#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "share_string.h"

typedef char * name_t;
typedef struct FriendList * friend_lst_t;
typedef struct PeopleList * people_lst_t;
typedef struct Person     * person_t;

struct FriendList {
  person_t     friend;
  friend_lst_t tail;
};

struct Person {
  name_t name;
  friend_lst_t friends;
};

struct PeopleList {
  struct Person p;
  people_lst_t tail;
};

person_t add_person(people_lst_t * plp, name_t name) {
  people_lst_t pl = *plp;
  for(; pl != NULL; pl = pl->tail)
    if(pl->p.name == name)
      return &pl->p;
  people_lst_t new_person = (people_lst_t)malloc(sizeof(struct PeopleList));
  new_person->p.name    = name;
  new_person->p.friends = NULL;
  new_person->tail      = *plp;
  *plp = new_person;
  return &new_person->p;
}

void add_friend(people_lst_t all_people, person_t person, name_t name) {
  friend_lst_t friends;
  for(friends = person->friends; friends != NULL; friends = friends->tail)
    if(friends->friend->name == name)
      return;
  friend_lst_t new_friend = (friend_lst_t)malloc(sizeof(struct FriendList));
  new_friend->friend = add_person(&all_people, name);
  new_friend->tail   = person->friends;
  person->friends    = new_friend;
}

// assumes p points into a buffer returned by getline
char * get_name_end(char * p) {
  // first name
  while(*p != ' ') 
    ++p;
  ++p; // skip the one space
  // last name
  while(*p != '\n' && *p != ' ')
    ++p;
  return p;
}

char * get_name_begin(char * p) {
  while(*p == ' ')
    ++p;
  if(*p == '\n' || *p == '\0')
    return NULL;
  return p;
}

people_lst_t get_friends(FILE *f) {
  words_t      w            = new_word_cache();
  people_lst_t pl           = NULL;
  char *       fileline     = NULL;
  size_t       fileline_sz;
  while(getline(&fileline,&fileline_sz,f) != -1) {
    char *   name_begin = get_name_begin(fileline);
    if(!name_begin)
      continue;
    char *   name_end   = get_name_end(name_begin);
    name_t   name       = find_word(w,name_begin,name_end - name_begin);
    person_t p          = add_person(&pl,name);
    while(1) {
      name_begin = get_name_begin(name_end);
      if(!name_begin)
	break;
      name_end = get_name_end(name_begin);
      name     = find_word(w,name_begin,name_end - name_begin);
      add_friend(pl,p,name);
      add_friend(pl,add_person(&pl,name),p->name);
    }
  }
  free(w);
  if(fileline != NULL)
    free(fileline);
  return pl;
}

void print_friends(people_lst_t pl) {
  printf("\n");
  for(; pl != NULL; pl = pl->tail) {
    printf("%s:", pl->p.name);
    friend_lst_t friends;
    for(friends = pl->p.friends; friends != NULL; friends = friends->tail)
      printf(" %s", friends->friend->name);
    printf("\n");
  }
}

int main(int argc, char** argv) {
  if(argc != 2) {
    fprintf(stderr,"usage: %s filename\n",argv[0]);
    return 1;
  }
  FILE * f = fopen(argv[1],"r");
  if(!f) {
    fprintf(stderr,"unable to open %s\n",argv[1]);
    return 1;
  }
  print_friends(get_friends(f));
  return 0;
}