#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>  // htons() and inet_addr()
#include <netinet/in.h> // struct sockaddr_in
#include <sys/socket.h>

#include "common.h"

int main(int argc, char* argv[]) {
    int ret,bytes_sent,recv_bytes;

    // variables for handling a socket
    int socket_desc;
    struct sockaddr_in server_addr = {0}; // some fields are required to be filled with 0

    /**
     *  TODO: create a socket for contacting the server
     *
     * Suggestions:
     * - protocollo AF_INET
     * - tipo SOCK_STREAM
     */

	socket_desc = socket(AF_INET, SOCK_STREAM, 0);

	if (socket_desc == -1) {
		perror("Errore nella creazione della socket");
		exit(EXIT_FAILURE);
	}

    if (DEBUG) fprintf(stderr, "Socket created...\n");

    /**
     *  TODO: set up parameters for the connection and initiate a connection to the server
     *
     * Suggestions:
     * - set the 3 fields of server:
     * - - server_addr.sin_addr.s_addr: we must specify the server address
     * - - server_addr.sin_family,
     * - - server_addr.sin_port (using htons() method)
     * - initiate a connection to the server
     * - - attention to the bind method:
     * - - it requires as second field struct sockaddr* addr, but our address is a struct sockaddr_in, hence we must cast it (struct sockaddr*) &server_addr
     */

	server_addr.sin_addr.s_addr = SERVER_ADDRESS;
	server_addr.sin_family = AF_INET;
	server_addr.sin_port = htons(SERVER_PORT);

	struct sockaddr *indirizzo_server = (struct sockaddr*) &server_addr;

	int connessione = connect(socket_desc, indirizzo_server, sizeof(*indirizzo_server));

	if (connessione == -1) {
		perror("Errore nella connect del client");
		exit(EXIT_FAILURE);
	}

    if (DEBUG) fprintf(stderr, "Connection established!\n");

    char buf[1024];
    size_t buf_len = sizeof(buf);
    int msg_len;
    memset(buf,0,buf_len);

    /**
     *  TODO: receive and display the welcome message from server
     *
     * Suggestions:
     * - set the 3 fields of server:
     * - - server_addr.sin_addr.s_addr: we must specify the server address
     * - - server_addr.sin_family,
     * - - server_addr.sin_port (using htons() method)
     * - initiate a connection to the server
     * - - attention to the bind method:
     * - - it requires as second field struct sockaddr* addr, but our address is a struct sockaddr_in, hence we must cast it (struct sockaddr*) &server_addr
     */

	recv_bytes = 0;
	ret = 0;
	int bytes_to_read = buf_len;

	bytes_sent = 0;
	int bytes_to_send;

	while(bytes_to_read > 0) {
		ret = recv(socket_desc, buf+ret, buf_len, 0);

		if (ret = 0) break;

		if (ret == -1) {
			if (errno == EINTR) continue;
			else {
				perror("Errore in ricezione");
				exit(EXIT_FAILURE);
			}
		}

		recv_bytes += ret;
		bytes_to_read -= ret;
	}

    if (DEBUG) fprintf(stderr, "Received message of %d bytes...\n",recv_bytes);

	printf("Ho ricevuto questo messaggio: %s \n", buf);

    // main loop
    while (1) {
        char* quit_command = SERVER_COMMAND;
        size_t quit_command_len = strlen(quit_command);

        printf("Insert your message: ");

        /* Read a line from stdin
         *
         * fgets() reads up to sizeof(buf)-1 bytes and on success
         * returns the first argument passed to it. */
        if (fgets(buf, sizeof(buf), stdin) != (char*)buf) {
            fprintf(stderr, "Error while reading from stdin, exiting...\n");
            exit(EXIT_FAILURE);
        }

        msg_len = strlen(buf);
//        buf[--msg_len] = '\0'; // remove '\n' from the end of the message

		/**
         *  TODO: send message to server
         *
         * Suggestions:
         * - send() with flags = 0 is equivalent to write() to a descriptor
         * - the number of bytes to send is msg_len as we have discarded '\n'
         * - deal with partially sent messages
         * - message size IS NOT buf size
         */

		bytes_to_send = msg_len;
		ret = 0;
		bytes_sent = 0;

		while(bytes_to_send > 0) {
			ret = send(socket_desc, buf+bytes_sent, msg_len, 0);

			if (ret == 0) break;

			if (ret == -1) {
				if (errno == EINTR) continue;
				else {
					perror("Errore nella send del client");
					exit(EXIT_FAILURE);
				}
			}

			bytes_sent += ret;
			bytes_to_send -= ret;
		}

        if (DEBUG) fprintf(stderr, "Sent message of %d bytes...\n", bytes_sent);


        /**
         *  TODO: After a quit command we won't receive any more data from
         *  the server, thus we must exit the main loop.
         *
         * Suggestions:
         * - compare the number of bytes sent with the length of the
         *   quit command that tells the server to close the connection
         *   (see SERVER_COMMAND macro in common.h)
         * - perform a byte-to-byte comparsion when required using
         *   memcmp(const void *ptr1, const void *ptr2, size_t num)
         * - exit from the cycle when there is nothing left to receive
         */

		char ginio[6] = SERVER_COMMAND;

		if (memcmp(ginio, buf, msg_len)) break;
        /**
         *  TODO: read message from server
         * Suggestions:
         * - recv() with flags = 0 is equivalent to read() from a descriptor
         * - for sockets, we get a 0 return value only when the peer closes
         *   the connection: if there are no bytes to read and we invoke
         *   recv() we will get stuck, because the call is blocking!
         * - deal with partially sent messages (we do not know the message size)
         */

		while(bytes_to_read > 0) {
			ret = recv(socket_desc, buf+ret, buf_len, 0);

			if (ret = 0) break;

			if (ret == -1) {
				if (errno == EINTR) continue;
				else {
					perror("Errore in ricezione");
					exit(EXIT_FAILURE);
				}
			}

			recv_bytes += ret;
			bytes_to_read -= ret;
		}

        if (DEBUG) fprintf(stderr, "Received answer of %d bytes...\n",recv_bytes);

        printf("Server response: %s\n", buf);
    }


    /**
     *  TODO: close socket and release unused resources
     */

    if (DEBUG) fprintf(stderr, "Socket closed...\n");

    if (DEBUG) fprintf(stderr, "Exiting...\n");

    exit(EXIT_SUCCESS);
}