#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct Golfer {
   char fName[80];
   char lName[80];
   int handicap;
} Golfer;

typedef struct ListNode {
   Golfer data;
   struct ListNode *next;
} ListNode;


void printRoster(ListNode *golfers);

void printBackwards(ListNode *golfers);

ListNode * findBestGolfer(ListNode *golfers);

//return the head of the list
ListNode * deleteGolfer(ListNode *target, ListNode *head, ListNode *tail);

void insertInOrder(ListNode **start, ListNode **tail, ListNode *golfer);

int main (int argc, char *argv[]) {

   Golfer g;
   strcpy(g.fName, "Roger");
   strcpy(g.lName, "Priebe");
   g.handicap = 18;

   printf("not in data%s, %s - %d\n", g.lName, g.fName, g.handicap);

   ListNode *head = NULL;
   ListNode *tail = NULL;

   FILE *fptr;
   fptr = fopen("golfers.dat", "r");

   if (fptr == NULL) {
      printf("not open!!\n");
      exit(-1);
   }
   else {
      char fName[80];
      char lName[80];
      int handicap;

      while (fscanf(fptr, "%s %s %d", fName, lName, &handicap) != EOF) {
         //create new node and set up to be insterted later
         ListNode *temp = (ListNode *) malloc(sizeof(ListNode));
         strcpy(temp->data.fName, fName);
         strcpy(temp->data.lName, lName);
         temp->data.handicap = handicap;
         temp->next = NULL;

         insertInOrder(&head, &tail, temp);

         //insert at head
         //temp->next = head;
         //head = temp;
/*         
         //insert at end  O(1) because of tail pointer

         if (head == NULL) {
            head = temp;
            tail = temp;
         }
         else {
           tail->next = temp;
           tail = temp;
         }     
*/   
      }

   }

   printRoster(head);

   printf("\n\n");
   printBackwards(head);

   ListNode *best = findBestGolfer(head);
   printf("The best golfer is %s.\n", best->data.fName);
printf("delete best\n\n");
   head = deleteGolfer(best, head, tail);

   printRoster(head);
printf("delete first\n\n");
   head = deleteGolfer(head, head, tail);

   printRoster(head);
printf("delete last\n\n");
   head = deleteGolfer(tail, head, tail);

   printRoster(head);
   return 0;
}

void printRoster(ListNode *golfers) {
   for (ListNode *p = golfers; p != NULL; p = p->next) {
      printf("%s, %s - %d\n", p->data.lName,p->data.fName, p->data.handicap);
   }
}


   
ListNode * findBestGolfer(ListNode *golfers) {
   if (golfers == NULL) {
      return NULL;
   }
   else {
      ListNode *best = golfers;
      
      ListNode *p = golfers->next;
      while (p != NULL) {
         if (p->data.handicap < best->data.handicap) {
            best = p;
         }

         p = p->next;
      }
       
      return best;
   }
} 
   
   
//return the head of the list
ListNode * deleteGolfer(ListNode *target, ListNode *head, ListNode *tail) {
   ListNode *p = head;
  
   if (head == NULL) {  //empty list
      return NULL;
   }
   else if (head == target) {  //remove first node
      if (head == tail) {  //only one element
         head = NULL;
         tail = NULL;
      }
      else {
         head = p->next;
      }
   }
   else {
      ListNode *prev = NULL;
      while (p != target) {
         prev = p;
         p = p->next;
      }

   printf("prev %d, p %d\n", prev->data.handicap, p->data.handicap);
      if (tail == target) {
         tail = prev;
printf("delete at tail\n");
      }
      

      prev->next = p->next;

   }
      
   free(target);  //or free(p);

   return head;
}

void insertInOrder(ListNode **start, ListNode **tail, ListNode *golfer) {
   ListNode *p = *start;
   ListNode *prev = NULL;

   if (p == NULL) {   //list is empty
      *start = golfer;
      *tail = golfer;
   }
   else {
      while ((p != NULL) && (p->data.handicap < golfer->data.handicap)) {
         prev = p;
         p = p->next;
      }
   
      if (prev == NULL) {  //inserting at head of list
         golfer->next = p;
         *start = golfer;
      }
      else {
         golfer->next = p;
         prev->next = golfer;

         if (*tail == prev) {
            *tail = golfer;
         }
      }   
   }
}

  
void printBackwards(ListNode *golfers) {
   if (golfers != NULL) {
      printBackwards(golfers->next);
      printf("BACK %s %s - %d\n", golfers->data.fName, golfers->data.lName, golfers->data.handicap);
   }
}