/**
 * TextAnalyzer.java
 * Boston University CAS CS 112 HW5
 * By Ian Denhardt and Leo Reyzin
 */

import java.awt.*;
import java.awt.event.*;
import java.io.IOException;
import java.util.Scanner;
import javax.swing.*;

//Our main class extends JFrame, which is essentially a window.
public class TextAnalyzerGUI extends JFrame{

	private TextAnalyzer ta = null;

	public TextAnalyzerGUI() {

		// A JFrame has one top level container, which we can get at like so:
		Container contentPane = getContentPane();

		// We want to line up our top-level components inside the JFrame vertically.
		contentPane.setLayout(new BoxLayout(contentPane, BoxLayout.Y_AXIS));

		// Create text areas in which to output errors and results.  
		// We need them now in order to create other components,
		// but will add them to the contentPane later
		JTextArea output = new JTextArea();
		JTextArea errorAndProgressMessage = new JTextArea();
			
		// JPanels allow us to group other components into one.
		// This panel contains a button that will open a file dialog when pressed,
		// and places to indicate the first and end word
		JPanel openFilePanel = new JPanel();
		// Lay it out horizontally
		openFilePanel.setLayout(new BoxLayout(openFilePanel, BoxLayout.X_AXIS));

		// create and place the button
		JButton openButton = new JButton("Click to select a file");
		openFilePanel.add(openButton);
		JLabel firstWordText = new JLabel("First word (blank for none):");
		openFilePanel.add(firstWordText);
		// The word PREFIX starts Jane Eyre  text,
		// after Project Gutenberg's initial text
		// It is important that the word PREFACE (all uppercase) doesn't appear in
		// Project Gutenberg's initial text
		JTextField firstWordInput = new JTextField("PREFACE");
		openFilePanel.add(firstWordInput);
		JLabel endWordText = new JLabel("End word (blank for none):");
		openFilePanel.add(endWordText);
		// The word END starts Project Gutenberg's end text
		// following Jane Eyre text
		// It is important that the word END (all uppercase) doesn't appear in
		// Jane Eyre text
		JTextField endWordInput = new JTextField("END");
		openFilePanel.add(endWordInput);
		openButton.addActionListener(new OpenListener(errorAndProgressMessage, firstWordInput, endWordInput));
		
		
		JPanel listWordsPanel = new JPanel();
		listWordsPanel.setLayout(new BoxLayout(listWordsPanel, BoxLayout.X_AXIS));

		JLabel beforeLowText = new JLabel("List all words occuring between ");
		listWordsPanel.add(beforeLowText);
		JTextField lowInput = new JTextField();
		listWordsPanel.add(lowInput);
		JLabel betweenLowAndHighText = new JLabel(" and ");
		listWordsPanel.add(betweenLowAndHighText);
		JTextField highInput = new JTextField();
		listWordsPanel.add(highInput);
		JLabel afterHighText = new JLabel (" times ");
		listWordsPanel.add(afterHighText);
		
 		JButton listWordsButton = new JButton("List");
		// We register an instance of the ListWordsListener, below, with the button.
		// when the button is pressed, the ListWordsListener's actionPerformed method will be called.
		listWordsButton.addActionListener(new ListWordsListener(lowInput, highInput, output));
		listWordsPanel.add(listWordsButton);	

		// Add everything to the main window.
		contentPane.add(openFilePanel);	
		
		errorAndProgressMessage.setEditable(false);
		// add scroll bar to the error window
		JScrollPane scroll1 = new JScrollPane(errorAndProgressMessage);
		scroll1.setPreferredSize(new Dimension(640, 160));
		contentPane.add(scroll1);
		
		contentPane.add(listWordsPanel);
		

		output.setEditable(false);
		// add scroll a bar to the output window
		JScrollPane scroll2 = new JScrollPane(output);
		scroll2.setPreferredSize(new Dimension(640, 480));
		contentPane.add(scroll2);
		


	}
	
	public static void main(String[] args) {
		TextAnalyzerGUI frame = new TextAnalyzerGUI();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setSize(800,600);
		frame.setVisible(true);
	}

	// This class is in charge of opening the file
	private class OpenListener implements ActionListener {
		private JTextArea out;
		private JTextField firstWord, endWord;

		// constructor: keeps track of where the information message (opened/failed) is to be displayed
		public OpenListener(JTextArea out, JTextField firstWord, JTextField endWord) {
			this.out = out;
			this.firstWord = firstWord;
			this.endWord = endWord;
		}

		// is invoked when file is chosen; sends the file for processing or displays a failure message
		public void actionPerformed(ActionEvent e) {
			JFileChooser chooser = new JFileChooser();
			int option = chooser.showOpenDialog(null);

			if(option == JFileChooser.APPROVE_OPTION) {
				try {
					Scanner fileScanner = new Scanner(chooser.getSelectedFile());
					out.setText("Opened file: " + chooser.getSelectedFile().getName()+"\n");
					ta = new TextAnalyzer();
					out.append(ta.readText(fileScanner, firstWord.getText(), endWord.getText()));
				} 
				catch (IOException exc) {
					out.setText("Unable to open file because of the following error: \""+exc.getMessage()+"\"");
					ta = null;
				}
			}
		}
	}

	// This class is in charge of processing requests to list words of a certain frequency 
	private class ListWordsListener implements ActionListener {
		private JTextField opA, opB;
		private JTextArea out;

		public ListWordsListener(JTextField opA, JTextField opB, JTextArea out) {
			this.opA = opA;
			this.opB = opB;
			this.out = out;
		}

		public void actionPerformed(ActionEvent e) {
			if (ta == null) {
				out.setText("Please select a file first!\n");
				return;
			}
			try {
				out.setText(ta.printWords(Integer.decode(opA.getText()), Integer.decode(opB.getText())));
			}
			catch (NumberFormatException exc) {
				out.setText("Please enter two integers above!");
			}
		}
	}
}