/**

 * 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.vm4brwsr;

import java.io.IOException;

import java.io.InputStream;

import javax.script.Invocable;

import javax.script.ScriptContext;

import javax.script.ScriptEngine;

import javax.script.ScriptException;

import org.testng.annotations.BeforeClass;

import static org.testng.Assert.*;

import org.testng.annotations.Test;

/** Implements loading class by class.

 *

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

 */

public class VMLazyTest {

    private static CharSequence codeSeq;

    private static Invocable code;

    @BeforeClass

    public void compileTheCode() throws Exception {

        StringBuilder sb = new StringBuilder();

        sb.append("\nfunction test(clazz, as, method) {");

        sb.append("\n  var l = new lazyVM(this);");

        sb.append("\n  var c = l.loadClass(clazz, as);");

        sb.append("\n  return c[method]();");

        sb.append("\n}");

        sb.append("\nfunction lazyVM(global) {");

        sb.append("\n  var self = this;");

        sb.append("\n  var glb = global;");

        sb.append("\n  lazyVM.prototype.loadClass = function(res, name) {");

        sb.append("\n    var script = org_apidesign_vm4brwsr_VMLazy(true)."

            + "toJavaScriptLjava_lang_StringLjava_lang_ObjectLjava_lang_ObjectAB("

            + "  glb, self,"

            + "  loader.get(res + '.class')"

            + ");");

        sb.append("\n    try {");

        sb.append("\n      new Function(script)(self, name);");

        sb.append("\n    } catch (ex) {");

        sb.append("\n      throw 'Cannot compile ' + res + ' error: ' + ex + ' script:\\n' + script;");

        sb.append("\n    };");

        sb.append("\n    return self[name](true);");

        sb.append("\n  };");

        sb.append("\n");

        sb.append("\n}\n");

        ScriptEngine[] arr = { null };

        code = StaticMethodTest.compileClass(sb, arr,

            "org/apidesign/vm4brwsr/VMLazy"

        );

        arr[0].getContext().setAttribute("loader", new FindBytes(), ScriptContext.ENGINE_SCOPE);

        codeSeq = sb;

    }

    @Test public void invokeStaticMethod() throws Exception {

        assertExec("Trying to get -1", "test", Double.valueOf(-1),

            "org/apidesign/vm4brwsr/StaticMethod", "org_apidesign_vm4brwsr_StaticMethod", "minusOneI"

        );

    }

    @Test public void loadDependantClass() throws Exception {

        assertExec("Trying to get zero", "test", Double.valueOf(0),

            "org/apidesign/vm4brwsr/InstanceSub", "org_apidesign_vm4brwsr_InstanceSub", "recallDblD"

        );

    }

    private static void assertExec(String msg, String methodName, Object expRes, Object... args) throws Exception {

        Object ret = null;

        try {

            ret = code.invokeFunction(methodName, args);

        } catch (ScriptException ex) {

            fail("Execution failed in\n" + StaticMethodTest.dumpJS(codeSeq), ex);

        } catch (NoSuchMethodException ex) {

            fail("Cannot find method in\n" + StaticMethodTest.dumpJS(codeSeq), ex);

        }

        if (ret == null && expRes == null) {

            return;

        }

        if (expRes.equals(ret)) {

            return;

        }

        assertEquals(ret, expRes, msg + "was: " + ret + "\n" + codeSeq);

    }

    public static final class FindBytes {

        public byte[] get(String name) throws IOException {

            InputStream is = VMLazyTest.class.getClassLoader().getResourceAsStream(name);

            if (is == null) {

                throw new IOException("Can't find " + name);

            }

            byte[] arr = new byte[is.available()];

            int len = is.read(arr);

            if (len != arr.length) {

                throw new IOException("Read only " + len + " wanting " + arr.length);

            }

            System.err.print("loader['" + name + "'] = [");

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

                if (i > 0) {

                    System.err.print(", ");

                }

                System.err.print(arr[i]);

            }

            System.err.println("]");

            return arr;

        }

    }

}