/*
 * FreeRTOS V202212.00
 * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * https://www.FreeRTOS.org
 * https://github.com/FreeRTOS
 *
 */

#pragma comment( lib, "ws2_32.lib" )

/* Win32 includes. */
#include <WinSock2.h>
#include <stdio.h>

/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"

/* FreeRTOS+CLI includes. */
#include "FreeRTOS_CLI.h"

/* Dimensions the buffer into which input characters are placed. */
#define cmdMAX_INPUT_SIZE              60

/* Dimensions the buffer into which string outputs can be placed. */
#define cmdMAX_OUTPUT_SIZE             1024

/* Dimensions the buffer passed to the recvfrom() call. */
#define cmdSOCKET_INPUT_BUFFER_SIZE    60

/*
 * Open and configure the UDP socket.
 */
static SOCKET prvOpenUDPSocket( void );

/*-----------------------------------------------------------*/

/*
 * Task that provides the input and output for the FreeRTOS+CLI command
 * interpreter.  In this case a UDP port is used.  See the URL in the comments
 * within main.c for the location of the online documentation.
 */
void vUDPCommandInterpreterTask( void * pvParameters )
{
    long lBytes, lByte;
    signed char cInChar, cInputIndex = 0;
    static signed char cInputString[ cmdMAX_INPUT_SIZE ], cOutputString[ cmdMAX_OUTPUT_SIZE ], cLocalBuffer[ cmdSOCKET_INPUT_BUFFER_SIZE ];
    BaseType_t xMoreDataToFollow;
    volatile int iErrorCode = 0;
    struct sockaddr_in xClient;
    int xClientAddressLength = sizeof( struct sockaddr_in );
    SOCKET xSocket;

    /* Just to prevent compiler warnings. */
    ( void ) pvParameters;

    /* Attempt to open the socket. */
    xSocket = prvOpenUDPSocket();

    if( xSocket != INVALID_SOCKET )
    {
        for( ; ; )
        {
            /* Wait for incoming data on the opened socket. */
            lBytes = recvfrom( xSocket, cLocalBuffer, sizeof( cLocalBuffer ), 0, ( struct sockaddr * ) &xClient, &xClientAddressLength );

            if( lBytes == SOCKET_ERROR )
            {
                /* Something went wrong, but it is not handled by this simple
                 * example. */
                iErrorCode = WSAGetLastError();
            }
            else
            {
                /* Process each received byte in turn. */
                lByte = 0;

                while( lByte < lBytes )
                {
                    /* The next character in the input buffer. */
                    cInChar = cLocalBuffer[ lByte ];
                    lByte++;

                    /* Newline characters are taken as the end of the command
                     * string. */
                    if( cInChar == '\n' )
                    {
                        /* Process the input string received prior to the
                         * newline. */
                        do
                        {
                            /* Pass the string to FreeRTOS+CLI. */
                            xMoreDataToFollow = FreeRTOS_CLIProcessCommand( cInputString, cOutputString, cmdMAX_OUTPUT_SIZE );

                            /* Send the output generated by the command's
                             * implementation. */
                            sendto( xSocket, cOutputString, strlen( cOutputString ), 0, ( SOCKADDR * ) &xClient, xClientAddressLength );
                        } while( xMoreDataToFollow != pdFALSE ); /* Until the command does not generate any more output. */

                        /* All the strings generated by the command processing
                         * have been sent.  Clear the input string ready to receive
                         * the next command. */
                        cInputIndex = 0;
                        memset( cInputString, 0x00, cmdMAX_INPUT_SIZE );

                        /* Transmit a spacer, just to make the command console
                         * easier to read. */
                        sendto( xSocket, "\r\n", strlen( "\r\n" ), 0, ( SOCKADDR * ) &xClient, xClientAddressLength );
                    }
                    else
                    {
                        if( cInChar == '\r' )
                        {
                            /* Ignore the character.  Newlines are used to
                             * detect the end of the input string. */
                        }
                        else if( cInChar == '\b' )
                        {
                            /* Backspace was pressed.  Erase the last character
                             * in the string - if any. */
                            if( cInputIndex > 0 )
                            {
                                cInputIndex--;
                                cInputString[ cInputIndex ] = '\0';
                            }
                        }
                        else
                        {
                            /* A character was entered.  Add it to the string
                             * entered so far.  When a \n is entered the complete
                             * string will be passed to the command interpreter. */
                            if( cInputIndex < cmdMAX_INPUT_SIZE )
                            {
                                cInputString[ cInputIndex ] = cInChar;
                                cInputIndex++;
                            }
                        }
                    }
                }
            }
        }
    }
    else
    {
        /* The socket could not be opened. */
        vTaskDelete( NULL );
    }
}
/*-----------------------------------------------------------*/

static SOCKET prvOpenUDPSocket( void )
{
    WSADATA xWSAData;
    WORD wVersionRequested;
    struct sockaddr_in xServer;
    SOCKET xSocket = INVALID_SOCKET;

    wVersionRequested = MAKEWORD( 2, 2 );

    /* Prepare to use WinSock. */
    if( WSAStartup( wVersionRequested, &xWSAData ) != 0 )
    {
        fprintf( stderr, "Could not open Windows connection.\n" );
    }
    else
    {
        xSocket = socket( AF_INET, SOCK_DGRAM, 0 );

        if( xSocket == INVALID_SOCKET )
        {
            fprintf( stderr, "Could not create socket.\n" );
            WSACleanup();
        }
        else
        {
            /* Zero out the server structure. */
            memset( ( void * ) &xServer, 0x00, sizeof( struct sockaddr_in ) );

            /* Set family and port. */
            xServer.sin_family = AF_INET;
            xServer.sin_port = htons( configUDP_CLI_PORT_NUMBER );

            /* Assign the loopback address */
            xServer.sin_addr.S_un.S_un_b.s_b1 = 127;
            xServer.sin_addr.S_un.S_un_b.s_b2 = 0;
            xServer.sin_addr.S_un.S_un_b.s_b3 = 0;
            xServer.sin_addr.S_un.S_un_b.s_b4 = 1;

            /* Bind the address to the socket. */
            if( bind( xSocket, ( struct sockaddr * ) &xServer, sizeof( struct sockaddr_in ) ) == -1 )
            {
                fprintf( stderr, "Could not socket to port %d.\n", configUDP_CLI_PORT_NUMBER );
                closesocket( xSocket );
                xSocket = INVALID_SOCKET;
                WSACleanup();
            }
        }
    }

    return xSocket;
}