#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h> 
#include <signal.h>
#include <unistd.h>
#include <errno.h>
#include <pthread.h>

//typedef void Sigfunc (int);

int searchRequest();
void * search(void * arg) ;
void * doit(void * arg) ;
static void recvfrom_alarm(int signo);

struct paramenter{
	struct sockaddr_in  clientaddr ;
	int fd ;
	char * fileName ;
};

int main(){
	//khoi tao socket udp
	int fd ;
	int nBytes ;
     if((fd = socket(AF_INET,SOCK_DGRAM,0)) < 0){
		perror("error when create socket") ;
          exit(1) ;
     }

	// khai bao cau truc dia chi cua server , client
     struct sockaddr_in serveraddr ;
	struct sockaddr_in clientaddr ;
	int len_sock_server = sizeof(serveraddr) ;
	int len_sock_client = sizeof(clientaddr) ;

	bzero(&serveraddr, len_sock_server) ;
     serveraddr.sin_family = AF_INET ;
     serveraddr.sin_port = htons(12345) ;
     serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);


	// lang nghe ket noi 
	if(bind(fd, (struct sockaddr*) &serveraddr,len_sock_server) < 0){
		perror("could not open socket") ;
		exit(1) ;
	}
//	tao thread de thuc hien thao tac yeu cau tim kiem file.

	pthread_t tid ;	
	pthread_create(&tid,NULL,search,NULL) ;
	
//	o luong chinh thuc hien viec lang nghe yeu cau tu cac may khac guoi toi.
	char * fileName ;
	fileName = (char*)malloc(25) ;

	for(;;){
		pthread_t newThread ;
		nBytes = recvfrom(fd, fileName, 25, 0 ,(struct sockaddr*) &clientaddr, &len_sock_client);
		if(nBytes < 0) {	
			perror("recvfrom"); 
			break;
		}
		
		// gan gia tri cho cac thanh phan cua bien cau truc paramenter.
		struct paramenter paramenters ;
		paramenters.fd = fd ;
		paramenters.fileName = (char*)malloc(25) ;
		strcpy(paramenters.fileName,fileName) ;
		paramenters.clientaddr = clientaddr ;
		// tao thread xu li viec tra loi request tu cac may.
		int t = pthread_create(&newThread,NULL,doit,(void *)¶menters) ;
		if(t != 0){
			perror("could not create new thread\n") ;
		}
	}

     return 0 ;
}
//---------------------------------------------------------------------------------------------------
// ham doit xu ly viec tra loi request tu cac may guoi den.
void * doit(void * arg){
	pthread_detach(pthread_self()) ;
    	int nbyte ;
	long size = 0;

	struct paramenter * assig ;
	assig = (struct paramenter *)arg ;

	char buff[100] = "ls /tmp/k51mmt/ |grep " ;
	strcat(buff,assig->fileName) ;
	char buff2[10] = " > newfile" ;
	strcat(buff,buff2);
    	system(buff);
	
     FILE * finput ;
    	finput = fopen("newfile", "r")  ;
	if(finput == NULL){
		perror("Error when open new file") ;
		return ;
	}

	fseek (finput, 0, SEEK_END);
	size = ftell(finput);

	if(size == 0){
		//printf("khong co ket qua") ;
		return ;
	}
	fseek (finput,0,SEEK_SET) ;

    	char * ch ;
	ch = (char *) malloc(1500) ;
	int n ;
	n = fread(ch,sizeof(char),1500,finput) ;
	if(n < 0){
		printf("can't read file\n") ;
	}
	// guoi du lieu toi may da hoi.
	nbyte = sendto((assig->fd),ch,n,0,(struct sockaddr*)&(assig->clientaddr),sizeof((assig->clientaddr))) ;
	if(nbyte < 0){
		perror("error when send data\n") ;
	}
	sleep(2) ;
	close(assig->fd) ;
	fclose(finput) ;
	//system("rm -f newfile") ;
}

//---------------------------------------------------------------------------------------------------
// ham search phuc vu thao tac tim kiem.
void * search(void* arg){
	pthread_detach(pthread_self()) ;
	for(;;){
		int number ;
		number = searchRequest() ;
		if(number == 0){
			printf("Khong co server nao co ten file chua tu khoa da nhap vao \n") ;
			printf("----------------------------------------------------------\n") ;
			printf("Nhap 1 de tim kiem voi tu khoa khac \n") ;
			printf("Nhap so bat ky (khac 1) de thoat \n") ;
			fflush(stdin) ;
			int c ;
			scanf("%d",&c) ;
			if(c == 1)
				continue ;
			else
				exit(1) ;
		}
		else{
			printf("Nhap 1 de tim kiem voi tu khoa khac \n") ;
			printf("Nhap 2 de xem list file phu hop download file tu 1 server xac dinh\n") ;
			printf("Nhap so bat ky (khac 1,2) de thoat \n") ;
			fflush(stdin) ;
			int c ;
			scanf("%d",&c) ;
			switch(c){
				case 1 :
					continue ;
				case 2 :
					//download() ;
					printf("download here\n") ;
					continue ;
				default :
					exit(1) ;
			}
		}
		printf("--------------------------------------------------\n") ;
	}
}

//---------------------------------------------------------------------------------------------------
static void recvfrom_alarm(int signo){
	return;
}

//---------------------------------------------------------------------------------------------------
/* ham searchRequest dung de guoi, nhan truy van toi cac may khac.
	ham nay tra lai gia tri int la so cac may tra loi truy van guoi di
	dong thoi hien thi ip, chi tiet cac file thoa man tren cac may do
*/

int searchRequest(){
	int result = 0;
	int sockfd ;
	int nBytes ;
	
	int len;
	struct sockaddr_in serveraddr ; 
	

     serveraddr.sin_family = AF_INET ;
     serveraddr.sin_port = htons(12345) ;
     serveraddr.sin_addr.s_addr = inet_addr("255.255.255.255");
	
	char fileName[25] ;
	if((sockfd = socket(AF_INET,SOCK_DGRAM,0)) < 0){
		perror("error when create socket") ;
		return ;
	}

	printf("Nhap ten file can tim kiem : \n") ;
	scanf("%s",fileName);
	
	const int on = 1 ;
	setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) ;
	// ham sysv_signal thay the ham signal 
	sysv_signal(SIGALRM, recvfrom_alarm);
	nBytes = sendto(sockfd, fileName, strlen(fileName), 0,(struct sockaddr*) &serveraddr , sizeof(serveraddr));
	alarm(5) ;

	
	for(;;){
		struct sockaddr_in	preply_addr ; 
		len = sizeof(preply_addr) ;
		char * recvString ;
		recvString = (char*)malloc(1500) ;
		int n ;
		n = recvfrom(sockfd, recvString, 1500, 0, (struct sockaddr*)&preply_addr, &len);	
		if(n < 0){
			if (errno == EINTR){
				printf("loi j cung phai noi 1 cau chu \n") ;
				break;
			}
			else
				continue;
		}
 		char out[128];
		const char *str;
		str = (char*)malloc(50) ;
		str = inet_ntoa(preply_addr.sin_addr) ;
		printf("from %s :\n %s \n",str,recvString) ;
		result ++ ;
	     //str = inet_ntop(AF_INET, &(((struct sockaddr_in *)preply_addr)->sin_addr), out, sizeof(out));
		//printf("from %s: %s \n",out, recvString);
	}	

	close(sockfd);
	return result ;
}