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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

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

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

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

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

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package org.netbeans.html.ko4j;

import java.lang.ref.ReferenceQueue;

import java.lang.ref.WeakReference;

import java.util.Collections;

import java.util.HashSet;

import java.util.Set;

import net.java.html.js.JavaScriptBody;

import net.java.html.js.JavaScriptResource;

import net.java.html.json.Model;

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

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

/** This is an implementation package - just

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

 * to access the functionality.

 * <p>

 * Provides binding between {@link Model models} and knockout.js running

 * inside a JavaFX WebView. 

 *

 * @author Jaroslav Tulach

 */

@JavaScriptResource("knockout-3.4.0.js")

final class Knockout extends WeakReference<Object> {

    private static final ReferenceQueue<Object> QUEUE = new ReferenceQueue();

    private static final Set<Knockout> active = Collections.synchronizedSet(new HashSet<Knockout>());

    @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 ? ko.utils.unwrapObservable(ret) : null;"

    )

    static Object getProperty(Object object, String property) {

        return null;

    }

    private PropertyBinding[] props;

    private FunctionBinding[] funcs;

    private Object js;

    private Object strong;

    public Knockout(Object model, Object js, PropertyBinding[] props, FunctionBinding[] funcs) {

        super(model, QUEUE);

        this.js = js;

        this.props = new PropertyBinding[props.length];

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

            this.props[i] = props[i].weak();

        }

        this.funcs = new FunctionBinding[funcs.length];

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

            this.funcs[i] = funcs[i].weak();

        }

        active.add(this);

    }

    static void cleanUp() {

        for (;;) {

            Knockout ko = (Knockout)QUEUE.poll();

            if (ko == null) {

                return;

            }

            active.remove(ko);

            clean(ko.js);

            ko.js = null;

            ko.props = null;

            ko.funcs = null;

        }

    }

    final void hold() {

        strong = get();

    }

    final Object getValue(int index) {

        return props[index].getValue();

    }

    final void setValue(int index, Object v) {

        if (v instanceof Knockout) {

            v = ((Knockout)v).get();

        }

        props[index].setValue(v);

    }

    final void call(int index, Object data, Object ev) {

        funcs[index].call(data, ev);

    }

    @JavaScriptBody(args = { "model", "prop", "oldValue", "newValue" }, 

        wait4js = false,

        body =

          "if (model) {\n"

        + "  var koProp = model[prop];\n"

        + "  if (koProp && koProp['valueHasMutated']) {\n"

        + "    if ((oldValue !== null || newValue !== null)) {\n"

        + "      koProp['valueHasMutated'](newValue);\n"

        + "    } else if (koProp['valueHasMutated']) {\n"

        + "      koProp['valueHasMutated']();\n"

        + "    }\n"

        + "  }\n"

        + "}\n"

    )

    public native static void valueHasMutated(

        Object model, String prop, Object oldValue, Object newValue

    );

    @JavaScriptBody(args = { "id", "bindings" }, body = 

        "var d = window['document'];\n" +

        "var e = id ? d['getElementById'](id) : d['body'];\n" +

        "ko['cleanNode'](e);\n" +

        "ko['applyBindings'](bindings, e);\n" +

        "return bindings['ko4j'];\n"

    )

    native static Object applyBindings(String id, Object bindings);

    @JavaScriptBody(args = { "cnt" }, body = 

        "var arr = new Array(cnt);\n" +

        "for (var i = 0; i < cnt; i++) arr[i] = new Object();\n" +

        "return arr;\n"

    )

    native static Object[] allocJS(int cnt);

    @JavaScriptBody(

        javacall = true,

        keepAlive = false,

        wait4js = false,

        args = { "ret", "copyFrom", "propNames", "propReadOnly", "propValues", "funcNames" },

        body = 

          "Object.defineProperty(ret, 'ko4j', { value : this });\n"

        + "function koComputed(index, name, readOnly, value) {\n"

