/*
 * Copyright (C) 2015, 2016 "IoT.bzh"
 * Author "Romain Forlot"
 * Author "Jose Bolo"
 *
 * 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.
 */
#define _GNU_SOURCE

#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <linux/can.h>

#include <json-c/json.h>

#include <afb/afb-binding.h>
#include <afb/afb-service-itf.h>

#define CAN_DEV "can0"

static const struct afb_binding_interface *interface;

// Initialize CAN hvac array that will be sent trough the socket
static char *can_hvac_components[8] = {
	"LeftTemperature",
	"RightTemperature",
	"Temperature",
	NULL,
	"FanSpeed",
	NULL,
	NULL,
	NULL
};

// Initialize CAN hvac array that will be sent trough the socket
static uint8_t can_hvac_values[8] = {
	21,	// LeftTemperature
	21,	// RightTemperature
	21,	// AverageTemperature
	240,	// Don't know why 240 but it was 0xF0 in the original amb hvacplugin
	0,	// FanSpeed
	1,	// Don't know why 1 but it was 0x01 in the original amb hvacplugin
	0,	// Don't know why 0 but it was 0x00 in the original amb hvacplugin
	0	// Don't know why 0 but it was 0x00 in the original amb hvacplugin
};

struct can_handler {
	int socket;
	struct sockaddr_can txAddress;
};

static struct can_handler can_handler = { .socket = -1 };

/*****************************************************************************************/
/*****************************************************************************************/
/**											**/
/**											**/
/**	   SECTION: HANDLE CAN DEVICE							**/
/**											**/
/**											**/
/*****************************************************************************************/
/*****************************************************************************************/

static int open_can_dev()
{
	struct ifreq ifr;

	can_handler.socket = socket(PF_CAN, SOCK_RAW, CAN_RAW);
	if (can_handler.socket < 0)
	{
		ERROR(interface, "socket could not be created");
	}
	else
	{
		// Attemts to open a socket to CAN bus
		strcpy(ifr.ifr_name, CAN_DEV);
		if(ioctl(can_handler.socket, SIOCGIFINDEX, &ifr) < 0)
		{
			ERROR(interface, "ioctl failed");
		}
		else
		{
			can_handler.txAddress.can_family = AF_CAN;
			can_handler.txAddress.can_ifindex = ifr.ifr_ifindex;

			// And bind it to txAddress
			if (bind(can_handler.socket, (struct sockaddr *)&can_handler.txAddress, sizeof(can_handler.txAddress)) < 0)
			{
				ERROR(interface, "bind failed");
			}
			else {
				return 0;
			}
		}
		close(can_handler.socket);
		can_handler.socket = -1;
	}
	return -1;
}

// Get original get temperature function from cpp hvacplugin code
static uint8_t get_temperature(uint8_t value)
{
	int result = ((0xF0 - 0x10) / 15) * value - 16;
	if (result < 0x10)
		result = 0x10;
	if (result > 0xF0)
		result = 0xF0;

	return (uint8_t)result;
}

static int write_can()
{
	struct can_frame txCanFrame;
	int rc = 0;

	rc = can_handler.socket;
	if (rc >= 0)
	{
		// Hardcoded can_id and dlc (data lenght code)
		txCanFrame.can_id = 0x30;
		txCanFrame.can_dlc = 8;
		txCanFrame.data[0] = get_temperature(can_hvac_values[0]);
		txCanFrame.data[1] = get_temperature(can_hvac_values[1]);
		txCanFrame.data[2] = get_temperature((can_hvac_values[0] + can_hvac_values[1]) / 2);
		txCanFrame.data[3] = can_hvac_values[3];
		txCanFrame.data[4] = can_hvac_values[4];
		txCanFrame.data[5] = can_hvac_values[5];
		txCanFrame.data[6] = can_hvac_values[6];
		txCanFrame.data[7] = can_hvac_values[7];

		rc = sendto(can_handler.socket, &txCanFrame, sizeof(struct can_frame), 0,
			(struct sockaddr*)&can_handler.txAddress, sizeof(can_handler.txAddress));
		if (rc < 0)
		{
			ERROR(interface, "Sending can frame failed");
		}
	}
	else
	{
		ERROR(interface, "socket not initialized");
	}
	return rc;
}

static uint8_t read_temp_left_zone()
{
	return can_hvac_values[0];
}

static uint8_t read_temp_right_zone()
{
	return can_hvac_values[1];
}

static uint8_t read_fanspeed()
{
	return can_hvac_values[4];
}

static int make_uint8(const char *str, uint8_t *value)
{
	long int x;
	char **end;

	if (str == NULL)
		return -1;

	x = strtol(str, &end, 10);
	if (end == str || *end)
		return -1;

	if (x < 0 || x > 255)
		return -1;

