// Name : client.c

// Author : Modnar

// Date : 2020/04/02

#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <assert.h>

#include <libgen.h>

#include <stdio.h>

#include <unistd.h>

#include <string.h>

#include <stdlib.h>

const int HISTORY_MSG_NUM = 10;

const int USER_INFO_SIZE = 64;

const int MESSAGE_SIZE = 256;

const int BUFFER_SIZE = USER_INFO_SIZE + MESSAGE_SIZE;

char *buffer;

void print_history_msg() {

for (int pos = 0; pos < HISTORY_MSG_NUM; ++pos) {

if (strlen(buffer+pos*BUFFER_SIZE) > 0) {

printf("%s\n", buffer+pos*BUFFER_SIZE);

} else {

break;

}

}

}

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

if (argc <= 2) {

printf("usage: %s ip_address port_number\n", basename(argv[0]));

return EXIT_FAILURE;

}

const char *ip = argv[1];

int port = atoi(argv[2]);

struct sockaddr_in server_address;

bzero(&server_address, sizeof(server_address));

server_address.sin_family = AF_INET;

inet_pton(AF_INET, ip, &server_address.sin_addr);

server_address.sin_port = htons(port);

int sockfd = socket(PF_INET, SOCK_STREAM, 0);

assert(sockfd >= 0);

char userMsg[MESSAGE_SIZE], recvMsg[MESSAGE_SIZE];

buffer = new char[HISTORY_MSG_NUM*BUFFER_SIZE];

if (connect(sockfd, (struct sockaddr *)&server_address, sizeof(server_address)) < 0) {

printf("connection failed\n");

} else {

bzero(userMsg, MESSAGE_SIZE);

recv(sockfd, recvMsg, MESSAGE_SIZE, 0);

printf("%s\n", recvMsg);

while (true) {

printf(">> ");

bzero(userMsg, MESSAGE_SIZE);

bzero(recvMsg, MESSAGE_SIZE);

fgets(userMsg, MESSAGE_SIZE, stdin);

if (strncmp(userMsg, "exit", 4) == 0) break;

if (userMsg[strlen(userMsg)-1] == '\n')

userMsg[strlen(userMsg)-1] = '\0';

// 这里仅考虑客户端处于稳定的网络环境下，因此并未对下列函数进行异常分析

send(sockfd, userMsg, strlen(userMsg), 0);

// if (strncmp(userMsg, "history", strlen("history")) == 0) {

if (strlen(userMsg) > 0 && userMsg[0] == '$') {

bzero(buffer, HISTORY_MSG_NUM*BUFFER_SIZE);

recv(sockfd, buffer, HISTORY_MSG_NUM*BUFFER_SIZE, 0);

print_history_msg();

continue;

}

recv(sockfd, recvMsg, MESSAGE_SIZE, 0);

printf("%s\n", recvMsg);

}

}

close(sockfd);

return EXIT_SUCCESS;

}