/*
 * Copyright 2004-2011 the Seasar Foundation and the Others.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 */
package org.seasar.mayaa.impl.ex.rhino;

import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.atomic.AtomicBoolean;

import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JTextArea;

import org.mozilla.javascript.Undefined;
import org.seasar.mayaa.impl.cycle.script.ScriptUtil;

/**
 * Mayaaの簡易デバッガ。
 * <p>
 * <code>
 * Packages.org.seasar.mayaa.impl.ex.rhino.MayaaDebugger.debug()
 * </code>
 * と実行した位置でJavaScriptの入力ウィンドウが開き、executeボタンまたはCtrl+Enterで実行。
 * 実行結果は{@link java.lang.System#out(java.lang.Object)}で出力される。
 * 内部を変更するスクリプトなどもそのまま実行できる。
 * </p>
 * <p>
 * このウィンドウが開いた状態ではTomcatが終了しないのでウィンドウをちゃんと閉じること。
 * </p>
 */
public class MayaaDebugger {

    private static final String EXIT_COMMAND = "";

    private static final int DEFAULT_WIDTH = 400;
    private static final int DEFAULT_HEIGHT = 300;

    private static boolean isNotLocalhost(final String remoteAddr) {
    	return (remoteAddr.equals("127.0.0.1") || remoteAddr.equals("0:0:0:0:0:0:0:1")) == false;
    }

    private static Object executeScript(final String script) {
    	return ScriptUtil.compile(script, Object.class).execute(null);
    }

    /**
     * デバッグ
     */
    public static void debug() {
        try {
            // REMOTE_ADDR が localhost でなければ何もしない
            Object remoteAddr = executeScript("${ request.underlyingContext.remoteAddr }");
            if (isNotLocalhost(String.valueOf(remoteAddr))) {
                return;
            }
            // page.skipdebugger が true の場合は起動しない
            Object skipResult = executeScript("${ page['skipdebugger'] }");
            if (skipResult != null && skipResult instanceof Boolean && ((Boolean) skipResult).booleanValue()) {
                return;
            }
        } catch (Throwable t) {
            t.printStackTrace();
            return;
        }

        openDebugWindow(DEFAULT_WIDTH, DEFAULT_HEIGHT);
    }

    private static void openDebugWindow(final int width, final int height) {
    	// 実行するスクリプトのキュー
        final BlockingQueue<String> scriptQueue = new ArrayBlockingQueue<String>(1);
        // 実行結果を格納するキュー （null不可なのでUndefinedを使う）
        final BlockingQueue<Object> resultQueue = new ArrayBlockingQueue<Object>(1);

        final AtomicBoolean dontShowAgain = new AtomicBoolean(false);

        String title = String.valueOf(executeScript("${ injectedNode.getSystemID() + ':' + injectedNode.getLineNumber() }"));

        // デバッグウィンドウ作成
        final JFrame frame = new JFrame("debug");
        frame.setTitle(title);
        frame.setLayout(new BorderLayout());
        final JCheckBox pageCloseCheck = new JCheckBox("Don't show again on this page scope");
        frame.getContentPane().add(pageCloseCheck, BorderLayout.NORTH);
        pageCloseCheck.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				dontShowAgain.set(pageCloseCheck.isSelected());
			}
		});

        final JTextArea textArea = new JTextArea();
        textArea.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 16));
        frame.getContentPane().add(textArea, BorderLayout.CENTER);
        final JButton execButton = new JButton("execute (CTRL+ENTER)");
        execButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(final ActionEvent e) {
                try {
                	// mayaaの実装をそのまま使うため${}で囲む。このため{@link #EXIT_COMMAND}を投げることはできない。
                    scriptQueue.put("${" + textArea.getText() + "}");
                    Object result = resultQueue.take();
                    if (result == Undefined.instance) {
                        result = null;
                    }
                    // 結果オブジェクトをSystem.outに出力
                    System.out.println(result);
                } catch (Throwable t) {
                    t.printStackTrace();
                }
            }
        });
        frame.getContentPane().add(execButton, BorderLayout.SOUTH);

        textArea.addKeyListener(new KeyListener() {
            @Override
            public void keyTyped(final KeyEvent e) {
                // do nothing.
            }
            @Override
            public void keyReleased(final KeyEvent e) {
                // do nothing.
            }
            @Override
            public void keyPressed(final KeyEvent e) {
                if (e.isControlDown() && e.getKeyCode() == KeyEvent.VK_ENTER) {
                    execButton.doClick();
                }
            }
        });

        frame.addWindowListener(new WindowAdapter() {
            @Override
            public void windowOpened(final WindowEvent e) {
                // do nothing.
            }
            @Override
            public void windowClosing(final WindowEvent e) {
            	// 閉じるときには空文字列をスクリプトキューに追加
                try {
                	if (dontShowAgain.get()) {
                		scriptQueue.put("${ page['skipdebugger'] = true; }");
                		resultQueue.take();
                	}
					scriptQueue.put(EXIT_COMMAND);
				} catch (InterruptedException e1) {
					e1.printStackTrace();
				}
            }
        });
        frame.setSize(width, height);
        frame.setVisible(true);

        try {
        	// スクリプトキューに空文字列が置かれるまでループ
            String text;
            while ((text = scriptQueue.take()).equals(EXIT_COMMAND) == false) {
                Object result = executeScript(text);
                if (result == null) {
                	// resultQueueはnull不可
                    result = Undefined.instance;
                }
                resultQueue.put(result);
            }
        } catch (InterruptedException e1) {
            e1.printStackTrace();
        } catch (Throwable t) {
            t.printStackTrace();
        } finally {
            if (resultQueue.size() == 0) {
                resultQueue.add(Undefined.instance);
            }
            frame.dispose();
        }
    }
}