/**

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

  *

  * Copyright 2013-2014 Oracle and/or its affiliates. All rights reserved.

  *

  * Oracle and Java are registered trademarks of Oracle and/or its affiliates.

  * Other names may be trademarks of their respective owners.

  *

  * The contents of this file are subject to the terms of either the GNU

  * General Public License Version 2 only ("GPL") or the Common

  * Development and Distribution License("CDDL") (collectively, the

  * "License"). You may not use this file except in compliance with the

  * License. You can obtain a copy of the License at

  * http://www.netbeans.org/cddl-gplv2.html

  * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the

  * specific language governing permissions and limitations under the

  * License.  When distributing the software, include this License Header

  * Notice in each file and include the License file at

  * nbbuild/licenses/CDDL-GPL-2-CP.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the GPL Version 2 section of the License file that

  * accompanied this code. If applicable, add the following below the

  * License Header, with the fields enclosed by brackets [] replaced by

  * your own identifying information:

  * "Portions Copyrighted [year] [name of copyright owner]"

  *

  * Contributor(s):

  *

  * The Original Software is NetBeans. The Initial Developer of the Original

  * Software is Oracle. Portions Copyright 2013-2014 Oracle. All Rights Reserved.

  *

  * If you wish your version of this file to be governed by only the CDDL

  * or only the GPL Version 2, indicate your decision by adding

  * "[Contributor] elects to include this software in this distribution

  * under the [CDDL or GPL Version 2] license." If you do not indicate a

  * single choice of license, a recipient has the option to distribute

  * your version of this file under either the CDDL, the GPL Version 2 or

  * to extend the choice of license to its licensees as provided above.

  * However, if you add GPL Version 2 code and therefore, elected the GPL

  * Version 2 license, then the option applies only if the new code is

  * made subject to such option by the copyright holder.

  */

 package org.netbeans.html.xhr4j;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.InputStreamReader;

 import java.io.OutputStream;

 import java.io.PushbackInputStream;

 import java.io.Reader;

 import java.io.UnsupportedEncodingException;

 import java.net.HttpURLConnection;

 import java.net.URL;

 import java.net.URLConnection;

 import java.util.concurrent.Callable;

 import java.util.concurrent.Executor;

 import java.util.concurrent.Executors;

 import java.util.concurrent.ThreadFactory;

 import java.util.logging.Logger;

 import net.java.html.js.JavaScriptBody;

 import org.netbeans.html.json.spi.JSONCall;

 /** This is an implementation package - just

  * include its JAR on classpath and use official {@link Context} API

  * to access the functionality.

  *

  * @author Jaroslav Tulach

  */

 final class LoadJSON implements Runnable {

     private static final Logger LOG = Logger.getLogger(LoadJSON.class.getName());

     private static final Executor REQ = Executors.newCachedThreadPool(new ThreadFactory() {

         @Override

         public Thread newThread(Runnable runnable) {

             Thread thread = Executors.defaultThreadFactory().newThread(runnable);

             thread.setDaemon(true);

             thread.setName("xhr4j daemon");

             return thread;

         }

     });

     private final JSONCall call;

     private final URL base;

     private LoadJSON(JSONCall call) {

         this.call = call;

         this.base = null;

     }

     public static void loadJSON(JSONCall call) {

         assert !"WebSocket".equals(call.getMethod());

         REQ.execute(new LoadJSON((call)));

     }

     @Override

     public void run() {

         final String url;

         Throwable error = null;

         Object json = null;

         if (call.isJSONP()) {

             url = call.composeURL("dummy");

         } else {

             url = call.composeURL(null);

         }

         try {

             final URL u = new URL(base, url.replace(" ", "%20"));

             URLConnection conn = u.openConnection();

             if (call.isDoOutput()) {

                 conn.setDoOutput(true);

             }

             String h = call.getHeaders();

             if (h != null) {

                 int pos = 0;

                 while (pos < h.length()) {

                     int tagEnd = h.indexOf(':', pos);

                     if (tagEnd == -1) {

                         break;

                     }

                     int r = h.indexOf('\r', tagEnd);

                     int n = h.indexOf('\n', tagEnd);

                     if (r == -1) {

                         r = h.length();

