#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <netdb.h>
#include <string.h>
#include <fcntl.h>
#include <sys/stat.h>

#define SERVER_PORT 21
#define SERVER_ADDR "94.132.140.155"

int	sockfd, sockDatafd;

int getAnswerCode(char * answer)
{
    char temp[4];
    int result;
    temp[0] = answer[0];
    temp[1] = answer[1];
    temp[2] = answer[2];
    temp[3] = '\0';
    result = atoi(temp);
    return result;
}

void parseURL(char * url,char * userName,char * password, char * host, char *filepath, char *filename){
    
    char userNameAndPass[50];
    userNameAndPass[0]=0;
    char hostAndPath[200];
    char urlcopy[256];
    int i, divisor, x;
    
    //shift(url,'@');
    //strcpy(urlcopy,url);
    
    sscanf(url,"ftp://%[a-zA-Z0-9:]@%[a-zA-Z0-9./:?&-]",userNameAndPass,hostAndPath);
    //printf("host= %s\n",hostAndPath);
    //printf("%s\n",userNameAndPass);
    if(strlen(userNameAndPass)==0){
        userName="anonymous";
        password="anonymous";
    }
    else{
        sscanf(userNameAndPass,"%[a-zA-Z0-9]:%[^@/:]",userName,password);
    }
    
    for(i= 0; i<strlen(hostAndPath); i++)
    {
	if (hostAndPath[i] == '/') break;
    }
    divisor = i;
    x= 0;
    for(i = 0 ; i < strlen(hostAndPath); i++)
    {
	if (i < divisor)
	{
	    host[x] = hostAndPath[i];
	    x++;
	}
	else if (i == divisor)
	{
	    host[x] = '\0';
	    x = 0;
	    
	}
	else if (i > divisor)
	{
	  filepath[x] = hostAndPath[i];
	  x++;
	}
    }
    
    filepath[x] = '\0';
    
    for(i = strlen(filepath)-1; i > 0; i--)
    {
	if (filepath[i] == '/') break;
    }
    divisor = i;
    x= 0;
    for(i = divisor+1; i < strlen(filepath); i++)
    {
	filename[x] = filepath[i];
	x++;
    }
    filename[x] = '\0';
}

int readFromSocket(int socket_id, char message[])
{
  char temp[2];
  char inBuf[256];
  int i, finish, j;
  char resultBuf[256];
  i = 0;
  finish = 0 ;
  strcpy(inBuf,"");
  strcpy(resultBuf,"");
  strcpy(temp,"");
  
  while(finish == 0)
  {
      strcpy(temp,"");
      strcpy(inBuf,"");
      j= 0;
      while(temp[0] != '\n')
      {
	  read(socket_id, temp, sizeof(char));
	  //strcat(inBuf,temp);
	  inBuf[j] = temp[0];
	  i++;
	  j++;

      }
      inBuf[j] = '\0';
      //strcat(inBuf,"\0");

      if (inBuf[3] == ' ')
      {
	  finish = 1;
      }
      
      strcat(resultBuf,inBuf);
  }

  strcpy(message, resultBuf);
  return i;
  
}
int readDataFromSocket(int socket_id, int fdlocal)
{
  char temp[2];
  char inBuf[256];
  int i;
  i = 0;
  
  strcpy(inBuf,"");
  strcpy(temp,"");
  while(read(socket_id, temp, sizeof(char)) != 0)
  {
      //strcat(inBuf,temp);
      write(fdlocal, temp, sizeof(char));
      i++;
  }
  write(fdlocal, '\0', sizeof(char));
  
  return i;
  
}
void getIpString(char inputString[], char ipString[], int *portNumber)
{
  char portString1[50], portString2[50], tempIpString[60];
  int found, i, stringPos, startPos, blocksFound, portNumber1, portNumber2;
  found = 0;
  i = 0;
  startPos = 0;
  blocksFound = 0;
  stringPos = 0;
  
  strcpy(tempIpString,"\0"); strcpy(portString1,"\0"); strcpy(portString2,"\0");
  
  while(found == 0 && startPos < strlen(inputString))
  {
      if (inputString[startPos] == '(') found = 1;
      startPos++;
  }
  //printf("passou. startPos: %d\n", startPos);
  for(i = startPos;i<strlen(inputString);i++)
  {
     if (blocksFound<4)
     {
	if(inputString[i] == ',')
	{
	    tempIpString[stringPos] = '.';
	    blocksFound++;
	    if (blocksFound == 4)
	    {
	      tempIpString[stringPos]='\0';
	      stringPos = -1;
	    }
	}
	else
	{
	  tempIpString[stringPos] = inputString[i];
	}
	stringPos++;
     }
     else if (blocksFound == 4)
     {
       if(inputString[i] == ',')
       {
	 blocksFound++;
	 portString1[stringPos] = '\0';
	 stringPos = 0;
       }
       else{
	 //printf("StringPos: %d - Atual: %c\n", stringPos,inputString[i]);
	 portString1[stringPos] = inputString[i];
	 stringPos++;
       }
     }
     else if (blocksFound == 5)
     {
       if(inputString[i] == ',') blocksFound++;
       else if (inputString[i] == ')') break;
       else
       {
	 portString2[stringPos] = inputString[i];
	 stringPos++;
       }
     }
  }
  
