/*  Bluetooth Mesh */

/*
 * Copyright (c) 2017 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr.h>
#include <sys/byteorder.h>

#include <net/buf.h>
#include <bluetooth/bluetooth.h>
#include <bluetooth/conn.h>
#include <bluetooth/gatt.h>
#include <bluetooth/mesh.h>

#define BT_DBG_ENABLED IS_ENABLED(CONFIG_BT_MESH_DEBUG_PROXY)
#define LOG_MODULE_NAME bt_mesh_proxy
#include "common/log.h"

#include "mesh.h"
#include "adv.h"
#include "net.h"
#include "rpl.h"
#include "transport.h"
#include "prov.h"
#include "beacon.h"
#include "foundation.h"
#include "access.h"
#include "proxy.h"

#define PDU_TYPE(data)     (data[0] & BIT_MASK(6))
#define PDU_SAR(data)      (data[0] >> 6)

/* Mesh Profile 1.0 Section 6.6:
 * "The timeout for the SAR transfer is 20 seconds. When the timeout
 *  expires, the Proxy Server shall disconnect."
 */
#define PROXY_SAR_TIMEOUT  K_SECONDS(20)

#define SAR_COMPLETE       0x00
#define SAR_FIRST          0x01
#define SAR_CONT           0x02
#define SAR_LAST           0x03

#define CFG_FILTER_SET     0x00
#define CFG_FILTER_ADD     0x01
#define CFG_FILTER_REMOVE  0x02
#define CFG_FILTER_STATUS  0x03

#define PDU_HDR(sar, type) (sar << 6 | (type & BIT_MASK(6)))

#define CLIENT_BUF_SIZE 65

#if defined(CONFIG_BT_MESH_DEBUG_USE_ID_ADDR)
#define ADV_OPT_USE_IDENTITY BT_LE_ADV_OPT_USE_IDENTITY
#else
#define ADV_OPT_USE_IDENTITY 0
#endif

#if defined(CONFIG_BT_MESH_PROXY_USE_DEVICE_NAME)
#define ADV_OPT_USE_NAME BT_LE_ADV_OPT_USE_NAME
#else
#define ADV_OPT_USE_NAME 0
#endif

#define ADV_OPT_PROV                                                           \
	(BT_LE_ADV_OPT_CONNECTABLE | BT_LE_ADV_OPT_SCANNABLE |                 \
	 BT_LE_ADV_OPT_ONE_TIME | ADV_OPT_USE_IDENTITY |                       \
	 BT_LE_ADV_OPT_USE_NAME)

#define ADV_OPT_PROXY                                                          \
	(BT_LE_ADV_OPT_CONNECTABLE | BT_LE_ADV_OPT_SCANNABLE |                 \
	 BT_LE_ADV_OPT_ONE_TIME | ADV_OPT_USE_IDENTITY |                       \
	 ADV_OPT_USE_NAME)

#define ADV_SLOW_INT                                                           \
	.interval_min = BT_GAP_ADV_SLOW_INT_MIN,                               \
	.interval_max = BT_GAP_ADV_SLOW_INT_MAX

#define ADV_FAST_INT                                                           \
	.interval_min = BT_GAP_ADV_FAST_INT_MIN_2,                             \
	.interval_max = BT_GAP_ADV_FAST_INT_MAX_2

#if defined(CONFIG_BT_MESH_GATT_PROXY)
static void proxy_send_beacons(struct k_work *work);
#endif

#if defined(CONFIG_BT_MESH_PB_GATT)
static bool prov_fast_adv;
#endif

static struct bt_mesh_proxy_client {
	struct bt_conn *conn;
	uint16_t filter[CONFIG_BT_MESH_PROXY_FILTER_SIZE];
	enum __packed {
		NONE,
		WHITELIST,
		BLACKLIST,
		PROV,
	} filter_type;
	uint8_t msg_type;
#if defined(CONFIG_BT_MESH_GATT_PROXY)
	struct k_work send_beacons;
#endif
	struct k_work_delayable  sar_timer;
	struct net_buf_simple    buf;
} clients[CONFIG_BT_MAX_CONN] = {
	[0 ... (CONFIG_BT_MAX_CONN - 1)] = {
#if defined(CONFIG_BT_MESH_GATT_PROXY)
		.send_beacons = Z_WORK_INITIALIZER(proxy_send_beacons),
#endif
	},
};

static sys_slist_t idle_waiters;
static atomic_t pending_notifications;
static uint8_t __noinit client_buf_data[CLIENT_BUF_SIZE * CONFIG_BT_MAX_CONN];

/* Track which service is enabled */
static enum {
	MESH_GATT_NONE,
	MESH_GATT_PROV,
	MESH_GATT_PROXY,
} gatt_svc = MESH_GATT_NONE;

static struct bt_mesh_proxy_client *find_client(struct bt_conn *conn)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(clients); i++) {
		if (clients[i].conn == conn) {
			return &clients[i];
		}
	}

	return NULL;
}

static void proxy_sar_timeout(struct k_work *work)
{
	struct k_work_delayable *dwork = k_work_delayable_from_work(work);
	struct bt_mesh_proxy_client *client =
		CONTAINER_OF(dwork, struct bt_mesh_proxy_client, sar_timer);

	if (!client->conn) {
		return;
	}

	if (!client->buf.len) {
		BT_DBG("No pending Proxy SAR message");
		return;
	}

	BT_WARN("Proxy SAR timeout");

