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 * modification, are permitted provided that the following conditions
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 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
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 *    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 led.cpp
 */


#include "led.h"

int LedController::update(LedControlData &control_data)
{
	while (_led_control_sub.updated() || _force_update) {
		// handle new state
		led_control_s led_control;

		if (_led_control_sub.copy(&led_control)) {

			// don't apply the new state just yet to avoid interrupting an ongoing blinking state
			for (int i = 0; i < BOARD_MAX_LEDS; ++i) {
				if (led_control.led_mask & (1 << i)) {
					// if next state has already a higher priority state than
					// led_control, set lower prio state directly, so that this
					// information is not lost
					if (_states[i].next_state.is_valid() && led_control.priority < _states[i].next_state.priority) {
						_states[i].set(led_control);

					} else {
						// if a lower prio event is already in next state and a
						// higher prio event is coming in
						if (_states[i].next_state.is_valid() && led_control.priority > _states[i].next_state.priority) {
							_states[i].apply_next_state();
						}

						_states[i].next_state.set(led_control);
					}
				}
			}
		}

		_force_update = false;
	}

	bool had_changes = false; // did one of the outputs change?

	// handle state updates
	hrt_abstime now = hrt_absolute_time();

	if (_last_update_call == 0) {
		_last_update_call = now;
		return 0;
	}

	uint16_t blink_delta_t = (uint16_t)((now - _last_update_call) / 100); // Note: this is in 0.1ms
	constexpr uint16_t breathe_duration = BREATHE_INTERVAL * BREATHE_STEPS / 100;

	int num_blinking_leds = 0;
	int num_blinking_do_not_change_state = 0;
	int current_priorities[BOARD_MAX_LEDS];

	for (int i = 0; i < BOARD_MAX_LEDS; ++i) {
		int priority = led_control_s::MAX_PRIORITY;

		for (; priority >= 0; --priority) {

			PerPriorityData &cur_data = _states[i].priority[priority];

			if (cur_data.mode == led_control_s::MODE_DISABLED) {
				continue; // handle next priority
			}

			// handle state updates
			uint16_t current_blink_duration = 0;

			switch (cur_data.mode) {
			case led_control_s::MODE_FLASH:
			case led_control_s::MODE_BLINK_FAST:
				current_blink_duration = BLINK_FAST_DURATION / 100;
				break;

			case led_control_s::MODE_BLINK_NORMAL:
				current_blink_duration = BLINK_NORMAL_DURATION / 100;
				break;

			case led_control_s::MODE_BLINK_SLOW:
				current_blink_duration = BLINK_SLOW_DURATION / 100;
				break;

			case led_control_s::MODE_BREATHE:
				_states[i].current_blinking_time += blink_delta_t;

				while (_states[i].current_blinking_time > breathe_duration) {
					_states[i].current_blinking_time -= breathe_duration;
				}

				had_changes = true;
				break;
			}

			if (current_blink_duration > 0) {
				++num_blinking_leds;

				if ((_states[i].current_blinking_time += blink_delta_t) > current_blink_duration) {
					_states[i].current_blinking_time -= current_blink_duration;

					if (cur_data.blink_times_left == 246) {
						// handle toggling for infinite case: decrease between 255 and 246
						// In order to handle the flash mode infinite case it needs a
						// total of 10 steps.
						cur_data.blink_times_left = 255;
						++num_blinking_do_not_change_state;

					} else if (--cur_data.blink_times_left == 0) {
						cur_data.mode = led_control_s::MODE_DISABLED;
						_states[i].current_blinking_time = 0;

					} else if (cur_data.blink_times_left % 2 == 1) {
						++num_blinking_do_not_change_state;
					}

					had_changes = true;

				} else {
					++num_blinking_do_not_change_state;
				}
			}

			break; // handle next led
		}

		current_priorities[i] = priority;

	}

	// handle next state:
	// only allow a state change if no led blinks or at least one of the blinking leds signals that it's ok to switch.
	// This makes sure all leds are kept in sync, but does not allow interrupting at arbitrary points.
	if (num_blinking_leds == 0 || num_blinking_leds > num_blinking_do_not_change_state) {
		for (int i = 0; i < BOARD_MAX_LEDS; ++i) {
			if (_states[i].next_state.is_valid()) {
				int next_priority = (int)_states[i].next_state.priority;

				if (next_priority >= current_priorities[i]) {
					_states[i].current_blinking_time = 0;
					had_changes = true;
				}

				_states[i].apply_next_state();
				_states[i].next_state.reset();
			}

		}
	}

	_last_update_call = now;

	if (!had_changes) {
		return 0;
	}

	// create output
	get_control_data(control_data);

	return 1;
}

void LedController::get_control_data(LedControlData &control_data)
{
	_breathe_enabled = false;

	for (int i = 0; i < BOARD_MAX_LEDS; ++i) {
		control_data.leds[i].color = led_control_s::COLOR_OFF; // set output to a defined state
		control_data.leds[i].brightness = 255;

		for (int priority = led_control_s::MAX_PRIORITY; priority >= 0; --priority) {
			bool flash_output_active = true;
			const PerPriorityData &cur_data = _states[i].priority[priority];

			if (cur_data.mode == led_control_s::MODE_DISABLED) {
				continue; // handle next priority
			}

			switch (cur_data.mode) {
			case led_control_s::MODE_ON:
				control_data.leds[i].color = cur_data.color;
				break;

			case led_control_s::MODE_BREATHE: {
					// fade on and off
					int counter = _states[i].current_blinking_time / (BREATHE_INTERVAL / 100);
					int n = counter >= (BREATHE_STEPS / 2) ? BREATHE_STEPS - counter : counter;
					control_data.leds[i].brightness = (n * n) * 255 / (BREATHE_STEPS * BREATHE_STEPS / 4); // (n/(steps/2))^2
					control_data.leds[i].color = cur_data.color;
					_breathe_enabled = true;
					break;
				}

			case led_control_s::MODE_FLASH:
				if (cur_data.blink_times_left % 10 < 6) { // 2 blinks, then turn off for the rest of the cycle
					flash_output_active = false;
				}

			/* FALLTHROUGH */
			case led_control_s::MODE_BLINK_FAST:
			case led_control_s::MODE_BLINK_NORMAL:
			case led_control_s::MODE_BLINK_SLOW:
				if (cur_data.blink_times_left % 2 == 0 && flash_output_active) {
					control_data.leds[i].color = cur_data.color;
				}

				break;
				// MODE_OFF does not need to be handled, it's already set above
			}

			break; // handle next led
		}
	}
}