/*
 * Copyright (C) 2015, 2016 "IoT.bzh"
 * Author "Romain Forlot" <romain.forlot@iot.bzh>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *	 http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <map>
#include <cerrno>
#include <vector>
#include <string>
#include <fcntl.h>
#include <unistd.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <json-c/json.h>
#include <linux/can/raw.h>

#include "can-bus.hpp"

#include "can-signals.hpp"
#include "can-decoder.hpp"
#include "../configuration.hpp"
#include "../utils/signals.hpp"
#include "../utils/openxc-utils.hpp"

extern "C"
{
	#include <afb/afb-binding.h>
}

/**
* @brief Class constructor
*
* @param struct afb_binding_interface *interface between daemon and binding
* @param int file handle to the json configuration file.
*/
can_bus_t::can_bus_t(int conf_file)
	: conf_file_{conf_file}
{
}

std::map<std::string, std::shared_ptr<can_bus_dev_t>> can_bus_t::can_devices_;

/**
 * @brief Will make the decoding operation on a classic CAN message. It will not
 * handle CAN commands nor diagnostic messages that have their own method to get
 * this happens.
 *
 * It will add to the vehicle_message queue the decoded message and tell the event push
 * thread to process it.
 *
 * @param[in] can_message - a single CAN message from the CAN socket read, to be decode.
 *
 * @return How many signals has been decoded.
 */
int can_bus_t::process_can_signals(can_message_t& can_message)
{
	int processed_signals = 0;
	std::vector <can_signal_t*> signals;
	openxc_DynamicField search_key, decoded_message;
	openxc_VehicleMessage vehicle_message;

	/* First we have to found which can_signal_t it is */
	search_key = build_DynamicField((double)can_message.get_id());
	configuration_t::instance().find_can_signals(search_key, signals);

	/* Decoding the message ! Don't kill the messenger ! */
	for(auto& sig : signals)
	{
		std::lock_guard<std::mutex> subscribed_signals_lock(get_subscribed_signals_mutex());
		std::map<std::string, struct afb_event>& s = get_subscribed_signals();

		/* DEBUG message to make easier debugger STL containers...
		DEBUG(binder_interface, "Operator[] key char: %s, event valid? %d", sig.generic_name, afb_event_is_valid(s[sig.generic_name]));
		DEBUG(binder_interface, "Operator[] key string: %s, event valid? %d", sig.generic_name, afb_event_is_valid(s[std::string(sig.generic_name)]));
		DEBUG(binder_interface, "Nb elt matched char: %d", (int)s.count(sig.generic_name));
		DEBUG(binder_interface, "Nb elt matched string: %d", (int)s.count(std::string(sig.generic_name)));*/
		if( s.find(sig->get_name()) != s.end() && afb_event_is_valid(s[sig->get_name()]))
		{
			decoded_message = decoder_t::translateSignal(*sig, can_message, configuration_t::instance().get_can_signals());

			openxc_SimpleMessage s_message = build_SimpleMessage(sig->get_name(), decoded_message);
			vehicle_message = build_VehicleMessage(s_message);

			std::lock_guard<std::mutex> decoded_can_message_lock(decoded_can_message_mutex_);
			push_new_vehicle_message(vehicle_message);
			new_decoded_can_message_.notify_one();
			processed_signals++;
		}
	}

	DEBUG(binder_interface, "process_can_signals: %d/%d CAN signals processed.", processed_signals, (int)signals.size());
	return processed_signals;
}

/**
 * @brief Will make the decoding operation on a diagnostic CAN message.It will add to
 * the vehicle_message queue the decoded message and tell the event push thread to process it.
 *
 * @param[in] manager - the diagnostic manager object that handle diagnostic communication
 * @param[in] can_message - a single CAN message from the CAN socket read, to be decode.
 *
 * @return How many signals has been decoded.
 */
int can_bus_t::process_diagnostic_signals(diagnostic_manager_t& manager, const can_message_t& can_message)
{
	int processed_signals = 0;

	std::lock_guard<std::mutex> subscribed_signals_lock(get_subscribed_signals_mutex());
	std::map<std::string, struct afb_event>& s = get_subscribed_signals();

	openxc_VehicleMessage vehicle_message = manager.find_and_decode_adr(can_message);
	if( (vehicle_message.has_simple_message && vehicle_message.simple_message.has_name) &&
		(s.find(vehicle_message.simple_message.name) != s.end() && afb_event_is_valid(s[vehicle_message.simple_message.name])))
	{
		std::lock_guard<std::mutex> decoded_can_message_lock(decoded_can_message_mutex_);
		push_new_vehicle_message(vehicle_message);
		new_decoded_can_message_.notify_one();
		processed_signals++;
	}

