/* This file is part of Mailfromd.             -*- c -*-
   Copyright (C) 2008 Sergey Poznyakoff

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3, 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>. */

#include "msg.h"

struct current_header {
	mu_header_t hdr;
};

static void *
alloc_header()
{
	return xzalloc(sizeof(struct current_header));
}

static void
destroy_header(void *data)
{
	struct current_header *chdr = data;
	mu_header_destroy(&chdr->hdr, NULL);
	free(chdr);
}

static void
free_header(void *data)
{
	struct current_header *chdr = data;
	mu_header_destroy(&chdr->hdr, NULL);
}

MF_DECLARE_DATA(HEADER, alloc_header, destroy_header, free_header)

static mu_header_t
get_current_header(eval_environ_t env, mu_stream_t mstr)
{
	struct current_header *chdr = MF_GET_DATA;
	if (!chdr->hdr) {
		mu_header_t hdr;
		char *text;
		int rc;
		mu_off_t size;
		size_t total;
		size_t start;
		
		rc = mu_stream_size (mstr, &size);
		MF_ASSERT(rc == 0,
			  mfe_failure,
			  "mu_stream_size: %s",
			  mu_strerror (rc));
		text = malloc (size + 1);
		MF_ASSERT(text != NULL,
			  mfe_failure,
			  _("Not enough memory"));
		rc = mu_stream_seek(mstr, 0, SEEK_SET);
		MF_ASSERT(rc == 0,
			  mfe_failure,
			  "mu_stream_seek: %s",
			  mu_strerror(rc));

		for (total = 0; total < size;) {
			size_t nrd;
			
			rc = mu_stream_sequential_read(mstr,
						       text + total,
						       size - total, &nrd);
			if (rc || nrd == 0)
				break;
			total += nrd;
		}
		text[total] = 0;

		/* FIXME: Reposition the stream at its end.
		   This call may happen in the middle of capturing
		   so I have to make sure to not disturb the capturing
		   process.
		   FIXME: MU: The env_reposition call is a kludge
		   necessary because MU stream interface does not offer
		   mu_stream_tell function.
		*/
		env_reposition(env);

		if (memcmp (text, "From ", 5) == 0)
			start = strcspn (text, "\n") + 1;
		else
			start = 0;
		rc = mu_header_create (&hdr, text + start, total - start,
				       NULL);
		free(text);
		MF_ASSERT(rc == 0,
			  mfe_failure,
			  "mu_header_create: %s",
			  mu_strerror (rc));
		chdr->hdr = hdr;
	}
	return chdr->hdr;
}
		
/* number current_header_count([string name]) */
MF_STATE(eoh)
MF_STATE(body)
MF_STATE(eom)
MF_CAPTURE
MF_DEFUN(current_header_count, NUMBER, OPTIONAL, STRING name)
{
	mu_header_t hdr = get_current_header(env, env_get_stream(env));
	size_t total;
	size_t count;
	int rc = mu_header_get_field_count (hdr, &total);
	
	MF_ASSERT(rc == 0,
		  mfe_failure,
		  "mu_header_get_field_count: %s",
		  mu_strerror (rc));
	if (MF_DEFINED(name)) {
		size_t i;
		count = 0;
		for (i = 1; i <= total; i++) {
			const char *sptr;
			if (mu_header_sget_field_name(hdr, i, &sptr) == 0
			    && strcasecmp(sptr, name) == 0)
				count++;
		}
	} else
		count = total;
	MF_RETURN(count);
}
END

/* string current_header_nth_name(number index) */
MF_STATE(eoh)
MF_STATE(body)
MF_STATE(eom)
MF_CAPTURE
MF_DEFUN(current_header_nth_name, STRING, NUMBER index)
{
	mu_header_t hdr = get_current_header(env, env_get_stream(env));
	const char *sptr;
	int rc = mu_header_sget_field_name(hdr, index, &sptr);

	if (rc == MU_ERR_NOENT)
		MF_THROW(mfe_not_found,
			 _("requested item (#%ld) not found"),
			 index);
	else if (rc != 0)
		MF_THROW(mfe_failure,
			 "mu_header_sget_field_name: %s",
			 mu_strerror(rc));
	MF_RETURN_STRING(sptr);
}
END

/* string current_header_nth_value(number index) */
MF_STATE(eoh)
MF_STATE(body)
MF_STATE(eom)
MF_CAPTURE
MF_DEFUN(current_header_nth_value, STRING, NUMBER index)
{
	mu_header_t hdr = get_current_header(env, env_get_stream(env));
	const char *sptr;
	int rc = mu_header_sget_field_value(hdr, index, &sptr);

	if (rc == MU_ERR_NOENT)
		MF_THROW(mfe_not_found,
			 _("requested item (#%ld) not found"),
			 index);
	else if (rc != 0)
		MF_THROW(mfe_failure,
			 "mu_header_sget_field_name: %s",
			 mu_strerror(rc));
	MF_RETURN_STRING(sptr);
}
END

/* string current_header(string name[, number index]) */
MF_STATE(eoh)
MF_STATE(body)	
MF_STATE(eom)
MF_CAPTURE
MF_DEFUN(current_header, STRING, STRING name, OPTIONAL, NUMBER index)
{
	mu_header_t hdr = get_current_header(env, env_get_stream(env));
	const char *sptr;
	int rc = mu_header_sget_value_n(hdr, name, MF_OPTVAL(index, 1),
					&sptr);

	if (rc == MU_ERR_NOENT)
		MF_THROW(mfe_not_found,
			 _("requested item (%s,%ld) not found"),
			 name, MF_OPTVAL(index, 1));
	else if (rc != 0)
		MF_THROW(mfe_failure,
			 "mu_header_sget_field_name: %s",
			 mu_strerror(rc));
	MF_RETURN_STRING(sptr);
}
END

MF_INIT