/*
 * Copyright (c) 2020 PANTHEON.tech, s.r.o. 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.stmt.reactor;

import static com.google.common.base.Verify.verify;
import static java.util.Objects.requireNonNull;

import com.google.common.base.VerifyException;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Streams;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import org.eclipse.jdt.annotation.NonNull;
import org.eclipse.jdt.annotation.Nullable;
import org.opendaylight.yangtools.concepts.Immutable;
import org.opendaylight.yangtools.yang.common.QName;
import org.opendaylight.yangtools.yang.common.QNameModule;
import org.opendaylight.yangtools.yang.model.api.meta.DeclaredStatement;
import org.opendaylight.yangtools.yang.model.api.meta.EffectiveStatement;
import org.opendaylight.yangtools.yang.model.api.meta.StatementDefinition;
import org.opendaylight.yangtools.yang.model.api.stmt.SchemaTreeEffectiveStatement;
import org.opendaylight.yangtools.yang.parser.spi.SchemaTreeNamespace;
import org.opendaylight.yangtools.yang.parser.spi.meta.CopyType;
import org.opendaylight.yangtools.yang.parser.spi.meta.EffectiveStatementState;
import org.opendaylight.yangtools.yang.parser.spi.meta.InferenceException;
import org.opendaylight.yangtools.yang.parser.spi.meta.NamespaceBehaviour.OnDemandSchemaTreeStorageNode;
import org.opendaylight.yangtools.yang.parser.spi.meta.NamespaceBehaviour.StorageNodeType;
import org.opendaylight.yangtools.yang.parser.spi.meta.StatementFactory;
import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContext;
import org.opendaylight.yangtools.yang.parser.spi.meta.StmtContextUtils;
import org.opendaylight.yangtools.yang.parser.spi.source.StatementSourceReference;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A statement which has been inferred to exist. Functionally it is equivalent to a SubstatementContext, but it is not
 * backed by a declaration (and declared statements). It is backed by a prototype StatementContextBase and has only
 * effective substatements, which are either transformed from that prototype or added by inference.
 */
final class InferredStatementContext<A, D extends DeclaredStatement<A>, E extends EffectiveStatement<A, D>>
        extends StatementContextBase<A, D, E> implements OnDemandSchemaTreeStorageNode {
    // An effective copy view, with enough information to decide what to do next
    private static final class EffectiveCopy implements Immutable {
        // Original statement
        private final ReactorStmtCtx<?, ?, ?> orig;
        // Effective view, if the statement is to be reused it equals to orig
        private final ReactorStmtCtx<?, ?, ?> copy;

        EffectiveCopy(final ReactorStmtCtx<?, ?, ?> orig, final ReactorStmtCtx<?, ?, ?> copy) {
            this.orig = requireNonNull(orig);
            this.copy = requireNonNull(copy);
        }

        boolean isReused() {
            return orig == copy;
        }

        ReactorStmtCtx<?, ?, ?> toChildContext(final @NonNull InferredStatementContext<?, ?, ?> parent) {
            return isReused() ? orig.replicaAsChildOf(parent) : copy;
        }

        ReactorStmtCtx<?, ?, ?> toReusedChild(final @NonNull InferredStatementContext<?, ?, ?> parent) {
            verify(isReused(), "Attempted to discard copy %s", copy);
            return orig.replicaAsChildOf(parent);
        }
    }

    private static final Logger LOG = LoggerFactory.getLogger(InferredStatementContext.class);

    // Sentinel objects for 'substatements', String is a good enough type
    private static final @NonNull String REUSED_SUBSTATEMENTS = "reused";
    private static final @NonNull String SWEPT_SUBSTATEMENTS = "swept";

    private final @NonNull StatementContextBase<A, D, E> prototype;
    private final @NonNull StatementContextBase<?, ?, ?> parent;
    private final @NonNull ReactorStmtCtx<A, D, E> originalCtx;
    private final QNameModule targetModule;
    private final A argument;