	return processed_signals;
}

/**
* @brief thread to decoding raw CAN messages.
*
* @desc It will take from the can_message_q_ queue the next can message to process then it will search
*  about signal subscribed if there is a valid afb_event for it. We only decode signal for which a
*  subscription has been made. Can message will be decoded using translateSignal that will pass it to the
*  corresponding decoding function if there is one assigned for that signal. If not, it will be the default
*  noopDecoder function that will operate on it.
*
*  Depending on the nature of message, if id match a diagnostic request corresponding id for a response
*  then decoding a diagnostic message else use classic CAN signals decoding functions.
*
*  TODO: make diagnostic messages parsing optionnal.
*/
void can_bus_t::can_decode_message()
{
	can_message_t can_message;

	while(is_decoding_)
	{
		std::unique_lock<std::mutex> can_message_lock(can_message_mutex_);
		new_can_message_cv_.wait(can_message_lock);
		can_message = next_can_message();

		if(configuration_t::instance().get_diagnostic_manager().is_diagnostic_response(can_message))
			process_diagnostic_signals(configuration_t::instance().get_diagnostic_manager(), can_message);
		else
			process_can_signals(can_message);
	}
}

/**
* @brief thread to push events to suscribers. It will read subscribed_signals map to look
* which are events that has to be pushed.
*/
void can_bus_t::can_event_push()
{
	openxc_VehicleMessage v_message;
	openxc_SimpleMessage s_message;
	json_object* jo;

	while(is_pushing_)
	{
		std::unique_lock<std::mutex> decoded_can_message_lock(decoded_can_message_mutex_);
		new_decoded_can_message_.wait(decoded_can_message_lock);
		v_message = next_vehicle_message();

		s_message = get_simple_message(v_message);
		{
			std::lock_guard<std::mutex> subscribed_signals_lock(get_subscribed_signals_mutex());
			std::map<std::string, struct afb_event>& s = get_subscribed_signals();
			if(s.find(std::string(s_message.name)) != s.end() && afb_event_is_valid(s[std::string(s_message.name)]))
			{
				jo = json_object_new_object();
				jsonify_simple(s_message, jo);
				afb_event_push(s[std::string(s_message.name)], jo);
			}
		}
	}
}

/**
* @brief Will initialize threads that will decode
*  and push subscribed events.
*/
void can_bus_t::start_threads()
{
	is_decoding_ = true;
	th_decoding_ = std::thread(&can_bus_t::can_decode_message, this);
	if(!th_decoding_.joinable())
		is_decoding_ = false;

	is_pushing_ = true;
	th_pushing_ = std::thread(&can_bus_t::can_event_push, this);
	if(!th_pushing_.joinable())
		is_pushing_ = false;
}

/**
* @brief Will stop all threads holded by can_bus_t object
*  which are decoding and pushing then will wait that's
* they'll finish their job.
*/
void can_bus_t::stop_threads()
{
	is_decoding_ = false;
	is_pushing_ = false;
}

/**
* @brief Will initialize can_bus_dev_t objects after reading
* the configuration file passed in the constructor. All CAN buses
* Initialized here will be added to a vector holding them for
* inventory and later access.
*
* That will initialize CAN socket reading too using a new thread.
*/
int can_bus_t::init_can_dev()
{
	std::vector<std::string> devices_name;
	int i = 0;
	size_t t;

	devices_name = read_conf();

	if (! devices_name.empty())
	{
		t = devices_name.size();

		for(const auto& device : devices_name)
		{
			can_bus_t::can_devices_[device] = std::make_shared<can_bus_dev_t>(device, i);
			if (can_bus_t::can_devices_[device]->open() == 0)
			{
				DEBUG(binder_interface, "Start reading thread");
				NOTICE(binder_interface, "%s device opened and reading", device.c_str());
				can_bus_t::can_devices_[device]->start_reading(*this);
				i++;
			}
			else
				ERROR(binder_interface, "Can't open device %s", device.c_str());
		}

		NOTICE(binder_interface, "Initialized %d/%d can bus device(s)", i, t);
		return 0;
	}
	ERROR(binder_interface, "init_can_dev: Error at CAN device initialization. No devices read from configuration file. Did you specify canbus JSON object ?");
	return 1;
}

