// Implements a dictionary's functionality

#include <stdbool.h>
#include <strings.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include "dictionary.h"

// Represents a node in a hash table
typedef struct node
{
    char word[LENGTH + 1];
    struct node *next;
}
node;

// Number of buckets in hash table
const unsigned int N = 1000;

// Hash table
node *table[N];

// Returns true if word is in dictionary else false
bool check(const char *word)
{
    node* temp = NULL;
    int h = hash(word);
    temp = table[h];

    do
    {
        int result = strcasecmp(word, temp->word);

        if (result == 0)
        {
            return true;
            break;
        }
        else
        {
            temp = temp->next;
        }
    }
    while (temp->next != NULL);

    return false;
}

/* Adapted by Neel Mehta from
 http://stackoverflow.com/questions/2571683/djb2-hash-function.
 */

// Hashes word to a number
unsigned int hash(const char *word)
 {
     unsigned long hash = 5381;

     for (const char* ptr = word; *ptr != '\0'; ptr++)
     {
         hash = ((hash << 5) + hash) + tolower(*ptr);
     }

     return hash % N;

 }

// Loads dictionary into memory, returning true if successful else false
int count;
bool load(const char *dictionary)
{
    FILE *dict = fopen(dictionary, "r");
    if (dict == NULL)
    {
        printf("Could not open dictionary.\n");
        return false;
    }

    char temp[46];
    count = 0;


    while (fscanf(dict, "%s", temp)!= EOF)
    {
        node* n = malloc(sizeof(node));
        if (n == NULL)
        {
            free(n);
            return false;
        }
        else
        {
            int h = hash(temp);
            strcpy(n->word, temp);
            n->next = table[h];
            table[h] = n;
            count++;
        }
    }
    fclose(dict);
    return true;
}

// Returns number of words in dictionary if loaded else 0 if not yet loaded
unsigned int size(void)
{
    if (!count || count == 0)
    {
        return 0;
    }
    else
    {
        return count;
    }
}

// Unloads dictionary from memory, returning true if successful else false
bool unload(void)
{
    node* temp = NULL;
    for (int i = 0; i <= N; i++)
    {
        temp = table[i];
        while (temp->next != NULL)
        {
            table[i] = temp->next;
            free(temp);
            temp = table[i];
        }
    }
    return true;
}