#define PY_SSIZE_T_CLEAN
#include <Python.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <zlib.h> // 引入 zlib 库
#include <fec.h>  // 引入 libfec 库
#include "hx_serial.h"
#include "hx_ringbuffer.h"
#include <pthread.h> // 引入 pthread 库

// 宏定义
// #define USE_FEC
#ifdef USE_FEC
#define FEC_SIZE 32 // 前向纠错冗余数据大小
#else
#define FEC_SIZE 0 // 前向纠错冗余数据大小
#endif

#define FRAME_HEADER 0xAA55                                             // 帧头
#define FRAME_SIZE (240)                                                // 每帧大小
#define HEADER_SIZE (4)                                                 // 帧头 + 帧序号 + 数据长度
#define CHECKSUM_SIZE (4)                                               // CRC32 校验和大小（4 字节）
#define DATA_SIZE (FRAME_SIZE - HEADER_SIZE - CHECKSUM_SIZE - FEC_SIZE) // 数据段大小
#define RING_BUFFER_SIZE (1024 * 10)                                    // 环形缓冲区大小 - default 10KB
#define QUEUE_MAX_SIZE 1024                                             // 队列最大容量

// 全局变量
static by_serial_t serial_port;
static by_ringbuf_t ring_buffer;
static uint8_t send_buffer[FRAME_SIZE];
static uint8_t frame_counter = 0;
static uint8_t data_len = 0;

uint8_t output_data[8192];
static int output_len = 0;

// 定义队列结构体
typedef struct
{
    uint8_t *data;
    int length;
} FrameData;

// 队列相关定义
static FrameData frame_queue[QUEUE_MAX_SIZE];                   // 存储接收到的数据帧
static int queue_head = 0;                                      // 队列头指针
static int queue_tail = 0;                                      // 队列尾指针
static pthread_mutex_t queue_mutex = PTHREAD_MUTEX_INITIALIZER; // 保护队列的互斥锁
static bool stop_receiving = false;                             // 控制接收线程停止的标志

// 前向声明
void *receive_thread_func(void *arg);

// 计算 CRC32 校验和
uint32_t calculate_crc32(const uint8_t *data, size_t length)
{
    return crc32(0, data, length);
}

// 解析一帧数据
int parse_frame(by_ringbuf_t *ringbuf, uint8_t *output_data, int *output_len)
{
    uint8_t frame[FRAME_SIZE];
    int available_data = by_ringbuf_available_data(ringbuf);
    
    // 检查是否有足够的数据解析一帧
    if (available_data < HEADER_SIZE + CHECKSUM_SIZE + FEC_SIZE)
    {
        return -1; // 数据不足，无法解析
    }

    // 查找帧头
    uint16_t header = FRAME_HEADER;
    int header_pos = by_ringbuf_find(ringbuf, (uint8_t *)&header, 2);
    if (header_pos < 0)
    {
        return -1; // 没有找到帧头
    }

    // 弹出帧头之前的数据
    by_ringbuf_pop(ringbuf, frame, header_pos);

    // 检查是否有足够的数据解析一帧
    if (by_ringbuf_available_data(ringbuf) < FRAME_SIZE)
    {
        return -1; // 数据不足，无法解析
    }

    // 读取帧数据
    by_ringbuf_pop(ringbuf, frame, FRAME_SIZE);

    // 解析帧序号、有效数据长度、数据段和 CRC32
    uint8_t seq = frame[2];
    uint8_t valid_data_len = frame[2 + 1];
    uint8_t *data_segment = &frame[2 + 1 + 1];
    uint32_t received_crc = *(uint32_t *)&frame[2 + 1 + 1 + DATA_SIZE];

    // 计算 CRC32 校验
    uint32_t calculated_crc = calculate_crc32(frame, HEADER_SIZE + DATA_SIZE + FEC_SIZE);
    if (received_crc != calculated_crc)
    {
        printf("CRC mismatch! Expected: %08X, Received: %08X\n", calculated_crc, received_crc);
        return -1; // CRC 校验失败，丢弃该帧
    }

    // 将有效数据拼接到输出缓冲区
    memcpy(&output_data[*output_len], data_segment, valid_data_len);
    *output_len += valid_data_len;

    printf("output len: %d\n", *output_len);

    printf("Received frame: seq=%d, len=%d\r\n", seq, valid_data_len);

    // 判断是否为最后一帧
    if (valid_data_len < DATA_SIZE)
    {
        printf("Received last frame!\n");
        return 1; // 最后一帧，解析完成
    }
    return 0; // 成功解析一帧，但可能还有更多帧
}

// 接收线程函数
void *receive_thread_func(void *arg)
{

    while (!stop_receiving)
    {

        // 从串口读取数据到环形缓冲区
        uint8_t buffer[FRAME_SIZE];
        int ret = by_serial_read(&serial_port, buffer, FRAME_SIZE);
        if (ret > 0)
        {
            by_ringbuf_append(&ring_buffer, buffer, ret);
        }

