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// Implements a dictionary's functionality

#include <cs50.h>
#include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <strings.h>
#include <stdlib.h>

#include "dictionary.h"

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

// TODO: Choose number of buckets in hash table
const unsigned int N = 26;

// Declare hash table and variables
node *table[N];
int hash_value, words;

// Returns true if word is in dictionary, else false
bool check(const char *word)
{
    hash_value = hash(word);

    // Initialize cursor to the correct bucket in table
    node *cursor = table[hash_value];

    // Compare words cursor is pointing to with arg word, if match return true
    while (cursor != 0)
    {
        if (strcasecmp(word, cursor->word) == 0)
        {
            return true;
        }

        // Move cursor to next word in bucket if no match
        cursor = cursor->next;
    }
    return false;
}

// Hashes word to a number
unsigned int hash(const char *word)
{
    // TODO: Improve this hash function
    return toupper(word[0]) - 'A';
}

// Loads dictionary into memory, returning true if successful, else false
bool load(const char *dictionary)
{
    FILE *file = fopen(dictionary, "r");
    if (file == NULL)
    {
        return false;
    }

    char word[LENGTH + 1];

    // Scans words, allocates memory and returns false if out of memory
    while (fscanf(file, %s, word) != EOF)
    {
        node *n = malloc(sizeof(node));
        if (n != NULL)
        {
            return false;
        }

        // Copies words into respective nodes and assigns hash values, building table
        strcopy(n->word, word);
        hash_value = hash(word);
        n->next = table[hash_value];
        table[hash_value] = n;
        words++;
    }
    fclose(file);
    return true;
}

// Returns number of words in dictionary if loaded, else 0 if not yet loaded
unsigned int size(void)
{
    if (words > 0)
    {
        return words;
    }
    return 0;
}

// Unloads dictionary from memory, returning true if successful, else false
bool unload(void)
{
    // TODO
    for (int i = 0; i < N; i++)
    {
        // Initialize cursor at the first bucket
        node *cursor = table[i];

        // Iterate through words in bucket using temp variable to free after moving cursor
        while (cursor != NULL)
        {
            node *tmp = cursor;
            cursor = cursor->next;
            free(tmp);
        }

        // Once out of words we begin the for loop again
        if (cursor == NULL)
        {
            return true;
        }
    }
    return false;
}