	bt_conn_disconnect(client->conn, BT_HCI_ERR_REMOTE_USER_TERM_CONN);
}

#if defined(CONFIG_BT_MESH_GATT_PROXY)
/* Next subnet in queue to be advertised */
static struct bt_mesh_subnet *beacon_sub;

static int proxy_segment_and_send(struct bt_conn *conn, uint8_t type,
				  struct net_buf_simple *msg);

static int filter_set(struct bt_mesh_proxy_client *client,
		      struct net_buf_simple *buf)
{
	uint8_t type;

	if (buf->len < 1) {
		BT_WARN("Too short Filter Set message");
		return -EINVAL;
	}

	type = net_buf_simple_pull_u8(buf);
	BT_DBG("type 0x%02x", type);

	switch (type) {
	case 0x00:
		(void)memset(client->filter, 0, sizeof(client->filter));
		client->filter_type = WHITELIST;
		break;
	case 0x01:
		(void)memset(client->filter, 0, sizeof(client->filter));
		client->filter_type = BLACKLIST;
		break;
	default:
		BT_WARN("Prohibited Filter Type 0x%02x", type);
		return -EINVAL;
	}

	return 0;
}

static void filter_add(struct bt_mesh_proxy_client *client, uint16_t addr)
{
	int i;

	BT_DBG("addr 0x%04x", addr);

	if (addr == BT_MESH_ADDR_UNASSIGNED) {
		return;
	}

	for (i = 0; i < ARRAY_SIZE(client->filter); i++) {
		if (client->filter[i] == addr) {
			return;
		}
	}

	for (i = 0; i < ARRAY_SIZE(client->filter); i++) {
		if (client->filter[i] == BT_MESH_ADDR_UNASSIGNED) {
			client->filter[i] = addr;
			return;
		}
	}
}

static void filter_remove(struct bt_mesh_proxy_client *client, uint16_t addr)
{
	int i;

	BT_DBG("addr 0x%04x", addr);

	if (addr == BT_MESH_ADDR_UNASSIGNED) {
		return;
	}

	for (i = 0; i < ARRAY_SIZE(client->filter); i++) {
		if (client->filter[i] == addr) {
			client->filter[i] = BT_MESH_ADDR_UNASSIGNED;
			return;
		}
	}
}

static void send_filter_status(struct bt_mesh_proxy_client *client,
			       struct bt_mesh_net_rx *rx,
			       struct net_buf_simple *buf)
{
	struct bt_mesh_net_tx tx = {
		.sub = rx->sub,
		.ctx = &rx->ctx,
		.src = bt_mesh_primary_addr(),
	};
	uint16_t filter_size;
	int i, err;

	/* Configuration messages always have dst unassigned */
	tx.ctx->addr = BT_MESH_ADDR_UNASSIGNED;

	net_buf_simple_reset(buf);
	net_buf_simple_reserve(buf, 10);

	net_buf_simple_add_u8(buf, CFG_FILTER_STATUS);

	if (client->filter_type == WHITELIST) {
		net_buf_simple_add_u8(buf, 0x00);
	} else {
		net_buf_simple_add_u8(buf, 0x01);
	}

	for (filter_size = 0U, i = 0; i < ARRAY_SIZE(client->filter); i++) {
		if (client->filter[i] != BT_MESH_ADDR_UNASSIGNED) {
			filter_size++;
		}
	}

	net_buf_simple_add_be16(buf, filter_size);

	BT_DBG("%u bytes: %s", buf->len, bt_hex(buf->data, buf->len));

	err = bt_mesh_net_encode(&tx, buf, true);
	if (err) {
		BT_ERR("Encoding Proxy cfg message failed (err %d)", err);
		return;
	}

	err = proxy_segment_and_send(client->conn, BT_MESH_PROXY_CONFIG, buf);
	if (err) {
		BT_ERR("Failed to send proxy cfg message (err %d)", err);
	}
}

static void proxy_cfg(struct bt_mesh_proxy_client *client)
{
	NET_BUF_SIMPLE_DEFINE(buf, BT_MESH_NET_MAX_PDU_LEN);
	struct bt_mesh_net_rx rx;
	uint8_t opcode;
	int err;

	err = bt_mesh_net_decode(&client->buf, BT_MESH_NET_IF_PROXY_CFG,
				 &rx, &buf);
	if (err) {
		BT_ERR("Failed to decode Proxy Configuration (err %d)", err);
		return;
	}

	rx.local_match = 1U;

	if (bt_mesh_rpl_check(&rx, NULL)) {
		BT_WARN("Replay: src 0x%04x dst 0x%04x seq 0x%06x",
			rx.ctx.addr, rx.ctx.recv_dst, rx.seq);
		return;
	}

	/* Remove network headers */
	net_buf_simple_pull(&buf, BT_MESH_NET_HDR_LEN);

