/****************************************************************************
 *
 *   Copyright (C) 2012 PX4 Development Team. All rights reserved.
 *   Author: Thomas Gubler <thomasgubler@student.ethz.ch>
 *           Julian Oes <joes@student.ethz.ch>
 *
 *
 * Redistribution and use in source and binary forms, with or without
 * 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
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name PX4 nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/* @file State machine helper functions implementations */

#include <stdio.h>
#include "state_machine_helper.h"

#include <uORB/uORB.h>
#include <uORB/topics/vehicle_status.h>
#include <systemlib/systemlib.h>
#include <arch/board/up_hrt.h>

static const char* system_state_txt[] = {
	"SYSTEM_STATE_PREFLIGHT",
	"SYSTEM_STATE_STANDBY",
	"SYSTEM_STATE_GROUND_READY",
	"SYSTEM_STATE_MANUAL",
	"SYSTEM_STATE_STABILIZED",
	"SYSTEM_STATE_AUTO",
	"SYSTEM_STATE_MISSION_ABORT",
	"SYSTEM_STATE_EMCY_LANDING",
	"SYSTEM_STATE_EMCY_CUTOFF",
	"SYSTEM_STATE_GROUND_ERROR",
	"SYSTEM_STATE_REBOOT",

};


void do_state_update(int status_pub, struct vehicle_status_s *current_status, commander_state_machine_t new_state)
{
	int invalid_state = false;

	switch (new_state) {
	case SYSTEM_STATE_MISSION_ABORT: {
			/* Indoor or outdoor */
			uint8_t flight_environment_parameter = (uint8_t)(global_data_parameter_storage->pm.param_values[PARAM_FLIGHT_ENV]);

			if (flight_environment_parameter == PX4_FLIGHT_ENVIRONMENT_OUTDOOR) {
				do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_EMCY_LANDING);

			} else {
				do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_EMCY_CUTOFF);
			}

			return;
		}
		break;

	case SYSTEM_STATE_EMCY_LANDING:
		/* Tell the controller to land */
		//TODO: add emcy landing code here

		fprintf(stderr, "[commander] EMERGENCY LANDING!\n");
		//global_data_send_mavlink_statustext_message_out("Commander: state: emergency landing", MAV_SEVERITY_INFO);
		break;

	case SYSTEM_STATE_EMCY_CUTOFF:
		/* Tell the controller to cutoff the motors (thrust = 0), make sure that this is not overwritten by another app and stays at 0 */
		//TODO: add emcy cutoff code here

		fprintf(stderr, "[commander] EMERGENCY MOTOR CUTOFF!\n");
		//global_data_send_mavlink_statustext_message_out("Commander: state: emergency cutoff", MAV_SEVERITY_INFO);
		break;

	case SYSTEM_STATE_GROUND_ERROR:
		fprintf(stderr, "[commander] GROUND ERROR, locking down propulsion system\n");
		//global_data_send_mavlink_statustext_message_out("Commander: state: ground error", MAV_SEVERITY_INFO);
		break;

	case SYSTEM_STATE_PREFLIGHT:
		//global_data_send_mavlink_statustext_message_out("Commander: state: preflight", MAV_SEVERITY_INFO);
		break;

	case SYSTEM_STATE_REBOOT:
		usleep(500000);
		reboot();
		break;

	case SYSTEM_STATE_STANDBY:
		//global_data_send_mavlink_statustext_message_out("Commander: state: standby", MAV_SEVERITY_INFO);
		break;

	case SYSTEM_STATE_GROUND_READY:
		//global_data_send_mavlink_statustext_message_out("Commander: state: armed", MAV_SEVERITY_INFO);

		//if in manual mode switch to manual state
//		if (current_status->remote_manual) {
//			printf("[commander] manual mode\n");
//			do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_MANUAL);
//			return;
//		}

		break;

	case SYSTEM_STATE_AUTO:
		//global_data_send_mavlink_statustext_message_out("Commander: state: auto", MAV_SEVERITY_INFO);
		break;

	case SYSTEM_STATE_STABILIZED:
		//global_data_send_mavlink_statustext_message_out("Commander: state: stabilized", MAV_SEVERITY_INFO);
		break;

	case SYSTEM_STATE_MANUAL:
		//global_data_send_mavlink_statustext_message_out("Commander: state: manual", MAV_SEVERITY_INFO);
		break;

	default:
		invalid_state = true;
		break;
	}

	if (invalid_state == false) {
		//publish the new state
		current_status->state_machine = new_state;
		current_status->counter++;
		current_status->timestamp = hrt_absolute_time();
		orb_publish(ORB_ID(vehicle_status), status_pub, current_status);
		printf("[commander] new state: %s\n", system_state_txt[new_state]);
	}
}


