#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <poll.h>

int main(int argc,char *argv[])
{
	int udpfd = 0;
	int ret = 0;
	struct pollfd fds[2];//監測檔案描述結構體陣列：2個
	struct sockaddr_in saddr;
	struct sockaddr_in caddr;

	bzero(&saddr,sizeof(saddr));
	saddr.sin_family = AF_INET;
	saddr.sin_port   = htons(8000);
	saddr.sin_addr.s_addr = htonl(INADDR_ANY);
	
	bzero(&caddr,sizeof(caddr));
	caddr.sin_family  = AF_INET;
	caddr.sin_port    = htons(8000);
	
	//建立套接字
	if( (udpfd = socket(AF_INET,SOCK_DGRAM, 0)) < 0)
	{
		perror("socket error");
		exit(-1);
	}
	
	//套接字埠綁字
	if(bind(udpfd, (struct sockaddr*)&saddr, sizeof(saddr)) != 0)
	{
		perror("bind error");
		close(udpfd);		
		exit(-1);
	}

	printf("input: \"sayto 192.168.220.X\" to sendmsg to somebody\033[32m\n");	
	fds[0].fd = 0;		//標準輸入描述符
	fds[1].fd = udpfd;	//udp描述符
	
	fds[0].events = POLLIN; // 普通或優先順序帶資料可讀  
    fds[1].events = POLLIN; // 普通或優先順序帶資料可讀
	
	while(1)
	{	
		// 監視並等待多個檔案（標準輸入，udp套接字）描述符的屬性變化（是否可讀）  
        // 沒有屬性變化，這個函式會阻塞，直到有變化才往下執行，這裡沒有設定超時  
        ret = poll(fds, 2, -1); 
		
		write(1,"UdpQQ:",6);
		
        if(ret == -1){ // 出錯  
            perror("poll()");  
        }
		else if(ret > 0){ // 準備就緒的檔案描述符  
            char buf[100] = {0};  
            if( ( fds[0].revents & POLLIN ) ==  POLLIN ){ // 標準輸入  
                
				fgets(buf, sizeof(buf), stdin);
				buf[strlen(buf) - 1] = '\0';
				if(strncmp(buf, "sayto", 5) == 0)
				{
					char ipbuf[16] = "";
					inet_pton(AF_INET, buf+6, &caddr.sin_addr);//給addr套接字地址再賦值.
					printf("\rsay to %s\n",inet_ntop(AF_INET,&caddr.sin_addr,ipbuf,sizeof(ipbuf)));
					continue;
				}
				else if(strcmp(buf, "exit")==0)
				{
					close(udpfd);
					exit(0);
				}
				sendto(udpfd, buf, strlen(buf),0,(struct sockaddr*)&caddr, sizeof(caddr));  
                  
            }
			else if( ( fds[1].revents & POLLIN ) ==  POLLIN ){ //udp套接字  
                struct sockaddr_in addr;
				char ipbuf[INET_ADDRSTRLEN] = "";
				socklen_t addrlen = sizeof(addr);
				
				bzero(&addr,sizeof(addr));
				
				recvfrom(udpfd, buf, 100, 0, (struct sockaddr*)&addr, &addrlen);
				printf("\r\033[31m[%s]:\033[32m%s\n",inet_ntop(AF_INET,&addr.sin_addr,ipbuf,sizeof(ipbuf)),buf);  
            }  
              
        }
		else if(0 == ret){ // 超時  
            printf("time out\n");  
        }  
	}
	
	return 0;
}