        // 尝试解析环形缓冲区中的数据
        while (1)
        {
            int parse_result = parse_frame(&ring_buffer, output_data, &output_len);
            if (parse_result == 1)
            {
                // 将解析后的数据放入队列
                pthread_mutex_lock(&queue_mutex);
                if ((queue_tail + 1) % QUEUE_MAX_SIZE != queue_head)
                { // 队列未满
                    frame_queue[queue_tail].data = malloc(output_len);
                    memcpy(frame_queue[queue_tail].data, output_data, output_len);
                    printf("output_len2: %d\n", output_len);
                    frame_queue[queue_tail].length = output_len;
                    queue_tail = (queue_tail + 1) % QUEUE_MAX_SIZE;
                }
                else
                {
                    printf("Queue is full, dropping frame!\n");
                }
                output_len = 0;
                pthread_mutex_unlock(&queue_mutex);
                break;
            }
            else if (parse_result == 0)
            {
                printf("Parsed data length: %d\n", output_len);
                break; // 数据不足或解析失败，退出循环
            }
            else if (parse_result == -1)
            {
                break; // 数据不足或解析失败，退出循环
            }
        }

        usleep(1000); // 避免占用过多 CPU
    }
    return NULL;
}

// 初始化串口
static PyObject *serial_init(PyObject *self, PyObject *args)
{
    const char *dev_name;
    if (!PyArg_ParseTuple(args, "s", &dev_name))
    {
        return NULL;
    }

    if (by_serial_init(&serial_port, dev_name) != 0)
    {
        PyErr_SetString(PyExc_IOError, "Failed to initialize serial port");
        return NULL;
    }

    // 初始化环形缓冲区
    if (by_ringbuf_init(&ring_buffer, RING_BUFFER_SIZE) != 0)
    {
        PyErr_SetString(PyExc_IOError, "Failed to initialize ring buffer");
        return NULL;
    }

    // 启动接收线程
    pthread_t receive_thread;
    stop_receiving = false;
    if (pthread_create(&receive_thread, NULL, receive_thread_func, NULL) != 0)
    {
        PyErr_SetString(PyExc_RuntimeError, "Failed to start receive thread");
        return NULL;
    }

    Py_RETURN_NONE;
}

// 发送数据
static PyObject *serial_send(PyObject *self, PyObject *args)
{
    const char *data;
    Py_ssize_t length;
    if (!PyArg_ParseTuple(args, "s#", &data, &length))
    {
        return NULL;
    }

    size_t offset = 0;
    while (offset < length)
    {
        memset(send_buffer, 0, FRAME_SIZE);

        // 构造帧头
        uint16_t header = FRAME_HEADER;
        memcpy(send_buffer, &header, 2);

        // 构造帧序号和数据长度
        memcpy(send_buffer + 2, &frame_counter, 1);
        if (length - offset > DATA_SIZE)
        {
            data_len = DATA_SIZE;
        }
        else
        {
            data_len = length - offset;
        }
        memcpy(send_buffer + 3, &data_len, 1);

        // 拷贝该帧对应数据段
        memcpy(send_buffer + HEADER_SIZE, data + offset, data_len);

        printf("Received frame: seq=%d, len=%d\r\n", frame_counter, data_len);

        // 计算 CRC32 校验和
        uint32_t crc = calculate_crc32(send_buffer, HEADER_SIZE + DATA_SIZE + FEC_SIZE);
        memcpy(send_buffer + HEADER_SIZE + DATA_SIZE + FEC_SIZE, &crc, CHECKSUM_SIZE);

        // 发送帧
        if (by_serial_write(&serial_port, (const char *)send_buffer, FRAME_SIZE) != 0)
        {
            PyErr_SetString(PyExc_IOError, "Failed to send data over serial port");
            return NULL;
        }

        offset += DATA_SIZE;
        frame_counter++;
        usleep(80000);
    }

    frame_counter = 0;
    Py_RETURN_NONE;
}

// 接收数据
static PyObject *serial_receive(PyObject *self, PyObject *args)
{
    pthread_mutex_lock(&queue_mutex);
    if (queue_head == queue_tail)
    {
        pthread_mutex_unlock(&queue_mutex);
        PyErr_SetString(PyExc_IOError, "No data available in the queue");
        return NULL;
    }

    // 获取队列中最早的数据包
    FrameData frame = frame_queue[queue_head];
    queue_head = (queue_head + 1) % QUEUE_MAX_SIZE;
    pthread_mutex_unlock(&queue_mutex);

    // 返回解析后的数据
    PyObject *result = Py_BuildValue("y#", frame.data, frame.length);
    free(frame.data); // 释放内存
    return result;
}

// 模块方法表
static PyMethodDef SerialMethods[] = {
    {"init", serial_init, METH_VARARGS, "Initialize serial port"},
    {"send", serial_send, METH_VARARGS, "Send data over serial port"},
    {"receive", serial_receive, METH_VARARGS, "Receive data from serial port"},
    {NULL, NULL, 0, NULL}};

// 模块定义
static struct PyModuleDef serialmodule = {
    PyModuleDef_HEAD_INIT,
    "serial_module",
    NULL,
    -1,
    SerialMethods};

// 模块初始化函数
PyMODINIT_FUNC PyInit_serial_module(void)
{
    return PyModule_Create(&serialmodule);
}