    /**
     * Effective substatements, lazily materialized. This field can have four states:
     * <ul>
     *   <li>it can be {@code null}, in which case no materialization has taken place</li>
     *   <li>it can be a {@link HashMap}, in which case partial materialization has taken place</li>
     *   <li>it can be a {@link List}, in which case full materialization has taken place</li>
     *   <li>it can be {@link SWEPT_SUBSTATEMENTS}, in which case materialized state is no longer available</li>
     * </ul>
     */
    private Object substatements;

    private InferredStatementContext(final InferredStatementContext<A, D, E> original,
            final StatementContextBase<?, ?, ?> parent) {
        super(original);
        this.parent = requireNonNull(parent);
        this.targetModule = original.targetModule;
        this.prototype = original.prototype;
        this.originalCtx = original.originalCtx;
        this.argument = original.argument;
        // Substatements are initialized here
        this.substatements = ImmutableList.of();
    }

    InferredStatementContext(final StatementContextBase<?, ?, ?> parent, final StatementContextBase<A, D, E> prototype,
            final CopyType myCopyType, final CopyType childCopyType, final QNameModule targetModule) {
        super(prototype, myCopyType, childCopyType);
        this.parent = requireNonNull(parent);
        this.prototype = requireNonNull(prototype);
        this.argument = targetModule == null ? prototype.argument()
                : prototype.definition().adaptArgumentValue(prototype, targetModule);
        this.targetModule = targetModule;

        final var origCtx = prototype.getOriginalCtx().orElse(prototype);
        verify(origCtx instanceof ReactorStmtCtx, "Unexpected original %s", origCtx);
        this.originalCtx = (ReactorStmtCtx<A, D, E>) origCtx;

        // Mark prototype as blocking statement cleanup
        prototype.incRef();
    }

    @Override
    public Collection<? extends StatementContextBase<?, ?, ?>> mutableDeclaredSubstatements() {
        return ImmutableList.of();
    }

    @Override
    public Collection<? extends Mutable<?, ?, ?>> mutableEffectiveSubstatements() {
        return mutableEffectiveSubstatements(ensureEffectiveSubstatements());
    }

    @Override
    public Iterable<? extends @NonNull StmtContext<?, ?, ?>> allSubstatements() {
        // No need to concat with declared
        return effectiveSubstatements();
    }

    @Override
    public Stream<? extends @NonNull StmtContext<?, ?, ?>> allSubstatementsStream() {
        // No need to concat with declared
        return effectiveSubstatements().stream();
    }

    @Override
    public StatementSourceReference sourceReference() {
        return originalCtx.sourceReference();
    }

    @Override
    public String rawArgument() {
        return originalCtx.rawArgument();
    }

    @Override
    public Optional<StmtContext<A, D, E>> getOriginalCtx() {
        return Optional.of(originalCtx);
    }

    @Override
    public Optional<StmtContext<A, D, E>> getPreviousCopyCtx() {
        return Optional.of(prototype);
    }

    @Override
    public D declared() {
        /*
         * Share original instance of declared statement between all effective statements which have been copied or
         * derived from this original declared statement.
         */
        return originalCtx.declared();
    }

    @Override
    public void removeStatementFromEffectiveSubstatements(final StatementDefinition statementDef) {
        substatements = removeStatementFromEffectiveSubstatements(ensureEffectiveSubstatements(), statementDef);
    }

    @Override
    public void removeStatementFromEffectiveSubstatements(final StatementDefinition statementDef,
            final String statementArg) {
        substatements = removeStatementFromEffectiveSubstatements(ensureEffectiveSubstatements(), statementDef,
            statementArg);
    }

    @Override
    public void addEffectiveSubstatement(final Mutable<?, ?, ?> substatement) {
        substatements = addEffectiveSubstatement(ensureEffectiveSubstatements(), substatement);
        afterAddEffectiveSubstatement(substatement);
    }

    @Override
    void addEffectiveSubstatementsImpl(final Collection<? extends Mutable<?, ?, ?>> statements) {
        substatements = addEffectiveSubstatementsImpl(ensureEffectiveSubstatements(), statements);
    }

    @Override
    InferredStatementContext<A, D, E> reparent(final StatementContextBase<?, ?, ?> newParent) {
        return new InferredStatementContext<>(this, newParent);
    }

    @Override
    E createEffective(final StatementFactory<A, D, E> factory) {
        // If we have not materialized we do not have a difference in effective substatements, hence we can forward
        // towards the source of the statement.
        accessSubstatements();
        return substatements == null ? tryToReusePrototype(factory) : createInferredEffective(factory);
    }

    private @NonNull E createInferredEffective(final @NonNull StatementFactory<A, D, E> factory) {
        return createInferredEffective(factory, this, streamDeclared(), streamEffective());
    }