	BT_DBG("%u bytes: %s", buf.len, bt_hex(buf.data, buf.len));

	if (buf.len < 1) {
		BT_WARN("Too short proxy configuration PDU");
		return;
	}

	opcode = net_buf_simple_pull_u8(&buf);
	switch (opcode) {
	case CFG_FILTER_SET:
		filter_set(client, &buf);
		send_filter_status(client, &rx, &buf);
		break;
	case CFG_FILTER_ADD:
		while (buf.len >= 2) {
			uint16_t addr;

			addr = net_buf_simple_pull_be16(&buf);
			filter_add(client, addr);
		}
		send_filter_status(client, &rx, &buf);
		break;
	case CFG_FILTER_REMOVE:
		while (buf.len >= 2) {
			uint16_t addr;

			addr = net_buf_simple_pull_be16(&buf);
			filter_remove(client, addr);
		}
		send_filter_status(client, &rx, &buf);
		break;
	default:
		BT_WARN("Unhandled configuration OpCode 0x%02x", opcode);
		break;
	}
}

static int beacon_send(struct bt_conn *conn, struct bt_mesh_subnet *sub)
{
	NET_BUF_SIMPLE_DEFINE(buf, 23);

	net_buf_simple_reserve(&buf, 1);
	bt_mesh_beacon_create(sub, &buf);

	return proxy_segment_and_send(conn, BT_MESH_PROXY_BEACON, &buf);
}

static int send_beacon_cb(struct bt_mesh_subnet *sub, void *cb_data)
{
	struct bt_mesh_proxy_client *client = cb_data;

	return beacon_send(client->conn, sub);
}

static void proxy_send_beacons(struct k_work *work)
{
	struct bt_mesh_proxy_client *client;

	client = CONTAINER_OF(work, struct bt_mesh_proxy_client, send_beacons);

	(void)bt_mesh_subnet_find(send_beacon_cb, client);
}

void bt_mesh_proxy_beacon_send(struct bt_mesh_subnet *sub)
{
	int i;

	if (!sub) {
		/* NULL means we send on all subnets */
		bt_mesh_subnet_foreach(bt_mesh_proxy_beacon_send);
		return;
	}

	for (i = 0; i < ARRAY_SIZE(clients); i++) {
		if (clients[i].conn) {
			beacon_send(clients[i].conn, sub);
		}
	}
}

static void node_id_start(struct bt_mesh_subnet *sub)
{
	sub->node_id = BT_MESH_NODE_IDENTITY_RUNNING;
	sub->node_id_start = k_uptime_get_32();

	Z_STRUCT_SECTION_FOREACH(bt_mesh_proxy_cb, cb) {
		if (cb->identity_enabled) {
			cb->identity_enabled(sub->net_idx);
		}
	}
}

void bt_mesh_proxy_identity_start(struct bt_mesh_subnet *sub)
{
	node_id_start(sub);

	/* Prioritize the recently enabled subnet */
	beacon_sub = sub;
}

void bt_mesh_proxy_identity_stop(struct bt_mesh_subnet *sub)
{
	sub->node_id = BT_MESH_NODE_IDENTITY_STOPPED;
	sub->node_id_start = 0U;

	Z_STRUCT_SECTION_FOREACH(bt_mesh_proxy_cb, cb) {
		if (cb->identity_disabled) {
			cb->identity_disabled(sub->net_idx);
		}
	}
}

int bt_mesh_proxy_identity_enable(void)
{
	BT_DBG("");

	if (!bt_mesh_is_provisioned()) {
		return -EAGAIN;
	}

	if (bt_mesh_subnet_foreach(node_id_start)) {
		bt_mesh_adv_update();
	}

	return 0;
}

#endif /* GATT_PROXY */

static void proxy_complete_pdu(struct bt_mesh_proxy_client *client)
{
	switch (client->msg_type) {
#if defined(CONFIG_BT_MESH_GATT_PROXY)
	case BT_MESH_PROXY_NET_PDU:
		BT_DBG("Mesh Network PDU");
		bt_mesh_net_recv(&client->buf, 0, BT_MESH_NET_IF_PROXY);
		break;
	case BT_MESH_PROXY_BEACON:
		BT_DBG("Mesh Beacon PDU");
		bt_mesh_beacon_recv(&client->buf);
		break;
	case BT_MESH_PROXY_CONFIG:
		BT_DBG("Mesh Configuration PDU");
		proxy_cfg(client);
		break;
#endif
#if defined(CONFIG_BT_MESH_PB_GATT)
	case BT_MESH_PROXY_PROV:
		BT_DBG("Mesh Provisioning PDU");
		bt_mesh_pb_gatt_recv(client->conn, &client->buf);
		break;
#endif
	default:
		BT_WARN("Unhandled Message Type 0x%02x", client->msg_type);
		break;
	}

	net_buf_simple_reset(&client->buf);
}

#define ATTR_IS_PROV(attr) (attr->user_data != NULL)

static ssize_t proxy_recv(struct bt_conn *conn,
			  const struct bt_gatt_attr *attr, const void *buf,
			  uint16_t len, uint16_t offset, uint8_t flags)
{
	struct bt_mesh_proxy_client *client = find_client(conn);
	const uint8_t *data = buf;

	if (!client) {
		return -ENOTCONN;
	}

	if (len < 1) {
		BT_WARN("Too small Proxy PDU");
		return -EINVAL;
	}

	if (ATTR_IS_PROV(attr) != (PDU_TYPE(data) == BT_MESH_PROXY_PROV)) {
		BT_WARN("Proxy PDU type doesn't match GATT service");
		return -EINVAL;
	}

	if (len - 1 > net_buf_simple_tailroom(&client->buf)) {
		BT_WARN("Too big proxy PDU");
		return -EINVAL;
	}

	switch (PDU_SAR(data)) {
	case SAR_COMPLETE:
		if (client->buf.len) {
			BT_WARN("Complete PDU while a pending incomplete one");
			return -EINVAL;
		}

		client->msg_type = PDU_TYPE(data);
		net_buf_simple_add_mem(&client->buf, data + 1, len - 1);
		proxy_complete_pdu(client);
		break;

