encoder.h

/*
 * Copyright (c) 2019 Ruslan V. Uss <unclerus@gmail.com>
 * Copyright (c) 2026 Chris Leishman (@cleishm)
 *
 * 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 of the copyright holder nor the names of itscontributors
 *    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 HOLDER 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 encoder.h
 * @defgroup encoder encoder
 * @{
 *
 * ESP-IDF HW timer-based driver for rotary encoders
 *
 * Copyright (c) 2019 Ruslan V. Uss <unclerus@gmail.com>
 * Copyright (c) 2026 Chris Leishman (@cleishm)
 *
 * BSD Licensed as described in the file LICENSE
 */
#ifndef __ENCODER_H__
#define __ENCODER_H__

#include <esp_err.h>
#include <driver/gpio.h>

#ifdef __cplusplus
extern "C" {
#endif

/**
 * Button state
 */
typedef enum
{
    RE_BTN_RELEASED = 0,      //!< Button currently released
    RE_BTN_PRESSED = 1,       //!< Button currently pressed
    RE_BTN_LONG_PRESSED = 2   //!< Button currently long pressed
} rotary_encoder_btn_state_t;

/**
 * Event type
 */
typedef enum
{
    RE_ET_CHANGED = 0,      //!< Encoder turned
    RE_ET_BTN_RELEASED,     //!< Button released
    RE_ET_BTN_PRESSED,      //!< Button pressed
    RE_ET_BTN_LONG_PRESSED, //!< Button long pressed (press time (us) > RE_BTN_LONG_PRESS_TIME_US)
    RE_ET_BTN_CLICKED       //!< Button was clicked
} rotary_encoder_event_type_t;

typedef struct rotary_encoder *rotary_encoder_handle_t;

/**
 * Event
 */
typedef struct
{
    rotary_encoder_event_type_t type;    //!< Event type
    rotary_encoder_handle_t sender;  //!< Encoder handle
    int32_t diff;                      //!< Difference between new and old positions (only if type == RE_ET_CHANGED)
} rotary_encoder_event_t;

/**
 * Callback type for encoder events.
 *
 * The callback is invoked from the ESP timer task context.
 * It must not block or call back into the library.
 */
typedef void (*rotary_encoder_event_cb_t)(const rotary_encoder_event_t *event, void *ctx);

/**
 * Per-encoder configuration
 */
typedef struct
{
    gpio_num_t pin_a;                    //!< Encoder pin A
    gpio_num_t pin_b;                    //!< Encoder pin B
    gpio_num_t pin_btn;                  //!< Button pin, or GPIO_NUM_NC if unused
    uint8_t btn_pressed_level;           //!< GPIO level when button is pressed (0 or 1).
    //!< When set to 1, the button pin may need a pull-down
    //!< resistor, either external or set via \c gpio_set_pull_mode()
    //!< before creating the encoder, as \c enable_internal_pullup
    //!< only enables pull-ups.
    bool enable_internal_pullup;         //!< Enable internal pull-up resistors on all encoder and
    //!< button GPIO pins. Pull-ups are always used, which is
    //!< correct for encoders wired with common to ground. When
    //!< \c btn_pressed_level is 1, the button pin may need a
    //!< pull-down instead — use an external resistor or call
    //!< \c gpio_set_pull_mode() before creating the encoder.
    //!< When false, pull resistors are left unchanged.
    uint32_t btn_dead_time_us;           //!< Button dead time in microseconds
    uint32_t btn_long_press_time_us;     //!< Long press threshold in microseconds
    uint32_t acceleration_threshold_ms;  //!< Acceleration threshold in milliseconds (acceleration starts below this interval)
    uint32_t acceleration_cap_ms;        //!< Acceleration cap in milliseconds (minimum interval, limits max acceleration)
    uint32_t polling_interval_us;        //!< Polling interval in microseconds
    rotary_encoder_event_cb_t callback;  //!< Event callback (required)
    void *callback_ctx;                  //!< User context passed to callback
} rotary_encoder_config_t;

#ifdef CONFIG_RE_BTN_PRESSED_LEVEL_0
#define RE_DEFAULT_BTN_PRESSED_LEVEL 0
#else
#define RE_DEFAULT_BTN_PRESSED_LEVEL 1
#endif

#define RE_DEFAULT_ENABLE_INTERNAL_PULLUP true

#define ROTARY_ENCODER_DEFAULT_CONFIG() { \
    .pin_a = GPIO_NUM_NC, \
    .pin_b = GPIO_NUM_NC, \
    .pin_btn = GPIO_NUM_NC, \
    .btn_pressed_level = RE_DEFAULT_BTN_PRESSED_LEVEL, \
    .enable_internal_pullup = RE_DEFAULT_ENABLE_INTERNAL_PULLUP, \
    .btn_dead_time_us = CONFIG_RE_BTN_DEAD_TIME_US, \
    .btn_long_press_time_us = CONFIG_RE_BTN_LONG_PRESS_TIME_US, \
    .acceleration_threshold_ms = CONFIG_RE_ACCELERATION_THRESHOLD, \
    .acceleration_cap_ms = CONFIG_RE_ACCELERATION_CAP, \
    .polling_interval_us = CONFIG_RE_INTERVAL_US, \
    .callback = NULL, \
    .callback_ctx = NULL, \
}

/**
 * @brief Create a new rotary encoder
 *
 * @param config Encoder configuration
 * @param[out] handle Encoder handle, populated on success
 * @return `ESP_OK` on success
 */
esp_err_t rotary_encoder_create(const rotary_encoder_config_t *config, rotary_encoder_handle_t *handle);

/**
 * @brief Delete a rotary encoder
 *
 * @param handle Encoder handle
 * @return `ESP_OK` on success
 */
esp_err_t rotary_encoder_delete(rotary_encoder_handle_t handle);

/**
 * @brief Enable acceleration on the rotary encoder
 *
 * @param handle Encoder handle
 * @param coeff Acceleration coefficient. Higher value means faster acceleration
 * @return esp_err_t
 */
esp_err_t rotary_encoder_enable_acceleration(rotary_encoder_handle_t handle, uint16_t coeff);

/**
 * @brief Disable acceleration on the rotary encoder
 *
 * @param handle Encoder handle
 * @return `ESP_OK` on success
 */
esp_err_t rotary_encoder_disable_acceleration(rotary_encoder_handle_t handle);

#ifdef __cplusplus
}
#endif

/**@}*/

#endif /* __ENCODER_H__ */