/*
 *
 *  BlueZ - Bluetooth protocol stack for Linux
 *
 *  Copyright (C) 2018  Intel Corporation. All rights reserved.
 *
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <sys/time.h>
#include <ell/ell.h>

#include "lib/bluetooth.h"
#include "lib/hci.h"

#include "monitor/bt.h"
#include "src/shared/hci.h"

#include "mesh/display.h"
#include "mesh/mesh-io.h"
#include "mesh/mesh-io-api.h"

#include "mesh/mesh-io-generic.h"

struct mesh_io_private {
	uint16_t index;
	struct bt_hci *hci;
	struct l_timeout *tx_timeout;
	struct l_queue *rx_regs;
	struct l_queue *tx_pkts;
	uint8_t filters[3]; /* Simple filtering on AD type only */
	bool sending;
	struct tx_pkt *tx;
	uint16_t interval;
};

struct pvt_rx_reg {
	uint8_t filter_id;
	mesh_io_recv_func_t cb;
	void *user_data;
};

struct process_data {
	struct mesh_io_private		*pvt;
	const uint8_t			*data;
	uint8_t				len;
	struct mesh_io_recv_info	info;
};

struct tx_pkt {
	struct mesh_io_send_info	info;
	bool				delete;
	uint8_t				len;
	uint8_t				pkt[30];
};

struct tx_pattern {
	const uint8_t			*data;
	uint8_t				len;
};

static uint32_t get_instant(void)
{
	struct timeval tm;
	uint32_t instant;

	gettimeofday(&tm, NULL);
	instant = tm.tv_sec * 1000;
	instant += tm.tv_usec / 1000;

	return instant;
}

static uint32_t instant_remaining_ms(uint32_t instant)
{
	instant -= get_instant();
	return instant;
}

static void process_rx_callbacks(void *v_rx, void *v_reg)
{
	struct pvt_rx_reg *rx_reg = v_rx;
	struct process_data *rx = v_reg;
	uint8_t ad_type;

	ad_type = rx->pvt->filters[rx_reg->filter_id - 1];

	if (rx->data[0] == ad_type && rx_reg->cb)
		rx_reg->cb(rx_reg->user_data, &rx->info, rx->data, rx->len);
}

static void process_rx(struct mesh_io_private *pvt, int8_t rssi,
					uint32_t instant,
					const uint8_t *data, uint8_t len)
{
	struct process_data rx = {
		.pvt = pvt,
		.data = data,
		.len = len,
		.info.instant = instant,
		.info.chan = 7,
		.info.rssi = rssi,
	};

	l_queue_foreach(pvt->rx_regs, process_rx_callbacks, &rx);
}

static void event_adv_report(struct mesh_io *io, const void *buf, uint8_t size)
{
	const struct bt_hci_evt_le_adv_report *evt = buf;
	const uint8_t *adv;
	uint32_t instant;
	uint8_t adv_len;
	uint16_t len = 0;
	int8_t rssi;

	if (evt->event_type != 0x03)
		return;

	if (evt->addr_type != BDADDR_LE_PUBLIC &&
			evt->addr_type != BDADDR_LE_RANDOM)
		return;

	instant = get_instant();
	adv = evt->data;
	adv_len = evt->data_len;

	/* rssi is just beyond last byte of data */
	rssi = (int8_t) adv[adv_len];

	while (len < adv_len - 1) {
		uint8_t field_len = adv[0];

		/* Check for the end of advertising data */
		if (field_len == 0)
			break;

		len += field_len + 1;

		/* Do not continue data parsing if got incorrect length */
		if (len > adv_len)
			break;

		/* TODO: Create an Instant to use */
		process_rx(io->pvt, rssi, instant, adv + 1, adv[0]);

		adv += field_len + 1;
	}
}

static void event_callback(const void *buf, uint8_t size, void *user_data)
{
	uint8_t event = l_get_u8(buf);
	struct mesh_io *io = user_data;

	switch (event) {
	case BT_HCI_EVT_LE_ADV_REPORT:
		event_adv_report(io, buf + 1, size - 1);
		break;

	default:
		l_info("Other Meta Evt - %d", event);
	}
}

static bool dev_init(uint16_t index, struct mesh_io *io)
{
	struct mesh_io_private *tmp;

	if (!io || io->pvt)
		return false;

	tmp = l_new(struct mesh_io_private, 1);

	if (tmp == NULL)
		return false;

	tmp->rx_regs = l_queue_new();
	tmp->tx_pkts = l_queue_new();
	if (!tmp->rx_regs || !tmp->tx_pkts)
		goto fail;

	tmp->hci = bt_hci_new_user_channel(index);
	if (!tmp->hci)
		goto fail;

	bt_hci_register(tmp->hci, BT_HCI_EVT_LE_META_EVENT,
						event_callback, io, NULL);

