button.c

/**
 * @file button.c
 * @brief Button driver with multi-click detection.
 * @author Ihar Hlukhau
 * @date 04/01/2026
 */

#include <stdatomic.h>

#include "button.h"
#include "comm_mngr.h"
#include "device_cmd.h"
#include "fault.h"
#include "led.h"

#include "driver/gpio.h"
#include "esp_timer.h"
#include "freertos/FreeRTOS.h"
#include "esp_log.h"

/** @brief GPIO pin for the button. */
#define BUTTON_PIN              19
/** @brief Number of clicks in the window to trigger mode switch. */
#define CLICKS_MODE_SWITCH      2
/** @brief Number of clicks in the window to trigger Matter fabric reset. */
#define CLICKS_MATTER_RESET     3
/** @brief Number of clicks in the window to trigger factory reset. */
#define CLICKS_FACTORY_RESET    4
/** @brief Click counting window duration (ms). */
#define CLICK_WINDOW_MS         2000
/** @brief Debounce duration during which button inputs are ignored (us). */
#define BUTTON_DEBOUNCE_TIME    (300 * 1000)

static const char *TAG = "BUTTON";
/** @brief Atomic click counter (read/written from both ISR and task context). */
static atomic_int s_click_count = 0;
/** @brief One-shot timer that fires when the click window expires. */
static TimerHandle_t xClickTimer;


/** @brief Timer callback: evaluate click count and trigger the corresponding action. */
static void vClickTimerCallback(__unused TimerHandle_t xTimer) {
    const int clicks = atomic_load(&s_click_count);

    if (clicks >= CLICKS_FACTORY_RESET) {
        device_cmd_factory_reset();
    } else if (clicks >= CLICKS_MATTER_RESET) {
        device_cmd_matter_factory_reset();
    } else if (clicks >= CLICKS_MODE_SWITCH) {
        led_show_pattern(LED_PATTERN_MODE_SWITCH);
        comm_mngr_request_switch();
    }

    atomic_store(&s_click_count, 0);
}

/** @brief GPIO ISR: increment click counter and (re)start the window timer. */
static void button_isr_handler(__unused void* arg) {
    static int64_t s_last_press_us = 0;

    /* Software debounce */
    const int64_t now = esp_timer_get_time();
    if (now - s_last_press_us < BUTTON_DEBOUNCE_TIME) { return; }
    s_last_press_us = now;

    atomic_fetch_add(&s_click_count, 1);

    BaseType_t xHigherPriorityTaskWoken = pdFALSE;
    xTimerStartFromISR(xClickTimer, &xHigherPriorityTaskWoken);

    portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
}

esp_err_t button_init(void) {
    esp_err_t err = ESP_OK;

    const gpio_config_t io_conf = {
        .intr_type = GPIO_INTR_NEGEDGE, // trigger on press (pull-up logic)
        .mode = GPIO_MODE_INPUT,
        .pin_bit_mask = (1ULL << BUTTON_PIN),
        .pull_up_en = 1,
    };
    err = gpio_config(&io_conf);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "GPIO config failed: %s", esp_err_to_name(err));
        fault_report(FAULT_BUTTON, ERROR_BUTTON_ISR_INIT, err);
        return ESP_FAIL;
    }

    err = gpio_install_isr_service(0);
    if (err != ESP_OK) {
        fault_report(FAULT_BUTTON, ERROR_BUTTON_ISR_INIT, err);
        return ESP_FAIL;
    }

    err = gpio_isr_handler_add(BUTTON_PIN, button_isr_handler, NULL);
    if (err != ESP_OK) {
        fault_report(FAULT_BUTTON, ERROR_BUTTON_ISR_INIT, err);
        return ESP_FAIL;
    }

    xClickTimer = xTimerCreate("ClickTimer", pdMS_TO_TICKS(CLICK_WINDOW_MS), pdFALSE, NULL, vClickTimerCallback);

    if (xClickTimer == NULL) {
        fault_report(FAULT_BUTTON, ERROR_BUTTON_TIMER_INIT, ESP_ERR_NO_MEM);
        return ESP_FAIL;
    }

    return ESP_OK;
}