#ifndef _COMMON_H_
#define _COMMON_H_

#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <strings.h>
#include <cstdlib>
#include <cstdio>
#include <cstddef>
#include <string>

namespace common{

#define D(exp,fmt,...) do {                     \
        if(!(exp)){                             \
            fprintf(stderr,fmt,##__VA_ARGS__);  \
            abort();                            \
        }                                       \
    }while(0)

static void setnonblock(int fd){
    fcntl(fd,F_SETFL,fcntl(fd,F_GETFL) | O_NONBLOCK);
}
static void setreuseaddr(int fd){
    int ok=1;
    setsockopt(fd,SOL_SOCKET,SO_REUSEADDR,&ok,sizeof(ok));
}

static void setaddress(const char* ip,int port,struct sockaddr_in* addr){
    bzero(addr,sizeof(*addr));
    addr->sin_family=AF_INET;
    inet_pton(AF_INET,ip,&(addr->sin_addr));
    addr->sin_port=htons(port);
}

static std::string address_to_string(struct sockaddr_in* addr){
    char ip[128];
    inet_ntop(AF_INET,&(addr->sin_addr),ip,sizeof(ip));
    char port[32];
    snprintf(port,sizeof(port),"%d",ntohs(addr->sin_port));
    std::string r;
    r=r+"("+ip+":"+port+")";
    return r;
}

static int new_tcp_server(int port){
    int fd=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    D(fd>0,"socket failed(%m)\n");
    setnonblock(fd);
    setreuseaddr(fd);
    sockaddr_in addr;
    setaddress("0.0.0.0",port,&addr);
    bind(fd,(struct sockaddr*)&addr,sizeof(addr));
    listen(fd,64); // backlog = 64
    return fd;
}

static int new_tcp_client(const char* ip,int port){
    int fd=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    setnonblock(fd);
    sockaddr_in addr;
    setaddress(ip,port,&addr);
    connect(fd,(struct sockaddr*)(&addr),sizeof(addr));
    return fd;
}

}; // namespace common

#endif // _COMMON_H_