	case SAR_FIRST:
		if (client->buf.len) {
			BT_WARN("First PDU while a pending incomplete one");
			return -EINVAL;
		}

		k_work_reschedule(&client->sar_timer, PROXY_SAR_TIMEOUT);
		client->msg_type = PDU_TYPE(data);
		net_buf_simple_add_mem(&client->buf, data + 1, len - 1);
		break;

	case SAR_CONT:
		if (!client->buf.len) {
			BT_WARN("Continuation with no prior data");
			return -EINVAL;
		}

		if (client->msg_type != PDU_TYPE(data)) {
			BT_WARN("Unexpected message type in continuation");
			return -EINVAL;
		}

		k_work_reschedule(&client->sar_timer, PROXY_SAR_TIMEOUT);
		net_buf_simple_add_mem(&client->buf, data + 1, len - 1);
		break;

	case SAR_LAST:
		if (!client->buf.len) {
			BT_WARN("Last SAR PDU with no prior data");
			return -EINVAL;
		}

		if (client->msg_type != PDU_TYPE(data)) {
			BT_WARN("Unexpected message type in last SAR PDU");
			return -EINVAL;
		}

		/* If this fails, the work handler exits early, as there's no
		 * active SAR buffer.
		 */
		(void)k_work_cancel_delayable(&client->sar_timer);
		net_buf_simple_add_mem(&client->buf, data + 1, len - 1);
		proxy_complete_pdu(client);
		break;
	}

	return len;
}

static int conn_count;

static void proxy_connected(struct bt_conn *conn, uint8_t err)
{
	struct bt_mesh_proxy_client *client;
	int i;

	BT_DBG("conn %p err 0x%02x", (void *)conn, err);

	conn_count++;

	/* Try to re-enable advertising in case it's possible */
	if (conn_count < CONFIG_BT_MAX_CONN) {
		bt_mesh_adv_update();
	}

	for (client = NULL, i = 0; i < ARRAY_SIZE(clients); i++) {
		if (!clients[i].conn) {
			client = &clients[i];
			break;
		}
	}

	if (!client) {
		BT_ERR("No free Proxy Client objects");
		return;
	}

	client->conn = bt_conn_ref(conn);
	client->filter_type = NONE;
	(void)memset(client->filter, 0, sizeof(client->filter));
	net_buf_simple_reset(&client->buf);
}

static void proxy_disconnected(struct bt_conn *conn, uint8_t reason)
{
	int i;

	BT_DBG("conn %p reason 0x%02x", (void *)conn, reason);

	conn_count--;

	for (i = 0; i < ARRAY_SIZE(clients); i++) {
		struct bt_mesh_proxy_client *client = &clients[i];

		if (client->conn == conn) {
			if (IS_ENABLED(CONFIG_BT_MESH_PB_GATT) &&
			    client->filter_type == PROV) {
				bt_mesh_pb_gatt_close(conn);
			}

			/* If this fails, the work handler exits early, as
			 * there's no active connection.
			 */
			(void)k_work_cancel_delayable(&client->sar_timer);
			bt_conn_unref(client->conn);
			client->conn = NULL;
			break;
		}
	}

	bt_mesh_adv_update();
}

struct net_buf_simple *bt_mesh_proxy_get_buf(void)
{
	struct net_buf_simple *buf = &clients[0].buf;

	net_buf_simple_reset(buf);

	return buf;
}

#if defined(CONFIG_BT_MESH_PB_GATT)
static void prov_ccc_changed(const struct bt_gatt_attr *attr, uint16_t value)
{
	BT_DBG("value 0x%04x", value);
}

static ssize_t prov_ccc_write(struct bt_conn *conn,
			   const struct bt_gatt_attr *attr, uint16_t value)
{
	struct bt_mesh_proxy_client *client;

	BT_DBG("value 0x%04x", value);

	if (value != BT_GATT_CCC_NOTIFY) {
		BT_WARN("Client wrote 0x%04x instead enabling notify", value);
		return BT_GATT_ERR(BT_ATT_ERR_VALUE_NOT_ALLOWED);
	}

	/* If a connection exists there must be a client */
	client = find_client(conn);
	__ASSERT(client, "No client for connection");

	if (client->filter_type == NONE) {
		client->filter_type = PROV;
		bt_mesh_pb_gatt_open(conn);
	}

	return sizeof(value);
}

/* Mesh Provisioning Service Declaration */
static struct _bt_gatt_ccc prov_ccc =
	BT_GATT_CCC_INITIALIZER(prov_ccc_changed, prov_ccc_write, NULL);

static struct bt_gatt_attr prov_attrs[] = {
	BT_GATT_PRIMARY_SERVICE(BT_UUID_MESH_PROV),

	BT_GATT_CHARACTERISTIC(BT_UUID_MESH_PROV_DATA_IN,
			       BT_GATT_CHRC_WRITE_WITHOUT_RESP,
			       BT_GATT_PERM_WRITE, NULL, proxy_recv,
			       (void *)1),

	BT_GATT_CHARACTERISTIC(BT_UUID_MESH_PROV_DATA_OUT,
			       BT_GATT_CHRC_NOTIFY, BT_GATT_PERM_NONE,
			       NULL, NULL, NULL),
	BT_GATT_CCC_MANAGED(&prov_ccc,
			    BT_GATT_PERM_READ | BT_GATT_PERM_WRITE),
};

static struct bt_gatt_service prov_svc = BT_GATT_SERVICE(prov_attrs);

int bt_mesh_proxy_prov_enable(void)
{
	int i;

