return(0);
		if (0 == p->pos && ! mlg_indent(p))
			return(0);
		mlg_mode(p, MD_INLINE_IN);
		break;
	default:
		if (0 != p->pos) {
			if ( ! mlg_newline(p))
				return(0);
			if ( ! mlg_indent(p))
				return(0);
		} else if ( ! mlg_indent(p))
			return(0);
		p->indent++;
		mlg_mode(p, MD_BLK_IN);
		break;
	}

	if ( ! ml_nputs(p->mbuf, "<", 1, &p->pos))
		return(0);

	res = (*p->cbs.ml_begintag)(p->mbuf, p->data, p->args, ns, tok,
			argc, (const char **)argv);
	if (-1 == res)
		return(0);

	assert(res >= 0);
	p->pos += (size_t)res;

	if ( ! ml_nputs(p->mbuf, ">", 1, &p->pos))
		return(0);

	switch (ns) {
	case (MD_NS_INLINE):
		break;
	default:
		if ( ! mlg_newline(p))
			return(0);
		break;
	}

	return(1);
}


static int
mlg_endtag(struct md_mlg *p, enum md_ns ns, int tok)
{
	ssize_t		 res;

	assert(MD_NS_DEFAULT != ns);

	switch (ns) {
	case (MD_NS_INLINE):
		break;
	default:
		p->indent--;
		if (0 != p->pos) {
			if ( ! mlg_newline(p))
				return(0);
			if ( ! mlg_indent(p))
				return(0);
		} else if ( ! mlg_indent(p))
			return(0);
		break;
	}

	if ( ! ml_nputs(p->mbuf, "</", 2, &p->pos))
		return(0);

	res = (*p->cbs.ml_endtag)(p->mbuf, p->data, p->args, ns, tok);
	if (-1 == res)
		return(0);

	assert(res >= 0);
	p->pos += (size_t)res;

	if ( ! ml_nputs(p->mbuf, ">", 1, &p->pos))
		return(0);
	
	switch (ns) {
	case (MD_NS_INLINE):
		mlg_mode(p, MD_INLINE_OUT);
		break;
	default:
		mlg_mode(p, MD_BLK_OUT);
		break;
	}

	return(1);
}


static int
mlg_indent(struct md_mlg *p)
{
	size_t		 count;

	count = p->indent > MAXINDENT ? 
		(size_t)MAXINDENT : p->indent;
	count *= INDENT;

	assert(0 == p->pos);
	return(ml_putchars(p->mbuf, ' ', count, &p->pos));
}


static int
mlg_newline(struct md_mlg *p)
{

	p->pos = 0;
	return(ml_nputs(p->mbuf, "\n", 1, NULL));
}


static void
mlg_mode(struct md_mlg *p, enum md_tok ns)
{

	p->flags &= ~ML_OVERRIDE_ONE;
	p->last = ns;
}


static int
mlg_data(struct md_mlg *p, int space, const char *start, char *buf)
{
	size_t		 sz;
	int		 c;

	assert(p->mbuf);
	assert(0 != p->indent);

	if (ML_OVERRIDE_ONE & p->flags || 
			ML_OVERRIDE_ALL & p->flags)
		space = 0;

	sz = strlen(buf);

	if (0 == p->pos) {
		if ( ! mlg_indent(p))
			return(0);

		c = ml_nputstring(p->mbuf, buf, sz, &p->pos);

		if (0 == c) {
			mlg_err(p, start, buf, "bad char sequence");
			return(0);
		} else if (c > 1) {
			mlg_warn(p, start, buf, "bogus char sequence");
			return(0);
		} else if (-1 == c)
			return(0);

		if (p->indent * INDENT + sz >= COLUMNS)
			if ( ! mlg_newline(p))
				return(0);

		return(1);
	}

	if (space && sz + p->pos >= COLUMNS) {
		if ( ! mlg_newline(p))
			return(0);
		if ( ! mlg_indent(p))
			return(0);
	} else if (space) {
		if ( ! ml_nputs(p->mbuf, " ", 1, &p->pos))
			return(0);
	}

	c = ml_nputstring(p->mbuf, buf, sz, &p->pos);

	if (0 == c) {
		mlg_err(p, start, buf, "bad char sequence");
		return(0);
	} else if (c > 1) {
		mlg_warn(p, start, buf, "bogus char sequence");
		return(0);
	} else if (-1 == c)
		return(0);

	return(1);
}


int
mlg_line(struct md_mlg *p, char *buf)
{

	return(roff_engine(p->tree, buf));
}


int
mlg_exit(struct md_mlg *p, int flush)
{
	int		 c;

	c = roff_free(p->tree, flush);
	free(p);

