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

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 * 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

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

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

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

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

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package org.netbeans.html.json.impl;

import java.io.IOException;

import java.io.InputStream;

import java.util.HashMap;

import java.util.Map;

import net.java.html.BrwsrCtx;

import org.apidesign.html.context.spi.Contexts;

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

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

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

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

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

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

/**

 *

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

 */

public final class JSON {

    private JSON() {

    }

    static Technology<?> findTechnology(BrwsrCtx c) {

        Technology<?> t = Contexts.find(c, Technology.class);

        return t == null ? EmptyTech.EMPTY : t;

    }

    static Transfer findTransfer(BrwsrCtx c) {

        Transfer t = Contexts.find(c, Transfer.class);

        return t == null ? EmptyTech.EMPTY : t;

    }

    static WSTransfer<?> findWSTransfer(BrwsrCtx c) {

        WSTransfer<?> t = Contexts.find(c, WSTransfer.class);

        return t == null ? EmptyTech.EMPTY : t;

    }

    public static void runInBrowser(BrwsrCtx c, Runnable runnable) {

        findTechnology(c).runSafe(runnable);

    }

    public static void extract(BrwsrCtx c, Object value, String[] props, Object[] values) {

        Transfer t = findTransfer(c);

        t.extract(value, props, values);

    }

    private static Object getProperty(BrwsrCtx c, Object obj, String prop) {

        if (prop == null) return obj;

        String[] arr = { prop };

        Object[] val = { null };

        extract(c, obj, arr, val);

        return val[0];

    }

    public static Object toJSON(Object value) {

        if (value == null) {

            return "null";

        }

        if (value instanceof Enum) {

            value = value.toString();

        }

        if (value instanceof String) {

            String s = (String)value;

            int len = s.length();

            StringBuilder sb = new StringBuilder(len + 10);

            sb.append('"');

            for (int i = 0; i < len; i++) {

                char ch = s.charAt(i);

                switch (ch) {

                    case '\"': sb.append("\\\""); break;

                    case '\n': sb.append("\\n"); break;

                    case '\r': sb.append("\\r"); break;

                    case '\t': sb.append("\\t"); break;

                    case '\\': sb.append("\\\\"); break;

                    default: sb.append(ch);

                }

            }

            sb.append('"');

            return sb.toString();

        }

        return value.toString();

    }

    public static String toString(BrwsrCtx c, Object obj, String prop) {

        obj = getProperty(c, obj, prop);

        return obj instanceof String ? (String)obj : null;

    }

    public static Number toNumber(BrwsrCtx c, Object obj, String prop) {

        obj = getProperty(c, obj, prop);

        if (!(obj instanceof Number)) {

            obj = Double.NaN;

        }

        return (Number)obj;

    }

    public static <M> M toModel(BrwsrCtx c, Class<M> aClass, Object data, Object object) {

        Technology<?> t = findTechnology(c);

        Object o = t.toModel(aClass, data);

        return aClass.cast(o);

    }

    public static boolean isSame(int a, int b) {

        return a == b;

    }

    public static boolean isSame(double a, double b) {

        return a == b;

    }

    public static boolean isSame(Object a, Object b) {

        if (a == b) {

            return true;

        }

        if (a == null || b == null) {

            return false;

        }

        return a.equals(b);

    }

    public static int hashPlus(Object o, int h) {

        return o == null ? h : h ^ o.hashCode();

    }

    public static <T> T extractValue(Class<T> type, Object val) {

        if (Number.class.isAssignableFrom(type)) {

            val = numberValue(val);

        }

        if (Boolean.class == type) {

            val = boolValue(val);

        }

        if (String.class == type) {

            val = stringValue(val);

        }

        if (Character.class == type) {

            val = charValue(val);

        }

        if (Integer.class == type) {

            val = val instanceof Number ? ((Number)val).intValue() : 0;

        }

        if (Long.class == type) {

            val = val instanceof Number  ? ((Number)val).longValue() : 0;

