/* Copyright (C) 2020  C. McEnroe <june@causal.agency>
 *
 * 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 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 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 <https://www.gnu.org/licenses/>.
 */

#include <assert.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <time.h>

#include "archive.h"

static const char *Mailto = {
	"mailto:[mailbox]@[host]?subject=[re][subject]&In-Reply-To=[messageID]"
};

static const char *Envelope = TEMPLATE(
	<details id="[messageID]">
	<summary>
		<h1><a href="#[messageID]">[subject]</a></h1>
		<address>
			<a href="[mailto]">[from]</a>
		</address>
		<time datetime="[utc]">[date]</time>
	</summary>
);

int htmlEnvelope(FILE *file, const struct Envelope *envelope) {
	struct Variable mailtoVars[] = {
		{ "mailbox", envelope->from.mailbox },
		{ "host", envelope->from.host },
		{ "re", (strncmp(envelope->subject, "Re: ", 4) ? "Re: " : "") },
		{ "subject", envelope->subject },
		{ "messageID", envelope->messageID },
		{0},
	};

	size_t cap = sizeof(Mailto);
	for (struct Variable *var = mailtoVars; var->value; ++var) {
		cap += ESCAPE_URL_CAP(strlen(var->value));
	}
	char *mailto = malloc(cap);
	if (!mailto) err(EX_OSERR, "malloc");

	FILE *url = fmemopen(mailto, cap, "w");
	if (!url) err(EX_OSERR, "fmemopen");

	int error = 0
		|| templateRender(url, Mailto, mailtoVars, escapeURL)
		|| fclose(url);
	assert(!error);

	const char *from = envelope->from.name;
	if (!from) from = envelope->from.mailbox;

	char utc[sizeof("0000-00-00T00:00:00Z")];
	strftime(utc, sizeof(utc), "%FT%TZ", gmtime(&envelope->utc));

	char date[256];
	strftime(date, sizeof(date), "%c %z", &envelope->date);

	struct Variable vars[] = {
		{ "messageID", envelope->messageID },
		{ "subject", envelope->subject },
		{ "mailto", mailto },
		{ "from", from },
		{ "utc", utc },
		{ "date", date },
		{0},
	};
	error = templateRender(file, Envelope, vars, escapeXML);

	free(mailto);
	return error;
}