#include <stdio.h>
#include <stdlib.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/adc.h"
#include "driver/ledc.h"

#define SAMPLE_CNT 2
static const adc1_channel_t adc_channel = ADC_CHANNEL_6;

#define LEDC_GPIO 18
static ledc_channel_config_t ledc_channel;

static void init_hw(void)
{
    adc1_config_width(ADC_WIDTH_BIT_12);
    adc1_config_channel_atten(adc_channel, ADC_ATTEN_DB_11);

    ledc_timer_config_t ledc_timer = {
        .duty_resolution = LEDC_TIMER_10_BIT,
        .freq_hz = 1000,
        .speed_mode = LEDC_LOW_SPEED_MODE,
        .timer_num = LEDC_TIMER_0,
        .clk_cfg = LEDC_AUTO_CLK,
    };
    ledc_timer_config(&ledc_timer);

    ledc_channel.channel = LEDC_CHANNEL_0;
    ledc_channel.duty = 0;
    ledc_channel.gpio_num = LEDC_GPIO;
    ledc_channel.speed_mode = LEDC_LOW_SPEED_MODE;
    ledc_channel.hpoint = 0;
    ledc_channel.timer_sel = LEDC_TIMER_0;
    ledc_channel_config(&ledc_channel);
}

void app_main(void)
{
    init_hw();

    while (1)
    {
        uint32_t adc_val = 0;
        for (int i = 0; i < SAMPLE_CNT; ++i)
        {
            adc_val += adc1_get_raw(adc_channel);
        }
        adc_val /= SAMPLE_CNT;

        ledc_set_duty(ledc_channel.speed_mode, ledc_channel.channel, adc_val);
        ledc_update_duty(ledc_channel.speed_mode, ledc_channel.channel);

        vTaskDelay(500 / portTICK_RATE_MS);
    }
}