/* $Id$ */
/*
 * 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 <sys/param.h>
#include <sys/stat.h>

#include <assert.h>
#include <err.h>
#include <fcntl.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "libmdocml.h"

#define	BUFFER_IN_DEF	BUFSIZ
#define	BUFFER_OUT_DEF	BUFSIZ
#define	BUFFER_LINE	BUFSIZ

struct md_rbuf {
	int		 fd;
	const char	*name;
	char		*buf;
	size_t		 bufsz;
	size_t		 line;
};

struct md_mbuf {
	int		 fd;
	const char	*name;
	char		*buf;
	size_t		 bufsz;
	size_t		 pos;
};

static void		 usage(void);

static int		 md_begin(const char *, const char *);
static int		 md_begin_io(const char *, const char *);
static int		 md_begin_bufs(struct md_mbuf *, struct md_rbuf *);
static int		 md_run(struct md_mbuf *, struct md_rbuf *);
static int		 md_line(struct md_mbuf *, const struct md_rbuf *,
				const char *, size_t);

static ssize_t		 md_buf_fill(struct md_rbuf *);
static int		 md_buf_flush(struct md_mbuf *);

static int		 md_buf_putchar(struct md_mbuf *, char);
static int		 md_buf_puts(struct md_mbuf *, 
				const char *, size_t);


int
main(int argc, char *argv[])
{
	int		 c;
	char		*out, *in;

	extern char	*optarg;
	extern int	 optind;

	out = NULL;
	
	while (-1 != (c = getopt(argc, argv, "o:")))
		switch (c) {
		case ('o'):
			out = optarg;
			break;
		default:
			usage();
			return(1);
		}

	argv += optind;
	if (1 != (argc -= optind)) {
		usage();
		return(1);
	}

	argc--;
	in = *argv++;

	return(md_begin(out, in));
}


static int
md_begin(const char *out, const char *in)
{
	char		 buf[MAXPATHLEN];

	assert(in);
	if (out)
		return(md_begin_io(out, in));

	if (strlcpy(buf, in, MAXPATHLEN) >= MAXPATHLEN)
		warnx("output filename too long");
	else if (strlcat(buf, ".html", MAXPATHLEN) >= MAXPATHLEN)
		warnx("output filename too long");
	else 
		return(md_begin_io(buf, in));

	return(1);
}


static int
md_begin_io(const char *out, const char *in)
{
	int		 c;
	struct md_rbuf	 fin;
	struct md_mbuf	 fout;

	assert(out);
	assert(in);

	/* TODO: accept "-" as both input and output. */

	fin.name = in;

	if (-1 == (fin.fd = open(fin.name, O_RDONLY, 0))) {
		warn("%s", fin.name);
		return(1);
	}

	fout.name = out;

	fout.fd = open(fout.name, O_WRONLY | O_CREAT | O_TRUNC, 0644);
	if (-1 == fout.fd) {
		warn("%s", fout.name);
		if (-1 == close(fin.fd))
			warn("%s", fin.name);
		return(1);
	}

	c = md_begin_bufs(&fout, &fin);

	if (-1 == close(fin.fd)) {
		warn("%s", in);
		c = 1;
	}
	if (-1 == close(fout.fd)) {
		warn("%s", out);
		c = 1;
	}

	return(c);
}


static int
md_begin_bufs(struct md_mbuf *out, struct md_rbuf *in)
{
	struct stat	 stin, stout;
	int		 c;

	assert(in);
	assert(out);

	if (-1 == fstat(in->fd, &stin)) {
		warn("%s", in->name);
		return(1);
	} else if (-1 == fstat(out->fd, &stout)) {
		warn("%s", out->name);
		return(1);
	}

	in->bufsz = MAX(stin.st_blksize, BUFFER_IN_DEF);

	out->bufsz = MAX(stout.st_blksize, BUFFER_OUT_DEF);

	if (NULL == (in->buf = malloc(in->bufsz))) {
		warn("malloc");
		return(1);
	} else if (NULL == (out->buf = malloc(out->bufsz))) {
		warn("malloc");
		free(in->buf);
		return(1);
	}

	c = md_run(out, in);

	free(in->buf);
	free(out->buf);

	return(c);
}


static ssize_t
md_buf_fill(struct md_rbuf *in)
{
	ssize_t		 ssz;

	assert(in);
	assert(in->buf);
	assert(in->bufsz > 0);
	assert(in->name);

	if (-1 == (ssz = read(in->fd, in->buf, in->bufsz))) 
		warn("%s", in->name);

	return(ssz);
}


static int
md_run(struct md_mbuf *out, struct md_rbuf *in)
{
	ssize_t		 sz, i;
	char		 line[BUFFER_LINE];
	size_t		 pos;

	assert(in);
	assert(out); 

	out->pos = 0;
	in->line = 1;

	/* LINTED */
	for (pos = 0; ; ) {
		if (-1 == (sz = md_buf_fill(in)))
			return(1);
		else if (0 == sz)
			break;

		for (i = 0; i < sz; i++) {
			if ('\n' == in->buf[i]) {
				if (md_line(out, in, line, pos))
					return(1);
				in->line++;
				pos = 0;
				continue;
			}

			if (pos < BUFFER_LINE) {
				/* LINTED */
				line[pos++] = in->buf[i];
				continue;
			}

			warnx("%s: line %zu too long",
					in->name, in->line);
			return(1);
		}
	}

	if (0 != pos && md_line(out, in, line, pos))
		return(1);

	return(md_buf_flush(out) ? 0 : 1);
}


static int
md_buf_flush(struct md_mbuf *buf)
{
	ssize_t		 sz;

	assert(buf);
	assert(buf->buf);
	assert(buf->name);

	if (0 == buf->pos)
		return(1);

	sz = write(buf->fd, buf->buf, buf->pos);

	if (-1 == sz) {
		warn("%s", buf->name);
		return(0);
	} else if ((size_t)sz != buf->pos) {
		warnx("%s: short write", buf->name);
		return(0);
	}

	buf->pos = 0;
	return(1);
}


static int
md_buf_putchar(struct md_mbuf *buf, char c)
{
	return(md_buf_puts(buf, &c, 1));
}


static int
md_buf_puts(struct md_mbuf *buf, const char *p, size_t sz)
{
	size_t		 ssz;

	assert(p);
	assert(buf);
	assert(buf->buf);

	while (buf->pos + sz > buf->bufsz) {
		ssz = buf->bufsz - buf->pos;
		(void)memcpy(buf->buf + buf->pos, p, ssz);
		p += ssz;
		sz -= ssz;
		buf->pos += ssz;

		if ( ! md_buf_flush(buf))
			return(0);
	}

	(void)memcpy(buf->buf + buf->pos, p, sz);
	buf->pos += sz;
	return(1);
}


static int
md_line(struct md_mbuf *out, const struct md_rbuf *in,
		const char *buf, size_t sz)
{

	/* FIXME: this is just a placeholder function. */

	assert(buf);
	assert(out);
	assert(in);

	if ( ! md_buf_puts(out, buf, sz))
		return(1);
	if ( ! md_buf_putchar(out, '\n'))
		return(1);

	return(0);
}


static void
usage(void)
{
	extern char	*__progname;

	(void)printf("usage: %s [-o outfile] infile\n", __progname);
}