	BT_DBG("");

	if (gatt_svc == MESH_GATT_PROV) {
		return -EALREADY;
	}

	if (gatt_svc != MESH_GATT_NONE) {
		return -EBUSY;
	}

	(void)bt_gatt_service_register(&prov_svc);
	gatt_svc = MESH_GATT_PROV;
	prov_fast_adv = true;

	for (i = 0; i < ARRAY_SIZE(clients); i++) {
		if (clients[i].conn) {
			clients[i].filter_type = PROV;
		}
	}


	return 0;
}

int bt_mesh_proxy_prov_disable(bool disconnect)
{
	int i;

	BT_DBG("");

	if (gatt_svc == MESH_GATT_NONE) {
		return -EALREADY;
	}

	if (gatt_svc != MESH_GATT_PROV) {
		return -EBUSY;
	}

	bt_gatt_service_unregister(&prov_svc);
	gatt_svc = MESH_GATT_NONE;

	for (i = 0; i < ARRAY_SIZE(clients); i++) {
		struct bt_mesh_proxy_client *client = &clients[i];

		if (!client->conn || client->filter_type != PROV) {
			continue;
		}

		if (disconnect) {
			bt_conn_disconnect(client->conn,
					   BT_HCI_ERR_REMOTE_USER_TERM_CONN);
		} else {
			bt_mesh_pb_gatt_close(client->conn);
			client->filter_type = NONE;
		}
	}

	bt_mesh_adv_update();

	return 0;
}

#endif /* CONFIG_BT_MESH_PB_GATT */

#if defined(CONFIG_BT_MESH_GATT_PROXY)
static void proxy_ccc_changed(const struct bt_gatt_attr *attr, uint16_t value)
{
	BT_DBG("value 0x%04x", value);
}

static ssize_t proxy_ccc_write(struct bt_conn *conn,
			       const struct bt_gatt_attr *attr, uint16_t value)
{
	struct bt_mesh_proxy_client *client;

	BT_DBG("value: 0x%04x", value);

	if (value != BT_GATT_CCC_NOTIFY) {
		BT_WARN("Client wrote 0x%04x instead enabling notify", value);
		return BT_GATT_ERR(BT_ATT_ERR_VALUE_NOT_ALLOWED);
	}

	/* If a connection exists there must be a client */
	client = find_client(conn);
	__ASSERT(client, "No client for connection");

	if (client->filter_type == NONE) {
		client->filter_type = WHITELIST;
		k_work_submit(&client->send_beacons);
	}

	return sizeof(value);
}

/* Mesh Proxy Service Declaration */
static struct _bt_gatt_ccc proxy_ccc =
	BT_GATT_CCC_INITIALIZER(proxy_ccc_changed, proxy_ccc_write, NULL);

static struct bt_gatt_attr proxy_attrs[] = {
	BT_GATT_PRIMARY_SERVICE(BT_UUID_MESH_PROXY),

	BT_GATT_CHARACTERISTIC(BT_UUID_MESH_PROXY_DATA_IN,
			       BT_GATT_CHRC_WRITE_WITHOUT_RESP,
			       BT_GATT_PERM_WRITE,
			       NULL, proxy_recv, NULL),

	BT_GATT_CHARACTERISTIC(BT_UUID_MESH_PROXY_DATA_OUT,
			       BT_GATT_CHRC_NOTIFY,
			       BT_GATT_PERM_NONE,
			       NULL, NULL, NULL),
	BT_GATT_CCC_MANAGED(&proxy_ccc,
			    BT_GATT_PERM_READ | BT_GATT_PERM_WRITE),
};

static struct bt_gatt_service proxy_svc = BT_GATT_SERVICE(proxy_attrs);

int bt_mesh_proxy_gatt_enable(void)
{
	int i;

	BT_DBG("");

	if (gatt_svc == MESH_GATT_PROXY) {
		return -EALREADY;
	}

	if (gatt_svc != MESH_GATT_NONE) {
		return -EBUSY;
	}

	(void)bt_gatt_service_register(&proxy_svc);
	gatt_svc = MESH_GATT_PROXY;

	for (i = 0; i < ARRAY_SIZE(clients); i++) {
		if (clients[i].conn) {
			clients[i].filter_type = WHITELIST;
		}
	}

	return 0;
}

void bt_mesh_proxy_gatt_disconnect(void)
{
	int i;

	BT_DBG("");

	for (i = 0; i < ARRAY_SIZE(clients); i++) {
		struct bt_mesh_proxy_client *client = &clients[i];

		if (client->conn && (client->filter_type == WHITELIST ||
				     client->filter_type == BLACKLIST)) {
			client->filter_type = NONE;
			bt_conn_disconnect(client->conn,
					   BT_HCI_ERR_REMOTE_USER_TERM_CONN);
		}
	}
}

int bt_mesh_proxy_gatt_disable(void)
{
	BT_DBG("");

	if (gatt_svc == MESH_GATT_NONE) {
		return -EALREADY;
	}

	if (gatt_svc != MESH_GATT_PROXY) {
		return -EBUSY;
	}

	bt_mesh_proxy_gatt_disconnect();

	bt_gatt_service_unregister(&proxy_svc);
	gatt_svc = MESH_GATT_NONE;

	return 0;
}

void bt_mesh_proxy_addr_add(struct net_buf_simple *buf, uint16_t addr)
{
	struct bt_mesh_proxy_client *client =
		CONTAINER_OF(buf, struct bt_mesh_proxy_client, buf);