/*
 * Private functions, update the state machine
 */
void state_machine_emergency_always_critical(int status_pub, struct vehicle_status_s *current_status)
{
	fprintf(stderr, "[commander] EMERGENCY HANDLER\n");
	/* Depending on the current state go to one of the error states */

	if (current_status->state_machine == SYSTEM_STATE_PREFLIGHT || current_status->state_machine == SYSTEM_STATE_STANDBY || current_status->state_machine == SYSTEM_STATE_GROUND_READY) {
		do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_GROUND_ERROR);

	} else if (current_status->state_machine == SYSTEM_STATE_AUTO || current_status->state_machine == SYSTEM_STATE_MANUAL) {
		do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_MISSION_ABORT);

	} else {
		fprintf(stderr, "[commander] Unknown system state: #%d\n", current_status->state_machine);
	}
}

void state_machine_emergency(int status_pub, struct vehicle_status_s *current_status) //do not call state_machine_emergency_always_critical if we are in manual mode for these errors
{
	if (current_status->state_machine != SYSTEM_STATE_MANUAL) { //if we are in manual: user can react to errors themself
		state_machine_emergency_always_critical(status_pub, current_status);

	} else {
		//global_data_send_mavlink_statustext_message_out("[commander] ERROR: take action immediately! (did not switch to error state because the system is in manual mode)", MAV_SEVERITY_CRITICAL);
	}

}



// /*
//  * Wrapper functions (to be used in the commander), all functions assume lock on current_status
//  */

// /* These functions decide if an emergency exits and then switch to SYSTEM_STATE_MISSION_ABORT or SYSTEM_STATE_GROUND_ERROR
//  *
//  * START SUBSYSTEM/EMERGENCY FUNCTIONS
//  * */

// void update_state_machine_subsystem_present(int status_pub, struct vehicle_status_s *current_status, subsystem_type_t *subsystem_type)
// {
// 	current_status->onboard_control_sensors_present |= 1 << *subsystem_type;
// 	current_status->counter++;
// 	current_status->timestamp = hrt_absolute_time();
// 	orb_publish(ORB_ID(vehicle_status), status_pub, current_status);
// }

// void update_state_machine_subsystem_notpresent(int status_pub, struct vehicle_status_s *current_status, subsystem_type_t *subsystem_type)
// {
// 	current_status->onboard_control_sensors_present &= ~(1 << *subsystem_type);
// 	current_status->counter++;
// 	current_status->timestamp = hrt_absolute_time();
// 	orb_publish(ORB_ID(vehicle_status), status_pub, current_status);

// 	/* if a subsystem was removed something went completely wrong */

// 	switch (*subsystem_type) {
// 	case SUBSYSTEM_TYPE_GYRO:
// 		//global_data_send_mavlink_statustext_message_out("Commander: gyro not present", MAV_SEVERITY_EMERGENCY);
// 		state_machine_emergency_always_critical(status_pub, current_status);
// 		break;

// 	case SUBSYSTEM_TYPE_ACC:
// 		//global_data_send_mavlink_statustext_message_out("Commander: accelerometer not present", MAV_SEVERITY_EMERGENCY);
// 		state_machine_emergency_always_critical(status_pub, current_status);
// 		break;

// 	case SUBSYSTEM_TYPE_MAG:
// 		//global_data_send_mavlink_statustext_message_out("Commander: magnetometer not present", MAV_SEVERITY_EMERGENCY);
// 		state_machine_emergency_always_critical(status_pub, current_status);
// 		break;

// 	case SUBSYSTEM_TYPE_GPS:
// 		{
// 			uint8_t flight_env = global_data_parameter_storage->pm.param_values[PARAM_FLIGHT_ENV];

