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 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
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 *    used to endorse or promote products derived from this software
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 ****************************************************************************/

/**
 * @file DatamanClient.cpp
 */

#include <dataman_client/DatamanClient.hpp>

DatamanClient::DatamanClient()
{
	_sync_perf = perf_alloc(PC_ELAPSED, "DatamanClient: sync");

	_dataman_request_pub.advertise();
	_dataman_response_sub = orb_subscribe(ORB_ID(dataman_response));

	if (_dataman_response_sub < 0) {
		PX4_ERR("Failed to subscribe (%i)", errno);

	} else {
		// make sure we don't get any stale response by doing an orb_copy
		dataman_response_s response{};
		orb_copy(ORB_ID(dataman_response), _dataman_response_sub, &response);

		_fds.fd = _dataman_response_sub;
		_fds.events = POLLIN;

		hrt_abstime timestamp = hrt_absolute_time();

		dataman_request_s request;
		request.timestamp = timestamp;
		request.request_type = DM_GET_ID;
		request.client_id = CLIENT_ID_NOT_SET;

		bool success = syncHandler(request, response, timestamp, 1000_ms);

		if (success && (response.client_id > CLIENT_ID_NOT_SET)) {

			_client_id = response.client_id;

		} else {
			PX4_ERR("Failed to get client ID!");
		}
	}
}

DatamanClient::~DatamanClient()
{
	perf_free(_sync_perf);

	if (_dataman_response_sub >= 0) {
		orb_unsubscribe(_dataman_response_sub);
	}
}

bool DatamanClient::syncHandler(const dataman_request_s &request, dataman_response_s &response,
				const hrt_abstime &start_time, hrt_abstime timeout)
{
	bool response_received = false;
	int32_t ret = 0;
	hrt_abstime time_elapsed = hrt_elapsed_time(&start_time);
	perf_begin(_sync_perf);
	_dataman_request_pub.publish(request);

	while (!response_received && (time_elapsed < timeout)) {

		uint32_t timeout_ms = 100;
		ret = px4_poll(&_fds, 1, timeout_ms);

		if (ret < 0) {
			PX4_ERR("px4_poll returned error: %" PRIu32, ret);
			break;

		} else if (ret == 0) {

			// No response received, send new request
			_dataman_request_pub.publish(request);

		} else {

			bool updated = false;
			orb_check(_dataman_response_sub, &updated);

			if (updated) {
				orb_copy(ORB_ID(dataman_response), _dataman_response_sub, &response);

				if (response.client_id == request.client_id) {

					if ((response.request_type == request.request_type) &&
					    (response.item == request.item) &&
					    (response.index == request.index)) {
						response_received = true;
						break;
					}

				} else if (request.client_id == CLIENT_ID_NOT_SET) {

					// validate timestamp from response.data
					if (0 == memcmp(&(request.timestamp), &(response.data), sizeof(hrt_abstime))) {
						response_received = true;
						break;
					}
				}
			}
		}

		time_elapsed = hrt_elapsed_time(&start_time);
	}

	perf_end(_sync_perf);

	if (!response_received && ret >= 0) {
		PX4_ERR("timeout after %" PRIu32 " ms!", static_cast<uint32_t>(timeout / 1000));
	}

	return response_received;
}

bool DatamanClient::readSync(dm_item_t item, uint32_t index, uint8_t *buffer, uint32_t length, hrt_abstime timeout)
{
	if (length > g_per_item_size[item]) {
		PX4_ERR("Length  %" PRIu32 " can't fit in data size for item  %" PRIi8, length, static_cast<uint8_t>(item));
		return false;
	}

	bool success = false;
	hrt_abstime timestamp = hrt_absolute_time();

	dataman_request_s request;
	request.timestamp = timestamp;
	request.index = index;
	request.data_length = length;
	request.client_id = _client_id;
	request.request_type = DM_READ;
	request.item = static_cast<uint8_t>(item);

	dataman_response_s response{};
	success = syncHandler(request, response, timestamp, timeout);

	if (success) {

		if (response.status != dataman_response_s::STATUS_SUCCESS) {

			success = false;
			PX4_ERR("readSync failed! status=%" PRIu8 ", item=%" PRIu8 ", index=%" PRIu32 ", length=%" PRIu32,
				response.status, static_cast<uint8_t>(item), index, length);