    @Override
    E createInferredEffective(final StatementFactory<A, D, E> factory, final InferredStatementContext<A, D, E> ctx,
            final Stream<? extends StmtContext<?, ?, ?>> declared,
            final Stream<? extends StmtContext<?, ?, ?>> effective) {
        return originalCtx.createInferredEffective(factory, ctx, declared, effective);
    }

    private @NonNull E tryToReusePrototype(final @NonNull StatementFactory<A, D, E> factory) {
        final E origEffective = prototype.buildEffective();
        final Collection<? extends @NonNull EffectiveStatement<?, ?>> origSubstatements =
            origEffective.effectiveSubstatements();

        // First check if we can reuse the entire prototype
        if (!factory.canReuseCurrent(this, prototype, origSubstatements)) {
            return internAlongCopyAxis(factory, tryToReuseSubstatements(factory, origEffective));
        }

        // We can reuse this statement let's see if all statements agree...
        // ... no substatements to deal with, we can freely reuse the original
        if (origSubstatements.isEmpty()) {
            LOG.debug("Reusing empty: {}", origEffective);
            substatements = ImmutableList.of();
            prototype.decRef();
            return origEffective;
        }

        // ... all are context independent, reuse the original
        if (allSubstatementsContextIndependent()) {
            LOG.debug("Reusing context-independent: {}", origEffective);
            substatements = noRefs() ? REUSED_SUBSTATEMENTS : reusePrototypeReplicas();
            prototype.decRef();
            return origEffective;
        }

        // ... copy-sensitive check
        final List<EffectiveCopy> declCopy = prototype.streamDeclared()
            .map(sub -> effectiveCopy((ReactorStmtCtx<?, ?, ?>) sub))
            .filter(Objects::nonNull)
            .collect(Collectors.toUnmodifiableList());
        final List<EffectiveCopy> effCopy = prototype.streamEffective()
            .map(sub -> effectiveCopy((ReactorStmtCtx<?, ?, ?>) sub))
            .filter(Objects::nonNull)
            .collect(Collectors.toUnmodifiableList());

        // ... are any copy-sensitive?
        if (allReused(declCopy) && allReused(effCopy)) {
            LOG.debug("Reusing after substatement check: {}", origEffective);
            substatements = noRefs() ? REUSED_SUBSTATEMENTS
                : reusePrototypeReplicas(Streams.concat(declCopy.stream(), effCopy.stream())
                    .map(copy -> copy.toReusedChild(this)));
            prototype.decRef();
            return origEffective;
        }

        // *sigh*, ok, heavy lifting through a shallow copy
        final List<ReactorStmtCtx<?, ?, ?>> declared = declCopy.stream()
            .map(copy -> copy.toChildContext(this))
            .collect(ImmutableList.toImmutableList());
        final List<ReactorStmtCtx<?, ?, ?>> effective = effCopy.stream()
            .map(copy -> copy.toChildContext(this))
            .collect(ImmutableList.toImmutableList());
        substatements = declared.isEmpty() ? effective
            : Streams.concat(declared.stream(), effective.stream()).collect(ImmutableList.toImmutableList());
        prototype.decRef();

        // Values are the effective copies, hence this efficiently deals with recursion.
        return internAlongCopyAxis(factory,
            originalCtx.createInferredEffective(factory, this, declared.stream(), effective.stream()));
    }

    private @NonNull E tryToReuseSubstatements(final @NonNull StatementFactory<A, D, E> factory,
            final @NonNull E original) {
        if (allSubstatementsContextIndependent()) {
            LOG.debug("Reusing substatements of: {}", prototype);
            substatements = noRefs() ? REUSED_SUBSTATEMENTS : reusePrototypeReplicas();
            prototype.decRef();
            return factory.copyEffective(this, original);
        }

