package com.ensemble.wordcount;

import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/**
 * This program may be used to count the number of occurences of words in a given file.
 * Words are not counted if they are contained within a larger word (eg "is" and "this")
 * 
 * @author Joe Robinson
 *
 */
public class WordCount {
	
	public static void main(String args[]) {

		//Need to use a concurrent hashmap as we will be modifying it as we loop through
		Map<String,Integer> wordCounts = new ConcurrentHashMap<String,Integer>();
		List<String> words = new ArrayList<String>();
		WordUtil wordUtil = new WordUtil();
		String filename = "";
		
		while (filename.equals("")) {	
	
			//If an argument has been entered, use it as the filename, if not prompt for one
			if (args.length > 0 && args[0] != null) {
				filename = args[0];
			} else {
				filename = readFilename();
			}
			
			try {
				words = wordUtil.readWordsFromFile(filename);
	
			} catch (IOException e) {
				System.out.println("Could not open file. Please try another.");
				filename = "";
				words = new ArrayList<String>();
			}
			
			//Check that the file actually contains some words, if not then prompt for another
			if (words.size() == 0) {
				System.out.println("File does not contain any words. Please try another file.");
				filename = "";
				words = new ArrayList<String>();
			}
			
		}
		wordCounts = wordUtil.countWords(words);

		List<String> sortedWords = wordUtil.sortWords(wordCounts);
		
		System.out.println();
		
		for (String word : sortedWords) {
			
			//Capitalise the first letter of the word for output
			char firstChar = Character.toUpperCase(word.charAt(0));
			String outputWord = firstChar + word.substring(1);
			
			System.out.println(outputWord + ": " + wordCounts.get(word));
		}
	}
	
	/**
	 * Prompt the user for a filename to read until one is entered, and confirm that it exists
	 * @return The filename, which is confirmed to exist
	 */
	private static String readFilename() {
		
		String filename = "";
		boolean fileExists = false;
		while (filename == null || filename.equals("") || !fileExists) {
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
			try {
				System.out.println("Please enter a file name to read, or type \"q\" to quit");
				filename = br.readLine();
			} catch (IOException e) {
				System.out.println("Could not read input");
				System.exit(1);
			}
			
			if (filename.equals("q")) {
				System.exit(0);
			}
			
			File file = new File(filename);
			
			if (file.exists()) {
				fileExists = true;
			} else {
				System.out.println("File does not exist. Try again");
			}
		}
		return filename;
	}
}