/**
 * LIN Sniffer
 */

#include <stdio.h>
#include <string.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "esp_err.h"
#include "esp_system.h"

#include "driver/gpio.h"
#include "driver/uart.h"

#define UART_NUM UART_NUM_1
#define UART_RX_GPIO GPIO_NUM_4
#define LIN_BAUDRATE 9600

static const char *TAG = "LIN_SNIFFER";

// Setup UART buffered IO with event queue
const int uart_buffer_size = (1024 * 2);
QueueHandle_t uart_queue;

void uart_event_task(void *pvParameters)
{
    uart_event_t event;

    while(1)
    {
        if (xQueueReceive(uart_queue, &event, portMAX_DELAY))
        {
            switch (event.type)
            {
                case UART_DATA:
                    ESP_LOGI(TAG, "UART_DATA: %d bytes", event.size);
                    break;

                case UART_BREAK:
                     ESP_LOGI(TAG, "UART_BREAK detected!");
                    break;

                case UART_FIFO_OVF:
                    ESP_LOGW(TAG, "FIFO overflow");
                    uart_flush_input(UART_NUM);
                    xQueueReset(uart_queue);
                    break;

                case UART_BUFFER_FULL:
                    ESP_LOGW(TAG, "RX buffer full");
                    uart_flush_input(UART_NUM);
                    xQueueReset(uart_queue);
                    break;

                default:
                    break;
            }
        }
    }
}

void app_main(void)
{
    ESP_LOGI(TAG, "Starting LIN Bus Sniffer");

    // Install UART driver using an event queue here
    ESP_ERROR_CHECK(uart_driver_install(
        UART_NUM,
        uart_buffer_size,
        uart_buffer_size,
        10,
        &uart_queue,
        0));

    // Configure UART
    uart_config_t uart_config = {
        .baud_rate = LIN_BAUDRATE,                  // Baudrate festlegen (z.B. 9600, 115200)
        .data_bits = UART_DATA_8_BITS,      // Datenbits: 5, 6, 7 oder 8
        .parity = UART_PARITY_DISABLE,      // Parität: DISABLE, EVEN, ODD
        .stop_bits = UART_STOP_BITS_1,      // Stopbits: 1, 1.5, 2
        .flow_ctrl = UART_HW_FLOWCTRL_DISABLE, // Flow Control: DISABLE, CTS_RTS, etc.
        .source_clk = UART_SCLK_DEFAULT,    // Taktquelle
    };
    ESP_ERROR_CHECK(uart_param_config(UART_NUM, &uart_config));

    // Set UART pins(TX, RX, RTS, CTS)
    gpio_pullup_en(UART_RX_GPIO);
    ESP_ERROR_CHECK(uart_set_pin(UART_NUM, UART_PIN_NO_CHANGE, UART_RX_GPIO, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE));

    // Start UART receive task
    xTaskCreate(uart_event_task, "uart event", 4096, NULL, 5, NULL);
        
    while (1) {
        vTaskDelay(pdMS_TO_TICKS(1000));
    }
}