	io->pvt = tmp;
	return true;

fail:
	l_queue_destroy(tmp->rx_regs, l_free);
	l_queue_destroy(tmp->tx_pkts, l_free);
	l_free(tmp);
	return false;
}

static bool dev_destroy(struct mesh_io *io)
{
	struct mesh_io_private *pvt = io->pvt;

	if (!pvt)
		return true;

	bt_hci_unref(pvt->hci);
	l_timeout_remove(pvt->tx_timeout);
	l_queue_destroy(pvt->rx_regs, l_free);
	l_queue_destroy(pvt->tx_pkts, l_free);
	l_free(pvt);
	io->pvt = NULL;

	return true;
}

static bool dev_caps(struct mesh_io *io, struct mesh_io_caps *caps)
{
	struct mesh_io_private *pvt = io->pvt;

	if (!pvt || !caps)
		return false;

	caps->max_num_filters = sizeof(pvt->filters);
	caps->window_accuracy = 50;

	return true;
}

static void send_cancel_done(const void *buf, uint8_t size,
							void *user_data)
{
	struct mesh_io_private *pvt = user_data;
	struct bt_hci_cmd_le_set_random_address cmd;

	if (!pvt)
		return;

	pvt->sending = false;

	/* At end of any burst of ADVs, change random address */
	l_getrandom(cmd.addr, 6);
	cmd.addr[5] |= 0xc0;
	bt_hci_send(pvt->hci, BT_HCI_CMD_LE_SET_RANDOM_ADDRESS,
				&cmd, sizeof(cmd), NULL, NULL, NULL);
}

static void send_cancel(struct mesh_io_private *pvt)
{
	struct bt_hci_cmd_le_set_adv_enable cmd;

	if (!pvt)
		return;

	if (!pvt->sending) {
		send_cancel_done(NULL, 0, pvt);
		return;
	}

	cmd.enable = 0x00;	/* Disable advertising */
	bt_hci_send(pvt->hci, BT_HCI_CMD_LE_SET_ADV_ENABLE,
				&cmd, sizeof(cmd),
				send_cancel_done, pvt, NULL);
}

static void set_send_adv_enable(const void *buf, uint8_t size,
							void *user_data)
{
	struct mesh_io_private *pvt = user_data;
	struct bt_hci_cmd_le_set_adv_enable cmd;

	if (!pvt)
		return;

	pvt->sending = true;
	cmd.enable = 0x01;	/* Enable advertising */
	bt_hci_send(pvt->hci, BT_HCI_CMD_LE_SET_ADV_ENABLE,
				&cmd, sizeof(cmd), NULL, NULL, NULL);
}

static void set_send_adv_data(const void *buf, uint8_t size,
							void *user_data)
{
	struct mesh_io_private *pvt = user_data;
	struct tx_pkt *tx;
	struct bt_hci_cmd_le_set_adv_data cmd;

	if (!pvt || !pvt->tx)
		return;

	tx = pvt->tx;
	if (tx->len >= sizeof(cmd.data))
		goto done;

	memset(&cmd, 0, sizeof(cmd));

	cmd.len = tx->len + 1;
	cmd.data[0] = tx->len;
	memcpy(cmd.data + 1, tx->pkt, tx->len);

	bt_hci_send(pvt->hci, BT_HCI_CMD_LE_SET_ADV_DATA,
					&cmd, sizeof(cmd),
					set_send_adv_enable, pvt, NULL);
done:
	if (tx->delete)
		l_free(tx);

	pvt->tx = NULL;
}

static void set_send_adv_params(const void *buf, uint8_t size,
							void *user_data)
{
	struct mesh_io_private *pvt = user_data;
	struct bt_hci_cmd_le_set_adv_parameters cmd;
	uint16_t hci_interval;

	if (!pvt)
		return;

	hci_interval = (pvt->interval * 16) / 10;
	cmd.min_interval = L_CPU_TO_LE16(hci_interval);
	cmd.max_interval = L_CPU_TO_LE16(hci_interval);
	cmd.type = 0x03; /* ADV_NONCONN_IND */
	cmd.own_addr_type = 0x01; /* ADDR_TYPE_RANDOM */
	cmd.direct_addr_type = 0x00;
	memset(cmd.direct_addr, 0, 6);
	cmd.channel_map = 0x07;
	cmd.filter_policy = 0x03;

	bt_hci_send(pvt->hci, BT_HCI_CMD_LE_SET_ADV_PARAMETERS,
				&cmd, sizeof(cmd),
				set_send_adv_data, pvt, NULL);
}

static void send_pkt(struct mesh_io_private *pvt, struct tx_pkt *tx,
							uint16_t interval)
{
	struct bt_hci_cmd_le_set_adv_enable cmd;

