#include "ds18b20.h"

extern "C" {
#include "onewire_bus.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
}

static const char *TAG = "ds18b20";

static onewire_bus_handle_t bus;

uint8_t ds_crc8(const uint8_t *data, int len)
{
    uint8_t crc = 0;
    for (int i = 0; i < len; i++) {
        uint8_t inbyte = data[i];
        for (int j = 0; j < 8; j++) {
            uint8_t mix = (crc ^ inbyte) & 0x01;
            crc >>= 1;
            if (mix) crc ^= 0x8C;
            inbyte >>= 1;
        }
    }
    return crc;
}

void ds18b20_init(gpio_num_t pin)
{
    onewire_bus_config_t bus_config = {};
    bus_config.bus_gpio_num = pin;

    onewire_bus_rmt_config_t rmt_config = {};
    rmt_config.max_rx_bytes = 10;

    ESP_ERROR_CHECK(onewire_new_bus_rmt(&bus_config, &rmt_config, &bus));

    ESP_LOGI(TAG, "OneWire bus initialized");
}

float ds18b20_read()
{
    uint8_t data[9];
    uint8_t buf[4] = {0x4E, 0, 0, 0x3F}; // 10-bit (0x3F)
    // reset
    ESP_ERROR_CHECK(onewire_bus_reset(bus));

    // SKIP ROM (один датчик)
    uint8_t cmd = 0xCC;
    ESP_ERROR_CHECK(onewire_bus_write_bytes(bus, &cmd, 1));
    //ESP_ERROR_CHECK(onewire_bus_write_bytes(bus, buf, 4));
    // CONVERT T
    cmd = 0x44;
    ESP_ERROR_CHECK(onewire_bus_write_bytes(bus, &cmd, 1));

    vTaskDelay(pdMS_TO_TICKS(750));

    // reset снова
    ESP_ERROR_CHECK(onewire_bus_reset(bus));

    // SKIP ROM
    cmd = 0xCC;
    ESP_ERROR_CHECK(onewire_bus_write_bytes(bus, &cmd, 1));

    // READ SCRATCHPAD
    cmd = 0xBE;
    ESP_ERROR_CHECK(onewire_bus_write_bytes(bus, &cmd, 1));

    ESP_ERROR_CHECK(onewire_bus_read_bytes(bus, data, 9));

    ESP_LOGI(TAG,
            "RAW: %02X %02X %02X %02X %02X %02X %02X %02X | CRC %02X",
            data[0], data[1], data[2], data[3],
            data[4], data[5], data[6], data[7], data[8]);

    uint8_t crc = ds_crc8(data, 8);
    if (crc != data[8]) {
        ESP_LOGW(TAG, "CRC error");
    }

    int16_t raw = (data[1] << 8) | data[0];
    return raw / 16.0f;
}