                     }

                     if (n == -1) {

                         n = h.length();

                     }

                     String key = h.substring(pos, tagEnd).trim();

                     String val = h.substring(tagEnd + 1, Math.min(r, n)).trim();

                     conn.setRequestProperty(key, val);;

                     pos = Math.max(r, n);

                 }

             }

             if (call.getMethod() != null && conn instanceof HttpURLConnection) {

                 ((HttpURLConnection) conn).setRequestMethod(call.getMethod());

             }

             if (call.isDoOutput()) {

                 final OutputStream os = conn.getOutputStream();

                 call.writeData(os);

                 os.flush();

             }

             final PushbackInputStream is = new PushbackInputStream(

                 conn.getInputStream(), 1

             );

             boolean[] arrayOrString = { false, false };

             detectJSONType(call.isJSONP(), is, arrayOrString);

             String response = readStream(is);

             if (call.isJSONP()) {

                 response = '(' + response;

             }

             json = new Result(response, arrayOrString[0], arrayOrString[1]);

         } catch (IOException ex) {

             error = ex;

         } finally {

             if (error != null) {

                 call.notifyError(error);

             } else {

                 call.notifySuccess(json);

             }

         }

     }

     private static final class Result implements Callable<Object> {

         private final String response;

         private final boolean array;

         private final boolean plain;

         Result(String response, boolean array, boolean plain) {

             this.response = response;

             this.array = array;

             this.plain = plain;

         }

         @Override

         public Object call() throws Exception {

             if (plain) {

                 return response;

             } else {

                 if (array) {

                     Object r = parse(response);

                     Object[] arr = r instanceof Object[] ? (Object[])r : new Object[] { r };

                     for (int i = 0; i < arr.length; i++) {

                         arr[i] = new JSObjToStr(response, arr[i]);

                     }

                     return arr;

                 } else {

                     return new JSObjToStr(response, parse(response));

                 }

             }

         }

     }

     private static final class JSObjToStr {

         final String str;

         final Object obj;

         public JSObjToStr(Object str, Object obj) {

             this.str = str == null ? "" : str.toString();

             this.obj = obj;

         }

         @Override

         public String toString() {

             return str;

         }

     }

     static String readStream(InputStream is) throws IOException, UnsupportedEncodingException {

         Reader r = new InputStreamReader(is, "UTF-8");

         StringBuilder sb = new StringBuilder();

         char[] arr = new char[4096];

         for (;;) {

             int len = r.read(arr);

             if (len == -1) {

                 break;

             }

             sb.append(arr, 0, len);

         }

         return sb.toString();

     }

     private static void detectJSONType(boolean skipAnything, final PushbackInputStream is, boolean[] arrayOrString) throws IOException {

         for (;;) {

             int ch = is.read();

             if (ch == -1) {

                 arrayOrString[1] = true;

                 break;

             }

             if (Character.isWhitespace(ch)) {

                 continue;

             }

             if (ch == '[') {

                 is.unread(ch);

                 arrayOrString[0] = true;

                 break;

             }

             if (ch == '{') {

                 is.unread(ch);

                 break;

             }

             if (!skipAnything) {

                 is.unread(ch);

                 arrayOrString[1] = true;

                 break;

             }

         }

     }

     @JavaScriptBody(args = {"object", "property"}, body =

         "var ret;\n" + 

         "if (property === null) ret = object;\n" + 

         "else if (object === null) ret = null;\n" + 

         "else ret = object[property];\n" + 

         "return ret ? (typeof ko === 'undefined' ? ret : ko.utils.unwrapObservable(ret)) : null;"

     )

     private static Object getProperty(Object object, String property) {

         return null;

     }

     @JavaScriptBody(args = {"s"}, body = "return eval('(' + s + ')');")

     static Object parse(String s) {

         throw new IllegalStateException("No parser context for " + s);

     }

     static void extractJSON(Object js, String[] props, Object[] values) {

         if (js instanceof JSObjToStr) {

             js = ((JSObjToStr)js).obj;

         }

         for (int i = 0; i < props.length; i++) {

             values[i] = getProperty(js, props[i]);

         }

     }

 }