#include "i2s_out.h"
#include "waveform.h"
#include "debug.h"

#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/i2s_std.h"
#include "driver/gpio.h"
#include "esp_log.h"

#define TAG        "i2s_out"
#define BUF_FRAMES 480

#define PIN_BCLK   GPIO_NUM_16
#define PIN_WS     GPIO_NUM_15
#define PIN_DOUT   GPIO_NUM_17

static i2s_chan_handle_t tx_handle;

void i2s_out_init(void)
{
    i2s_chan_config_t chan_cfg = I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_0, I2S_ROLE_MASTER);
    chan_cfg.dma_frame_num = BUF_FRAMES;
    ESP_ERROR_CHECK(i2s_new_channel(&chan_cfg, &tx_handle, NULL));

    i2s_std_config_t std_cfg = {
        .clk_cfg  = I2S_STD_CLK_DEFAULT_CONFIG(SAMPLE_RATE),
        .slot_cfg = I2S_STD_PHILIPS_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_16BIT, I2S_SLOT_MODE_STEREO),
        .gpio_cfg = {
            .mclk = I2S_GPIO_UNUSED,
            .bclk = PIN_BCLK,
            .ws   = PIN_WS,
            .dout = PIN_DOUT,
            .din  = I2S_GPIO_UNUSED,
            .invert_flags = {
                .mclk_inv = false,
                .bclk_inv = false,
                .ws_inv   = false,
            },
        },
    };
    ESP_ERROR_CHECK(i2s_channel_init_std_mode(tx_handle, &std_cfg));
    ESP_ERROR_CHECK(i2s_channel_enable(tx_handle));

    ESP_LOGI(TAG, "I2S TX initialized: 48kHz 16-bit stereo, BCLK=%d WS=%d DOUT=%d",
             PIN_BCLK, PIN_WS, PIN_DOUT);
}

static void i2s_out_task(void *arg)
{
    int16_t buf[BUF_FRAMES * 2];
    size_t bytes_written;

    DBG("i2s_out_task started");

    for (;;) {
        for (int i = 0; i < BUF_FRAMES; i++) {
            buf[i * 2]     = waveform_next_sample(0);
            buf[i * 2 + 1] = waveform_next_sample(1);
        }
        i2s_channel_write(tx_handle, buf, sizeof(buf), &bytes_written, portMAX_DELAY);
    }
}

void i2s_out_start_task(void)
{
    xTaskCreatePinnedToCore(i2s_out_task, "i2s_out", 4096, NULL, 10, NULL, 1);
}