/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8; fill-column: 160 -*- */
/*
 *  Copyright (C) 2000 Helix Code Inc.
 *
 *  Authors: Michael Zucchi <notzed@helixcode.com>
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public License
 *  as published by the Free Software Foundation; either version 2 of
 *  the License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public
 *  License along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <string.h>
#include "camel-stream-filter.h"

#define d(x)
/*#include <stdio.h>*/

struct _filter {
	struct _filter *next;
	int id;
	CamelMimeFilter *filter;
};

struct _CamelStreamFilterPrivate {
	struct _filter *filters;
	int filterid;		/* next filter id */
	
	char *realbuffer;	/* buffer - READ_PAD */
	char *buffer;		/* READ_SIZE bytes */

	char *filtered;		/* the filtered data */
	size_t filteredlen;

	int last_was_read;	/* was the last op read or write? */
};

#define READ_PAD (64)		/* bytes padded before buffer */
#define READ_SIZE (4096)

#define _PRIVATE(o) (((CamelStreamFilter *)(o))->priv)

static void camel_stream_filter_class_init (CamelStreamFilterClass *klass);
static void camel_stream_filter_init       (CamelStreamFilter *obj);

static	ssize_t   do_read       (CamelStream *stream, char *buffer, size_t n);
static	ssize_t   do_write      (CamelStream *stream, const char *buffer, size_t n);
static	int       do_flush      (CamelStream *stream);
static	int       do_close      (CamelStream *stream);
static	gboolean  do_eos        (CamelStream *stream);
static	int       do_reset      (CamelStream *stream);

static CamelStreamClass *camel_stream_filter_parent;

static void
camel_stream_filter_class_init (CamelStreamFilterClass *klass)
{
	CamelStreamClass *camel_stream_class = (CamelStreamClass *) klass;

	camel_stream_filter_parent = CAMEL_STREAM_CLASS (camel_type_get_global_classfuncs (camel_stream_get_type ()));

	camel_stream_class->read = do_read;
	camel_stream_class->write = do_write;
	camel_stream_class->flush = do_flush;
	camel_stream_class->close = do_close;
	camel_stream_class->eos = do_eos; 
	camel_stream_class->reset = do_reset;

}

static void
camel_stream_filter_init (CamelStreamFilter *obj)
{
	struct _CamelStreamFilterPrivate *p;
	
	_PRIVATE(obj) = p = g_malloc0(sizeof(*p));
	p->realbuffer = g_malloc(READ_SIZE + READ_PAD);
	p->buffer = p->realbuffer + READ_PAD;
	p->last_was_read = TRUE;
}

static void
camel_stream_filter_finalize(CamelObject *o)
{
	CamelStreamFilter *filter = (CamelStreamFilter *)o;
	struct _CamelStreamFilterPrivate *p = _PRIVATE(filter);
	struct _filter *fn, *f;

	f = p->filters;
	while (f) {
		fn = f->next;
		camel_object_unref((CamelObject *)f->filter);
		g_free(f);
		f = fn;
	}
	g_free(p->realbuffer);
	g_free(p);
	camel_object_unref((CamelObject *)filter->source);
}

CamelType
camel_stream_filter_get_type (void)
{
	static CamelType type = CAMEL_INVALID_TYPE;
	
	if (type == CAMEL_INVALID_TYPE) {
		type = camel_type_register (CAMEL_STREAM_TYPE, "CamelStreamFilter",
					    sizeof (CamelStreamFilter),
					    sizeof (CamelStreamFilterClass),
					    (CamelObjectClassInitFunc) camel_stream_filter_class_init,
					    NULL,
					    (CamelObjectInitFunc) camel_stream_filter_init,
					    (CamelObjectFinalizeFunc) camel_stream_filter_finalize);
	}
	
	return type;
}

/**
 * camel_stream_filter_new:
 *
 * Create a new CamelStreamFilter object.
 * 
 * Return value: A new CamelStreamFilter object.
 **/
CamelStreamFilter *
camel_stream_filter_new_with_stream(CamelStream *stream)
{
	CamelStreamFilter *new = CAMEL_STREAM_FILTER ( camel_object_new (camel_stream_filter_get_type ()));

	new->source = stream;
	camel_object_ref ((CamelObject *)stream);

	return new;
}

/**
 * camel_stream_filter_add:
 * @filter: Initialised CamelStreamFilter.
 * @mf:  Filter to perform processing on stream.
 * 
 * Add a new CamelMimeFilter to execute during the processing of this
 * stream.  Each filter added is processed after the previous one.
 *
 * Note that a filter should only be added to a single stream
 * at a time, otherwise unpredictable results may occur.
 * 
 * Return value: A filter id for this CamelStreamFilter.
 **/
int
camel_stream_filter_add(CamelStreamFilter *filter, CamelMimeFilter *mf)
{
	struct _CamelStreamFilterPrivate *p = _PRIVATE(filter);
	struct _filter *fn, *f;

	fn = g_malloc(sizeof(*fn));
	fn->id = p->filterid++;
	fn->filter = mf;
	camel_object_ref((CamelObject *)mf);

	/* sure, we could use a GList, but we wouldn't save much */
	f = (struct _filter *)&p->filters;
	while (f->next)
		f = f->next;
	f->next = fn;
	fn->next = NULL;
	return fn->id;
}

