esphome-xiaomi_bslamp2/sensor/slider_sensor.h

#pragma once 

#include <cmath>
#include "../common.h"
#include "../front_panel_hal.h"
#include "esphome/components/sensor/sensor.h"

namespace esphome {
namespace xiaomi {
namespace bslamp2 {

/**
 * A sensor for the touch slider on the front panel of the 
 * Xiaomi Mijia Bedside Lamp 2.
 *
 * This sensor publishes the level at which the slider was touched, so it
 * can be used to implement automations.  Note that it does not represent
 * the brightness of the LED lights (this is implemented by the light output
 * component), nor the level as displayed by the slider using the front
 * panel light (this is implemented by the slider light component).
 */
class XiaomiBslamp2SliderSensor : public sensor::Sensor, public Component {
public:
    void set_parent(FrontPanelHAL *front_panel) { front_panel_ = front_panel; }
    void set_range_from(float from) { range_from_ = from; }
    void set_range_to(float to) { range_to_ = to; }

    void setup() {
        slope_ = (range_to_ - range_from_) / 19.0f;

        front_panel_->add_on_event_callback(
            [this](EVENT ev) {
                if ((ev & FLAG_PART_MASK) == FLAG_PART_SLIDER) {
                    float level = (ev & FLAG_LEVEL_MASK) >> FLAG_LEVEL_SHIFT; 

                    // Slider level 1 is really hard to touch. It is between
                    // the power button and the slider space, so it doesn't
                    // look like this one was ever meant to be used, or that
                    // the design was faulty on this. Therefore, level 1 is
                    // ignored. The resulting range of levels is 0-19.
                    float corrected_level = max(0.0f, level - 2.0f);

                    float final_level = range_from_ + (slope_ * corrected_level);
                    this->publish_state(final_level); 
                }
            }
        );
    }

    void dump_config() {
        ESP_LOGCONFIG(TAG, "Front panel slider sensor:");
        ESP_LOGCONFIG(TAG, "  Range from: %f", range_from_);
        ESP_LOGCONFIG(TAG, "  Range to: %f", range_to_);
    }

protected:
    FrontPanelHAL *front_panel_;
    float range_from_;
    float range_to_;
    float slope_;
};
    
} // namespace bslamp2
} // namespace xiaomi
} // namespace esphome