#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/time.h>
#include <values.h>
#include <time.h>

#define SERVER_PORT   1400
#define MAX_COMPUTATION 10
#define FALSE         0
#define TRUE          (!FALSE)
#define SUCCESS       0
#define FAILED        -1

struct incomedata {
  double income;     /* income */
  double family;     /* the number of members of family */
};

double calc_tax(struct incomedata data)
{
  double tax;
  double income = data.income;
  double f = data.family;
  double i_f = income / f;

  if (i_f <= 22610.0) {
    tax = 0;
  }
  else if (i_f <= 49400.0) {
    tax = (income * 0.12) - (2713.20 * f);
  }
  else if (i_f <= 87020.0) {
    tax = (income * 0.25) - (9140.40 * f);
  }
  else if (i_f <= 140900.0) {
    tax = (income * 0.35) - (17842.40 * f);
  }
  else if (i_f <= 229260.0) {
    tax = (income * 0.45) - (31932.40 * f);
  }
  else if (i_f <= 282730.0) {
    tax = (income * 0.50) - (43395.40 * f);
  }
  else {
    tax = (income * 0.568) - (62621.04 * f);
  }

  return tax;
}

int main(int argc, char *argv[])
{
  int fd;    /* socket descriptor */
  int newfd;
  struct sockaddr_in srv;
  struct sockaddr_in cli;
  int cli_len = sizeof(cli);
  struct incomedata idata;
  double tax;
  int i;

  /* Create the Socket */
  if ((fd = socket(PF_INET, SOCK_STREAM, 0)) == FAILED) {
    perror("socket");
    exit(FAILED);
  }
  
  /* Prepare for Bind */
  srv.sin_family = AF_INET;
  srv.sin_port = htons(SERVER_PORT);
  srv.sin_addr.s_addr = htonl(INADDR_ANY);
  
  /* Bind */
  if (bind(fd, (struct sockaddr *)&srv, sizeof(srv)) == FAILED) {
    perror("bind");
    exit(FAILED);
  }

  for (i = 0; i < MAX_COMPUTATION; i++) {
    /* Listen */
    if (listen(fd, 5) == FAILED) {
      perror("listen");
      exit(FAILED);
    }
    
    /* Accept */
    if ((newfd = accept(fd, (struct sockaddr*)&cli, &cli_len)) == FAILED) {
      perror("accept");
      exit(FAILED);
    }
    
    /* Read */
    if (read(newfd, &idata, sizeof(struct incomedata)) < sizeof(struct incomedata)) {
      perror("read");
      exit(FAILED);
    }
    
    tax = calc_tax(idata);
    
    /* Write */
    if (write(newfd, &tax, sizeof(tax)) < sizeof(tax)) {
      perror("write");
      exit(FAILED);
    }
    
    if (shutdown(newfd, SHUT_RDWR) == FAILED) {
      perror("shutdown(newfd)");
    }
    if (close(newfd) == FAILED) {
      perror("close(newfd)");
    }

  }

#if 0
  if (shutdown(fd, SHUT_RDWR) == FAILED) {
    perror("shutdown(fd)");
  }
#endif

  if (close(fd) == FAILED) {
    perror("close(fd)");
  }

  return (SUCCESS);
}