/*
 * Copyright (c) 2015 Cisco Systems, Inc. and others.  All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */
package org.opendaylight.yangtools.yang.parser.spi.meta;

import java.util.Collection;
import java.util.stream.Stream;
import org.eclipse.jdt.annotation.NonNull;
import org.opendaylight.yangtools.yang.model.api.meta.DeclaredStatement;
import org.opendaylight.yangtools.yang.model.api.meta.EffectiveStatement;
import org.opendaylight.yangtools.yang.parser.spi.meta.EffectiveStmtCtx.Current;

/**
 * An entity capable of creating {@link DeclaredStatement} and {@link EffectiveStatement} instances for a particular
 * type. This interface is usually realized as an implementation-specific combination with {@link StatementSupport}.
 *
 * @param <A> Argument type
 * @param <D> Declared Statement representation
 * @param <E> Effective Statement representation
 */
public interface StatementFactory<A, D extends DeclaredStatement<A>, E extends EffectiveStatement<A, D>> {
    /**
     * Create a {@link DeclaredStatement} for specified context.
     *
     * @param ctx Statement context
     * @return A declared statement instance.
     */
    @NonNull D createDeclared(@NonNull StmtContext<A, D, ?> ctx);

    /**
     * Create a {@link EffectiveStatement} for specified context.
     *
     * @param stmt Effective capture of this statement's significant state
     * @param declaredSubstatements effectively-visible declared substatements
     * @param inferredSubstatements effectively-visible inferred substatements
     * @return An effective statement instance
     */
    // FIXME: we really want a single coherent 'effectiveSubstatements' stream
    @NonNull E createEffective(@NonNull Current<A, D> stmt,
        Stream<? extends StmtContext<?, ?, ?>> declaredSubstatements,
        Stream<? extends StmtContext<?, ?, ?>> inferredSubstatements);

    /**
     * Create a {@link EffectiveStatement} copy of provided original for specified context.
     *
     * @param stmt Effective capture of this statement's significant state
     * @param original Original effective statement
     * @return An effective statement instance
     * @throws NullPointerException if any argument is null
     */
    @NonNull E copyEffective(@NonNull Current<A, D> stmt, @NonNull E original);

    /**
     * Determine reactor copy behaviour of a statement instance. Implementations classes are required to determine
     * their operations with regard to their statements being replicated into different contexts -- potentially sharing
     * instantiations.
     *
     * <p>
     * Implementations are examine {@code copy} as to whether it would result in the same semantics as {@code current}
     * does, provided that {@code current}'s {@code substatements} are properly propagated.
     *
     * @param copy Copy of current effective context
     * @param current Current effective context
     * @param substatements Current effective substatements
     * @return True if the differences between {@code copy} and {@code current} do not affect this statement's effective
     *         semantics.
     * @throws NullPointerException if any argument is null
     */
    boolean canReuseCurrent(@NonNull Current<A, D> copy, @NonNull Current<A, D> current,
        @NonNull Collection<? extends EffectiveStatement<?, ?>> substatements);
}