	BT_DBG("filter_type %u addr 0x%04x", client->filter_type, addr);

	if (client->filter_type == WHITELIST) {
		filter_add(client, addr);
	} else if (client->filter_type == BLACKLIST) {
		filter_remove(client, addr);
	}
}

static bool client_filter_match(struct bt_mesh_proxy_client *client,
				uint16_t addr)
{
	int i;

	BT_DBG("filter_type %u addr 0x%04x", client->filter_type, addr);

	if (client->filter_type == BLACKLIST) {
		for (i = 0; i < ARRAY_SIZE(client->filter); i++) {
			if (client->filter[i] == addr) {
				return false;
			}
		}

		return true;
	}

	if (addr == BT_MESH_ADDR_ALL_NODES) {
		return true;
	}

	if (client->filter_type == WHITELIST) {
		for (i = 0; i < ARRAY_SIZE(client->filter); i++) {
			if (client->filter[i] == addr) {
				return true;
			}
		}
	}

	return false;
}

bool bt_mesh_proxy_relay(struct net_buf_simple *buf, uint16_t dst)
{
	bool relayed = false;
	int i;

	BT_DBG("%u bytes to dst 0x%04x", buf->len, dst);

	for (i = 0; i < ARRAY_SIZE(clients); i++) {
		struct bt_mesh_proxy_client *client = &clients[i];
		NET_BUF_SIMPLE_DEFINE(msg, 32);

		if (!client->conn) {
			continue;
		}

		if (!client_filter_match(client, dst)) {
			continue;
		}

		/* Proxy PDU sending modifies the original buffer,
		 * so we need to make a copy.
		 */
		net_buf_simple_reserve(&msg, 1);
		net_buf_simple_add_mem(&msg, buf->data, buf->len);

		bt_mesh_proxy_send(client->conn, BT_MESH_PROXY_NET_PDU, &msg);
		relayed = true;
	}

	return relayed;
}

#endif /* CONFIG_BT_MESH_GATT_PROXY */

static void notify_complete(struct bt_conn *conn, void *user_data)
{
	sys_snode_t *n;

	if (atomic_dec(&pending_notifications) > 1) {
		return;
	}

	BT_DBG("");

	while ((n = sys_slist_get(&idle_waiters))) {
		CONTAINER_OF(n, struct bt_mesh_proxy_idle_cb, n)->cb();
	}
}

static int proxy_send(struct bt_conn *conn, const void *data,
		      uint16_t len)
{
	struct bt_gatt_notify_params params = {
		.data = data,
		.len = len,
		.func = notify_complete,
	};
	int err;

	BT_DBG("%u bytes: %s", len, bt_hex(data, len));

#if defined(CONFIG_BT_MESH_GATT_PROXY)
	if (gatt_svc == MESH_GATT_PROXY) {
		params.attr = &proxy_attrs[3];
	}
#endif
#if defined(CONFIG_BT_MESH_PB_GATT)
	if (gatt_svc == MESH_GATT_PROV) {
		params.attr = &prov_attrs[3];
	}
#endif

	if (!params.attr) {
		return 0;
	}

	err = bt_gatt_notify_cb(conn, &params);
	if (!err) {
		atomic_inc(&pending_notifications);
	}

	return err;
}

static int proxy_segment_and_send(struct bt_conn *conn, uint8_t type,
				  struct net_buf_simple *msg)
{
	uint16_t mtu;

	BT_DBG("conn %p type 0x%02x len %u: %s", (void *)conn, type, msg->len,
	       bt_hex(msg->data, msg->len));

	/* ATT_MTU - OpCode (1 byte) - Handle (2 bytes) */
	mtu = bt_gatt_get_mtu(conn) - 3;
	if (mtu > msg->len) {
		net_buf_simple_push_u8(msg, PDU_HDR(SAR_COMPLETE, type));
		return proxy_send(conn, msg->data, msg->len);
	}

	net_buf_simple_push_u8(msg, PDU_HDR(SAR_FIRST, type));
	proxy_send(conn, msg->data, mtu);
	net_buf_simple_pull(msg, mtu);

	while (msg->len) {
		if (msg->len + 1 < mtu) {
			net_buf_simple_push_u8(msg, PDU_HDR(SAR_LAST, type));
			proxy_send(conn, msg->data, msg->len);
			break;
		}

		net_buf_simple_push_u8(msg, PDU_HDR(SAR_CONT, type));
		proxy_send(conn, msg->data, mtu);
		net_buf_simple_pull(msg, mtu);
	}

	return 0;
}

int bt_mesh_proxy_send(struct bt_conn *conn, uint8_t type,
		       struct net_buf_simple *msg)
{
	struct bt_mesh_proxy_client *client = find_client(conn);

	if (!client) {
		BT_ERR("No Proxy Client found");
		return -ENOTCONN;
	}

	if ((client->filter_type == PROV) != (type == BT_MESH_PROXY_PROV)) {
		BT_ERR("Invalid PDU type for Proxy Client");
		return -EINVAL;
	}

	return proxy_segment_and_send(conn, type, msg);
}

#if defined(CONFIG_BT_MESH_PB_GATT)
static uint8_t prov_svc_data[20] = {
	BT_UUID_16_ENCODE(BT_UUID_MESH_PROV_VAL),
};

static const struct bt_data prov_ad[] = {
	BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
	BT_DATA_BYTES(BT_DATA_UUID16_ALL,
		      BT_UUID_16_ENCODE(BT_UUID_MESH_PROV_VAL)),
	BT_DATA(BT_DATA_SVC_DATA16, prov_svc_data, sizeof(prov_svc_data)),
};
#endif /* PB_GATT */