        + "  var orig = copyFrom ? copyFrom[name] : null;\n"

        + "  if (!ko['isObservable'](orig)) {\n"

        + "    orig = null;\n"

        + "    var trigger = ko['observable']()['extend']({'notify':'always'});\n"

        + "  } else {\n"

        + "    var trigger = orig;\n"

        + "  }\n"

        + "  function realGetter() {\n"

        + "    var self = ret['ko4j'];\n"

        + "    try {\n"

        + "      var v = self ? self.@org.netbeans.html.ko4j.Knockout::getValue(I)(index) : null;\n"

        + "      return v;\n"

        + "    } catch (e) {\n"

        + "      alert(\"Cannot call getValue on \" + self + \" prop: \" + name + \" error: \" + e);\n"

        + "    }\n"

        + "  }\n"

        + "  var activeGetter = orig ? orig : function() { return value; };\n"

        + "  var bnd = {\n"

        + "    'read': function() {\n"

        + "      trigger();\n"

        + "      if (orig) {\n"

        + "        var r = orig();\n"

        + "      } else {\n"

        + "        var r = activeGetter();\n"

        + "        activeGetter = realGetter;\n"

        + "      }\n"

        + "      if (r) try { var br = r.valueOf(); } catch (err) {}\n"

        + "      return br === undefined ? r: br;\n"

        + "    },\n"

        + "    'owner': ret\n"

        + "  };\n"

        + "  if (!readOnly) {\n"

        + "    function write(val) {\n"

        + "      if (orig) orig(val);\n"

        + "      var self = ret['ko4j'];\n"

        + "      if (!self) return;\n"

        + "      var model = val ? val['ko4j'] : null;\n"

        + "      self.@org.netbeans.html.ko4j.Knockout::setValue(ILjava/lang/Object;)(index, model ? model : val);\n"

        + "    };\n"

        + "    bnd['write'] = write;\n"

        + "    if (orig) {\n"

        + "      write(orig());\n"

        + "      orig.subscribe(write);\n"

        + "    }\n"

        + "  };\n"

        + "  var cmpt = ko['computed'](bnd);\n"

        + "  cmpt['valueHasMutated'] = function(val) {\n"

        + "    if (arguments.length === 1) activeGetter = function() { return val; };\n"

        + "    trigger(val);\n"

        + "  };\n"

        + "  ret[name] = cmpt;\n"

        + "}\n"

        + "for (var i = 0; i < propNames.length; i++) {\n"

        + "  koComputed(i, propNames[i], propReadOnly[i], propValues[i]);\n"

        + "}\n"

        + "function koExpose(index, name) {\n"

        + "  ret[name] = function(data, ev) {\n"

        + "    var self = ret['ko4j'];\n"

        + "    if (!self) return;\n"

        + "    self.@org.netbeans.html.ko4j.Knockout::call(ILjava/lang/Object;Ljava/lang/Object;)(index, data, ev);\n"

        + "  };\n"

        + "}\n"

        + "for (var i = 0; i < funcNames.length; i++) {\n"

        + "  koExpose(i, funcNames[i]);\n"

        + "}\n"

        )

    native void wrapModel(

        Object ret, Object copyFrom,

        String[] propNames, Boolean[] propReadOnly, Object propValues,

        String[] funcNames

    );

    @JavaScriptBody(args = { "js" }, wait4js = false, body = 

        "delete js['ko4j'];\n" +

        "for (var p in js) {\n" +

        "  delete js[p];\n" +

        "};\n" +

        "\n"

    )

    private static native void clean(Object js);

    @JavaScriptBody(args = { "o" }, body = "return o['ko4j'] ? o['ko4j'] : o;")

    private static native Object toModelImpl(Object wrapper);

    static Object toModel(Object wrapper) {

        Object o = toModelImpl(wrapper);

        if (o instanceof Knockout) {

            return ((Knockout)o).get();

        } else {

            return o;

        }

    }

}