/* 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 <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <sysexits.h>
#include <time.h>

#include "archive.h"

const char *atomBaseURL;

static char *atomID(const struct Envelope *envelope) {
	struct Variable vars[] = {
		{ "messageID", envelope->messageID },
		{0},
	};
	return templateURL("mid:[messageID]", vars);
}

static int atomAuthor(FILE *file, struct Address addr) {
	// TODO: Conditionally include <email>.
	const char *template = TEMPLATE(
		<author>
			<name>[name]</name>
			<email>[mailbox]@[host]</email>
		</author>
	);
	struct Variable vars[] = {
		{ "name", addressName(addr) },
		{ "mailbox", addr.mailbox },
		{ "host", addr.host },
		{0},
	};
	return templateRender(file, template, vars, escapeXML);
}

static char *atomEntryURL(const struct Envelope *envelope) {
	struct Variable vars[] = {
		{ "name", pathSafe(envelope->messageID) },
		{0},
	};
	return templateURL("/message/[name].mbox", vars);
}

int atomEntryOpen(FILE *file, const struct Envelope *envelope) {
	const char *template = TEMPLATE(
		<entry>
		<id>[id]</id>
		<title>[title]</title>
		<updated>[updated]</updated>
		<link rel="alternate" type="application/mbox" href="[base][url]"/>
	);
	char *id = atomID(envelope);
	char updated[sizeof("0000-00-00T00:00:00Z")];
	strftime(updated, sizeof(updated), "%FT%TZ", gmtime(&envelope->time));
	char *url = atomEntryURL(envelope);
	struct Variable vars[] = {
		{ "id", id },
		{ "title", envelope->subject },
		{ "updated", updated },
		{ "base", (atomBaseURL ? atomBaseURL : "") },
		{ "url", url },
		{0},
	};
	int error = 0
		|| templateRender(file, template, vars, escapeXML)
		|| atomAuthor(file, envelope->from);
	free(id);
	free(url);
	return error;
}

int atomContent(FILE *file, const char *content) {
	const char *template = TEMPLATE(
		<content type="text">[content]</content>
	);
	struct Variable vars[] = {
		{ "content", content },
		{0},
	};
	return templateRender(file, template, vars, escapeXML);
}

int atomEntryClose(FILE *file) {
	return templateRender(file, TEMPLATE(</entry>), NULL, NULL);
}

static char *atomFeedURL(const struct Envelope *envelope, const char *type) {
	struct Variable vars[] = {
		{ "name", pathSafe(envelope->messageID) },
		{ "type", type },
		{0},
	};
	return templateURL("/thread/[name].[type]", vars);
}

int atomFeedOpen(FILE *file, const struct Envelope *envelope) {
	const char *template = TEMPLATE(
		<[q]xml version="1.0" encoding="utf-8"[q]>
		<feed xmlns="http://www.w3.org/2005/Atom">
		<id>[id]</id>
		<title>[title]</title>
		<updated>[updated]</updated>
		<link rel="self" href="[base][atom]"/>
		<link rel="alternate" type="text/html" href="[base][html]"/>
		<link rel="alternate" type="application/mbox" href="[base][mbox]"/>
	);
	char *id = atomID(envelope);
	time_t now = time(NULL);
	char updated[sizeof("0000-00-00T00:00:00Z")];
	strftime(updated, sizeof(updated), "%FT%TZ", gmtime(&now));
	char *atom = atomFeedURL(envelope, "atom");
	char *html = atomFeedURL(envelope, "html");
	char *mbox = atomFeedURL(envelope, "mbox");
	struct Variable vars[] = {
		{ "q", "?" },
		{ "id", id },
		{ "title", envelope->subject },
		{ "updated", updated },
		{ "base", (atomBaseURL ? atomBaseURL : "") },
		{ "atom", atom },
		{ "html", html },
		{ "mbox", mbox },
		{0},
	};
	int error = 0
		|| templateRender(file, template, vars, escapeXML)
		|| atomAuthor(file, envelope->from);
	free(id);
	free(atom);
	free(html);
	free(mbox);
	return error;
}

int atomFeedClose(FILE *file) {
	return templateRender(file, TEMPLATE(</feed>), NULL, NULL);
}