	(*p->cbs.ml_free)(p->data);

	return(c);
}


struct md_mlg *
mlg_alloc(const struct md_args *args, 
		const struct md_rbuf *rbuf,
		struct md_mbuf *mbuf, 
		const struct ml_cbs *cbs)
{
	struct roffcb	 cb;
	struct md_mlg	*p;

	cb.roffhead = mlg_roffhead;
	cb.rofftail = mlg_rofftail;
	cb.roffin = mlg_roffin;
	cb.roffout = mlg_roffout;
	cb.roffblkin = mlg_roffblkin;
	cb.roffblkheadin = mlg_roffblkheadin;
	cb.roffblkheadout = mlg_roffblkheadout;
	cb.roffblkbodyin = mlg_roffblkbodyin;
	cb.roffblkbodyout = mlg_roffblkbodyout;
	cb.roffblkout = mlg_roffblkout;
	cb.roffspecial = mlg_roffspecial;
	cb.roffmsg = mlg_roffmsg;
	cb.roffdata = mlg_roffdata;

	if (NULL == (p = calloc(1, sizeof(struct md_mlg))))
		err(1, "calloc");

	p->args = args;
	p->mbuf = mbuf;
	p->rbuf = rbuf;

	(void)memcpy(&p->cbs, cbs, sizeof(struct ml_cbs));

	if (NULL == (p->tree = roff_alloc(&cb, p))) 
		free(p);
	else if ( ! (*p->cbs.ml_alloc)(&p->data))
		free(p);
	else
		return(p);

	return(NULL);
}


static int
mlg_roffhead(void *arg, const struct tm *tm, const char *os, 
		const char *title, const char *sec, const char *vol)
{
	struct md_mlg	*p;

	assert(arg);
	p = (struct md_mlg *)arg;

	mlg_mode(p, MD_BLK_IN);

	if ( ! (*p->cbs.ml_begin)(p->mbuf, p->args, tm, os, title, sec, vol))
		return(0);

	p->indent++;
	return(mlg_newline(p));
}


static int
mlg_rofftail(void *arg)
{
	struct md_mlg	*p;

	assert(arg);
	p = (struct md_mlg *)arg;

	if (0 != p->pos)
		if ( ! mlg_newline(p))
			return(0);

	if ( ! (*p->cbs.ml_end)(p->mbuf, p->args))
		return(0);

	mlg_mode(p, MD_BLK_OUT);

	return(mlg_newline(p));
}


static int
mlg_roffspecial(void *arg, int tok, const char *start, char **more)
{
	struct md_mlg	*p;

	assert(arg);
	p = (struct md_mlg *)arg;

	switch (tok) {
	case (ROFF_Bt):
		assert(NULL == *more);
		if ( ! mlg_begintag(p, MD_NS_INLINE, tok, NULL, NULL))
			return(0);
		if ( ! ml_puts(p->mbuf, "is currently in beta "
					"test.", &p->pos))
			return(0);
		if ( ! mlg_endtag(p, MD_NS_INLINE, tok))
			return(0);
		break;

	case (ROFF_Xr):
		if ( ! *more) {
			mlg_err(p, start, start, "missing argument");
			return(0);
		}
		if ( ! mlg_begintag(p, MD_NS_INLINE, tok, NULL, NULL))
			return(0);
		if ( ! ml_puts(p->mbuf, *more++, &p->pos))
			return(0);
		if (*more) {
			if ( ! ml_nputs(p->mbuf, "(", 1, &p->pos))
				return(0);
			if ( ! ml_puts(p->mbuf, *more++, &p->pos))
				return(0);
			if ( ! ml_nputs(p->mbuf, ")", 1, &p->pos))
				return(0);
		}
		if (*more) {
			mlg_err(p, start, start, "too many arguments");
			return(0);
		}
		if ( ! mlg_endtag(p, MD_NS_INLINE, tok))
			return(0);
		break;

	case (ROFF_Nm):
		assert(*more);
		if ( ! mlg_begintag(p, MD_NS_INLINE, tok, NULL, NULL))
			return(0);
		if ( ! ml_puts(p->mbuf, *more++, &p->pos))
			return(0);
		assert(NULL == *more);
		if ( ! mlg_endtag(p, MD_NS_INLINE, tok))
			return(0);
		break;

	case (ROFF_Ns):
		p->flags |= ML_OVERRIDE_ONE;
		break;

	case (ROFF_Sm):
		assert(*more);
		if (0 == strcmp(*more, "on"))
			p->flags |= ML_OVERRIDE_ALL;
		else
			p->flags &= ~ML_OVERRIDE_ALL;
		break;