	pvt->tx = tx;
	pvt->interval = interval;

	if (!pvt->sending) {
		set_send_adv_params(NULL, 0, pvt);
		return;
	}

	cmd.enable = 0x00;	/* Disable advertising */
	bt_hci_send(pvt->hci, BT_HCI_CMD_LE_SET_ADV_ENABLE,
				&cmd, sizeof(cmd),
				set_send_adv_params, pvt, NULL);
}

static void tx_timeout(struct l_timeout *timeout, void *user_data)
{
	struct mesh_io_private *pvt = user_data;
	struct tx_pkt *tx;
	uint16_t ms;
	uint8_t count;

	if (!pvt)
		return;

	tx = l_queue_pop_head(pvt->tx_pkts);
	if (!tx) {
		l_timeout_remove(timeout);
		pvt->tx_timeout = NULL;
		send_cancel(pvt);
		return;
	}

	if (tx->info.type == MESH_IO_TIMING_TYPE_GENERAL) {
		ms = tx->info.u.gen.interval;
		count = tx->info.u.gen.cnt;
		if (count != MESH_IO_TX_COUNT_UNLIMITED)
			tx->info.u.gen.cnt--;
	} else {
		ms = 25;
		count = 1;
	}

	tx->delete = !!(count == 1);

	send_pkt(pvt, tx, ms);

	if (count == 1) {
		/* send_pkt will delete when done */
		tx = l_queue_peek_head(pvt->tx_pkts);
		if (tx && tx->info.type == MESH_IO_TIMING_TYPE_POLL_RSP) {
			ms = instant_remaining_ms(tx->info.u.poll_rsp.instant +
						tx->info.u.poll_rsp.delay);
		}
	} else
		l_queue_push_tail(pvt->tx_pkts, tx);

	if (timeout) {
		pvt->tx_timeout = timeout;
		l_timeout_modify_ms(timeout, ms);
	} else
		pvt->tx_timeout = l_timeout_create_ms(ms, tx_timeout,
								pvt, NULL);
}

static void tx_worker(void *user_data)
{
	struct mesh_io_private *pvt = user_data;
	struct tx_pkt *tx;
	uint32_t delay;

	tx = l_queue_peek_head(pvt->tx_pkts);
	if (!tx)
		return;

	switch (tx->info.type) {
	case MESH_IO_TIMING_TYPE_GENERAL:
		if (tx->info.u.gen.min_delay == tx->info.u.gen.max_delay)
			delay = tx->info.u.gen.min_delay;
		else {
			l_getrandom(&delay, sizeof(delay));
			delay %= tx->info.u.gen.max_delay -
						tx->info.u.gen.min_delay;
			delay += tx->info.u.gen.min_delay;
		}
		break;

	case MESH_IO_TIMING_TYPE_POLL:
		if (tx->info.u.poll.min_delay == tx->info.u.poll.max_delay)
			delay = tx->info.u.poll.min_delay;
		else {
			l_getrandom(&delay, sizeof(delay));
			delay %= tx->info.u.poll.max_delay -
						tx->info.u.poll.min_delay;
			delay += tx->info.u.poll.min_delay;
		}
		break;

	case MESH_IO_TIMING_TYPE_POLL_RSP:
		/* Delay until Instant + Delay */
		delay = instant_remaining_ms(tx->info.u.poll_rsp.instant +
						tx->info.u.poll_rsp.delay);
		if (delay > 255)
			delay = 0;
		break;

	default:
		return;
	}

	if (!delay)
		tx_timeout(pvt->tx_timeout, pvt);
	else if (pvt->tx_timeout)
		l_timeout_modify_ms(pvt->tx_timeout, delay);
	else
		pvt->tx_timeout = l_timeout_create_ms(delay, tx_timeout,
								pvt, NULL);
}

static bool send_tx(struct mesh_io *io, struct mesh_io_send_info *info,
					const uint8_t *data, uint16_t len)
{
	struct mesh_io_private *pvt = io->pvt;
	struct tx_pkt *tx;
	bool sending = false;

	if (!info || !data || !len || len > sizeof(tx->pkt))
		return false;


	tx = l_new(struct tx_pkt, 1);
	if (!tx)
		return false;

	memcpy(&tx->info, info, sizeof(tx->info));
	memcpy(&tx->pkt, data, len);
	tx->len = len;

	if (info->type == MESH_IO_TIMING_TYPE_POLL_RSP)
		l_queue_push_head(pvt->tx_pkts, tx);
	else {
		sending = !l_queue_isempty(pvt->tx_pkts);
		l_queue_push_tail(pvt->tx_pkts, tx);
	}

	if (!sending) {
		l_timeout_remove(pvt->tx_timeout);
		pvt->tx_timeout = NULL;
		l_idle_oneshot(tx_worker, pvt, NULL);
	}

