/****************************************************************************
 *
 *   Copyright (c) 2013-2020 PX4 Development Team. All rights reserved.
 *
 * 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,
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 ****************************************************************************/

/**
 * Multicopter position controller.
 */

#pragma once

#include <commander/px4_custom_mode.h>
#include <drivers/drv_hrt.h>
#include <lib/controllib/blocks.hpp>
#include <lib/flight_tasks/FlightTasks.hpp>
#include <lib/hysteresis/hysteresis.h>
#include <lib/mathlib/mathlib.h>
#include <lib/matrix/matrix/math.hpp>
#include <lib/perf/perf_counter.h>
#include <lib/systemlib/mavlink_log.h>
#include <lib/weather_vane/WeatherVane.hpp>
#include <px4_platform_common/px4_config.h>
#include <px4_platform_common/defines.h>
#include <px4_platform_common/module.h>
#include <px4_platform_common/module_params.h>
#include <px4_platform_common/px4_work_queue/ScheduledWorkItem.hpp>
#include <px4_platform_common/posix.h>
#include <px4_platform_common/tasks.h>
#include <uORB/Publication.hpp>
#include <uORB/Subscription.hpp>
#include <uORB/SubscriptionCallback.hpp>
#include <uORB/topics/home_position.h>
#include <uORB/topics/landing_gear.h>
#include <uORB/topics/parameter_update.h>
#include <uORB/topics/vehicle_attitude_setpoint.h>
#include <uORB/topics/vehicle_control_mode.h>
#include <uORB/topics/vehicle_land_detected.h>
#include <uORB/topics/vehicle_local_position.h>
#include <uORB/topics/vehicle_local_position_setpoint.h>
#include <uORB/topics/vehicle_status.h>
#include <uORB/topics/vehicle_trajectory_waypoint.h>
#include <uORB/topics/hover_thrust_estimate.h>

#include "PositionControl/PositionControl.hpp"
#include "Takeoff/Takeoff.hpp"

#include <float.h>

class MulticopterPositionControl : public ModuleBase<MulticopterPositionControl>, public control::SuperBlock,
	public ModuleParams, public px4::WorkItem
{
public:
	MulticopterPositionControl(bool vtol = false);
	~MulticopterPositionControl() override;

	/** @see ModuleBase */
	static int task_spawn(int argc, char *argv[]);

	/** @see ModuleBase */
	static int custom_command(int argc, char *argv[]);

	/** @see ModuleBase */
	static int print_usage(const char *reason = nullptr);

	bool init();

private:
	void Run() override;

	Takeoff _takeoff; /**< state machine and ramp to bring the vehicle off the ground without jumps */

	uORB::Publication<vehicle_attitude_setpoint_s>	_vehicle_attitude_setpoint_pub;
	orb_advert_t _mavlink_log_pub{nullptr};

	uORB::Publication<vehicle_local_position_setpoint_s>	_local_pos_sp_pub{ORB_ID(vehicle_local_position_setpoint)};	/**< vehicle local position setpoint publication */

	uORB::SubscriptionCallbackWorkItem _local_pos_sub{this, ORB_ID(vehicle_local_position)};	/**< vehicle local position */

	uORB::Subscription _vehicle_land_detected_sub{ORB_ID(vehicle_land_detected)};	/**< vehicle land detected subscription */
	uORB::Subscription _control_mode_sub{ORB_ID(vehicle_control_mode)};		/**< vehicle control mode subscription */
	uORB::Subscription _parameter_update_sub{ORB_ID(parameter_update)};		/**< notification of parameter updates */
	uORB::Subscription _home_pos_sub{ORB_ID(home_position)}; 			/**< home position */
	uORB::Subscription _hover_thrust_estimate_sub{ORB_ID(hover_thrust_estimate)};
	uORB::Subscription _trajectory_setpoint_sub{ORB_ID(trajectory_setpoint)};
	uORB::Subscription _vehicle_constraints_sub{ORB_ID(vehicle_constraints)};

	hrt_abstime	_time_stamp_last_loop{0};		/**< time stamp of last loop iteration */

	int _task_failure_count{0};         /**< counter for task failures */

	/**< vehicle-land-detection: initialze to landed */
	vehicle_land_detected_s _vehicle_land_detected = {
		.timestamp = 0,
		.alt_max = -1.0f,
		.freefall = false,
		.ground_contact = true,
		.maybe_landed = true,
		.landed = true,
	};

	vehicle_control_mode_s	_control_mode{};		/**< vehicle control mode */
	vehicle_local_position_s _local_pos{};			/**< vehicle local position */
	home_position_s	_home_pos{};			/**< home position */

	int8_t _old_landing_gear_position{landing_gear_s::GEAR_KEEP};

