#include <stdio.h>
#include <stdlib.h>
#include "studlist.h"

int main()
{
  Record r;
  int i;
 
  /* initialize */
  head = make_1node( r, NULL );

  listprint();

  
  /* insert list member */
  /* CTL+D to escape this loop */
  while (1) {
    printf("Insert new student data: (ID Surname Givenname Age) -> ");
    
    if (scanf("%d %s %s %d", &r.id, r.surname, r.givenname, &r.age) != 4) {
      printf("\n");
      break;
    }
    if (insert(r) == NULL) {
      printf("ID %d is already on the list!\n", r.id);
    }
    listprint();
  }
  printf("\n");
  return 0;
}

/* First find item r                         */
/* if it doesn't exist, insert it after head */
/* return new node(inserted), NULL(already exist) */
NodePointer insert(Record r)
{
  NodePointer newnode;

  if (finditem(r.id) == NULL) {
    newnode = make_1node(r, head->next);   /* 新しいノードを作成 */
    head->next = newnode;          /* headの下に新しいノードをつなぐ */
    return newnode;
  }
  else return NULL;
}

/* print all items in the list from head to tail */
void listprint(void)
{
  NodePointer n;

  printf("Head - \n");
  for(n = head->next; n != NULL; n = n->next){
    printf("  %7d %-12s %-12s %d\n", n->data.id, n->data.surname, n->data.givenname, n->data.age);
  }
  printf("\n");
}

/* 引数にidの値を与えて検索する関数 */
NodePointer finditem(int sid)
{
  NodePointer n;

  for (n = head; n->next != NULL; n = n->next) { /* headの下から順にポインタnextをたどる */
    if (n->next->data.id == sid) return n;   /* sidと同じ値が見つかったら一つ手前のノードを指すポインタを返す */
  }
  return NULL;
}

NodePointer make_1node(Record r, NodePointer p)
{
  NodePointer n;

  if ((n = (NodePointer) malloc(sizeof(struct node)) ) == NULL) {
    printf("Error in memory allocation\n");
    exit(8);
  }

  n->data = r;
  n->next = p;
  return n;
}