	*value = (uint8_t)x;
	return 0;
}

/*****************************************************************************************/
/*****************************************************************************************/
/**											**/
/**											**/
/**	   SECTION: BINDING VERBS IMPLEMENTATION					**/
/**											**/
/**											**/
/*****************************************************************************************/
/*****************************************************************************************/

/*
 * @brief Get fan speed HVAC system
 *
 * @param struct afb_req : an afb request structure
 *
 */
static void get_fanspeed(struct afb_req request)
{
	json_object *ret_json;
	uint8_t fanspeed = read_fanspeed();

	ret_json = json_object_new_object();
	json_object_object_add(ret_json, "FanSpeed", json_object_new_int(fanspeed));

	afb_req_success(request, ret_json, NULL);
}

/*
 * @brief Read Consign right zone temperature for HVAC system
 *
 * @param struct afb_req : an afb request structure
 *
 */
static void get_temp_right_zone(struct afb_req request)
{
	json_object *ret_json;
	uint8_t temp = read_temp_right_zone();

	ret_json = json_object_new_object();
	json_object_object_add(ret_json, "RightTemperature", json_object_new_int(temp));

	afb_req_success(request, ret_json, NULL);
}

/*
 * @brief Read Consign left zone temperature for HVAC system
 *
 * @param struct afb_req : an afb request structure
 *
 */
static void get_temp_left_zone(struct afb_req request)
{
	json_object *ret_json;
	uint8_t temp = read_temp_left_zone();

	ret_json = json_object_new_object();
	json_object_object_add(ret_json, "LeftTemperature", json_object_new_int(temp));

	afb_req_success(request, ret_json, NULL);
}

/*
 * @brief Read all values
 *
 * @param struct afb_req : an afb request structure
 *
 */
static void get_all(struct afb_req request)
{
	json_object *ret_json;

	ret_json = json_object_new_object();
	json_object_object_add(ret_json, "LeftTemperature", json_object_new_int(read_temp_left_zone()));
	json_object_object_add(ret_json, "RightTemperature", json_object_new_int(read_temp_right_zone()));
	json_object_object_add(ret_json, "FanSpeed", json_object_new_int(read_fanspeed()));

	afb_req_success(request, ret_json, NULL);
}

/*
 * @brief Set a component value using a json object retrieved from request
 *
 * @param struct afb_req : an afb request structure
 *
 */
static void set(struct afb_req request)
{
	int i, rc, nerr, nchg;
	const char *val, *key;
	struct json_object *query;
	struct json_object_iterator iter;
	struct json_object_iterator iter_end;

	query = afb_req_json(request);
	iter = json_object_iter_begin(query);
	iter_end = json_object_iter_end(query);

	/*
	 * Loop over the json object that will set every component
	 * which it will find in it.
	 */
	nchg = nerr = 0;
	while(!json_object_iter_equal(&iter, &iter_end))
	{
		key = json_object_iter_peek_name(&iter);
		i = 0;
		while (i < 8 && can_hvac_components[i] != NULL && strcmp(can_hvac_components[i], key) != 0)
		{
			i++;
		}
		if (i < 8)
		{
			val = afb_req_value(request, key);
			rc = make_uint8(val, &can_hvac_values[i]);
			if (rc < 0)
				nerr++;
			else
				nchg++;
		}
		else
		{
			// not found! ignore the error silently
			nerr++;
		}

		json_object_iter_next(&iter);
	}

	rc = nchg ? write_can() : 0;
	if (rc < 0)
		afb_req_fail(request, "error", "CAN error");
	else
		afb_req_success(request, NULL, nerr ? "error detected" : NULL);
}

// TODO: Have to change session management flag to AFB_SESSION_CHECK to use token auth
static const struct afb_verb_desc_v1 verbs[]= {
	{"get_temp_left_zone"	 , AFB_SESSION_NONE, get_temp_left_zone	, "Get the left zone temperature"},
	{"get_temp_right_zone"	 , AFB_SESSION_NONE, get_temp_right_zone	, "Get the right zone temperature"},
	{"get_fanspeed"	 , AFB_SESSION_NONE, get_fanspeed	, "Read fan speed"},
	{"get_all"	 , AFB_SESSION_NONE, get_all	, "Read all values"},
	{"set"	 , AFB_SESSION_NONE, set	, "Set a HVAC component value"},
	{NULL}
};

static const struct afb_binding binding_desc = {
	.type = AFB_BINDING_VERSION_1,
	.v1 = {
		.info = "hvac service",
		.prefix = "hvac",
		.verbs = verbs
	}
};

const struct afb_binding *afbBindingV1Register (const struct afb_binding_interface *itf)
{
	interface = itf;

	return &binding_desc;
}

int afbBindingV1ServiceInit(struct afb_service service)
{
	return open_can_dev();
}