		} else {
			memcpy(buffer, response.data, length);
		}
	}

	return success;
}

bool DatamanClient::writeSync(dm_item_t item, uint32_t index, uint8_t *buffer, uint32_t length, hrt_abstime timeout)
{
	if (length > g_per_item_size[item]) {
		PX4_ERR("Length  %" PRIu32 " can't fit in data size for item  %" PRIi8, length, static_cast<uint8_t>(item));
		return false;
	}

	bool success = false;
	hrt_abstime timestamp = hrt_absolute_time();

	dataman_request_s request;
	request.timestamp = timestamp;
	request.index = index;
	request.data_length = length;
	request.client_id = _client_id;
	request.request_type = DM_WRITE;
	request.item = static_cast<uint8_t>(item);

	memcpy(request.data, buffer, length);

	dataman_response_s response{};
	success = syncHandler(request, response, timestamp, timeout);

	if (success) {

		if (response.status != dataman_response_s::STATUS_SUCCESS) {

			success = false;
			PX4_ERR("writeSync failed! status=%" PRIu8 ", item=%" PRIu8 ", index=%" PRIu32 ", length=%" PRIu32,
				response.status, static_cast<uint8_t>(item), index, length);
		}
	}

	return success;
}

bool DatamanClient::clearSync(dm_item_t item, hrt_abstime timeout)
{
	bool success = false;
	hrt_abstime timestamp = hrt_absolute_time();

	dataman_request_s request;
	request.timestamp = timestamp;
	request.client_id = _client_id;
	request.request_type = DM_CLEAR;
	request.item = static_cast<uint8_t>(item);

	dataman_response_s response{};
	success = syncHandler(request, response, timestamp, timeout);

	if (success) {

		if (response.status != dataman_response_s::STATUS_SUCCESS) {

			success = false;
			PX4_ERR("clearSync failed! status=%" PRIu8 ", item=%" PRIu8,
				response.status, static_cast<uint8_t>(item));
		}
	}

	return success;
}

bool DatamanClient::readAsync(dm_item_t item, uint32_t index, uint8_t *buffer, uint32_t length)
{
	if (length > g_per_item_size[item]) {
		PX4_ERR("Length  %" PRIu32 " can't fit in data size for item  %" PRIi8, length, static_cast<uint8_t>(item));
		return false;
	}

	bool success = false;

	if (_state == State::Idle) {

		hrt_abstime timestamp = hrt_absolute_time();

		dataman_request_s request;
		request.timestamp = timestamp;
		request.index = index;
		request.data_length = length;
		request.client_id = _client_id;
		request.request_type = DM_READ;
		request.item = static_cast<uint8_t>(item);

		_active_request.timestamp = timestamp;
		_active_request.request_type = DM_READ;
		_active_request.item = item;
		_active_request.index = index;
		_active_request.buffer = buffer;
		_active_request.length = length;

		_state = State::RequestSent;

		_dataman_request_pub.publish(request);

		success = true;
	}

	return success;
}

bool DatamanClient::writeAsync(dm_item_t item, uint32_t index, uint8_t *buffer, uint32_t length)
{
	if (length > g_per_item_size[item]) {
		PX4_ERR("Length  %" PRIu32 " can't fit in data size for item  %" PRIi8, length, static_cast<uint8_t>(item));
		return false;
	}

	bool success = false;

	if (_state == State::Idle) {

		hrt_abstime timestamp = hrt_absolute_time();

		dataman_request_s request;
		request.timestamp = timestamp;
		request.index = index;
		request.data_length = length;
		request.client_id = _client_id;
		request.request_type = DM_WRITE;
		request.item = static_cast<uint8_t>(item);

		memcpy(request.data, buffer, length);

		_active_request.timestamp = timestamp;
		_active_request.request_type = DM_WRITE;
		_active_request.item = item;
		_active_request.index = index;
		_active_request.buffer = buffer;
		_active_request.length = length;

		_state = State::RequestSent;

		_dataman_request_pub.publish(request);

		success = true;
	}

	return success;
}

bool DatamanClient::clearAsync(dm_item_t item)
{
	bool success = false;

	if (_state == State::Idle) {

		hrt_abstime timestamp = hrt_absolute_time();

		dataman_request_s request;
		request.timestamp = timestamp;
		request.client_id = _client_id;
		request.request_type = DM_CLEAR;
		request.item = static_cast<uint8_t>(item);
		request.index = 0;