// 			if (flight_env == PX4_FLIGHT_ENVIRONMENT_OUTDOOR) {
// 				//global_data_send_mavlink_statustext_message_out("Commander: GPS not present", MAV_SEVERITY_EMERGENCY);
// 				state_machine_emergency(status_pub, current_status);
// 			}
// 		}
// 		break;

// 	default:
// 		break;
// 	}

// }

// void update_state_machine_subsystem_enabled(int status_pub, struct vehicle_status_s *current_status, subsystem_type_t *subsystem_type)
// {
// 	current_status->onboard_control_sensors_enabled |= 1 << *subsystem_type;
// 	current_status->counter++;
// 	current_status->timestamp = hrt_absolute_time();
// 	orb_publish(ORB_ID(vehicle_status), status_pub, current_status);
// }

// void update_state_machine_subsystem_disabled(int status_pub, struct vehicle_status_s *current_status, subsystem_type_t *subsystem_type)
// {
// 	current_status->onboard_control_sensors_enabled &= ~(1 << *subsystem_type);
// 	current_status->counter++;
// 	current_status->timestamp = hrt_absolute_time();
// 	orb_publish(ORB_ID(vehicle_status), status_pub, current_status);

// 	/* if a subsystem was disabled something went completely wrong */

// 	switch (*subsystem_type) {
// 	case SUBSYSTEM_TYPE_GYRO:
// 		//global_data_send_mavlink_statustext_message_out("Commander: EMERGENCY - gyro disabled", MAV_SEVERITY_EMERGENCY);
// 		state_machine_emergency_always_critical(status_pub, current_status);
// 		break;

// 	case SUBSYSTEM_TYPE_ACC:
// 		//global_data_send_mavlink_statustext_message_out("Commander: EMERGENCY - accelerometer disabled", MAV_SEVERITY_EMERGENCY);
// 		state_machine_emergency_always_critical(status_pub, current_status);
// 		break;

// 	case SUBSYSTEM_TYPE_MAG:
// 		//global_data_send_mavlink_statustext_message_out("Commander: EMERGENCY - magnetometer disabled", MAV_SEVERITY_EMERGENCY);
// 		state_machine_emergency_always_critical(status_pub, current_status);
// 		break;

// 	case SUBSYSTEM_TYPE_GPS:
// 		{
// 			uint8_t flight_env = (uint8_t)(global_data_parameter_storage->pm.param_values[PARAM_FLIGHT_ENV]);

// 			if (flight_env == PX4_FLIGHT_ENVIRONMENT_OUTDOOR) {
// 				//global_data_send_mavlink_statustext_message_out("Commander: EMERGENCY - GPS disabled", MAV_SEVERITY_EMERGENCY);
// 				state_machine_emergency(status_pub, current_status);
// 			}
// 		}
// 		break;

// 	default:
// 		break;
// 	}

// }


// void update_state_machine_subsystem_healthy(int status_pub, struct vehicle_status_s *current_status, subsystem_type_t *subsystem_type)
// {
// 	current_status->onboard_control_sensors_health |= 1 << *subsystem_type;
// 	current_status->counter++;
// 	current_status->timestamp = hrt_absolute_time();
// 	orb_publish(ORB_ID(vehicle_status), status_pub, current_status);

// 	switch (*subsystem_type) {
// 	case SUBSYSTEM_TYPE_GYRO:
// 		//TODO state machine change (recovering)
// 		break;

// 	case SUBSYSTEM_TYPE_ACC:
// 		//TODO state machine change
// 		break;

// 	case SUBSYSTEM_TYPE_MAG:
// 		//TODO state machine change
// 		break;

// 	case SUBSYSTEM_TYPE_GPS:
// 		//TODO state machine change
// 		break;

// 	default:
// 		break;
// 	}


// }


// void update_state_machine_subsystem_unhealthy(int status_pub, struct vehicle_status_s *current_status, subsystem_type_t *subsystem_type)
// {
// 	bool previosly_healthy = (bool)(current_status->onboard_control_sensors_health & 1 << *subsystem_type);
// 	current_status->onboard_control_sensors_health &= ~(1 << *subsystem_type);
// 	current_status->counter++;
// 	current_status->timestamp = hrt_absolute_time();
// 	orb_publish(ORB_ID(vehicle_status), status_pub, current_status);

// 	/* if we received unhealthy message more than *_HEALTH_COUNTER_LIMIT, switch to error state */