	case (ROFF_Ex):
		assert(*more);
		if ( ! mlg_begintag(p, MD_NS_INLINE, tok, NULL, NULL))
			return(0);
		if ( ! ml_puts(p->mbuf, "The ", &p->pos))
			return(0);
		if ( ! mlg_begintag(p, MD_NS_INLINE, ROFF_Xr, NULL, NULL))
			return(0);
		if ( ! ml_puts(p->mbuf, *more++, &p->pos))
			return(0);
		if ( ! mlg_endtag(p, MD_NS_INLINE, ROFF_Xr))
			return(0);
		if ( ! ml_puts(p->mbuf, " utility exits 0 on success, "
					"and &gt;0 if an error "
					"occurs.", &p->pos))
			return(0);
		assert(NULL == *more);
		if ( ! mlg_endtag(p, MD_NS_INLINE, tok))
			return(0);
		break;

	case (ROFF_Ud):
		assert(NULL == *more);
		if ( ! mlg_begintag(p, MD_NS_INLINE, tok, NULL, NULL))
			return(0);
		if ( ! ml_puts(p->mbuf, "currently under "
					"development.", &p->pos))
			return(0);
		if ( ! mlg_endtag(p, MD_NS_INLINE, tok))
			return(0);
		break;

	default:
		mlg_err(p, start, start, "`%s' not yet supported",
				toknames[tok]);
		return(0);
	}

	return(1);
}


static int
mlg_roffblkin(void *arg, int tok, int *argc, char **argv)
{

	return(mlg_begintag((struct md_mlg *)arg, 
				MD_NS_BLOCK, tok, argc, argv));
}


static int
mlg_roffblkout(void *arg, int tok)
{

	return(mlg_endtag((struct md_mlg *)arg, MD_NS_BLOCK, tok));
}


static int
mlg_roffblkbodyin(void *arg, int tok, int *argc, char **argv)
{

	return(mlg_begintag((struct md_mlg *)arg, 
				MD_NS_BODY, tok, argc, argv));
}


static int
mlg_roffblkbodyout(void *arg, int tok)
{

	return(mlg_endtag((struct md_mlg *)arg, MD_NS_BODY, tok));
}


static int
mlg_roffblkheadin(void *arg, int tok, int *argc, char **argv)
{

	return(mlg_begintag((struct md_mlg *)arg, 
				MD_NS_HEAD, tok, argc, argv));
}


static int
mlg_roffblkheadout(void *arg, int tok)
{

	return(mlg_endtag((struct md_mlg *)arg, MD_NS_HEAD, tok));
}


static int
mlg_roffin(void *arg, int tok, int *argc, char **argv)
{

	return(mlg_begintag((struct md_mlg *)arg, 
				MD_NS_INLINE, tok, argc, argv));
}


static int
mlg_roffout(void *arg, int tok)
{

	return(mlg_endtag((struct md_mlg *)arg, MD_NS_INLINE, tok));
}


static void
mlg_roffmsg(void *arg, enum roffmsg lvl, 
		const char *buf, const char *pos, char *msg)
{

	mlg_msg((struct md_mlg *)arg, lvl, buf, pos, msg);
}


static int
mlg_roffdata(void *arg, int space, const char *start, char *buf)
{
	struct md_mlg	*p;

	assert(arg);
	p = (struct md_mlg *)arg;

	if ( ! mlg_data(p, space, start, buf))
		return(0);

	mlg_mode(p, MD_TEXT);

	return(1);
}


static void
mlg_vmsg(struct md_mlg *p, enum roffmsg lvl, const char *start, 
		const char *pos, const char *fmt, va_list ap)
{
	char		 buf[128];

	(void)vsnprintf(buf, sizeof(buf), fmt, ap);
	mlg_msg(p, lvl, start, pos, buf);
}


static void
mlg_warn(struct md_mlg *p, const char *start, 
		const char *pos, const char *fmt, ...)
{
	va_list		 ap;

	va_start(ap, fmt);
	mlg_vmsg(p, ROFF_WARN, start, pos, fmt, ap);
	va_end(ap);
}


static void
mlg_err(struct md_mlg *p, const char *start, 
		const char *pos, const char *fmt, ...)
{
	va_list		 ap;

	va_start(ap, fmt);
	mlg_vmsg(p, ROFF_ERROR, start, pos, fmt, ap);
	va_end(ap);
}


static void
mlg_msg(struct md_mlg *p, enum roffmsg lvl, 
		const char *buf, const char *pos, char *msg)
{
	char		*level;

	switch (lvl) {
	case (ROFF_WARN):
		if ( ! (MD_WARN_ALL & p->args->warnings))
			return;
		level = "warning";
		break;
	case (ROFF_ERROR):
		level = "error";
		break;
	default:
		abort();
	}
	
	if (pos)
		(void)fprintf(stderr, "%s:%zu: %s: %s (column %zu)\n", 
				p->rbuf->name, p->rbuf->line, level, 
				msg, pos - buf);
	else
		(void)fprintf(stderr, "%s: %s: %s\n", 
				p->rbuf->name, level, msg);
}