/*
 * Copyright 2019-2020 The Polypheny Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * This file incorporates code covered by the following terms:
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.polypheny.db.schema.impl;


import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.List;
import org.polypheny.db.schema.TableMacro;
import org.polypheny.db.schema.TranslatableTable;
import org.polypheny.db.util.Static;


/**
 * Implementation of {@link TableMacro} based on a method.
 */
public class TableMacroImpl extends ReflectiveFunctionBase implements TableMacro {

    /**
     * Private constructor; use {@link #create}.
     */
    private TableMacroImpl( Method method ) {
        super( method );
    }


    /**
     * Creates a {@code TableMacro} from a class, looking for an "eval" method. Returns null if there is no such method.
     */
    public static TableMacro create( Class<?> clazz ) {
        final Method method = findMethod( clazz, "eval" );
        if ( method == null ) {
            return null;
        }
        return create( method );
    }


    /**
     * Creates a {@code TableMacro} from a method.
     */
    public static TableMacro create( final Method method ) {
        Class clazz = method.getDeclaringClass();
        if ( !Modifier.isStatic( method.getModifiers() ) ) {
            if ( !classHasPublicZeroArgsConstructor( clazz ) ) {
                throw Static.RESOURCE.requireDefaultConstructor( clazz.getName() ).ex();
            }
        }
        final Class<?> returnType = method.getReturnType();
        if ( !TranslatableTable.class.isAssignableFrom( returnType ) ) {
            return null;
        }
        return new TableMacroImpl( method );
    }


    /**
     * Applies arguments to yield a table.
     *
     * @param arguments Arguments
     * @return Table
     */
    @Override
    public TranslatableTable apply( List<Object> arguments ) {
        try {
            Object o = null;
            if ( !Modifier.isStatic( method.getModifiers() ) ) {
                final Constructor<?> constructor = method.getDeclaringClass().getConstructor();
                o = constructor.newInstance();
            }
            return (TranslatableTable) method.invoke( o, arguments.toArray() );
        } catch ( IllegalArgumentException e ) {
            throw new RuntimeException( "Expected " + Arrays.toString( method.getParameterTypes() ) + " actual " + arguments, e );
        } catch ( IllegalAccessException | InvocationTargetException | NoSuchMethodException | InstantiationException e ) {
            throw new RuntimeException( e );
        }
    }
}

