#include  <rtthread.h>
#include  <windows.h>
#include  <mmsystem.h>
#include  <stdio.h>
#include "serial.h"

struct serial_int_rx serial_rx;
extern struct rt_device serial_device;

/*
 * Handler for OSKey Thread
 */
static HANDLE       OSKey_Thread;
static DWORD        OSKey_ThreadID;

static DWORD WINAPI ThreadforKeyGet(LPVOID lpParam);
void rt_hw_usart_init(void)
{

	/*
	 * create serial thread that revice key input from keyboard
	 */

    OSKey_Thread = CreateThread(NULL,
                                 0,
                                 (LPTHREAD_START_ROUTINE)ThreadforKeyGet,
                                 0,
                                 CREATE_SUSPENDED,
                                 &OSKey_ThreadID);
    if(OSKey_Thread == NULL)
    {
        //Display Error Message

        return;
    }
    SetThreadPriority(OSKey_Thread,
                      THREAD_PRIORITY_NORMAL);
    SetThreadPriorityBoost(OSKey_Thread,
                           TRUE);
    SetThreadAffinityMask(OSKey_Thread,
                          0x01);
    /*
     * Start OS get key Thread
     */
    ResumeThread(OSKey_Thread);

}

/*
 * 方向键(←)： 0xe04b 
 * 方向键(↑)： 0xe048 
 * 方向键(→)： 0xe04d 
 * 方向键(↓)： 0xe050 
 */
static int savekey(unsigned char key)
{
	/* save on rx buffer */
	{
		rt_base_t level;

		/* disable interrupt */
        //暂时关闭中断，因为要操作uart数据结构
		level = rt_hw_interrupt_disable();

		/* save character */
		serial_rx.rx_buffer[serial_rx.save_index] = key;
		serial_rx.save_index ++;
	    //下面的代码检查save_index是否已经到到缓冲区尾部，如果是则回转到头部，称为一个环形缓冲区	
		if (serial_rx.save_index >= SERIAL_RX_BUFFER_SIZE)
			serial_rx.save_index = 0;

        //这种情况表示反转后的save_index追上了read_index，则增大read_index，丢弃一个旧的数据
		/* if the next position is read index, discard this 'read char' */
		if (serial_rx.save_index == serial_rx.read_index)
		{
			serial_rx.read_index ++;
			if (serial_rx.read_index >= SERIAL_RX_BUFFER_SIZE)
				serial_rx.read_index = 0;
		}

		/* enable interrupt */
		//uart数据结构已经操作完成，重新使能中断
		rt_hw_interrupt_enable(level);
	}

	/* invoke callback */
	if (serial_device.rx_indicate != RT_NULL)
	{
		rt_size_t rx_length;

		/* get rx length */
		rx_length = serial_rx.read_index > serial_rx.save_index ?
			SERIAL_RX_BUFFER_SIZE - serial_rx.read_index + serial_rx.save_index :
			serial_rx.save_index - serial_rx.read_index;

		serial_device.rx_indicate(&serial_device, rx_length);
	}
	return 0;
}
static DWORD WINAPI ThreadforKeyGet(LPVOID lpParam)
{
	unsigned char key;

    (void)lpParam;              //prevent compiler warnings

    for(;;)
    {
		key = _getch();//getchar();
		if (key == 0xE0)
		{
			key = _getch();

			if (key == 0x48) //up key , 0x1b 0x5b 0x41
			{
				savekey(0x1b);
				savekey(0x5b);
				savekey(0x41);
			}
			else if (key == 0x50)//0x1b 0x5b 0x42
			{
				savekey(0x1b);
				savekey(0x5b);
				savekey(0x42);
			}

			continue;
		}

		savekey(key);
    }
} /*** ThreadforKeyGet ***/