/*
 * SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Unlicense OR CC0-1.0
 */

/* I2S Digital Microphone Recording Example */
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <sys/unistd.h>
#include <sys/stat.h>
#include "sdkconfig.h"
#include "esp_log.h"
#include "esp_err.h"
#include "esp_system.h"
#include "esp_vfs_fat.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/i2s_pdm.h"
#include "driver/gpio.h"
#include "driver/spi_common.h"

#include "sdkconfig.h"

static const char *TAG = "pdm_rec_example";

#define SPI_DMA_CHAN        SPI_DMA_CH_AUTO
#define NUM_CHANNELS        (1) // For mono recording only!
#define SAMPLE_SIZE         (16 * 1024)
#define SAMPLE_RATE         44100
#define BYTE_RATE           (SAMPLE_RATE * (16 / 8)) * 1

i2s_chan_handle_t rx_handle = NULL;

static int16_t i2s_readraw_buff[SAMPLE_SIZE];
size_t bytes_read;

// STD simplex pins
#define EXAMPLE_I2S_BCLK_IO1        GPIO_NUM_2      // I2S bit clock io number
#define EXAMPLE_I2S_WS_IO1          GPIO_NUM_3      // I2S word select io number
#define EXAMPLE_I2S_DOUT_IO1        GPIO_NUM_4      // I2S data out io number
#define EXAMPLE_I2S_DIN_IO1         GPIO_NUM_5      // I2S data in io number
#define EXAMPLE_I2S_CLK_GPIO        GPIO_NUM_16
#define EXAMPLE_I2S_DATA_GPIO       EXAMPLE_I2S_DIN_IO1

void init_microphone(void)
{
    i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_AUTO, I2S_ROLE_MASTER);
    ESP_ERROR_CHECK(i2s_new_channel(&chan_cfg, NULL, &rx_handle));

    i2s_pdm_rx_config_t pdm_rx_cfg = {
        .clk_cfg = I2S_PDM_RX_CLK_DEFAULT_CONFIG(SAMPLE_RATE),
        /* The default mono slot is the left slot (whose 'select pin' of the PDM microphone is pulled down) */
        .slot_cfg = I2S_PDM_RX_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_MONO),
        .gpio_cfg = {
            .clk = EXAMPLE_I2S_CLK_GPIO,
            .din = EXAMPLE_I2S_DATA_GPIO,
            .invert_flags = {
                .clk_inv = false,
            },
        },
    };
    ESP_ERROR_CHECK(i2s_channel_init_pdm_rx_mode(rx_handle, &pdm_rx_cfg));
    ESP_ERROR_CHECK(i2s_channel_enable(rx_handle));
}


void app_main() {
    printf("PDM microphone recording example start\n--------------------------------------\n");
    // Acquire a I2S PDM channel for the PDM digital microphone
    init_microphone();
    // Start Recording
    // Stop I2S driver and destroy
    ESP_ERROR_CHECK(i2s_channel_disable(rx_handle));
    ESP_ERROR_CHECK(i2s_del_channel(rx_handle));
}