  portString2[stringPos] = '\0';
  //printf("PortNumber1: %s, PortNumber2: %s \n", portString1, portString2);
  portNumber1 = atoi(portString1);
  portNumber2 = atoi(portString2);
  (* portNumber) = (portNumber1 * 256) + portNumber2;
  
  strcpy(ipString,tempIpString);
  
   
  
}


int main(int argc, char** argv){

	
	struct	sockaddr_in server_addr;
	struct	sockaddr_in server_addr_data;
	struct hostent *hostnameObject;
	char	buf[] = "Mensagem de teste na travessia da pilha TCP/IP\n"; 
	char	connectionIP[50];
	char	inBuf[256];
	char	temp[2];
	int	bytes, i, bytesRead, bytesWritten;
	char	passiveIP[50];
	int	passivePort;
	int	destinationFile;
	int	answerCode;
	int	verbose;
	char url[256], userName[256], userPassword[256], hostPath[256], filePath[256], fileName[256];

	verbose = 0 ;
	if (argc > 3)
	{
	    printf("Incorrect number of arguments\n Usage: download ftp://[<user>:<password>@]<host>/<url-path>\n");
	    return;
	}
	else
	{
	    parseURL(argv[1], userName, userPassword, hostPath, filePath, fileName);
	    if(argc == 2)
	    {
		verbose = 0;
	    }
	    else
	    {
		if(strcmp(argv[2],"--verbose") == 0) verbose = 1;
		else verbose = 0;
	    }
	}
	
	/*printf("username: %s\n",userName);
	printf("password: %s\n",userPassword);
	printf("hostpath: %s\n",hostPath);
	printf("filepath: %s\n",filePath);
	printf("filename: %s\n",fileName);*/
	
	
	
	
	// GET IP FROM URL
	
	 if ((hostnameObject=gethostbyname(hostPath)) == NULL) {  
            herror("gethostbyname");
            exit(1);
        }
	
	
	strcpy(connectionIP,inet_ntoa(*((struct in_addr *)hostnameObject->h_addr)));
	
	//printf("IP: %s\n", connectionIP);
	
	/*server address handling*/
	bzero((char*)&server_addr,sizeof(server_addr));
	server_addr.sin_family = AF_INET;
	server_addr.sin_addr.s_addr = inet_addr(connectionIP);	/*32 bit Internet address network byte ordered*/
	server_addr.sin_port = htons(SERVER_PORT);		/*server TCP port must be network byte ordered */
    
	/*open an TCP socket*/
	if ((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0) {
    		perror("socket()");
        	exit(0);
    	}
	/*connect to the server*/
    	if(connect(sockfd, 
	           (struct sockaddr *)&server_addr, 
		   sizeof(server_addr)) < 0){
        	perror("connect()");
		exit(0);
	}
	
	
	
	//READ WELCOME MESSAGE
	bytesRead = readFromSocket(sockfd, inBuf);
	if(verbose == 1) printf("READ (%d BYTES): %s\n",bytesRead, inBuf);
	answerCode = getAnswerCode(inBuf);
	if (answerCode != 220)
	{
	    printf("Error: BAD WELCOME MESSAGE\nAplication will now quit.\n");
	    return -1;
	}
	
	//SEND USERNAME
	strcpy(buf,"USER ");  strcat(buf,userName);  strcat(buf,"\n");
	bytesWritten = write(sockfd, buf, strlen(buf));
	if(verbose == 1) printf("Bytes escritos %d\nWROTE:  %s \n", bytesWritten, buf);
  
	
	bytesRead = readFromSocket(sockfd,inBuf);
	if(verbose == 1) printf("READ (%d BYTES): %s\n",bytesRead, inBuf);
	answerCode = getAnswerCode(inBuf);
	if (answerCode != 331)
	{
	    printf("Error: BAD USER RESPONSE\nAplication will now quit.\n");
	    return -1;
	}
	
	
	//SEND PASSWORD
	strcpy(buf,"PASS ");  strcat(buf,userPassword);  strcat(buf,"\n");
	bytesWritten = write(sockfd, buf, strlen(buf));
	if(verbose == 1) printf("Bytes escritos %d\nWROTE:  %s \n", bytesWritten, buf);

	
	bytesRead = readFromSocket(sockfd,inBuf);
	if(verbose == 1) printf("READ (%d BYTES): %s\n",bytesRead, inBuf);
	answerCode = getAnswerCode(inBuf);
	if (answerCode != 230)
	{
	    printf("Error: LOGIN FAILED\nAplication will now quit.\n");
	    return -1;
	}
	