        }

        if (Short.class == type) {

            val = val instanceof Number ? ((Number)val).shortValue() : 0;

        }

        if (Byte.class == type) {

            val = val instanceof Number ? ((Number)val).byteValue() : 0;

        }        

        if (Double.class == type) {

            val = val instanceof Number ? ((Number)val).doubleValue() : Double.NaN;

        }

        if (Float.class == type) {

            val = val instanceof Number ? ((Number)val).floatValue() : Float.NaN;

        }

        return type.cast(val);

    }

    protected static boolean isNumeric(Object val) {

        return ((val instanceof Integer) || (val instanceof Long) || (val instanceof Short) || (val instanceof Byte));

    }

    public static String stringValue(Object val) {

        if (val instanceof Boolean) {

            return ((Boolean)val ? "true" : "false");

        }

        if (isNumeric(val)) {

            return Long.toString(((Number)val).longValue());

        }

        if (val instanceof Float) {

            return Float.toString((Float)val);

        }

        if (val instanceof Double) {

            return Double.toString((Double)val);

        }

        return (String)val;

    }

    public static Number numberValue(Object val) {

        if (val instanceof String) {

            try {

                return Double.valueOf((String)val);

            } catch (NumberFormatException ex) {

                return Double.NaN;

            }

        }

        if (val instanceof Boolean) {

            return (Boolean)val ? 1 : 0;

        }

        return (Number)val;

    }

    public static Character charValue(Object val) {

        if (val instanceof Number) {

            return Character.toChars(numberValue(val).intValue())[0];

        }

        if (val instanceof Boolean) {

            return (Boolean)val ? (char)1 : (char)0;

        }

        if (val instanceof String) {

            String s = (String)val;

            return s.isEmpty() ? (char)0 : s.charAt(0);

        }

        return (Character)val;

    }

    public static Boolean boolValue(Object val) {

        if (val instanceof String) {

            return Boolean.parseBoolean((String)val);

        }

        if (val instanceof Number) {

            return numberValue(val).doubleValue() != 0.0;

        }

        return Boolean.TRUE.equals(val);

    }

    public static void loadJSON(

        BrwsrCtx c, RcvrJSON callback,

        String urlBefore, String urlAfter, String method,

        Object data

    ) {

        JSONCall call = PropertyBindingAccessor.createCall(c, callback, urlBefore, urlAfter, method, data);

        Transfer t = findTransfer(c);

        t.loadJSON(call);

    }

    public static WS openWS(

        BrwsrCtx c, RcvrJSON r, String url, Object data

    ) {

        WS ws = WSImpl.create(findWSTransfer(c), r);

        ws.send(c, url, data);

        return ws;

    }

    public static abstract class WS {

        private WS() {

        }

        public abstract void send(BrwsrCtx ctx, String url, Object model);

    }

    private static final class WSImpl<Socket> extends WS {

        private final WSTransfer<Socket> trans;

        private final RcvrJSON rcvr;

        private Socket socket;

        private String prevURL;

        private WSImpl(WSTransfer<Socket> trans, RcvrJSON rcvr) {

            this.trans = trans;

            this.rcvr = rcvr;

        }

        static <Socket> WS create(WSTransfer<Socket> t, RcvrJSON r) {

            return new WSImpl<Socket>(t, r);

        }

        @Override

        public void send(BrwsrCtx ctx, String url, Object data) {

            Socket s = socket;

            if (s == null) {

                if (data != null) {

                    throw new IllegalStateException("WebSocket is not opened yet. Call with null data, was: " + data);

                }

                JSONCall call = PropertyBindingAccessor.createCall(ctx, rcvr, url, null, "WebSocket", null);

                socket = trans.open(url, call);

                prevURL = url;

                return;

            }

            if (data == null) {

                trans.close(s);

                socket = null;

                return;

            }

            if (!prevURL.equals(url)) {

                throw new IllegalStateException(

                    "Can't call to different URL " + url + " was: " + prevURL + "!"