// 	switch (*subsystem_type) {
// 	case SUBSYSTEM_TYPE_GYRO:
// 		//global_data_send_mavlink_statustext_message_out("Commander: gyro unhealthy", MAV_SEVERITY_CRITICAL);

// 		if (previosly_healthy) 	//only throw emergency if previously healthy
// 			state_machine_emergency_always_critical(status_pub, current_status);

// 		break;

// 	case SUBSYSTEM_TYPE_ACC:
// 		//global_data_send_mavlink_statustext_message_out("Commander: accelerometer unhealthy", MAV_SEVERITY_CRITICAL);

// 		if (previosly_healthy) 	//only throw emergency if previously healthy
// 			state_machine_emergency_always_critical(status_pub, current_status);

// 		break;

// 	case SUBSYSTEM_TYPE_MAG:
// 		//global_data_send_mavlink_statustext_message_out("Commander: magnetometer unhealthy", MAV_SEVERITY_CRITICAL);

// 		if (previosly_healthy) 	//only throw emergency if previously healthy
// 			state_machine_emergency_always_critical(status_pub, current_status);

// 		break;

// 	case SUBSYSTEM_TYPE_GPS:
// //			//TODO: remove this block
// //			break;
// //			///////////////////
// 		//global_data_send_mavlink_statustext_message_out("Commander: GPS unhealthy", MAV_SEVERITY_CRITICAL);

// //				printf("previosly_healthy = %u\n", previosly_healthy);
// 		if (previosly_healthy) 	//only throw emergency if previously healthy
// 			state_machine_emergency(status_pub, current_status);

// 		break;

// 	default:
// 		break;
// 	}

// }


/* END SUBSYSTEM/EMERGENCY FUNCTIONS*/


void update_state_machine_got_position_fix(int status_pub, struct vehicle_status_s *current_status)
{
	/* Depending on the current state switch state */
	if (current_status->state_machine == SYSTEM_STATE_PREFLIGHT) {
		do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_STANDBY);
	}
}

void update_state_machine_no_position_fix(int status_pub, struct vehicle_status_s *current_status)
{
	/* Depending on the current state switch state */
	if (current_status->state_machine == SYSTEM_STATE_STANDBY || current_status->state_machine == SYSTEM_STATE_GROUND_READY || current_status->state_machine == SYSTEM_STATE_AUTO) {
		state_machine_emergency(status_pub, current_status);
	}
}

void update_state_machine_arm(int status_pub, struct vehicle_status_s *current_status)
{
	if (current_status->state_machine == SYSTEM_STATE_STANDBY) {
		printf("[commander] arming\n");
		do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_GROUND_READY);
	} /*else if (current_status->state_machine == SYSTEM_STATE_AUTO) {

		printf("[commander] landing\n");
		do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_GROUND_READY);
	}*/
}

void update_state_machine_disarm(int status_pub, struct vehicle_status_s *current_status)
{
	if (current_status->state_machine == SYSTEM_STATE_GROUND_READY || current_status->state_machine == SYSTEM_STATE_MANUAL || current_status->state_machine == SYSTEM_STATE_PREFLIGHT) {
		printf("[commander] going standby\n");
		do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_STANDBY);

	} else if (current_status->state_machine == SYSTEM_STATE_STABILIZED || current_status->state_machine == SYSTEM_STATE_AUTO) {
		printf("[commander] MISSION ABORT!\n");
		do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_STANDBY);
	}
}

void update_state_machine_mode_manual(int status_pub, struct vehicle_status_s *current_status)
{
	if (current_status->state_machine == SYSTEM_STATE_GROUND_READY || current_status->state_machine == SYSTEM_STATE_STABILIZED || current_status->state_machine == SYSTEM_STATE_AUTO) {
		printf("[commander] manual mode\n");
		do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_MANUAL);
	}
}

void update_state_machine_mode_stabilized(int status_pub, struct vehicle_status_s *current_status)
{
	if (current_status->state_machine == SYSTEM_STATE_GROUND_READY || current_status->state_machine == SYSTEM_STATE_MANUAL || current_status->state_machine == SYSTEM_STATE_AUTO) {
		printf("[commander] stabilized mode\n");
		do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_STABILIZED);
	}
}

void update_state_machine_mode_auto(int status_pub, struct vehicle_status_s *current_status)
{
	if (current_status->state_machine == SYSTEM_STATE_GROUND_READY || current_status->state_machine == SYSTEM_STATE_MANUAL || current_status->state_machine == SYSTEM_STATE_STABILIZED) {
		printf("[commander] auto mode\n");
		do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_AUTO);
	}
}


uint8_t update_state_machine_mode_request(int status_pub, struct vehicle_status_s *current_status, uint8_t mode)
{
	commander_state_machine_t current_system_state = current_status->state_machine;

	printf("in update state request\n");
	uint8_t ret = 1;