#if defined(CONFIG_BT_MESH_GATT_PROXY)

#define ID_TYPE_NET  0x00
#define ID_TYPE_NODE 0x01

#define NODE_ID_LEN  19
#define NET_ID_LEN   11

#define NODE_ID_TIMEOUT (CONFIG_BT_MESH_NODE_ID_TIMEOUT * MSEC_PER_SEC)

static uint8_t proxy_svc_data[NODE_ID_LEN] = {
	BT_UUID_16_ENCODE(BT_UUID_MESH_PROXY_VAL),
};

static const struct bt_data node_id_ad[] = {
	BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
	BT_DATA_BYTES(BT_DATA_UUID16_ALL,
		      BT_UUID_16_ENCODE(BT_UUID_MESH_PROXY_VAL)),
	BT_DATA(BT_DATA_SVC_DATA16, proxy_svc_data, NODE_ID_LEN),
};

static const struct bt_data net_id_ad[] = {
	BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
	BT_DATA_BYTES(BT_DATA_UUID16_ALL,
		      BT_UUID_16_ENCODE(BT_UUID_MESH_PROXY_VAL)),
	BT_DATA(BT_DATA_SVC_DATA16, proxy_svc_data, NET_ID_LEN),
};

static int node_id_adv(struct bt_mesh_subnet *sub, int32_t duration)
{
	struct bt_le_adv_param fast_adv_param = {
		.options = ADV_OPT_PROXY,
		ADV_FAST_INT,
	};
	uint8_t tmp[16];
	int err;

	BT_DBG("");

	proxy_svc_data[2] = ID_TYPE_NODE;

	err = bt_rand(proxy_svc_data + 11, 8);
	if (err) {
		return err;
	}

	(void)memset(tmp, 0, 6);
	memcpy(tmp + 6, proxy_svc_data + 11, 8);
	sys_put_be16(bt_mesh_primary_addr(), tmp + 14);

	err = bt_encrypt_be(sub->keys[SUBNET_KEY_TX_IDX(sub)].identity, tmp,
			    tmp);
	if (err) {
		return err;
	}

	memcpy(proxy_svc_data + 3, tmp + 8, 8);

	err = bt_mesh_adv_start(&fast_adv_param, duration, node_id_ad,
				ARRAY_SIZE(node_id_ad), NULL, 0);
	if (err) {
		BT_WARN("Failed to advertise using Node ID (err %d)", err);
		return err;
	}

	return 0;
}

static int net_id_adv(struct bt_mesh_subnet *sub, int32_t duration)
{
	struct bt_le_adv_param slow_adv_param = {
		.options = ADV_OPT_PROXY,
		ADV_SLOW_INT,
	};
	int err;

	BT_DBG("");

	proxy_svc_data[2] = ID_TYPE_NET;

	BT_DBG("Advertising with NetId %s",
	       bt_hex(sub->keys[SUBNET_KEY_TX_IDX(sub)].net_id, 8));

	memcpy(proxy_svc_data + 3, sub->keys[SUBNET_KEY_TX_IDX(sub)].net_id, 8);

	err = bt_mesh_adv_start(&slow_adv_param, duration, net_id_ad,
				ARRAY_SIZE(net_id_ad), NULL, 0);
	if (err) {
		BT_WARN("Failed to advertise using Network ID (err %d)", err);
		return err;
	}

	return 0;
}

static bool advertise_subnet(struct bt_mesh_subnet *sub)
{
	if (sub->net_idx == BT_MESH_KEY_UNUSED) {
		return false;
	}

	return (sub->node_id == BT_MESH_NODE_IDENTITY_RUNNING ||
		bt_mesh_gatt_proxy_get() == BT_MESH_GATT_PROXY_ENABLED);
}

static struct bt_mesh_subnet *next_sub(void)
{
	struct bt_mesh_subnet *sub = NULL;

	if (!beacon_sub) {
		beacon_sub = bt_mesh_subnet_next(NULL);
		if (!beacon_sub) {
			/* No valid subnets */
			return NULL;
		}
	}

	sub = beacon_sub;
	do {
		if (advertise_subnet(sub)) {
			beacon_sub = sub;
			return sub;
		}

		sub = bt_mesh_subnet_next(sub);
	} while (sub != beacon_sub);

	/* No subnets to advertise on */
	return NULL;
}

static int sub_count_cb(struct bt_mesh_subnet *sub, void *cb_data)
{
	int *count = cb_data;

	if (advertise_subnet(sub)) {
		(*count)++;
	}

	return 0;
}

static int sub_count(void)
{
	int count = 0;

	(void)bt_mesh_subnet_find(sub_count_cb, &count);

	return count;
}

static int gatt_proxy_advertise(struct bt_mesh_subnet *sub)
{
	int32_t remaining = SYS_FOREVER_MS;
	int subnet_count;
	int err = -EBUSY;

	BT_DBG("");

	if (conn_count == CONFIG_BT_MAX_CONN) {
		BT_DBG("Connectable advertising deferred (max connections)");
		return -ENOMEM;
	}

	sub = beacon_sub ? beacon_sub : bt_mesh_subnet_next(beacon_sub);
	if (!sub) {
		BT_WARN("No subnets to advertise on");
		return -ENOENT;
	}

	subnet_count = sub_count();
	BT_DBG("sub_count %u", subnet_count);
	if (subnet_count > 1) {
		int32_t max_timeout;