/**
* @brief read the conf_file_ and will parse json objects
* in it searching for canbus objects devices name.
*
* @return Vector of can bus device name string.
*/
std::vector<std::string> can_bus_t::read_conf()
{
	std::vector<std::string> ret;
	json_object *jo, *canbus;
	int n, i;
	const char* taxi;

	FILE *fd = fdopen(conf_file_, "r");
	if (fd)
	{
		std::string fd_conf_content;
		std::fseek(fd, 0, SEEK_END);
		fd_conf_content.resize(std::ftell(fd));
		std::rewind(fd);
		std::fread(&fd_conf_content[0], 1, fd_conf_content.size(), fd);
		std::fclose(fd);

		DEBUG(binder_interface, "Configuration file content : %s", fd_conf_content.c_str());
		jo = json_tokener_parse(fd_conf_content.c_str());

		if (jo == NULL || !json_object_object_get_ex(jo, "canbus", &canbus))
		{
			ERROR(binder_interface, "Can't find canbus node in the configuration file. Please review it.");
			ret.clear();
		}
		else if (json_object_get_type(canbus) != json_type_array)
		{
			taxi = json_object_get_string(canbus);
			DEBUG(binder_interface, "Can bus found: %s", taxi);
			ret.push_back(std::string(taxi));
		}
		else
		{
			n = json_object_array_length(canbus);
			for (i = 0 ; i < n ; i++)
				ret.push_back(json_object_get_string(json_object_array_get_idx(canbus, i)));
		}
		return ret;
	}
	ERROR(binder_interface, "Problem at reading the conf file");
	ret.clear();
	return ret;
}

/**
* @brief return new_can_message_cv_ member
*
* @return  return new_can_message_cv_ member
*/
std::condition_variable& can_bus_t::get_new_can_message_cv()
{
	return new_can_message_cv_;
}

/**
* @brief return can_message_mutex_ member
*
* @return  return can_message_mutex_ member
*/
std::mutex& can_bus_t::get_can_message_mutex()
{
	return can_message_mutex_;
}

/**
* @brief Return first can_message_t on the queue
*
* @return a can_message_t
*/
can_message_t can_bus_t::next_can_message()
{
	can_message_t can_msg;

	if(!can_message_q_.empty())
	{
		can_msg = can_message_q_.front();
		can_message_q_.pop();
		DEBUG(binder_interface, "next_can_message: Here is the next can message : id %X, length %X, data %02X%02X%02X%02X%02X%02X%02X%02X", can_msg.get_id(), can_msg.get_length(),
			can_msg.get_data()[0], can_msg.get_data()[1], can_msg.get_data()[2], can_msg.get_data()[3], can_msg.get_data()[4], can_msg.get_data()[5], can_msg.get_data()[6], can_msg.get_data()[7]);
		return can_msg;
	}

	return can_msg;
}

/**
* @brief Push a can_message_t into the queue
*
* @param the const reference can_message_t object to push into the queue
*/
void can_bus_t::push_new_can_message(const can_message_t& can_msg)
{
	can_message_q_.push(can_msg);
}

/**
* @brief Return first openxc_VehicleMessage on the queue
*
* @return a openxc_VehicleMessage containing a decoded can message
*/
openxc_VehicleMessage can_bus_t::next_vehicle_message()
{
	openxc_VehicleMessage v_msg;

	if(! vehicle_message_q_.empty())
	{
		v_msg = vehicle_message_q_.front();
		vehicle_message_q_.pop();
		DEBUG(binder_interface, "next_vehicle_message: next vehicle message poped");
		return v_msg;
	}

	return v_msg;
}

/**
* @brief Push a openxc_VehicleMessage into the queue
*
* @param the const reference openxc_VehicleMessage object to push into the queue
*/
void can_bus_t::push_new_vehicle_message(const openxc_VehicleMessage& v_msg)
{
	vehicle_message_q_.push(v_msg);
}

/**
* @brief Return a map with the can_bus_dev_t initialized
*
* @return map can_bus_dev_m_ map
*/
const std::map<std::string, std::shared_ptr<can_bus_dev_t>>& can_bus_t::get_can_devices() const
{
	return can_bus_t::can_devices_;
}

/**
* @brief Return the shared pointer on the can_bus_dev_t initialized 
* with device_name "bus"
*
* @param[in] bus - CAN bus device name to retrieve.
*
* @return A shared pointer on an object can_bus_dev_t
*/
std::shared_ptr<can_bus_dev_t> can_bus_t::get_can_device(std::string bus)
{
	return can_bus_t::can_devices_[bus];
}