/*
 * Copyright (C) 2014 John Crispin <blogic@openwrt.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation
 *
 * 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.
 */

#include <sys/types.h>
#include <arpa/inet.h>

#include <stdio.h>

#include <libubus.h>
#include <libubox/vlist.h>
#include <libubox/uloop.h>

#include "util.h"
#include "ubus.h"
#include "cache.h"
#include "service.h"
#include "interface.h"

static struct ubus_auto_conn conn;
static struct blob_buf b;

static int
mdns_reload(struct ubus_context *ctx, struct ubus_object *obj,
		struct ubus_request_data *req, const char *method,
		struct blob_attr *msg)
{
	service_init(1);
	return 0;
}

static int
mdns_scan(struct ubus_context *ctx, struct ubus_object *obj,
		struct ubus_request_data *req, const char *method,
		struct blob_attr *msg)
{
	cache_scan();
	return 0;
}

static int
mdns_browse(struct ubus_context *ctx, struct ubus_object *obj,
		struct ubus_request_data *req, const char *method,
		struct blob_attr *msg)
{
	struct cache_service *s, *q;
	char *buffer = (char *) mdns_buf;
	void *c1 = NULL, *c2;

	blob_buf_init(&b, 0);
	avl_for_each_element(&services, s, avl) {
		char *local;
		if (*((char *) s->avl.key) != '_')
			continue;
		snprintf(buffer, MAX_NAME_LEN, "%s", (const char *) s->avl.key);
		local = strstr(buffer, ".local");
		if (local)
			*local = '\0';
		if (!strcmp(buffer, "_tcp") || !strcmp(buffer, "_udp"))
			continue;

		if (!c1) {
			c1 = blobmsg_open_table(&b, buffer);
		}
		snprintf(buffer, MAX_NAME_LEN, "%s", (const char *) s->entry);
		local = strstr(buffer, "._");
		if (local)
			*local = '\0';
		c2 = blobmsg_open_table(&b, buffer);
		strncat(buffer, ".local", MAX_NAME_LEN);
		cache_dump_records(&b, buffer);
		cache_dump_records(&b, s->entry);
		blobmsg_close_table(&b, c2);
		q = avl_next_element(s, avl);
		if (!q || avl_is_last(&services, &s->avl) || strcmp(s->avl.key, q->avl.key)) {
			blobmsg_close_table(&b, c1);
			c1 = NULL;
		}
	}
	ubus_send_reply(ctx, req, b.head);

	return UBUS_STATUS_OK;
}

static int
mdns_hosts(struct ubus_context *ctx, struct ubus_object *obj,
		struct ubus_request_data *req, const char *method,
		struct blob_attr *msg)
{
	struct cache_service *s;
	char *buffer = (char *) mdns_buf;
	void *c;

	blob_buf_init(&b, 0);
	avl_for_each_element(&services, s, avl) {
		char *local;
		if (*((char *) s->avl.key) == '_')
			continue;
		snprintf(buffer, MAX_NAME_LEN, "%s", (const char *) s->entry);
		local = strstr(buffer, "._");
		if (local)
			*local = '\0';
		c = blobmsg_open_table(&b, buffer);
		strncat(buffer, ".local", MAX_NAME_LEN);
		cache_dump_records(&b, buffer);
		cache_dump_records(&b, s->entry);
		blobmsg_close_table(&b, c);
	}
	ubus_send_reply(ctx, req, b.head);

	return UBUS_STATUS_OK;
}

enum {
	CFG_INTERFACES,
	CFG_KEEP,
	CFG_MAX
};

static const struct blobmsg_policy config_policy[] = {
	[CFG_INTERFACES]	= { "interfaces", BLOBMSG_TYPE_ARRAY },
	[CFG_KEEP]		= { "keep", BLOBMSG_TYPE_BOOL },
};

static int
mdns_set_config(struct ubus_context *ctx, struct ubus_object *obj,
		    struct ubus_request_data *req, const char *method,
		    struct blob_attr *msg)
{
	struct blob_attr *data[CFG_MAX], *cur;
	int rem, keep = false;

	blobmsg_parse(config_policy, CFG_MAX, data, blob_data(msg), blob_len(msg));
	if (!data[CFG_INTERFACES])
		return UBUS_STATUS_INVALID_ARGUMENT;

	if (!blobmsg_check_attr_list(data[CFG_INTERFACES], BLOBMSG_TYPE_STRING))
		return UBUS_STATUS_INVALID_ARGUMENT;

