/**
 * Dictionary.java
 *
 * This class provides a searchable word list, plus a primitive
 * spelling-correction facility.  Its constructor takes the name
 * of an alphabetized file of words, one word per line, as a
 * parameter.
 *
 * This class is part of an exercise on profiling, and thus has
 * been left intentionally in a non-optimal state.
 */

import java.util.*;
import java.io.*;

public class Dictionary
{
    private ArrayList  mWords;

    public Dictionary( String fileName )
    {
        mWords = new ArrayList();

        try
        {
            Scanner in = new Scanner( new File( fileName ) );
            while( in.hasNext() )
                mWords.add( in.next() );
        }
        catch( IOException e )
        {
            System.err.println( e.getMessage() );
        }
    }

    /**
     * Returns true if the specified string is in the dictionary's
     * word list, and false otherwise.  Case-insensitive.
     */
    public boolean isWord( String s )
    {
        for( int k=0; k < mWords.size()  &&  s.toLowerCase().compareTo( mWords.get( k ) ) <= 0; k++ )
        {
            if( s.toLowerCase().equals( mWords.get( k ) ) )
                return true;
        }

        return false;
    }

    /**
     * Returns the word in the dictionary word list that is "closest"
     * to the specified string.  Closeness is determined by the
     * stringDistance method.
     */
    public String getClosestMatch( String s )
    {
        if( mWords.size() == 0 )
            return "";

        String t = s.toLowerCase();

        int indexOfClosestMatch = 0;
        int closestDistance = stringDistance( t, (String)mWords.get( 0 ) );
        for( int k=1; k < mWords.size(); k++ )
        {
            int distance = stringDistance( t, (String)mWords.get( k ) );
            if( distance < closestDistance )
            {
                closestDistance = distance;
                indexOfClosestMatch = k;
            }
        }

        return (String)mWords.get( indexOfClosestMatch );
    }

    /**
     * Returns the "distance" between the specified strings.
     * Though the real spelling-correction action is right
     * here, in the present context, it doesn't really matter
     * how we define distance, so a simple-minded approach is
     * used here.
     */
    private static int stringDistance( String a, String b )
    {
        int distance = 0;
        int k;
        for( k=0; k < a.length(); k++ )
        {
            if( k >= b.length()  ||  a.charAt( k ) != b.charAt( k ) )
                distance++;
        }

        if( k < b.length() )
            distance += (b.length() - k);

        return distance;
    }
}