/**
 * Copyright (C) 2009-2013 FoundationDB, LLC
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.foundationdb.sql.server;

import com.foundationdb.ais.model.Parameter;
import com.foundationdb.qp.operator.QueryBindings;
import com.foundationdb.server.error.ExternalRoutineInvocationException;
import com.foundationdb.server.explain.Attributes;
import com.foundationdb.server.explain.CompoundExplainer;
import com.foundationdb.server.explain.ExplainContext;
import com.foundationdb.server.explain.Label;
import com.foundationdb.server.explain.PrimitiveExplainer;

import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.ResultSet;
import java.util.ArrayDeque;
import java.util.Queue;

public class ServerJavaMethod extends ServerJavaRoutine
{
    private Method method;
    private Class<?>[] parameterTypes;
    private Object[] methodArgs;
    private Object methodResult;
    
    public ServerJavaMethod(ServerQueryContext context,
                            QueryBindings bindings,
                            ServerRoutineInvocation invocation,
                            Method method) {
        super(context, bindings, invocation);
        this.method = method;
        parameterTypes = method.getParameterTypes();
    }

    @Override
    public void push() {
        super.push();
        methodArgs = methodArgs(parameterTypes);
    }

    protected static Object[] methodArgs(Class<?>[] parameterTypes) {
        Object[] result = new Object[parameterTypes.length];
        for (int i = 0; i < parameterTypes.length; i++) {
            Class<?> outputType = parameterTypes[i].getComponentType();
            if (outputType != null) {
                result[i] = Array.newInstance(outputType, 1);
            }
        }
        return result;
    }

    @Override
    public void setInParameter(Parameter parameter, ServerJavaValues values, int index) {
        Class<?> clazz = parameterTypes[index];
        if (clazz.isArray() && clazz != byte[].class) {
            Array.set(methodArgs[index], 0, 
                      values.getObject(index, clazz.getComponentType()));
        }
        else {
            methodArgs[index] = values.getObject(index, clazz);
        }
    }

    @Override
    public void invokeShielded() {
        try {
            methodResult = method.invoke(null, methodArgs);
        }
        catch (IllegalAccessException ex) {
            throw new ExternalRoutineInvocationException(getInvocation().getRoutineName(), ex);
        }
        catch (InvocationTargetException ex) {
            throw new ExternalRoutineInvocationException(getInvocation().getRoutineName(), ex.getTargetException());
        }
    }

    @Override
    public Object getOutParameter(Parameter parameter, int index) {
        if (parameter.getDirection() == Parameter.Direction.RETURN) {
            return methodResult;
        }
        else {
            return Array.get(methodArgs[index], 0);
        }
    }
    
    @Override
    public Queue<ResultSet> getDynamicResultSets() {
        Queue<ResultSet> result = new ArrayDeque<>();
        for (int i = 0; i < parameterTypes.length; i++) {
            Class<?> outputType = parameterTypes[i].getComponentType();
            if ((outputType != null) && ResultSet.class.isAssignableFrom(outputType)) {
                ResultSet rs = (ResultSet)Array.get(methodArgs[i], 0);
                if (rs != null)
                    result.add(rs);
            }
        }
        return result;
    }

    @Override
    public CompoundExplainer getExplainer(ExplainContext context) {
        Attributes atts = new Attributes();
        atts.put(Label.PROCEDURE_IMPLEMENTATION, 
                 PrimitiveExplainer.getInstance(method.toString()));
        return new ServerCallExplainer(getInvocation(), atts, context);
    }

}