	DEFINE_PARAMETERS(
		// Position Control
		(ParamFloat<px4::params::MPC_XY_P>) _param_mpc_xy_p,
		(ParamFloat<px4::params::MPC_Z_P>) _param_mpc_z_p,
		(ParamFloat<px4::params::MPC_XY_VEL_P_ACC>) _param_mpc_xy_vel_p_acc,
		(ParamFloat<px4::params::MPC_XY_VEL_I_ACC>) _param_mpc_xy_vel_i_acc,
		(ParamFloat<px4::params::MPC_XY_VEL_D_ACC>) _param_mpc_xy_vel_d_acc,
		(ParamFloat<px4::params::MPC_Z_VEL_P_ACC>) _param_mpc_z_vel_p_acc,
		(ParamFloat<px4::params::MPC_Z_VEL_I_ACC>) _param_mpc_z_vel_i_acc,
		(ParamFloat<px4::params::MPC_Z_VEL_D_ACC>) _param_mpc_z_vel_d_acc,
		(ParamFloat<px4::params::MPC_XY_VEL_MAX>) _param_mpc_xy_vel_max,
		(ParamFloat<px4::params::MPC_Z_VEL_MAX_UP>) _param_mpc_z_vel_max_up,
		(ParamFloat<px4::params::MPC_Z_VEL_MAX_DN>) _param_mpc_z_vel_max_dn,
		(ParamFloat<px4::params::MPC_TILTMAX_AIR>) _param_mpc_tiltmax_air,
		(ParamFloat<px4::params::MPC_THR_HOVER>) _param_mpc_thr_hover,
		(ParamBool<px4::params::MPC_USE_HTE>) _param_mpc_use_hte,

		// Takeoff / Land
		(ParamFloat<px4::params::MPC_SPOOLUP_TIME>) _param_mpc_spoolup_time, /**< time to let motors spool up after arming */
		(ParamFloat<px4::params::MPC_TKO_RAMP_T>) _param_mpc_tko_ramp_t, /**< time constant for smooth takeoff ramp */
		(ParamFloat<px4::params::MPC_TKO_SPEED>) _param_mpc_tko_speed,
		(ParamFloat<px4::params::MPC_LAND_SPEED>) _param_mpc_land_speed,

		(ParamFloat<px4::params::MPC_VEL_MANUAL>) _param_mpc_vel_manual,
		(ParamFloat<px4::params::MPC_XY_CRUISE>) _param_mpc_xy_cruise,
		(ParamFloat<px4::params::MPC_LAND_ALT2>) _param_mpc_land_alt2, /**< downwards speed limited below this altitude */
		(ParamInt<px4::params::MPC_POS_MODE>) _param_mpc_pos_mode,
		(ParamInt<px4::params::MPC_ALT_MODE>) _param_mpc_alt_mode,
		(ParamFloat<px4::params::MPC_TILTMAX_LND>) _param_mpc_tiltmax_lnd, /**< maximum tilt for landing and smooth takeoff */
		(ParamFloat<px4::params::MPC_THR_MIN>) _param_mpc_thr_min,
		(ParamFloat<px4::params::MPC_THR_MAX>) _param_mpc_thr_max
	);

	control::BlockDerivative _vel_x_deriv; /**< velocity derivative in x */
	control::BlockDerivative _vel_y_deriv; /**< velocity derivative in y */
	control::BlockDerivative _vel_z_deriv; /**< velocity derivative in z */

	PositionControl _control; /**< class for core PID position control */
	PositionControlStates _states{}; /**< structure containing vehicle state information for position control */

	hrt_abstime _last_warn = 0; /**< timer when the last warn message was sent out */

	bool _in_failsafe = false; /**< true if failsafe was entered within current cycle */

	bool _hover_thrust_initialized{false};

	/** Timeout in us for trajectory data to get considered invalid */
	static constexpr uint64_t TRAJECTORY_STREAM_TIMEOUT_US = 500_ms;
	/** If Flighttask fails, keep 0.2 seconds the current setpoint before going into failsafe land */
	static constexpr uint64_t LOITER_TIME_BEFORE_DESCEND = 200_ms;
	/** During smooth-takeoff, below ALTITUDE_THRESHOLD the yaw-control is turned off ant tilt is limited */
	static constexpr float ALTITUDE_THRESHOLD = 0.3f;

	static constexpr float MAX_SAFE_TILT_DEG = 89.f; // Numerical issues above this value due to tanf

	systemlib::Hysteresis _failsafe_land_hysteresis{false}; /**< becomes true if task did not update correctly for LOITER_TIME_BEFORE_DESCEND */

	WeatherVane *_wv_controller{nullptr};
	Vector3f _wv_dcm_z_sp_prev{0, 0, 1};

	perf_counter_t _cycle_perf;

	/**
	 * Update our local parameter cache.
	 * Parameter update can be forced when argument is true.
	 * @param force forces parameter update.
	 */
	int parameters_update(bool force);

	/**
	 * Check for changes in subscribed topics.
	 */
	void poll_subscriptions();

	/**
	 * Check for validity of positon/velocity states.
	 * @param vel_sp_z velocity setpoint in z-direction
	 */
	void set_vehicle_states(const float &vel_sp_z);

	/**
	 * Limit altitude based on land-detector.
	 * @param setpoint needed to detect vehicle intention.
	 */
	void limit_altitude(vehicle_local_position_setpoint_s &setpoint);

	/**
	 * Adjust the setpoint during landing.
	 * Thrust is adjusted to support the land-detector during detection.
	 * @param setpoint gets adjusted based on land-detector state
	 */
	void limit_thrust_during_landing(vehicle_attitude_setpoint_s &setpoint);

	/**
	 * Failsafe.
	 * If flighttask fails for whatever reason, then do failsafe. This could
	 * occur if the commander fails to switch to a mode in case of invalid states or
	 * setpoints. The failsafe will occur after LOITER_TIME_BEFORE_DESCEND. If force is set
	 * to true, the failsafe will be initiated immediately.
	 */
	void failsafe(const hrt_abstime &now, vehicle_local_position_setpoint_s &setpoint, const PositionControlStates &states,
		      const bool force, bool warn);

	/**
	 * Reset setpoints to NAN
	 */
	void reset_setpoint_to_nan(vehicle_local_position_setpoint_s &setpoint);
};