/**

 * Back 2 Browser Bytecode Translator

 * Copyright (C) 2012 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.

 *

 * 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://opensource.org/licenses/GPL-2.0.

 */

package org.apidesign.bck2brwsr.htmlpage;

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.bck2brwsr.core.JavaScriptBody;

import org.json.JSONArray;

import org.json.JSONException;

import org.json.JSONObject;

import org.json.JSONTokener;

/**

 *

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

 */

public final class ConvertTypes {

    ConvertTypes() {

    }

    public static String toString(Object object, String property) {

        Object ret = getProperty(object, property);

        return ret == null ? null : ret.toString();

    }

    public static double toDouble(Object object, String property) {

        Object ret = getProperty(object, property);

        return ret instanceof Number ? ((Number)ret).doubleValue() : Double.NaN;

    }

    public static int toInt(Object object, String property) {

        Object ret = getProperty(object, property);

        return ret instanceof Number ? ((Number)ret).intValue() : Integer.MIN_VALUE;

    }

    public static <T> T toModel(Class<T> modelClass, Object object, String property) {

        Object ret = getProperty(object, property);

        if (ret instanceof JSObject) {

            Object real = ((JSObject)ret).getMember("koModel");

            if (real != null) {

                ret = real;

            }

        }

        if (ret == null || modelClass.isInstance(ret)) {

            return modelClass.cast(ret);

        }

        throw new IllegalStateException("Value " + ret + " is not of type " + modelClass);

    }

    public static String toJSON(Object value) {

        if (value == null) {

            return "null";

        }

        if (value instanceof String) {

            return '"' + 

                ((String)value).

                    replace("\"", "\\\"").

                    replace("\n", "\\n").

                    replace("\r", "\\r").

                    replace("\t", "\\t")

                + '"';

        }

        return value.toString();

    }

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

        body = "if (property === null) return object;\n"

        + "var p = object[property]; return p ? p : null;"

    )

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

        if (property == null) {

            return object;

        } else {

            if (object instanceof JSObject) {

                JSObject jo = (JSObject)object;

                return jo.getMember(property);

            }

            return 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"

        );

    }

    public static String createJSONP(Object[] jsonResult, Runnable whenDone) {

        return "json" + Integer.toHexString(whenDone.hashCode());

    }

    @JavaScriptBody(args = { "url", "jsonResult", "whenDone", "jsonp" }, body = "throw 'ignore';")

    public static void loadJSON(

        String url, Object[] jsonResult, Runnable whenDone, String jsonp

    ) {

        LoadJSON.REQ.execute(new LoadJSON(url, jsonResult, whenDone, jsonp));

    }

    private static final class LoadJSON implements Runnable {

        static final Executor REQ = Executors.newCachedThreadPool();

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

        private final String url;

        private final Object[] jsonResult;

        private final Runnable whenDone;

        private final String jsonp;

        private final URL base;

        LoadJSON(String url, Object[] jsonResult, Runnable whenDone, String jsonp) {

            this.url = url;

            this.jsonResult = jsonResult;

            this.whenDone = whenDone;

            this.jsonp = jsonp;

            URL b;

            try {

                b = new URL(findBaseURL());

            } catch (MalformedURLException ex) {

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

                b = null;

            }

            this.base = b;

        }

        @Override

        public void run() {

            if (Platform.isFxApplicationThread()) {

                whenDone.run();

                return;

            }

            try {

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

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

                boolean array = false;

                if (jsonp != null) {

                    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);

                jsonResult[0] = convertToArray(obj);

            } catch (JSONException | IOException ex) {

                jsonResult[0] = 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;

            }

        }

    }

    @JavaScriptBody(args = { "url", "jsonp" }, body = 

        "var scrpt = window.document.createElement('script');\n "

        + "scrpt.setAttribute('src', url);\n "

        + "scrpt.setAttribute('id', jsonp);\n "

        + "scrpt.setAttribute('type', 'text/javascript');\n "

        + "var body = document.getElementsByTagName('body')[0];\n "

        + "body.appendChild(scrpt);\n"

    )

    private static void loadJSONP(String url, String jsonp) {

    }

    @JavaScriptBody(args = { "jsonObject", "props", "values" }, body = "throw 'ignore extractJSON';")

    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);

                }

            }

        }

    }

}