#include    <sys/types.h>
#include    <stdio.h>
#include    <stdlib.h>
#include    <unistd.h>
#include    <errno.h>
#include    <string.h>
#include    <sys/socket.h>
#include    <netdb.h>
#include    <pthread.h>

// Miniature server to exercise getaddrinfo(2).

int
claim_port( const char * port )
{
    struct addrinfo     addrinfo;
    struct addrinfo *   result;
    int         sd;
    char            message[256];
    int         on = 1;

    addrinfo.ai_flags = AI_PASSIVE;     // for bind()
    addrinfo.ai_family = AF_INET;       // IPv4 only
    addrinfo.ai_socktype = SOCK_STREAM; // Want TCP/IP
    addrinfo.ai_protocol = 0;       // Any protocol
    addrinfo.ai_canonname = NULL;
    addrinfo.ai_addrlen = 0;
    addrinfo.ai_addr = NULL;
    addrinfo.ai_canonname = NULL;
    addrinfo.ai_next = NULL;
    if ( getaddrinfo( 0, port, &addrinfo, &result ) != 0 )      // want port 3000
    {
        fprintf( stderr, "\x1b[1;31mgetaddrinfo( %s ) failed errno is %s.  File %s line %d.\x1b[0m\n", port, strerror( errno ), __FILE__, __LINE__ );
        return -1;
    }
    else if ( errno = 0, (sd = socket( result->ai_family, result->ai_socktype, result->ai_protocol )) == -1 )
    {
        write( 1, message, sprintf( message, "socket() failed.  File %s line %d.\n", __FILE__, __LINE__ ) );
        freeaddrinfo( result );
        return -1;
    }
    else if ( setsockopt( sd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on) ) == -1 )
    {
        write( 1, message, sprintf( message, "setsockopt() failed.  File %s line %d.\n", __FILE__, __LINE__ ) );
        freeaddrinfo( result );
        close( sd );
        return -1;
    }
    else if ( bind( sd, result->ai_addr, result->ai_addrlen ) == -1 )
    {
        freeaddrinfo( result );
        close( sd );
        write( 1, message, sprintf( message, "\x1b[2;33mBinding to port %s ...\x1b[0m\n", port ) );
        return -1;
    }
    else if ( listen( sd, 100 ) == -1 )
    {
        printf( "listen() failed in file %s line %d\n", __FILE__, __LINE__ );
        close( sd );
        return 0;
    }
    else
    {
        write( 1, message, sprintf( message,  "\x1b[1;32mSUCCESS : Bind to port %s\x1b[0m\n", port ) );
        freeaddrinfo( result );
        return sd;          // bind() succeeded;
    }
}

int
main( int argc, char ** argv )
{
    int         sd;
    char            message[256];
    socklen_t       ic;
    int         fd;
    struct sockaddr_in      senderAddr;
    char            request[2048];
    char            temp;
    int         i;
    int         limit, size;
    int         ignore;

    if ( argc < 2 )
    {
        fprintf( stderr, "\x1b[1;31mMust specify port number on command line.  File %s line %d.\x1b[0m\n", __FILE__, __LINE__ );
        exit( 1 );
    }
    else if ( sscanf( argv[1], "%d", &ignore ) == 0 )
    {
        fprintf( stderr, "\x1b[1;31mMust specify port number as integerr on command line.  File %s line %d.\x1b[0m\n", __FILE__, __LINE__ );
        exit( 1 );
    }
    else if ( (sd = claim_port( argv[1] )) == -1 )
    {
        write( 1, message, sprintf( message,  "\x1b[1;31mCould not bind to port %s errno %s\x1b[0m\n", "3000", strerror( errno ) ) );
        return 1;
    }
    else
    {
        ic = sizeof(senderAddr);
        while ( (fd = accept( sd, (struct sockaddr *)&senderAddr, &ic )) != -1 )
        {
            while ( read( fd, request, sizeof(request) ) > 0 )
            {
                printf( "server receives input:  %s\n", request );
                size = strlen( request );
                limit = strlen( request ) / 2;
                for ( i = 0 ; i < limit ; i++ )
                {
                    temp = request[i];
                    request[i] = request[size - i - 1];
                    request[size - i - 1] = temp;
                }
                write( fd, request, strlen(request) + 1 );
            }
            close( fd );
        }
        printf( "No longer accepting incoming connections file %s line %d\n", __FILE__, __LINE__ );
        close( sd );
        return 0;
    }
}