#include "spi_shiftout.h"
#include "driver/gpio.h"
#include "esp_log.h"
#include <stdlib.h>
#include <string.h>

static const char *TAG = "spi_shiftout";

spi_shiftout_t *spi_shiftout_init(int32_t frequency, gpio_num_t data_pin, gpio_num_t clock_pin, gpio_num_t latch_pin,
                                  gpio_num_t output_enable_pin, spi_host_device_t host, uint8_t shift_out_length)
{
    spi_shiftout_t *cfg = (spi_shiftout_t *)calloc(1, sizeof(spi_shiftout_t) + shift_out_length - 1);
    if (!cfg) {
        ESP_LOGE(TAG, "Failed to allocate memory for spi_shiftout_t");
        return NULL;
    }
    cfg->latch_pin           = latch_pin;
    cfg->output_enable_pin   = output_enable_pin;
    cfg->output_enable_value = 255; // Default value for output enable
    cfg->shift_out_length    = shift_out_length;
    cfg->ledc_channel        = LEDC_CHANNEL_0; // or another available channel
    cfg->ledc_timer          = LEDC_TIMER_0;   // or another available timer
    if (output_enable_pin >= 0) {
        // Configure OE pin for PWM (LEDC)
        ledc_timer_config_t ledc_timer = {
            .speed_mode      = LEDC_LOW_SPEED_MODE, //
            .timer_num       = cfg->ledc_timer,     //
            .duty_resolution = LEDC_TIMER_8_BIT,    //
            .freq_hz         = 8000,                // TODO: test this value
            .clk_cfg         = LEDC_AUTO_CLK        //
        };
        ledc_timer_config(&ledc_timer);
        ledc_channel_config_t ledc_channel = {
            .gpio_num            = cfg->output_enable_pin,   //
            .speed_mode          = LEDC_LOW_SPEED_MODE,      //
            .channel             = cfg->ledc_channel,        //
            .timer_sel           = cfg->ledc_timer,          //
            .duty                = cfg->output_enable_value, // 100% duty (fully enabled)
            .hpoint              = 0,                        //
            .flags.output_invert = 0                         //
        };
        ledc_channel_config(&ledc_channel);
    }
    // Configure the SPI bus
    spi_bus_config_t buscfg = {
        .miso_io_num     = -1,                   //
        .mosi_io_num     = data_pin,             //
        .sclk_io_num     = clock_pin,            //
        .quadwp_io_num   = -1,                   //
        .quadhd_io_num   = -1,                   //
        .max_transfer_sz = shift_out_length * 8, //
        .flags           = 0                     //
    };
    spi_device_interface_config_t devcfg = {
        .clock_speed_hz = frequency, // Clock out at 2 MHz
        .mode           = 0,         // SPI mode 0
        .spics_io_num   = -1,        // CS pin
        .queue_size     = 1,         //
        .pre_cb         = 0,         //
    };
    esp_err_t ret;
    // Initialize the SPI bus
    ret = spi_bus_initialize(host, &buscfg, SPI_DMA_CH_AUTO);
    ESP_ERROR_CHECK(ret);
    ret = spi_bus_add_device(host, &devcfg, &cfg->spi);
    ESP_ERROR_CHECK(ret);
    gpio_config_t latch_conf = {
        .pin_bit_mask = (1ULL << latch_pin),   //
        .mode         = GPIO_MODE_OUTPUT,      //
        .pull_up_en   = GPIO_PULLUP_ENABLE,    //
        .pull_down_en = GPIO_PULLDOWN_DISABLE, //
        .intr_type    = GPIO_INTR_DISABLE      //
    };
    gpio_config(&latch_conf);
    gpio_set_level(latch_pin, 1);
    return cfg;
}

void spi_shiftout_write(spi_shiftout_t *cfg, uint8_t oe_val)
{
    esp_err_t         ret;
    spi_transaction_t t;
    gpio_set_level(cfg->latch_pin, 0);
    memset(&t, 0, sizeof(t));                                // Zero out the transaction
    t.length    = 8 * cfg->shift_out_length;                 // Command is 8 bits
    t.tx_buffer = cfg->shift_out;                            // Data
    ret         = spi_device_polling_transmit(cfg->spi, &t); // Transmit!
    gpio_set_level(cfg->latch_pin, 1);
    assert(ret == ESP_OK); // Should have had no issues.
    if (cfg->output_enable_pin >= 0 && oe_val != cfg->output_enable_value) {
        cfg->output_enable_value = oe_val;
        ledc_set_duty(LEDC_LOW_SPEED_MODE, cfg->ledc_channel, oe_val);
        ledc_update_duty(LEDC_LOW_SPEED_MODE, cfg->ledc_channel);
    }
}