// Provided by Stuart Reges
// Minor changes by Mike Sccott
// 5/9/05
//
// AnagramMain contains a main program that prompts a user for the name of a
// dictionary file and then gives the user the opportunity to find anagrams of
// various phrases.  It constructs an AnagramSolver object to do the actual
// search for anagrams that match the user's phrases.

import java.io.File;
import java.io.FileNotFoundException;
import java.util.HashSet;
import java.util.List;
import java.util.Scanner;
import java.util.Set;

public class AnagramMain {
    
    public static void main(String[] args){
        System.out.println("Welcome to the anagram solver.");
        System.out.println();

        Scanner console = new Scanner(System.in);
        System.out.print("What is the name of the dictionary file? ");
        HashSet<String> words = readWords(console.nextLine());

        // if successfully read in words from file, solve anagrams
        if(words != null) {
            solveAnagrams(words, console);
        } else {
            System.out.println("Did not find dictionary file. Exiting.");
        }
        console.close();
    }

    /*
     * pre: words != null, console connected to System.in.
     * words contains dictionary. Words will be emptied by the time
     * this method completes.
     * main loop of program. Called after words are loaded from file.
     * Asks user for phrase and max number of words until phrase
     * with 0 characters entered.
     */
    private static void solveAnagrams(Set<String> words, Scanner console) {
        if (words == null) {
            throw new NullPointerException("The parameter words cannot be null");
        }
        AnagramSolver solver = new AnagramSolver(words);
        Stopwatch timer = new Stopwatch();
        boolean go = true;
        do {
            System.out.println();
            System.out.print("phrase to scramble (return to quit)? ");
            String phrase = console.nextLine();
            go = phrase.length() != 0;
            if (go) {
                System.out.print("Max words to include (0 for no max)? ");
                int max = console.nextInt();
                console.nextLine();  // to skip newline after int
                timer.start();
                List<List<String>> anagrams = solver.getAnagrams(phrase, max);
                timer.stop();
                System.out.println("Time to find and print anagrams: " + timer);
                showAnagrams(anagrams, max, phrase);
            }
        } while(go); 
    }

    /*
     * Display the resulting anagrams from a given phrase.
     * pre: anagrams != null
     */
    private static void showAnagrams(List<List<String>> anagrams, int max,
            String phrase) {
        if (anagrams == null) {
            throw new NullPointerException("The parameter anagrams (List of List of Strings) "
                            + "cannot be null.");
        }
        System.out.print("Found " + anagrams.size() + " anagram(s) " +
                "for " + phrase);
        if (max != 0) {
            System.out.println(" with a " + "limit of no more than " + max + " words.");
        } else {
            System.out.println(" with no limit on the number of words.");
        }
        for (List<String> anagram : anagrams) {
            System.out.println(anagram);
        }
    }

    /*
     * pre: dictionaryFileName != null
     * Ask for a file name and read words from that file.
     * returns a HashSet of the String from the file.
     */
    public static HashSet<String> readWords(String dictionaryFileName) {
        if (dictionaryFileName == null) {
            throw new NullPointerException("The parameter dictionaryFileName (String) "
                            + "cannot be null.");
        }
        HashSet<String> result;
        try {
            Scanner input = new Scanner(new File(dictionaryFileName));
            // read dictionary into a hash set
            result = new HashSet<>();
            while (input.hasNextLine()) {
                String st = input.nextLine().trim();
                if (st.length() > 0) {
                    result.add(st);
                }
            }
            input.close();
        } catch (FileNotFoundException e) {
            System.out.println("Problems reading from file: " + e);
            e.printStackTrace();
            System.out.println("\nReturing null;");
            result = null;
        }
        return result;
    }
}