/*

 * Copyright (c) 1996, 2006, Oracle and/or its affiliates. All rights reserved.

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

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

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

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package org.apidesign.bck2brwsr.emul.reflect;

import java.lang.reflect.Array;

import java.lang.reflect.Method;

import java.util.Enumeration;

import org.apidesign.bck2brwsr.core.JavaScriptBody;

/** Utilities to work on methods.

 *

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

 */

public abstract class MethodImpl {

    public static MethodImpl INSTANCE;

    static {

        try {

            Class.forName(Method.class.getName());

        } catch (ClassNotFoundException ex) {

            throw new IllegalStateException(ex);

        }

    }

    protected abstract Method create(Class<?> declaringClass, String name, Object data, String sig);

    //

    // bck2brwsr implementation

    //

    @JavaScriptBody(args = {"clazz", "prefix"},

        body = ""

        + "var c = clazz.cnstr.prototype;"

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

        + "for (m in c) {\n"

        + "  if (m.indexOf(prefix) === 0) {\n"

        + "     arr.push(m);\n"

        + "     arr.push(c[m]);\n"

        + "  }"

        + "}\n"

        + "return arr;")

    private static native Object[] findMethodData(

        Class<?> clazz, String prefix);

    public static Method findMethod(

        Class<?> clazz, String name, Class<?>... parameterTypes) {

        Object[] data = findMethodData(clazz, name + "__");

        BIG: for (int i = 0; i < data.length; i += 2) {

            String sig = ((String) data[0]).substring(name.length() + 2);

            Method tmp = INSTANCE.create(clazz, name, data[1], sig);

            Class<?>[] tmpParms = tmp.getParameterTypes();

            if (parameterTypes.length != tmpParms.length) {

                continue;

            }

            for (int j = 0; j < tmpParms.length; j++) {

                if (!parameterTypes[j].equals(tmpParms[j])) {

                    continue BIG;

                }

            }

            return tmp;

        }

        return null;

    }

    public static Method[] findMethods(Class<?> clazz, int mask) {

        Object[] namesAndData = findMethodData(clazz, "");

        int cnt = 0;

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

            String sig = (String) namesAndData[i];

            Object data = namesAndData[i + 1];

            int middle = sig.indexOf("__");

            if (middle == -1) {

                continue;

            }

            String name = sig.substring(0, middle);

            sig = sig.substring(middle + 2);

            final Method m = INSTANCE.create(clazz, name, data, sig);

            if ((m.getModifiers() & mask) == 0) {

                continue;

            }

            namesAndData[cnt++] = m;

        }

        Method[] arr = new Method[cnt];

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

            arr[i] = (Method) namesAndData[i];

        }

        return arr;

    }

    static String toSignature(Method m) {

        StringBuilder sb = new StringBuilder();

        sb.append(m.getName()).append("__");

        appendType(sb, m.getReturnType());

        Class<?>[] arr = m.getParameterTypes();

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

            appendType(sb, arr[i]);

        }

        return sb.toString();

    }

    private static void appendType(StringBuilder sb, Class<?> type) {

        if (type == Integer.TYPE) {

            sb.append('I');

            return;

        }

        if (type == Long.TYPE) {

            sb.append('J');

            return;

        }

        if (type == Double.TYPE) {

            sb.append('D');

            return;

        }

        if (type == Float.TYPE) {

            sb.append('F');

            return;

        }

        if (type == Byte.TYPE) {

            sb.append('B');

            return;

        }

        if (type == Boolean.TYPE) {

            sb.append('Z');

            return;

        }

        if (type == Short.TYPE) {

            sb.append('S');

            return;

        }

        if (type == Void.TYPE) {

            sb.append('V');

            return;

        }

        if (type == Character.TYPE) {

            sb.append('C');

            return;

        }

        if (type.isArray()) {

            sb.append("_3");

            appendType(sb, type.getComponentType());

            return;

        }

        sb.append('L').append(type.getName().replace('.', '_'));

        sb.append("_2");

    }

    public static int signatureElements(String sig) {

        Enumeration<Class> en = signatureParser(sig);

        int cnt = 0;

        while (en.hasMoreElements()) {

            en.nextElement();

            cnt++;

        }

        return cnt;

    }

    public static Enumeration<Class> signatureParser(final String sig) {

        class E implements Enumeration<Class> {

            int pos;

            public boolean hasMoreElements() {

                return pos < sig.length();

            }

            public Class nextElement() {

                switch (sig.charAt(pos++)) {

                    case 'I':

                        return Integer.TYPE;

                    case 'J':

                        return Long.TYPE;

                    case 'D':

                        return Double.TYPE;

                    case 'F':

                        return Float.TYPE;

                    case 'B':

                        return Byte.TYPE;

                    case 'Z':

                        return Boolean.TYPE;

                    case 'S':

                        return Short.TYPE;

                    case 'V':

                        return Void.TYPE;

                    case 'C':

                        return Character.TYPE;

                    case 'L':

                        try {

                            int up = sig.indexOf("_2", pos);

                            String type = sig.substring(pos, up);

                            pos = up + 2;

                            return Class.forName(type.replace('_', '.'));

                        } catch (ClassNotFoundException ex) {

                            throw new IllegalStateException(ex);

                        }

                    case '_': {

                        char nch = sig.charAt(pos++);

                        assert nch == '3' : "Can't find '3' at " + sig.substring(pos - 1);

                        final Class compType = nextElement();

                        return Array.newInstance(compType, 0).getClass();

                    }

                }

                throw new UnsupportedOperationException(sig + " at " + pos);

            }

        }

        return new E();

    }

}