/**
 * camel_stream_filter_remove:
 * @filter: Initialised CamelStreamFilter.
 * @id: Filter id, as returned from camel_stream_filter_add().
 * 
 * Remove a processing filter from the stream, by id.
 **/
void
camel_stream_filter_remove(CamelStreamFilter *filter, int id)
{
	struct _CamelStreamFilterPrivate *p = _PRIVATE(filter);
	struct _filter *fn, *f;

	f = (struct _filter *)&p->filters;
	while (f && f->next) {
		fn = f->next;
		if (fn->id == id) {
			f->next = fn->next;
			camel_object_unref((CamelObject *)fn->filter);
			g_free(fn);
		}
		f = f->next;
	}
}

static ssize_t
do_read (CamelStream *stream, char *buffer, size_t n)
{
	CamelStreamFilter *filter = (CamelStreamFilter *)stream;
	struct _CamelStreamFilterPrivate *p = _PRIVATE(filter);
	ssize_t size;
	struct _filter *f;

	p->last_was_read = TRUE;

	if (p->filteredlen<=0) {
		int presize = READ_SIZE;

		size = camel_stream_read(filter->source, p->buffer, READ_SIZE);
		if (size <= 0) {
			/* this is somewhat untested */
			if (camel_stream_eos(filter->source)) {
				f = p->filters;
				p->filtered = p->buffer;
				p->filteredlen = 0;
				while (f) {
					camel_mime_filter_complete(f->filter, p->filtered, p->filteredlen,
								   presize, &p->filtered, &p->filteredlen, &presize);
					f = f->next;
				}
				size = p->filteredlen;
			}
			if (size <= 0)
				return size;
		} else {
			f = p->filters;
			p->filtered = p->buffer;
			p->filteredlen = size;

			d(printf ("\n\nOriginal content: '"));
			d(fwrite(p->filtered, sizeof(char), p->filteredlen, stdout));
			d(printf("'\n"));

			while (f) {
				camel_mime_filter_filter(f->filter, p->filtered, p->filteredlen, presize,
							 &p->filtered, &p->filteredlen, &presize);

				d(printf ("Filtered content (%s): '",
					  camel_type_to_name(((CamelObject *)f->filter)->s.type)));
				d(fwrite(p->filtered, sizeof(char), p->filteredlen, stdout));
				d(printf("'\n"));

				f = f->next;
			}
		}
	}

	size = MIN(n, p->filteredlen);
	memcpy(buffer, p->filtered, size);
	p->filteredlen -= size;
	p->filtered += size;

	return size;
}

/* Note: Since the caller expects to write out as much as they asked us to
   write (for 'success'), we return what they asked us to write (for 'success')
   rather than the true number of written bytes */
static ssize_t
do_write (CamelStream *stream, const char *buf, size_t n)
{
	CamelStreamFilter *filter = (CamelStreamFilter *)stream;
	struct _CamelStreamFilterPrivate *p = _PRIVATE(filter);
	struct _filter *f;
	int presize;
	char *buffer = (char *)buf;
	size_t len = n;

	p->last_was_read = FALSE;

	d(printf ("\n\nWriting: Original content: '"));
	d(fwrite(buffer, sizeof(char), len, stdout));
	d(printf("'\n"));

	f = p->filters;
	presize = 0;
	while (f) {
		camel_mime_filter_filter(f->filter, buffer, len, presize, &buffer, &len, &presize);

		d(printf ("Filtered content (%s): '",
			  camel_type_to_name(((CamelObject *)f->filter)->s.type)));
		d(fwrite(buffer, sizeof(char), len, stdout));
		d(printf("'\n"));

		f = f->next;
	}

	if (camel_stream_write(filter->source, buffer, len) != len)
		return -1;

	return n;
}

static int
do_flush (CamelStream *stream)
{
	CamelStreamFilter *filter = (CamelStreamFilter *)stream;
	struct _CamelStreamFilterPrivate *p = _PRIVATE(filter);
	struct _filter *f;
	char *buffer;
	int len, presize;

	if (p->last_was_read) {
		g_warning("Flushing a filter stream without writing to it");
		return 0;
	}

	buffer = "";
	len = 0;
	presize = 0;
	f = p->filters;
	
	d(printf ("\n\nFlushing: Original content: '"));
	d(fwrite(buffer, sizeof(char), len, stdout));
	d(printf("'\n"));

	while (f) {
		camel_mime_filter_complete(f->filter, buffer, len, presize, &buffer, &len, &presize);

		d(printf ("Filtered content (%s): '",
			  camel_type_to_name(((CamelObject *)f->filter)->s.type)));
		d(fwrite(buffer, sizeof(char), len, stdout));
		d(printf("'\n"));

		f = f->next;
	}
	if (len > 0 && camel_stream_write(filter->source, buffer, len) == -1)
		return -1;
	return camel_stream_flush(filter->source);
}

static int
do_close (CamelStream *stream)
{
	CamelStreamFilter *filter = (CamelStreamFilter *)stream;
	struct _CamelStreamFilterPrivate *p = _PRIVATE(filter);

	if (!p->last_was_read) {
		do_flush(stream);
	}
	return camel_stream_close(filter->source);
}

static gboolean
do_eos (CamelStream *stream)
{
	CamelStreamFilter *filter = (CamelStreamFilter *)stream;
	struct _CamelStreamFilterPrivate *p = _PRIVATE(filter);

	if (p->filteredlen > 0)
		return FALSE;

	return camel_stream_eos(filter->source);
}

static int
do_reset (CamelStream *stream)
{
	CamelStreamFilter *filter = (CamelStreamFilter *)stream;
	struct _CamelStreamFilterPrivate *p = _PRIVATE(filter);
	struct _filter *f;

	p->filteredlen = 0;

	/* and reset filters */
	f = p->filters;
	while (f) {
		camel_mime_filter_reset(f->filter);
		f = f->next;
	}

	return camel_stream_reset(filter->source);
}