/**

 * 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.kofx;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.util.logging.Level;

import java.util.logging.Logger;

import net.java.html.js.JavaScriptBody;

import net.java.html.json.Model;

import netscape.javascript.JSObject;

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

import org.apidesign.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 <jtulach@netbeans.org>

 */

public final class Knockout {

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

    /** used by tests */

    static Knockout next;

    private final Object model;

    Knockout(Object model) {

        this.model = model == null ? this : model;

    }

    public Object koData() {

        return model;

    }

    static Object toArray(Object[] arr) {

        return InvokeJS.KObject.call("array", arr);

    }

    private static int cnt;

    public static <M> Knockout createBinding(Object model) {

        Object bindings = InvokeJS.create(model, ++cnt);

        return new Knockout(bindings);

    }

    public void valueHasMutated(String prop) {

        valueHasMutated((JSObject) model, prop);

    }

    public static void valueHasMutated(JSObject model, String prop) {

        LOG.log(Level.FINE, "property mutated: {0}", prop);

        try {

            Object koProp = model.getMember(prop);

            if (koProp instanceof JSObject) {

                ((JSObject)koProp).call("valueHasMutated");

            }

        } catch (Throwable t) {

            LOG.log(Level.WARNING, "valueHasMutated failed for " + model + " prop: " + prop, t);

        }

    }

    static void bind(

        Object bindings, Object model, PropertyBinding pb, boolean primitive, boolean array

    ) {

        final String prop = pb.getPropertyName();

        try {

            InvokeJS.bind(bindings, pb, prop, "getValue", pb.isReadOnly() ? null : "setValue", primitive, array);

            ((JSObject)bindings).setMember("ko-fx.model", model);

            LOG.log(Level.FINE, "binding defined for {0}: {1}", new Object[]{prop, ((JSObject)bindings).getMember(prop)});

        } catch (Throwable ex) {

            LOG.log(Level.WARNING, "binding failed for {0} on {1}", new Object[]{prop, bindings});

        }

    }

    static void expose(Object bindings, FunctionBinding f) {

        final String prop = f.getFunctionName();

        try {

            InvokeJS.expose(bindings, f, prop, "call");

        } catch (Throwable ex) {

            LOG.log(Level.SEVERE, "Cannot define binding for " + prop + " in model " + f, ex);

        }

    }

    static void applyBindings(Object bindings) {

        InvokeJS.applyBindings(bindings);

    }

    private static final class InvokeJS {

        static final JSObject KObject;

        static {

            final InputStream koScript = Knockout.class.getResourceAsStream("knockout-2.2.1.js");

            assert koScript != null : "Can't load knockout.js";

            BufferedReader r = new BufferedReader(new InputStreamReader(koScript));

            StringBuilder sb = new StringBuilder();

            for (;;) {

                try {

                    String l = r.readLine();

                    if (l == null) {

                        break;

                    }

                    sb.append(l).append('\n');

                } catch (IOException ex) {

                    throw new IllegalStateException(ex);

                }

            }

            exec(sb.toString());

            Object ko = exec("ko");

            assert ko != null : "Knockout library successfully defined 'ko'";

            Console.register();

            KObject = (JSObject) kObj();

        }

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

        private static native Object exec(String s);

        @JavaScriptBody(args = {}, body =

                  "  var k = {};"

                + "  k.array= function() {"

                + "    return Array.prototype.slice.call(arguments);"

                + "  };"

                + "  return k;"

        )

        private static native Object kObj();

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

                  "    var ret = {};"

                + "    ret.toString = function() { return 'KObject' + cnt + ' value: ' + value + ' props: ' + Object.keys(this); };"

                + "    return ret;"

        )

        static native Object create(Object value, int cnt);

        @JavaScriptBody(args = { "bindings", "model", "prop", "sig" }, body = 

                "    bindings[prop] = function(data, ev) {"

              //            + "         console.log(\"  callback on prop: \" + prop);"

              + "      model[sig](data, ev);"

              + "    };"

        )

        static native Object expose(Object bindings, Object model, String prop, String sig);

        @JavaScriptBody(args = { "bindings", "model", "prop", "getter", "setter", "primitive", "array" }, body = 

                  "    var bnd = {"

                + "      read: function() {"

                + "      try {"

                + "        var v = model[getter]();"

        //        + "      console.log(\" getter value \" + v + \" for property \" + prop);"

        //        + "      try { v = v.koData(); } catch (ignore) {"

        //        + "        console.log(\"Cannot convert to koData: \" + ignore);"

        //        + "      };"

        //        + "      console.log(\" getter ret value \" + v);"

        //        + "      for (var pn in v) {"

        //        + "         console.log(\"  prop: \" + pn + \" + in + \" + v + \" = \" + v[pn]);"

        //        + "         if (typeof v[pn] == \"function\") console.log(\"  its function value:\" + v[pn]());"

        //        + "      }"

        //        + "      console.log(\" all props printed for \" + (typeof v));"

                + "        return v;"

                + "      } catch (e) {"

                + "        alert(\"Cannot call \" + getter + \" on \" + model + \" error: \" + e);"

                + "      }"

                + "    },"

                + "    owner: bindings"

        //        + "  ,deferEvaluation: true"

                + "    };"

                + "    if (setter != null) {"

                + "      bnd.write = function(val) {"

                + "        model[setter](primitive ? new Number(val) : val);"

                + "      };"

                + "    };"

                + "    bindings[prop] = ko.computed(bnd);"

        )

        static native void bind(Object binding, Object model, String prop, String getter, String setter, boolean primitive, boolean array);

        @JavaScriptBody(args = { "bindings" }, body = "ko.applyBindings(bindings);")

        private static native void applyBindings(Object bindings);

    }

}