		_active_request.timestamp = timestamp;
		_active_request.request_type = DM_CLEAR;
		_active_request.item = item;
		_active_request.index = request.index;
		_state = State::RequestSent;

		_dataman_request_pub.publish(request);

		success = true;
	}

	return success;
}

void DatamanClient::update()
{
	if (_state == State::RequestSent) {

		bool updated = false;
		orb_check(_dataman_response_sub, &updated);

		dataman_response_s response;

		if (updated) {
			orb_copy(ORB_ID(dataman_response), _dataman_response_sub, &response);

			if ((response.client_id == _client_id) &&
			    (response.request_type == _active_request.request_type) &&
			    (response.item == _active_request.item) &&
			    (response.index == _active_request.index)) {

				if (response.request_type == DM_READ) {
					memcpy(_active_request.buffer, response.data, _active_request.length);
				}

				_response_status = response.status;

				if (_response_status != dataman_response_s::STATUS_SUCCESS) {

					PX4_ERR("Async request type %" PRIu8 " failed! status=%" PRIu8 " item=%" PRIu8 " index=%" PRIu32,
						response.request_type, response.status, static_cast<uint8_t>(_active_request.item), _active_request.index);
				}

				_state = State::ResponseReceived;
			}
		}

		if (_state == State::RequestSent) {

			/* Retry the request if there is no answer */
			if (((_active_request.request_type != DM_CLEAR) && (hrt_elapsed_time(&_active_request.timestamp) > 100_ms)) ||
			    (hrt_elapsed_time(&_active_request.timestamp) > 1000_ms)
			   ) {

				hrt_abstime timestamp = hrt_absolute_time();

				_active_request.timestamp = timestamp;

				dataman_request_s request;
				request.timestamp = timestamp;
				request.index = _active_request.index;
				request.data_length = _active_request.length;
				request.client_id = _client_id;
				request.request_type = static_cast<uint8_t>(_active_request.request_type);
				request.item = static_cast<uint8_t>(_active_request.item);

				if (_active_request.request_type == DM_WRITE) {
					memcpy(request.data, _active_request.buffer, _active_request.length);
				}

				_dataman_request_pub.publish(request);

				_state = State::RequestSent;
			}
		}
	}
}

bool DatamanClient::lastOperationCompleted(bool &success)
{
	bool completed = false;
	success = false;

	if (_state == State::ResponseReceived) {

		if (_response_status == dataman_response_s::STATUS_SUCCESS) {
			success = true;
		}

		_state = State::Idle;
		completed = true;
	}

	return completed;
}

void DatamanClient::abortCurrentOperation()
{
	_state = State::Idle;
}

DatamanCache::DatamanCache(const char *cache_miss_perf_counter_name, uint32_t num_items)
	: _cache_miss_perf(perf_alloc(PC_COUNT, cache_miss_perf_counter_name))
{
	_items = new Item[num_items] {};

	if (_items != nullptr) {
		_num_items = num_items;

	} else {
		PX4_ERR("alloc failed");
	}
}

DatamanCache::~DatamanCache()
{
	delete[] _items;
	perf_free(_cache_miss_perf);
}

void DatamanCache::resize(uint32_t num_items)
{
	Item *new_items = new Item[num_items] {};

	if (new_items != nullptr) {
		uint32_t num_min = num_items < _num_items ? num_items : _num_items;

		for (uint32_t i = 0; i < num_min; ++i) {
			new_items[i] = _items[i];
		}

		delete[] _items;
		_items = new_items;
		_num_items = num_items;

	} else {
		PX4_ERR("alloc failed");
	}
}

bool DatamanCache::load(dm_item_t item, uint32_t index)
{
	if (!_items) {
		return false;
	}

	bool success = false;
	bool duplicate = false;

	//Prevent duplicates
	for (uint32_t i = 0; i < _num_items; ++i) {

		if (_items[i].cache_state != State::Idle &&
		    _items[i].cache_state != State::Error &&
		    _items[i].response.item == item &&
		    _items[i].response.index == index) {
			duplicate = true;
			break;
		}
	}

	if (!duplicate && (_item_counter < _num_items)) {

		_items[_load_index].cache_state = State::RequestPrepared;
		_items[_load_index].response.item = item;
		_items[_load_index].response.index = index;

