/**

 * 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.ide.editor;

import java.lang.reflect.Method;

import java.util.HashMap;

import java.util.Map;

/**

 * JNI Helper.

 * To facilitate lookup of methods by name and signature, instead of manually parsing signatures,

 * constructs the map of all methods and uses Class.getName() to generate almost-correct signatures.

 */

class JNIHelper {

    static Method method(String clazz, String method, String signature) {

        final Map<String, Method> methods = methodMap(JNIHelper.clazz(clazz));

        return methods.get(methodKey(method, signature));

    }

    static Class<?> clazz(String clazz) {

        try {

            return Class.forName(clazz);

        } catch (ClassNotFoundException e) {

            throw new IllegalArgumentException(e);

        }

    }

    static Map<String, Method> methodMap(final Class<?> clazz) {

        final Map<String, Method> map = new HashMap<String, Method>();

        final Method[] methods = clazz.getDeclaredMethods();

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

            final Method method = methods[i];

            map.put(methodKey(method.getName(), signature(method)), method);

        }

        return map;

    }

    static String methodKey(String method, String signature) {

        return method + '@' + signature;

    }

    static String signature(final Method method) {

        final Class<?>[] parameterTypes = method.getParameterTypes();

        final StringBuilder b = new StringBuilder();

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

            b.append(signature(parameterTypes[j]));

        }

        return b.toString();

    }

    static String signature(final Class<?> clazz) {

        if (clazz == boolean.class) return "Z";

        else if (clazz == byte.class) return "B";

        else if (clazz == char.class) return "C";

        else if (clazz == double.class) return "D";

        else if (clazz == float.class) return "F";

        else if (clazz == int.class) return "I";

        else if (clazz == long.class) return "J";

        else if (clazz == short.class) return "S";

        else if (clazz == void.class) return "V";

        else if (clazz.isArray()) return clazz.getName().replace('.','/');

        else return "L" + clazz.getName().replace('.','/') + ";";

    }

}