// Hunter Schafer, CSE 143
// This program counts the number of words in a large file.                                               
// It demonstrates the use of a Set collection.                                              

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

public class WordCount {
    public static void main(String[] args) throws FileNotFoundException {
        System.out.println("Reading file...");
        //Scanner input = new Scanner(new File("smallmoby.txt"));
        Scanner input = new Scanner(new File("mobydick.txt"));

        long start = System.currentTimeMillis();

        //int uniqueWords = countUnique(input);
        printWordCounts(input);

        long end = System.currentTimeMillis();
        long elapsed = end - start;

        //System.out.println("The file has " + uniqueWords + " words.");
        System.out.println("Took " + elapsed + " ms.");
    }

    // Returns the number of unique tokens in the input Scanner
    // Also prints out all the tokens.
    public static int countUnique(Scanner input) {
        //List<String> words = new LinkedList<String>();
        Set<String> words = new HashSet<String>();

        while (input.hasNext()) {
            String word = input.next();
            words.add(word);
        }

        // Can't do this :(
        // for (int i = 0; i < words.size(); i++) {
        for (String word : words) { 
            System.out.println(word);
        }

        return words.size();
    }

    // Prints out the number of times each unique token appears in the given Scanner
    public static void printWordCounts(Scanner input) {
        Map<String, Integer> wordCounts = new TreeMap<String, Integer>();

        while (input.hasNext()) {
            String word = input.next(); // "flew" 
            if (!wordCounts.containsKey(word)) {
                wordCounts.put(word, 1);
            } else {
                int count = wordCounts.get(word); // 1
                wordCounts.put(word, count + 1);
            }               
        }

        for (String key : wordCounts.keySet()) {
            System.out.println(key + " " + wordCounts.get(key));
        }


        // Find all the words that appear a given number of times
        Map<Integer, Set<String>> countsToWords = new HashMap<Integer, Set<String>>();
        for (String key : wordCounts.keySet()) {
            int count = wordCounts.get(key);

            /*
               if (!countsToWords.containsKey(count)) {
               Set<String> words = new TreeSet<String>();
               words.add(key);  
               countsToWords.put(count, words);
               } else {
               Set<String> words = countsToWords.get(count);
               words.add(key);
            // countsToWords.put(count, words);
               }
               */

            // general case, set up case
            if (!countsToWords.containsKey(count)) {
                countsToWords.put(count, new TreeSet<String>());
            }

            Set<String> words = countsToWords.get(count);
            words.add(key);
        }
        //System.out.println(countsToWords);
    }
}