/**

 * 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.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.lang.reflect.Method;

import java.util.List;

import java.util.logging.Level;

import java.util.logging.Logger;

import javafx.scene.web.WebEngine;

import netscape.javascript.JSObject;

import org.apidesign.bck2brwsr.core.ExtraJavaScript;

import org.apidesign.bck2brwsr.core.JavaScriptBody;

/** Provides binding between models and 

 *

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

 */

@ExtraJavaScript(resource = "/org/apidesign/bck2brwsr/htmlpage/knockout-2.2.1.js")

public 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);

    }

    public static <M> Knockout applyBindings(

        Object model, String[] propsGettersAndSetters,

        String[] methodsAndSignatures

    ) {

        Object bindings = InvokeJS.KObject.call("create", model);

        applyImpl(propsGettersAndSetters, model.getClass(), bindings, model, methodsAndSignatures);

        return new Knockout(bindings);

    }

    public static <M> Knockout applyBindings(

        Class<M> modelClass, M model, String[] propsGettersAndSetters,

        String[] methodsAndSignatures

    ) {

        Object bindings = next;

        next = null;

        if (bindings == null) {

            bindings = InvokeJS.KObject.call("create", model);

        }

        applyImpl(propsGettersAndSetters, modelClass, bindings, model, methodsAndSignatures);

        applyBindings(bindings);

        return new Knockout(bindings);

    }

    public void valueHasMutated(String prop) {

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

        try {

            JSObject koProp = (JSObject) ((JSObject) model).getMember(prop);

            koProp.call("valueHasMutated");

        } catch (Throwable t) {

            LOG.log(Level.WARNING, "valueHasMutated failed for {0}", model);

        }

    }

    @JavaScriptBody(args = { "id", "ev" }, body = "ko.utils.triggerEvent(window.document.getElementById(id), ev.substring(2));")

    public static void triggerEvent(String id, String ev) {

        JSObject js = (JSObject) web().executeScript("(function () {"

            + "  var x = {}; "

            + "  x.trigger= function(id, ev) { "

            + "    ko.utils.triggerEvent(window.document.getElementById(id), ev.substring(2));;\n"

            + "  };"

            + "  return x;"

            + "})()");

        js.call("trigger", id, ev);

    }

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

          "var bnd = {\n"

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

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

        + "    if (array) v = v.koArray();\n"

        + "    return v;\n"

        + "  },\n"

        + "  'owner': bindings\n"

        + "};\n"

        + "if (setter != null) {\n"

        + "  bnd['write'] = function(val) {\n"

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

        + "  };\n"

        + "}\n"

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

    )

    private static void bind(

        Object bindings, Object model, String prop, String getter, String setter, boolean primitive, boolean array

    ) {

        WebEngine e = web();

        if (e == null) {

            return;

        }

        JSObject bnd = (JSObject) e.executeScript("var x = {}; x.bnd = "

        + "new Function('ko', 'bindings', 'model', 'prop', 'getter', 'setter', 'primitive', 'array', '"

        + "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);'"

        + "); x;");

        Object ko = e.executeScript("ko");

        try {

            KOProperty kop = new KOProperty(model, strip(getter), strip(setter));

            bnd.call("bnd", ko, bindings, kop, prop, "get", "set", primitive, array);

            ((JSObject)bindings).setMember("koModel", 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});

        }

    }

    private static String strip(String mangled) {

        if (mangled == null) {

            return null;

        }

        int under = mangled.indexOf("__");

        return mangled.substring(0, under);

    }

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

        "bindings[prop] = function(data, ev) { model[sig](data, ev); };"

    )

    private static void expose(

        Object bindings, Object model, String prop, String sig

    ) {

        WebEngine e = web();

        if (e == null) {

            return;

        }

        try {

            KOFunction f = new KOFunction(model, strip(sig));

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

        } catch (Throwable ex) {

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

        }

    }

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

    private static void applyBindings(Object bindings) {

        if (web() != null) {

            JSObject ko = (JSObject) web().executeScript("ko");

            ko.call("applyBindings", bindings);

        }

    }

    private static WebEngine web() {

        return (WebEngine) System.getProperties().get("webEngine");

    }

    private static void applyImpl(

        String[] propsGettersAndSetters,

        Class<?> modelClass,

        Object bindings,

        Object model,

        String[] methodsAndSignatures

    ) throws IllegalStateException, SecurityException {

        for (int i = 0; i < propsGettersAndSetters.length; i += 4) {

            try {

                Method getter = modelClass.getMethod(propsGettersAndSetters[i + 3]);

                bind(bindings, model, propsGettersAndSetters[i],

                    propsGettersAndSetters[i + 1],

                    propsGettersAndSetters[i + 2],

                    getter.getReturnType().isPrimitive(),

                    List.class.isAssignableFrom(getter.getReturnType()));

            } catch (NoSuchMethodException ex) {

                throw new IllegalStateException(ex.getMessage());

            }

        }

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

            expose(

                bindings, model, methodsAndSignatures[i], methodsAndSignatures[i + 1]);

        }

    }

    private static final class InvokeJS {

        static final JSObject KObject;

        static {

            BufferedReader r = new BufferedReader(new InputStreamReader(Knockout.class.getResourceAsStream("knockout-2.2.1.js")));

            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);

                }

            }

            web().executeScript(sb.toString());

            Object ko = web().executeScript("ko");

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

            Console.register(web());

            KObject = (JSObject) web().executeScript(

                "(function(scope) {"

                + "  var kCnt = 0; "

                + "  scope.KObject = {};"

                + "  scope.KObject.create= function(value) {"

                + "    var cnt = ++kCnt;"

                + "    var ret = {};"

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

                + "    return ret;"

                + "  };"

                + "  scope.KObject.array= function() {"

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

                + "  };"

                + "  scope.KObject.expose = function(bindings, model, prop, sig) {"

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

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

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

                + "    };"

                + "  };"

                + "})(window); window.KObject");

        }

    }

}