		_load_index = (_load_index + 1) % _num_items;

		++_item_counter;

		success = true;
	}

	return success;
}

bool DatamanCache::loadWait(dm_item_t item, uint32_t index, uint8_t *buffer, uint32_t length, hrt_abstime timeout)
{
	if (length > g_per_item_size[item]) {
		PX4_ERR("Length %" PRIu32 " can't fit in data size for item %" PRIi8, length, static_cast<uint8_t>(item));
		return false;
	}

	if (!_items) {
		return false;
	}

	bool success = false;
	bool item_found = false;

	for (uint32_t i = 0; i < _num_items; ++i) {
		if ((_items[i].response.item == item) &&
		    (_items[i].response.index == index)) {
			item_found = true;

			if (_items[i].cache_state == State::ResponseReceived) {
				memcpy(buffer, _items[i].response.data, length);
				success = true;
				break;
			}
		}
	}

	if (!success && (timeout > 0)) {
		perf_count(_cache_miss_perf);
		success = _client.readSync(item, index, buffer, length, timeout);

		// Cache the item if not found already (it could be in the process of being loaded)
		if (success && !item_found && _item_counter < _num_items) {
			_items[_load_index].cache_state = State::ResponseReceived;
			_items[_load_index].response.item = item;
			_items[_load_index].response.index = index;
			memcpy(_items[_load_index].response.data, buffer, length);

			_load_index = (_load_index + 1) % _num_items;

			++_item_counter; // Still increase the counter here
		}
	}

	return success;
}

bool DatamanCache::writeWait(dm_item_t item, uint32_t index, uint8_t *buffer, uint32_t length, hrt_abstime timeout)
{
	if (length > g_per_item_size[item]) {
		PX4_ERR("Length  %" PRIu32 " can't fit in data size for item  %" PRIi8, length, static_cast<uint8_t>(item));
		return false;
	}

	bool success = _client.writeSync(item, index, buffer, length, timeout);

	if (success && _items) {
		for (uint32_t i = 0; i < _num_items; ++i) {
			if ((_items[i].response.item == item) &&
			    (_items[i].response.index == index) &&
			    ((_items[i].cache_state == State::ResponseReceived) ||
			     (_items[i].cache_state == State::RequestPrepared))) {

				memcpy(_items[i].response.data, buffer, length);
				_items[i].cache_state = State::ResponseReceived;
				break;
			}
		}
	}

	return success;
}

void DatamanCache::update()
{
	if (_item_counter > 0) {

		_client.update();

		bool success = false;
		bool response_success = false;

		switch (_items[_update_index].cache_state) {
		case State::Idle:
			break;

		case State::ResponseReceived:
			// Skip it
			changeUpdateIndex();
			break;

		case State::RequestPrepared:

			success = _client.readAsync(static_cast<dm_item_t>(_items[_update_index].response.item),
						    _items[_update_index].response.index,
						    _items[_update_index].response.data,
						    g_per_item_size[_items[_update_index].response.item]);

			if (success) {
				_items[_update_index].cache_state = State::RequestSent;

			} else {
				_items[_update_index].cache_state = State::Error;
			}

			break;

		case State::RequestSent:

			if (_client.lastOperationCompleted(response_success)) {

				if (response_success) {

					_items[_update_index].cache_state = State::ResponseReceived;
					changeUpdateIndex();

				} else {
					_items[_update_index].cache_state = State::Error;
				}
			}

			break;

		case State::Error:
			// Handled below
			break;
		}

		if (_items[_update_index].cache_state == State::Error) {
			PX4_ERR("Caching: item %" PRIu8 ", index %" PRIu32", status %" PRIu8,
				_items[_update_index].response.item, _items[_update_index].response.index,
				_items[_update_index].response.status);

			changeUpdateIndex();
		}

	}
}

void DatamanCache::invalidate()
{
	for (uint32_t i = 0; i < _num_items; ++i) {
		_items[i].cache_state = State::Idle;
	}

	_update_index = 0;
	_item_counter = 0;
	_load_index = 0;
	_client.abortCurrentOperation();
}

inline void DatamanCache::changeUpdateIndex()
{
	_update_index = (_update_index + 1) % _num_items;

	if (_item_counter > 0) {
		--_item_counter;
	}
}