	return true;
}

static bool find_by_ad_type(const void *a, const void *b)
{
	const struct tx_pkt *tx = a;
	uint8_t ad_type = L_PTR_TO_UINT(b);

	return !ad_type || ad_type == tx->pkt[0];
}

static bool find_by_pattern(const void *a, const void *b)
{
	const struct tx_pkt *tx = a;
	const struct tx_pattern *pattern = b;

	if (tx->len < pattern->len)
		return false;

	return (!memcmp(tx->pkt, pattern->data, pattern->len));
}

static bool tx_cancel(struct mesh_io *io, uint8_t *data, uint8_t len)
{
	struct mesh_io_private *pvt = io->pvt;
	struct tx_pkt *tx;

	if (!data)
		return false;

	if (len == 1) {
		do {
			tx = l_queue_remove_if(pvt->tx_pkts, find_by_ad_type,
							L_UINT_TO_PTR(data[0]));
			l_free(tx);
		} while (tx);
	}  else {
		struct tx_pattern pattern = {
			.data = data,
			.len = len
		};

		do {
			tx = l_queue_remove_if(pvt->tx_pkts, find_by_pattern,
								&pattern);
			l_free(tx);
		} while (tx);
	}

	if (l_queue_isempty(pvt->tx_pkts)) {
		send_cancel(pvt);
		l_timeout_remove(pvt->tx_timeout);
		pvt->tx_timeout = NULL;
	}

	return true;
}

static bool find_by_filter_id(const void *a, const void *b)
{
	const struct pvt_rx_reg *rx_reg = a;
	uint8_t filter_id = L_PTR_TO_UINT(b);

	return rx_reg->filter_id == filter_id;
}

static bool recv_register(struct mesh_io *io, uint8_t filter_id,
				mesh_io_recv_func_t cb, void *user_data)
{
	struct bt_hci_cmd_le_set_scan_enable cmd;
	struct mesh_io_private *pvt = io->pvt;
	struct pvt_rx_reg *rx_reg;
	bool scanning;

	l_info("%s %d", __func__, filter_id);
	if (!cb || !filter_id || filter_id > sizeof(pvt->filters))
		return false;

	rx_reg = l_queue_remove_if(pvt->rx_regs, find_by_filter_id,
						L_UINT_TO_PTR(filter_id));

	if (!rx_reg) {
		rx_reg = l_new(struct pvt_rx_reg, 1);
		if (!rx_reg)
			return false;
	}

	rx_reg->filter_id = filter_id;
	rx_reg->cb = cb;
	rx_reg->user_data = user_data;

	scanning = !l_queue_isempty(pvt->rx_regs);

	l_queue_push_head(pvt->rx_regs, rx_reg);

	if (!scanning) {
		cmd.enable = 0x01;	/* Enable scanning */
		cmd.filter_dup = 0x00;	/* Report duplicates */
		bt_hci_send(pvt->hci, BT_HCI_CMD_LE_SET_SCAN_ENABLE,
				&cmd, sizeof(cmd), NULL, NULL, NULL);
	}

	return true;
}

static bool recv_deregister(struct mesh_io *io, uint8_t filter_id)
{
	struct bt_hci_cmd_le_set_scan_enable cmd;
	struct mesh_io_private *pvt = io->pvt;

	struct pvt_rx_reg *rx_reg;

	rx_reg = l_queue_remove_if(pvt->rx_regs, find_by_filter_id,
						L_UINT_TO_PTR(filter_id));

	if (rx_reg)
		l_free(rx_reg);

	if (l_queue_isempty(pvt->rx_regs)) {
		cmd.enable = 0x00;	/* Disable scanning */
		cmd.filter_dup = 0x00;	/* Report duplicates */
		bt_hci_send(pvt->hci, BT_HCI_CMD_LE_SET_SCAN_ENABLE,
				&cmd, sizeof(cmd), NULL, NULL, NULL);

	}

	return true;
}

static bool filter_set(struct mesh_io *io,
		uint8_t filter_id, const uint8_t *data, uint8_t len,
		mesh_io_status_func_t callback, void *user_data)
{
	struct mesh_io_private *pvt = io->pvt;

	l_info("%s id: %d, --> %2.2x", __func__, filter_id, data[0]);
	if (!data || !len || !filter_id || filter_id > sizeof(pvt->filters))
		return false;

	pvt->filters[filter_id - 1] = data[0];

	/* TODO: Delayed Call to successful status */

	return true;
}

const struct mesh_io_api mesh_io_generic = {
	.init = dev_init,
	.destroy = dev_destroy,
	.caps = dev_caps,
	.send = send_tx,
	.reg = recv_register,
	.dereg = recv_deregister,
	.set = filter_set,
	.cancel = tx_cancel,
};