package file_manager;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.net.MalformedURLException;
import java.net.URL;

import javax.swing.JButton;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.event.HyperlinkEvent;
import javax.swing.event.HyperlinkListener;

public class WebBrowser extends JFrame implements HyperlinkListener {
	
	private static final long serialVersionUID = 1L;
	//panel pro URL adresu
	private JTextField urlpanel;
	//JEditorPane pro zobrazeni stranky
	private JEditorPane editor;
	//statovy radek pro informace
	private JLabel status;
	//naposled pouzita url adresa
	private String LastUrl = null;
	//tlacitko zpet
	public JButton back = new JButton("Back");
	
	public WebBrowser() {
		//zakladni nastaveni grafickeho rozhrani - JFrame
		setTitle("Web Browser");
		setSize(600, 300);

		//close operation
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		//vytvoreni menu 
		JMenuBar topmenu = new JMenuBar();
		JMenu file = new JMenu("File");
		JMenuItem exit = new JMenuItem("Exit");
		topmenu.add(file);
		file.add(exit);
		this.setJMenuBar(topmenu);
		exit.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent arg0) {
				System.exit(1);
			}
		});

		//horni panel s ovladanim
		JPanel toppanel = new JPanel();
		//textove pole pro URL adresu
		urlpanel = new JTextField("");
		urlpanel.setPreferredSize(new Dimension(20, 20));
		urlpanel.setPreferredSize(new Dimension(getSize().width - 200, 20));
		
		back.setEnabled(false);
		back.addActionListener(new ActionListener(){
			public void actionPerformed( ActionEvent arg0 ){
				LoadHtmlPage(LastUrl);
			}
		});
		
		//tlacitko pro odeslani formulare
		JButton go = new JButton("Go");
		
		//action listener pro odeslani formualre
		go.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent arg0) {
				//prejde na stranku
				LoadHtmlPage(urlpanel.getText());
			}
		});
		
		toppanel.add( back );
		toppanel.add(urlpanel);
		toppanel.add(go);
		add(toppanel);
		
		
		//stavovy radek
		JPanel statusBar = new JPanel();
		//nastaveni defaultniho textu
		status = new JLabel("Insert URL");
		statusBar.add(status);
		statusBar.setBackground(Color.WHITE);

		//vytvoreni JEditorPane
		editor = new JEditorPane();
		//content type pro html
		editor.setContentType("text/html");
		//muzete si nastavit true :-)
		editor.setEditable(false);
		
		//vytvoříme hyperlink listener
		editor.addHyperlinkListener(this);

		//content pane
		getContentPane().setLayout(new BorderLayout());
		getContentPane().add(toppanel, BorderLayout.NORTH);
		getContentPane().add(new JScrollPane(editor), BorderLayout.CENTER);

		this.add(statusBar, BorderLayout.SOUTH);

		setVisible(true);
	}

	//funkce zkontroluje zadanou URL adresu
	//v pripade ze souhlasi, vytvori promennou typu URL a vola funkci pro nacteni
	public void LoadHtmlPage( String ur) {
		//nastaveni statusu
		status.setText("Loading...");
	
		//nastaveni posledni URL adresy
		this.LastUrl = this.urlpanel.getText().trim();
		//aktivace tlacitka zpet
		back.setEnabled(true);
		
		//kontrola, zda existuje URL adresa
		if (ur.trim().length() == 0) {
			status.setText("URL is empty");
			return;
		}
	
		//kontrola, zda url adresa zacina http://
		if (ur.startsWith("http://") == false) {
			ur = "http://" + ur;
		}
	
		try {
			//vytvoreni nove URL
			URL url = new URL(ur);
			GoToPage(url);
		} catch (MalformedURLException e) {
			e.printStackTrace();
		}
	}

	//funkce nacita obsah URL adresy do promenne editor, do ktere ji zobrazi jako HTML
	public void GoToPage(URL url) {
		//zmena kurzoru na Wait
		setCursor(Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR));
		try {
			@SuppressWarnings("unused")
			URL currentUrl = editor.getPage();
			//zobrazeni stranky
			editor.setPage(url);

			URL newUrl = editor.getPage();
			//nastaveni titulku okna
			this.setTitle(newUrl.getHost());
			//nastaveni url adresy v panelu
			urlpanel.setText(newUrl.toString());
		} catch (Exception e) {
			//doplneni statusu
			status.setText("Load Failed");
		} finally {
			//zmena statusu
			status.setText("Compete...");

			//vraceni puvodniho kurzoru
			setCursor(Cursor.getDefaultCursor());
		}
	}

	//funkce volana pomoci Hyperlink Listeneru
	public void hyperlinkUpdate(HyperlinkEvent event) {
		//zjistime EventType
		HyperlinkEvent.EventType eventType = event.getEventType();
		//pokud je Activated (klik levym tlacitkem mysi: )
		if (eventType == HyperlinkEvent.EventType.ACTIVATED) {
			//prejdeme na stranku
			LoadHtmlPage(event.getURL().toString());
		}
	}

	public static void main(String[] args) {
		new WebBrowser();
	}
}