/*
 * MTG RFID Companion - WS2812B Neopixel LED manager (RMT)
 */

#include "esp_log.h"
#include "driver/rmt_tx.h"
#include "driver/rmt_encoder.h"
#include "hw_pins.h"
#include "led_manager.h"

static const char *TAG = "led";

static rmt_channel_handle_t s_tx_chan = NULL;
static rmt_encoder_handle_t s_enc = NULL;

esp_err_t led_manager_init(void)
{
    if (s_tx_chan != NULL) {
        return ESP_OK;
    }

    rmt_tx_channel_config_t chan_cfg = {
        .gpio_num = HW_NEOPIXEL_GPIO,
        .clk_src = RMT_CLK_SRC_DEFAULT,
        .resolution_hz = 10 * 1000 * 1000, /* 100 ns per tick */
        .mem_block_symbols = 64,
        .trans_queue_depth = 4,
    };
    esp_err_t ret = rmt_new_tx_channel(&chan_cfg, &s_tx_chan);
    if (ret != ESP_OK) {
        ESP_LOGE(TAG, "rmt_new_tx_channel failed: %s", esp_err_to_name(ret));
        return ret;
    }

    rmt_bytes_encoder_config_t enc_cfg = {
        .bit0 = {
            .duration0 = 4, /* T0H ~ 400 ns */
            .level0 = 1,
            .duration1 = 8, /* T0L ~ 800 ns */
            .level1 = 0,
        },
        .bit1 = {
            .duration0 = 9, /* T1H ~ 900 ns */
            .level0 = 1,
            .duration1 = 4, /* T1L ~ 400 ns */
            .level1 = 0,
        },
    };
    ret = rmt_new_bytes_encoder(&enc_cfg, &s_enc);
    if (ret != ESP_OK) {
        ESP_LOGE(TAG, "rmt_new_bytes_encoder failed: %s", esp_err_to_name(ret));
        return ret;
    }

    ret = rmt_enable(s_tx_chan);
    if (ret != ESP_OK) {
        ESP_LOGE(TAG, "rmt_enable failed: %s", esp_err_to_name(ret));
        return ret;
    }

    ESP_LOGI(TAG, "WS2812B LED ready on GPIO %d", HW_NEOPIXEL_GPIO);
    return ESP_OK;
}

esp_err_t led_manager_set_color(uint8_t r, uint8_t g, uint8_t b)
{
    if (s_tx_chan == NULL) {
        esp_err_t ret = led_manager_init();
        if (ret != ESP_OK) {
            return ret;
        }
    }

    /* WS2812B expects GRB byte order */
    uint8_t txbuf[3] = { g, r, b };

    rmt_transmit_config_t tx_cfg = {
        .loop_count = 0, /* one-shot; LED latches and holds the level */
    };
    esp_err_t ret = rmt_transmit(s_tx_chan, s_enc, txbuf, sizeof(txbuf), &tx_cfg);
    if (ret != ESP_OK) {
        return ret;
    }
    return rmt_tx_wait_all_done(s_tx_chan, pdMS_TO_TICKS(50));
}

esp_err_t led_manager_off(void)
{
    return led_manager_set_color(0, 0, 0);
}