/**

 * HTML via Java(tm) Language Bindings

 * Copyright (C) 2013 Jaroslav Tulach <jaroslav.tulach@apidesign.org>

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, version 2 of the License.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details. apidesign.org

 * designates this particular file as subject to the

 * "Classpath" exception as provided by apidesign.org

 * in the License file that accompanied this code.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program. Look for COPYING file in the top folder.

 * If not, see http://wiki.apidesign.org/wiki/GPLwithClassPathException

 */

package org.apidesign.html.kofx;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.PushbackInputStream;

import java.io.Reader;

import java.net.MalformedURLException;

import java.net.URL;

import java.util.Iterator;

import java.util.concurrent.Executor;

import java.util.concurrent.Executors;

import java.util.logging.Level;

import java.util.logging.Logger;

import javafx.application.Platform;

import javafx.scene.web.WebEngine;

import netscape.javascript.JSObject;

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

import org.json.JSONArray;

import org.json.JSONException;

import org.json.JSONObject;

import org.json.JSONTokener;

/** This is an implementation package - just

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

 * to access the functionality.

 *

 * @author Jaroslav Tulach <jtulach@netbeans.org>

 */

final class LoadJSON implements Runnable {

    private static final Logger LOG = FXContext.LOG;

    private static final Executor REQ = Executors.newCachedThreadPool();

    private final JSONCall call;

    private final URL base;

    private Throwable error;

    private Object json;

    private LoadJSON(JSONCall call) {

        this.call = call;

        URL b;

        try {

            b = new URL(findBaseURL());

        } catch (MalformedURLException ex) {

            LOG.log(Level.SEVERE, "Can't find base url for " + call.composeURL("dummy"), ex);

            b = null;

        }

        this.base = b;

    }

    public static void loadJSON(JSONCall call) {

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

    }

    @Override

    public void run() {

        if (Platform.isFxApplicationThread()) {

            if (error != null) {

                call.notifyError(error);

            } else {

                call.notifySuccess(json);

            }

            return;

        }

        final String url;

        if (call.isJSONP()) {

            url = call.composeURL("dummy");

        } else {

            url = call.composeURL(null);

        }

        try {

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

            final PushbackInputStream is = new PushbackInputStream(u.openStream(), 1);

            boolean array = false;

            if (call.isJSONP()) {

                for (;;) {

                    int ch = is.read();

                    if (ch == -1) {

                        break;

                    }

                    if (ch == '[') {

                        is.unread(ch);

                        array = true;

                        break;

                    }

                    if (ch == '{') {

                        is.unread(ch);

                        break;

                    }

                }

            } else {

                int ch = is.read();

                array = ch == '[';

                is.unread(ch);

            }

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

            JSONTokener tok = new JSONTokener(r);

            Object obj = array ? new JSONArray(tok) : new JSONObject(tok);

            json = convertToArray(obj);

        } catch (JSONException | IOException ex) {

            error = ex;

            LOG.log(Level.WARNING, "Cannot connect to " + url, ex);

        } finally {

            Platform.runLater(this);

        }

    }

    private static Object convertToArray(Object o) throws JSONException {

        if (o instanceof JSONArray) {

            JSONArray ja = (JSONArray)o;

            Object[] arr = new Object[ja.length()];

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

                arr[i] = convertToArray(ja.get(i));

            }

            return arr;

        } else if (o instanceof JSONObject) {

            JSONObject obj = (JSONObject)o;

            Iterator it = obj.keys();

            while (it.hasNext()) {

                String key = (String)it.next();

                obj.put(key, convertToArray(obj.get(key)));

            }

            return obj;

        } else {

            return o;

        }

    }

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

        if (jsonObject instanceof JSONObject) {

            JSONObject obj = (JSONObject)jsonObject;

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

                try {

                    values[i] = obj.has(props[i]) ? obj.get(props[i]) : null;

                } catch (JSONException ex) {

                    LoadJSON.LOG.log(Level.SEVERE, "Can't read " + props[i] + " from " + jsonObject, ex);

                }

            }

        }

        if (jsonObject instanceof JSObject) {

            JSObject obj = (JSObject)jsonObject;

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

                Object val = obj.getMember(props[i]);

                values[i] = isDefined(val) ? val : null;

            }

        }

    }

    private static String findBaseURL() {

        WebEngine eng = (WebEngine) System.getProperties().get("webEngine");

        return (String) eng.executeScript(

            "var h;"

            + "if (!!window && !!window.location && !!window.location.href)\n"

            + "  h = window.location.href;\n"

            + "else "

            + "  h = null;"

            + "h\n");

    }

    private static boolean isDefined(Object val) {

        return !"undefined".equals(val);

    }

}