#include <stdio.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdint.h>

int construct_socket();
char *get_query(char *host, char *page);

#define HOST "divine.fi.muni.cz"
#define PAGE "/"
#define PORT 0x5000u
#define USERAGENT "HTMLGET 1.0"

// the address of divine.fi.muni.cz
#define ADDR 0xa133fb93

/* declare a few things currently missing from DIVINE's libc */

struct in_addr
{
    uint32_t s_addr;
};

struct sockaddr_in
{
    short            sin_family;   // e.g. AF_INET
    unsigned short   sin_port;     // e.g. htons(3490)
    struct in_addr   sin_addr;     // see struct in_addr, below
    char             sin_zero[8];  // zero this if you want to
};

int main(int argc, char **argv)
{
  struct sockaddr_in *remote;
  int socket;
  int actionResult;
  char *query;
  char buffer[ BUFSIZ + 1 ];

  socket = construct_socket();

  remote = (struct sockaddr_in *)malloc( sizeof( struct sockaddr_in ) );
  if ( !remote )
      return 1;
  remote->sin_family = AF_INET;

  remote->sin_addr.s_addr = ADDR;
  memset( remote->sin_zero, 0, 8 );

  remote->sin_port = PORT;

  if ( connect( socket, ( struct sockaddr * )remote, sizeof( struct sockaddr ) ) < 0 ) {
    perror( "Error: Could not connect" );
    exit( 1 );
  }

  query = get_query( HOST, PAGE );
  fprintf( stderr, "Query is:\n<<START>>\n%s<<END>>\n", query );

  int sent = 0;
  while ( sent < strlen( query ) ) {
    actionResult = send( socket, query+sent, strlen( query ) - sent, 0 );
    if ( actionResult == -1 ) {
      perror( "Error: Can't send query" );
      exit( 1 );
    }
    sent += actionResult;
  }
  memset( buffer, 0, sizeof( buffer ) );

  int htmlStart = 0;
  char *htmlContent = NULL;
  while( ( actionResult = recv( socket, buffer, BUFSIZ, 0 ) ) > 0 ) {

    if ( htmlStart == 0 ) {
      htmlContent = strstr( buffer, "\r\n\r\n" );
      if ( htmlContent != NULL ) {
        htmlStart = 1;
        htmlContent += 4;
      }

    } else
      htmlContent = buffer;

    if( htmlStart )
      fprintf( stdout, "%s", htmlContent );

    memset( buffer, 0, actionResult );
  }

  if ( actionResult < 0 )
    perror( "Error: Not receiving data" );

  // clean up
  free( query );
  free( remote );
  close( socket );
  return 0;
}

int construct_socket()
{
  int _socket;
  if ( ( _socket = socket( AF_INET, SOCK_STREAM, 6 ) ) < 0 ) {
    perror( "Error: Unable to create TCP socket" );
    exit( 1 );
  }
  return _socket;
}

char *get_query(char *host, char *page)
{
  char *query;
  char *getpage = page;
  char *tpl = "GET /%s HTTP/1.0\r\nHost: %s\r\nUser-Agent: %s\r\n\r\n";

  if ( getpage[0] == '/' ) {
    getpage = getpage + 1;
    fprintf( stderr,"Removing leading \"/\", converting %s to %s\n", page, getpage );
  }

  query = (char *)malloc( strlen( host ) + strlen( getpage )
                        + strlen( USERAGENT ) + strlen( tpl ) - 5 );

  sprintf( query, tpl, getpage, host, USERAGENT );
  return query;
}