	/* Switch on HIL if in standby */
	if ((current_system_state == SYSTEM_STATE_STANDBY) && (mode & MAV_MODE_FLAG_HIL_ENABLED)) {
		/* Enable HIL on request */
		current_status->mode |= MAV_MODE_FLAG_HIL_ENABLED;
	}

	/* NEVER actually switch off HIL without reboot */
	if ((current_status->mode & MAV_MODE_FLAG_HIL_ENABLED) && !(mode & MAV_MODE_FLAG_HIL_ENABLED)) {
		fprintf(stderr, "[commander] DENYING request to switch of HIL. Please power cycle (safety reasons)\n");
		ret = ERROR;
	}

	//TODO: clarify mapping between mavlink enum MAV_MODE and the state machine, then add more decisions to the switch (see also the system_state_loop function in mavlink.c)
	switch (mode) {
	case MAV_MODE_MANUAL_ARMED: //= SYSTEM_STATE_ARMED
		if (current_system_state == SYSTEM_STATE_STANDBY) {
			/* Set armed flag */
			current_status->mode |= MAV_MODE_FLAG_SAFETY_ARMED;
			/* Set manual input enabled flag */
			current_status->mode |= MAV_MODE_FLAG_MANUAL_INPUT_ENABLED;
			do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_GROUND_READY);
			ret = OK;
		}

		break;

	case MAV_MODE_MANUAL_DISARMED:
		if (current_system_state == SYSTEM_STATE_GROUND_READY) {
			/* Clear armed flag, leave manual input enabled */
			current_status->mode &= ~MAV_MODE_FLAG_SAFETY_ARMED;
			do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_STANDBY);
			ret = OK;
		}

		break;

	default:
		break;
	}

	#warning STATE MACHINE IS INCOMPLETE HERE

//	if(ret != 0) //Debug
//	{
//		strcpy(mavlink_statustext_msg_content.values[0].string_value, "Commander: command rejected");
//		global_data_send_mavlink_message_out(&mavlink_statustext_msg_content);
//	}

	return ret;
}

uint8_t update_state_machine_custom_mode_request(int status_pub, struct vehicle_status_s *current_status, uint8_t custom_mode) //TODO: add more checks to avoid state switching in critical situations
{
	commander_state_machine_t current_system_state = current_status->state_machine;

	uint8_t ret = 1;

	switch (custom_mode) {
	case SYSTEM_STATE_GROUND_READY:
		break;

	case SYSTEM_STATE_STANDBY:
		break;

	case SYSTEM_STATE_REBOOT:
		printf("try to reboot\n");

		if (current_system_state == SYSTEM_STATE_STANDBY || current_system_state == SYSTEM_STATE_PREFLIGHT) {
			printf("system will reboot\n");
			//global_data_send_mavlink_statustext_message_out("Rebooting autopilot.. ", MAV_SEVERITY_INFO);
			do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_REBOOT);
			ret = 0;
		}

		break;

	case SYSTEM_STATE_AUTO:
		printf("try to switch to auto/takeoff\n");

		if (current_system_state == SYSTEM_STATE_GROUND_READY || current_system_state == SYSTEM_STATE_MANUAL) {
			do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_AUTO);
			printf("state: auto\n");
			ret = 0;
		}

		break;

	case SYSTEM_STATE_MANUAL:
		printf("try to switch to manual\n");

		if (current_system_state == SYSTEM_STATE_GROUND_READY || current_system_state == SYSTEM_STATE_AUTO) {
			do_state_update(status_pub, current_status, (commander_state_machine_t)SYSTEM_STATE_MANUAL);
			printf("state: manual\n");
			ret = 0;
		}

		break;

	default:
		break;
	}

	return ret;
}