	keep = data[CFG_KEEP] && blobmsg_get_bool(data[CFG_KEEP]);
	if (!keep) {
		vlist_update(&interfaces);
		ubus_notify(ctx, obj, "set_config", NULL, 1000);
	}

	blobmsg_for_each_attr(cur, data[CFG_INTERFACES], rem)
		interface_add(blobmsg_data(cur));

	if (!keep)
		vlist_flush(&interfaces);

	return 0;
}

enum query_attr {
	QUERY_QUESTION,
	QUERY_IFACE,
	QUERY_TYPE,
	QUERY_MAX
};

static const struct blobmsg_policy query_policy[QUERY_MAX] = {
	[QUERY_QUESTION]= { "question", BLOBMSG_TYPE_STRING },
	[QUERY_IFACE]	= { "interface", BLOBMSG_TYPE_STRING },
	[QUERY_TYPE]	= { "type", BLOBMSG_TYPE_INT32 },
};

static int
mdns_query(struct ubus_context *ctx, struct ubus_object *obj,
		    struct ubus_request_data *req, const char *method,
		    struct blob_attr *msg)
{
	struct blob_attr *tb[QUERY_MAX], *c;
	const char *question = "_services._dns-sd._udp.local";
	const char *ifname;
	int type = TYPE_ANY;

	blobmsg_parse(query_policy, QUERY_MAX, tb, blob_data(msg), blob_len(msg));

	if (!(c = tb[QUERY_IFACE]))
		return UBUS_STATUS_INVALID_ARGUMENT;

	ifname = blobmsg_get_string(c);

	if ((c = tb[QUERY_QUESTION]))
		question = blobmsg_get_string(c);

	if ((c = tb[QUERY_TYPE]))
		type = blobmsg_get_u32(c);

	struct interface *iface_v4 = interface_get(ifname, 0, 1);
	struct interface *iface_v6 = interface_get(ifname, 1, 1);

	if (!iface_v4 && !iface_v6)
		return UBUS_STATUS_NOT_FOUND;

	if (!strcmp(method, "query")) {
		if (iface_v4)
			dns_send_question(iface_v4, question, type, 0);

		if (iface_v6)
			dns_send_question(iface_v6, question, type, 0);

		return UBUS_STATUS_OK;
	} else if (!strcmp(method, "fetch")) {
		blob_buf_init(&b, 0);
		void *k = blobmsg_open_array(&b, "records");
		cache_dump_recursive(&b, question, type, iface_v4 ? iface_v4 : iface_v6);
		blobmsg_close_array(&b, k);
		ubus_send_reply(ctx, req, b.head);
		return UBUS_STATUS_OK;
	} else {
		return UBUS_STATUS_INVALID_ARGUMENT;
	}
}


static const struct ubus_method mdns_methods[] = {
	UBUS_METHOD("set_config", mdns_set_config, config_policy),
	UBUS_METHOD("query", mdns_query, query_policy),
	UBUS_METHOD("fetch", mdns_query, query_policy),
	UBUS_METHOD_NOARG("scan", mdns_scan),
	UBUS_METHOD_NOARG("browse", mdns_browse),
	UBUS_METHOD_NOARG("hosts", mdns_hosts),
	UBUS_METHOD_NOARG("reload", mdns_reload),
};

static struct ubus_object_type mdns_object_type =
	UBUS_OBJECT_TYPE("mdns", mdns_methods);

static struct ubus_object mdns_object = {
	.name = "mdns",
	.type = &mdns_object_type,
	.methods = mdns_methods,
	.n_methods = ARRAY_SIZE(mdns_methods),
};

static void
ubus_connect_handler(struct ubus_context *ctx)
{
	int ret;

	ret = ubus_add_object(ctx, &mdns_object);
	if (ret)
		fprintf(stderr, "Failed to add object: %s\n", ubus_strerror(ret));
}

void
ubus_startup(void)
{
	conn.cb = ubus_connect_handler;
	ubus_auto_connect(&conn);
}

int ubus_service_list(ubus_data_handler_t cb)
{
	uint32_t id;
	int ret;

	blob_buf_init(&b, 0);
	ret = ubus_lookup_id(&conn.ctx, "service", &id);
	if (ret)
		return ret;

	return ubus_invoke(&conn.ctx, id, "list", b.head, cb, NULL, 5 * 1000);
}