/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
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 *  https://www.apache.org/licenses/LICENSE-2.0
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 *
 * Other licenses:
 * -----------------------------------------------------------------------------
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 * Apache-2.0 license and offer limited warranties, support, maintenance, and
 * commercial database integrations.
 *
 * For more information, please visit: https://www.jooq.org/legal/licensing
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package org.jooq;

import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

/**
 * A context object for {@link QueryPart} traversal passed to registered
 * {@link VisitListener}'s.
 * <p>
 * This type is a {@link Scope} with whose lifecycle is shared with the parent
 * rendering {@link Context} scope. It also shares the latter's {@link #data()}
 * map.
 *
 * @author Lukas Eder
 * @see VisitListener
 */
public interface VisitContext extends Scope {

    /**
     * The most recent clause that was encountered through
     * {@link Context#start(Clause)}.
     */
    @NotNull
    Clause clause();

    /**
     * A path of clauses going through the visiting tree.
     * <p>
     * This returns all previous clauses that were encountered through
     * {@link Context#start(Clause)} and that haven't been removed yet through
     * {@link Context#end(Clause)}. In other words, <code>VisitContext</code>
     * contains a stack of clauses.
     */
    @NotNull
    Clause @NotNull [] clauses();

    /**
     * This is the same as calling {@link #clauses()}<code>.length</code>.
     */
    int clausesLength();

    /**
     * The most recent {@link QueryPart} that was encountered through
     * {@link Context#visit(QueryPart)}.
     */
    @NotNull
    QueryPart queryPart();

    /**
     * Replace the most recent {@link QueryPart} that was encountered through
     * {@link Context#visit(QueryPart)}.
     * <p>
     * This method can be called by {@link VisitListener} implementation
     * methods, in particular by {@link VisitListener#visitStart(VisitContext)}.
     *
     * @param part The new <code>QueryPart</code>.
     */
    void queryPart(QueryPart part);

    /**
     * A path of {@link QueryPart}s going through the visiting tree.
     * <p>
     * This returns all previous <code>QueryParts</code> that were encountered
     * through {@link Context#visit(QueryPart)}. In other words,
     * <code>VisitContext</code> contains a stack of <code>QueryParts</code>.
     */
    @NotNull
    QueryPart @NotNull [] queryParts();

    /**
     * This is the same as calling {@link #queryParts()}<code>.length</code>.
     */
    int queryPartsLength();

    /**
     * The underlying {@link RenderContext} or {@link BindContext} object.
     */
    @NotNull
    Context<?> context();

    /**
     * The underlying {@link RenderContext} or <code>null</code>, if the
     * underlying context is a {@link BindContext}.
     * <p>
     * [#2694] [#2695] As of jOOQ 3.2, the {@link QueryPart} traversal SPI
     * through {@link VisitListener} is only implemented for
     * {@link RenderContext}. Hence, you may need to inline bind values if
     * applicable.
     */
    @Nullable
    RenderContext renderContext();

    /**
     * The underlying {@link BindContext} or <code>null</code>, if the
     * underlying context is a {@link RenderContext}.
     *
     * @throws UnsupportedOperationException [#2694] [#2695] As of jOOQ 3.2,
     *             this method is not yet implemented as {@link QueryPart}
     *             traversal SPI through {@link VisitListener} is only
     *             implemented for {@link RenderContext}
     */
    @Nullable
    BindContext bindContext() throws UnsupportedOperationException;
}