                    + " Close the socket by calling it will null data first!"

                );

            }

            JSONCall call = PropertyBindingAccessor.createCall(ctx, rcvr, prevURL, null, "WebSocket", data);

            trans.send(s, call);

        }

    }

    private static final Map<Class,FromJSON<?>> froms;

    static {

        Map<Class,FromJSON<?>> m = new HashMap<Class,FromJSON<?>>();

        froms = m;

    }

    public static void register(FromJSON<?> from) {

        froms.put(from.factoryFor(), from);

    }

    public static boolean isModel(Class<?> clazz) {

        return findFrom(clazz) != null; 

    }

    private static FromJSON<?> findFrom(Class<?> clazz) {

        for (int i = 0; i < 2; i++) {

            FromJSON<?> from = froms.get(clazz);

            if (from == null) {

                initClass(clazz);

            } else {

                return from;

            }

        }

        return null;

    }

    public static <Model> Model bindTo(Model model, BrwsrCtx c) {

        FromJSON<?> from = findFrom(model.getClass());

        if (from == null) {

            throw new IllegalArgumentException();

        }

        return (Model) from.cloneTo(model, c);

    }

    public static <T> T readStream(BrwsrCtx c, Class<T> modelClazz, InputStream data) 

    throws IOException {

        Transfer tr = findTransfer(c);

        return read(c, modelClazz, tr.toJSON((InputStream)data));

    }

    public static <T> T read(BrwsrCtx c, Class<T> modelClazz, Object data) {

        if (data == null) {

            return null;

        }

        if (modelClazz == String.class) {

            return modelClazz.cast(data.toString());

        }

        for (int i = 0; i < 2; i++) {

            FromJSON<?> from = froms.get(modelClazz);

            if (from == null) {

                initClass(modelClazz);

            } else {

                return modelClazz.cast(from.read(c, data));

            }

        }

        throw new NullPointerException();

    }

    static void initClass(Class<?> modelClazz) {

        try {

            // try to resolve the class

            ClassLoader l;

            try {

                l = modelClazz.getClassLoader();

            } catch (SecurityException ex) {

                l = null;

            }

            if (l != null) {

                Class.forName(modelClazz.getName(), true, l);

            }

            modelClazz.newInstance();

        } catch (Exception ex) {

            // ignore and try again

        }

    }

    private static final class EmptyTech

    implements Technology<Object>, Transfer, WSTransfer<Void> {

        private static final EmptyTech EMPTY = new EmptyTech();

        @Override

        public Object wrapModel(Object model) {

            return model;

        }

        @Override

        public void valueHasMutated(Object data, String propertyName) {

        }

        @Override

        public void bind(PropertyBinding b, Object model, Object data) {

        }

        @Override

        public void expose(FunctionBinding fb, Object model, Object d) {

        }

        @Override

        public void applyBindings(Object data) {

        }

        @Override

        public Object wrapArray(Object[] arr) {

            return arr;

        }

        @Override

        public void extract(Object obj, String[] props, Object[] values) {

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

                values[i] = null;

            }

        }

        @Override

        public void loadJSON(JSONCall call) {

            call.notifyError(new UnsupportedOperationException());

        }

        @Override

        public <M> M toModel(Class<M> modelClass, Object data) {

            return modelClass.cast(data);

        }

        @Override

        public Object toJSON(InputStream is) throws IOException {

            throw new IOException("Not supported");

        }

        @Override

        public synchronized void runSafe(Runnable r) {

            r.run();

        }

        @Override

        public Void open(String url, JSONCall onReply) {

            onReply.notifyError(new UnsupportedOperationException("WebSockets not supported!"));

            return null;

        }

        @Override

        public void send(Void socket, JSONCall data) {

        }

        @Override

        public void close(Void socket) {

        }

    }

}