	
	//ENTER PASSIVE MODE
	strcpy(buf,"PASV\n");
	bytesWritten = write(sockfd, buf, strlen(buf));
	if(verbose == 1) printf("Bytes escritos %d\nWROTE:  %s \n", bytesWritten, buf);
	
	
	bytesRead = readFromSocket(sockfd,inBuf);
	if(verbose == 1) printf("READ (%d BYTES): %s\n",bytesRead, inBuf);
	answerCode = getAnswerCode(inBuf);
	if (answerCode != 227)
	{
	    printf("Error: COULDN'T ENTER PASSIVE MODE\nAplication will now quit.\n");
	    return -1;
	}
	
	
	//PARSE PASSIVE MODE IP
	//printf("TESTE DA FUNCAO\n");

	getIpString(inBuf, passiveIP, &passivePort);
	
	//printf("PassiveIP: %s\nPassivePort: %d\n",passiveIP, passivePort);
	
	
	//SECOND SOCKET CONFIGURATION & OPENING
	
	/*Data Socket Configuration*/
	bzero((char*)&server_addr_data,sizeof(server_addr_data));
	server_addr_data.sin_family = AF_INET;
	server_addr_data.sin_addr.s_addr = inet_addr(passiveIP);	/*32 bit Internet address network byte ordered*/
	server_addr_data.sin_port = htons(passivePort);		/*server TCP port must be network byte ordered */
	
	
	/*open an TCP socket*/
	if ((sockDatafd = socket(AF_INET,SOCK_STREAM,0)) < 0) {
		perror("socket()");
		exit(0);
	}
	/*connect to the server*/
	if(connect(sockDatafd, 
		  (struct sockaddr *)&server_addr_data, 
		  sizeof(server_addr_data)) < 0){
		perror("connect()");
		exit(0);
	}
	
	
	
	
	// ASK FOR FILE
	//strcpy(buf,"RETR folder1\\potato2.txt\n");
	strcpy(buf,"RETR ");  strcat(buf,filePath);  strcat(buf,"\n");
	bytesWritten = write(sockfd, buf, strlen(buf));
	if(verbose == 1) printf("Bytes escritos %d\nWROTE:  %s \n", bytesWritten, buf);
	
	bytesRead = readFromSocket(sockfd,inBuf);
	if(verbose == 1) printf("READ (%d BYTES): %s\n",bytesRead, inBuf);
	answerCode = getAnswerCode(inBuf);
	if (answerCode != 150)
	{
	    printf("Error: COULDN'T OPEN CONNECTION FOR THE FILE\nAplication will now quit.\n");
	    return -1;
	}
	
	
	
	destinationFile = open(fileName, O_WRONLY | O_CREAT);
	//RECEIVE FILE ON 2ND SOCKET
	bytesRead = readDataFromSocket(sockDatafd,destinationFile);
	printf("DOWNLOADED %d BYTES OF DATA\n",bytesRead);
	
	
	
	// READ FROM FIRST SOCKET THAT THE TRANSFER WAS COMPLETED
	bytesRead = readFromSocket(sockfd,inBuf);
	if(verbose == 1) printf("READ (%d BYTES): %s\n",bytesRead, inBuf);
	answerCode = getAnswerCode(inBuf);
	if (answerCode != 226)
	{
	    printf("Error: TRANSFER COULDN'T BE COMPLETED\nAplication will now quit.\n");
	    return -1;
	}
	
	
	
	//QUIT FROM SERVER
	//strcpy(buf,"RETR folder1\\potato2.txt\n");
	strcpy(buf,"QUIT ");  strcat(buf,filePath);  strcat(buf,"\n");
	bytesWritten = write(sockfd, buf, strlen(buf));
	if(verbose == 1) printf("Bytes escritos %d\nWROTE:  %s \n", bytesWritten, buf);
	
	bytesRead = readFromSocket(sockfd,inBuf);
	if(verbose == 1) printf("READ (%d BYTES): %s\n",bytesRead, inBuf);
	answerCode = getAnswerCode(inBuf);
	if (answerCode != 221)
	{
	    printf("Error: COULDN'T CLOSE CONNECTION\nAplication will now quit.\n");
	    return -1;
	}
	
	
	close(sockDatafd);
	close(sockfd);
	
	
	// CHANGE FILE PERMISSIONS
	
	chmod(fileName, S_IRUSR|S_IRGRP|S_IROTH|S_IWUSR);
	
	
	
	exit(0);
}