#include <rpc/rpc.h>
#include <stdio.h>
#include <string.h>
#include "ftp.h"

extern __thread int errno;

/*
 * Gets the requested file from the server by calling the
 * remote procedure in a loop
 */
int get_file(char *host, char *name)
{
    CLIENT *clnt;
	int total_bytes = 0, write_bytes;
    readfile_res *result;
	request req;
	FILE *file;

    /*
	 * Initialize the request with the file name 
	 */
	req.name = name;

    /*
     * Create client handle used for calling FTPPROG on
     * the server designated on the command line. Use
     * the tcp protocol when contacting the server.
     */
    clnt = clnt_create(host, FTPPROG, FTPVER, "tcp");
    if (clnt == NULL) {
        /*
         * Couldn't establish connection with server.
         * Print error message and stop.
         */
         clnt_pcreateerror(host);
         exit(1);
    }

	/*
	 * Open the file for writing on the client machine
	 */
    file = fopen(name, "w");

    /*
     * Call the remote procedure retrieve_file on the server.
	 * During each iteration of the loop remote procedure is
	 * called and only 1024 bytes of data is read and returned
	 * by the server. The loop terminates when the data returned
	 * from the server is less than 1024 bytes
     */
	while (1) {
		/*
		 * Specifies the byte position where the next read should be
		 * started in the server.
		 */
		req.start = total_bytes;

        result = retrieve_file_1(&req, clnt);
        if (result == NULL) {
            /*
             * An RPC error occurred while calling the server.
             * Print error message and stop.
             */
            clnt_perror(clnt, host);
            exit(1);
        }

        /*
         * We successfully called the remote procedure.
         */
        if (result->errno != 0) {
            /*
             * A remote system error occurred.
             * Print error message and stop.
             */
            errno = result->errno;
            perror(name);
            exit(1);
        }

        /*
         * Successfully got a chunk of the file.
         * Write into our local file and update the
		 * total bytes of data read till now.
         */
		write_bytes = fwrite(result->readfile_res_u.chunk.data, 1, result->readfile_res_u.chunk.bytes, file);
		total_bytes += result->readfile_res_u.chunk.bytes;
		if (result->readfile_res_u.chunk.bytes < MAXLEN) 
		    break;
	}

	fclose(file);

	return 0;
}

/*
 * Stores the file on the server by calling the remote
 * procedure in a loop
 */
int put_file(char *host, char *name)
{
    CLIENT *clnt;
    char data[1024];
	int read_bytes;
    int *result;
	chunksend chunk;
	FILE *file;

    /*
     * Create client handle used for calling FTPPROG on
     * the server designated on the command line. Use
     * the tcp protocol when contacting the server.
     */
    clnt = clnt_create(host, FTPPROG, FTPVER, "tcp");
    if (clnt == NULL) {
        /*
         * Couldn't establish connection with server.
         * Print error message and stop.
         */
         clnt_pcreateerror(host);
         exit(1);
    }

    /*
	 * Open the file that should be stored on the server
	 */
    file = fopen(name, "r");

    /*
	 * Initialize the chunk to be sent with the name
	 * of the file
	 */ 
	chunk.name = name;

    /*
     * Call the remote procedure readdir on the server
	 * in a loop sending only 1024 bytes of data in each
	 * iteration. The loop terminates once the data less
	 * than 1024 bytes is sent.
     */
	while (1) {
		read_bytes = fread(data, 1, MAXLEN, file);

        chunk.data = data;
		chunk.bytes = read_bytes;
        result = send_file_1(&chunk, clnt);

        if (result == NULL) {
            /*
             * An RPC error occurred while calling the server.
             * Print error message and stop.
             */
            clnt_perror(clnt, host);
            exit(1);
        }

        /*
         * Okay, we successfully called the remote procedure.
         */
        if (*result != 0) {
            /*
             * A remote system error occurred.
             * Print error message and stop.
             */
            errno = *result;
            perror(name);
            exit(1);
        }

        /*
         * Successfully got a chunk of the file.
         * Write into our local file.
         */
		if (read_bytes < MAXLEN) 
		    break;
	}

	fclose(file);

	return 0;
}

/*
 * Handles commands read on the command line and calls
 * the appropriate function to handle the command
 */
int read_command(char *host)
{
	char command[MAXLEN];

	printf("> ");
	fflush(stdin);
	gets(command);

    if (strncmp(command, "get", 3) == 0) {
		return get_file(host, command+4);
	} else if(strncmp(command, "put", 3) == 0){
		return put_file(host, command+4);
	} else if(strncmp(command, "exit", 4) == 0){
		exit(0);
    } else {
		return -1;
	}
}

int main(int argc, char *argv[])
{
   int result;

   if (argc != 2) {
        fprintf(stderr, "usage: %s host\n", argv[0]);
        exit(1);
   }

   /*
    * Command handling loop
	*/
   while(TRUE) {
	   result = read_command(argv[1]);
   }

   return 0;
}