		/* We use NODE_ID_TIMEOUT as a starting point since it may
		 * be less than 60 seconds. Divide this period into at least
		 * 6 slices, but make sure that a slice is at least one
		 * second long (to avoid excessive rotation).
		 */
		max_timeout = NODE_ID_TIMEOUT / MAX(subnet_count, 6);
		max_timeout = MAX(max_timeout, 1 * MSEC_PER_SEC);

		if (remaining > max_timeout || remaining == SYS_FOREVER_MS) {
			remaining = max_timeout;
		}
	}

	if (sub->node_id == BT_MESH_NODE_IDENTITY_RUNNING) {
		uint32_t active = k_uptime_get_32() - sub->node_id_start;

		if (active < NODE_ID_TIMEOUT) {
			remaining = NODE_ID_TIMEOUT - active;
			BT_DBG("Node ID active for %u ms, %d ms remaining",
			       active, remaining);
			err = node_id_adv(sub, remaining);
		} else {
			bt_mesh_proxy_identity_stop(sub);
			BT_DBG("Node ID stopped");
		}
	}

	if (sub->node_id == BT_MESH_NODE_IDENTITY_STOPPED) {
		err = net_id_adv(sub, remaining);
	}

	BT_DBG("Advertising %d ms for net_idx 0x%04x", remaining, sub->net_idx);

	beacon_sub = bt_mesh_subnet_next(beacon_sub);

	return err;
}
#endif /* GATT_PROXY */

#if defined(CONFIG_BT_MESH_PB_GATT)
static size_t gatt_prov_adv_create(struct bt_data prov_sd[1])
{
	const struct bt_mesh_prov *prov = bt_mesh_prov_get();
	size_t uri_len;

	memcpy(prov_svc_data + 2, prov->uuid, 16);
	sys_put_be16(prov->oob_info, prov_svc_data + 18);

	if (!prov->uri) {
		return 0;
	}

	uri_len = strlen(prov->uri);
	if (uri_len > 29) {
		/* There's no way to shorten an URI */
		BT_WARN("Too long URI to fit advertising packet");
		return 0;
	}

	prov_sd[0].type = BT_DATA_URI;
	prov_sd[0].data_len = uri_len;
	prov_sd[0].data = prov->uri;

	return 1;
}
#endif /* CONFIG_BT_MESH_PB_GATT */

int bt_mesh_proxy_adv_start(void)
{
	BT_DBG("");

	if (gatt_svc == MESH_GATT_NONE) {
		return -ENOENT;
	}

#if defined(CONFIG_BT_MESH_PB_GATT)
	if (!bt_mesh_is_provisioned()) {
		struct bt_le_adv_param fast_adv_param = {
			.options = ADV_OPT_PROV,
			ADV_FAST_INT,
		};
		struct bt_data prov_sd[1];
		size_t prov_sd_len;
		int err;

		prov_sd_len = gatt_prov_adv_create(prov_sd);

		if (!prov_fast_adv) {
			struct bt_le_adv_param slow_adv_param = {
				.options = ADV_OPT_PROV,
				ADV_SLOW_INT,
			};

			return bt_mesh_adv_start(&slow_adv_param,
						 SYS_FOREVER_MS, prov_ad,
						 ARRAY_SIZE(prov_ad), prov_sd,
						 prov_sd_len);
		}

		/* Advertise 60 seconds using fast interval */
		err = bt_mesh_adv_start(&fast_adv_param, (60 * MSEC_PER_SEC),
						prov_ad, ARRAY_SIZE(prov_ad),
						prov_sd, prov_sd_len);
		if (!err) {
			prov_fast_adv = false;
		}

		return err;
	}
#endif /* PB_GATT */

#if defined(CONFIG_BT_MESH_GATT_PROXY)
	if (bt_mesh_is_provisioned()) {
		return gatt_proxy_advertise(next_sub());
	}
#endif /* GATT_PROXY */

	return -ENOTSUP;
}

#if defined(CONFIG_BT_MESH_GATT_PROXY)
static void subnet_evt(struct bt_mesh_subnet *sub, enum bt_mesh_key_evt evt)
{
	if (evt == BT_MESH_KEY_DELETED) {
		if (sub == beacon_sub) {
			beacon_sub = NULL;
		}
	} else {
		bt_mesh_proxy_beacon_send(sub);
	}
}

BT_MESH_SUBNET_CB_DEFINE(subnet_evt);
#endif

static struct bt_conn_cb conn_callbacks = {
	.connected = proxy_connected,
	.disconnected = proxy_disconnected,
};

int bt_mesh_proxy_init(void)
{
	int i;

	/* Initialize the client receive buffers */
	for (i = 0; i < ARRAY_SIZE(clients); i++) {
		struct bt_mesh_proxy_client *client = &clients[i];

		client->buf.size = CLIENT_BUF_SIZE;
		client->buf.__buf = client_buf_data + (i * CLIENT_BUF_SIZE);

		k_work_init_delayable(&client->sar_timer, proxy_sar_timeout);
	}

	bt_conn_cb_register(&conn_callbacks);

	return 0;
}

void bt_mesh_proxy_on_idle(struct bt_mesh_proxy_idle_cb *cb)
{
	if (!atomic_get(&pending_notifications)) {
		cb->cb();
		return;
	}

	sys_slist_append(&idle_waiters, &cb->n);
}