        // Fall back to full instantiation, which populates our substatements. Then check if we should be reusing
        // the substatement list, as this operation turned out to not affect them.
        final E effective = createInferredEffective(factory);
        // Since we have forced instantiation to deal with this case, we also need to reset the 'modified' flag
        setUnmodified();

        if (sameSubstatements(original.effectiveSubstatements(), effective)) {
            LOG.debug("Reusing unchanged substatements of: {}", prototype);
            return factory.copyEffective(this, original);
        }
        return effective;
    }

    private @NonNull E internAlongCopyAxis(final StatementFactory<A, D, E> factory, final @NonNull E stmt) {
        if (!isModified()) {
            final EffectiveStatementState state = factory.extractEffectiveState(stmt);
            if (state != null) {
                return prototype.unmodifiedEffectiveSource().attachEffectiveCopy(state, stmt);
            }
        }
        return stmt;
    }

    private List<ReactorStmtCtx<?, ?, ?>> reusePrototypeReplicas() {
        return reusePrototypeReplicas(Streams.concat(prototype.streamDeclared(), prototype.streamEffective()));
    }

    private List<ReactorStmtCtx<?, ?, ?>> reusePrototypeReplicas(final Stream<StmtContext<?, ?, ?>> stream) {
        return stream
            .map(stmt -> {
                final ReplicaStatementContext<?, ?, ?> ret = ((ReactorStmtCtx<?, ?, ?>) stmt).replicaAsChildOf(this);
                ret.buildEffective();
                return ret;
            })
            .collect(Collectors.toUnmodifiableList());
    }

    private static boolean sameSubstatements(final Collection<?> original, final EffectiveStatement<?, ?> effective) {
        final Collection<?> copied = effective.effectiveSubstatements();
        if (copied != effective.effectiveSubstatements() || original.size() != copied.size()) {
            // Do not bother if result is treating substatements as transient
            return false;
        }

        final Iterator<?> oit = original.iterator();
        final Iterator<?> cit = copied.iterator();
        while (oit.hasNext()) {
            verify(cit.hasNext());
            // Identity comparison on purpose to side-step whatever equality there might be. We want to reuse instances
            // after all.
            if (oit.next() != cit.next()) {
                return false;
            }
        }
        verify(!cit.hasNext());
        return true;
    }

    private static boolean allReused(final List<EffectiveCopy> entries) {
        return entries.stream().allMatch(EffectiveCopy::isReused);
    }

    @Override
    ReactorStmtCtx<A, D, E> unmodifiedEffectiveSource() {
        return isModified() ? this : prototype.unmodifiedEffectiveSource();
    }

    @Override
    boolean hasEmptySubstatements() {
        if (substatements == null) {
            return prototype.hasEmptySubstatements();
        }
        return substatements instanceof HashMap ? false : ((List<?>) substatements).isEmpty();
    }

    @Override
    boolean noSensitiveSubstatements() {
        accessSubstatements();
        if (substatements == null) {
            // No difference, defer to prototype
            return prototype.allSubstatementsContextIndependent();
        }
        if (substatements instanceof List) {
            // Fully materialized, walk all statements
            return noSensitiveSubstatements(castEffective(substatements));
        }

        // Partially-materialized. This case has three distinct outcomes:
        // - prototype does not have a sensitive statement (1)
        // - protype has a sensitive substatement, and
        //   - we have not marked is as unsupported (2)
        //   - we have marked it as unsupported (3)
        //
        // Determining the outcome between (2) and (3) is a bother, this check errs on the side of false negative side
        // and treats (3) as (2) -- i.e. even if we marked a sensitive statement as unsupported, we still consider it
        // as affecting the result.
        return prototype.allSubstatementsContextIndependent()
            && noSensitiveSubstatements(castMaterialized(substatements).values());
    }

    @Override
    <X, Z extends EffectiveStatement<X, ?>> @NonNull Optional<X> findSubstatementArgumentImpl(
            final @NonNull Class<Z> type) {
        if (substatements instanceof List) {
            return super.findSubstatementArgumentImpl(type);
        }

        final Optional<X> templateArg = prototype.findSubstatementArgument(type);
        if (templateArg.isEmpty()) {
            return templateArg;
        }
        if (SchemaTreeEffectiveStatement.class.isAssignableFrom(type)) {
            // X is known to be QName
            return (Optional<X>) templateArg.map(template -> ((QName) template).bindTo(targetModule));
        }
        return templateArg;
    }

    @Override
    boolean hasSubstatementImpl(final @NonNull Class<? extends EffectiveStatement<?, ?>> type) {
        return substatements instanceof List ? super.hasSubstatementImpl(type)
            // We do not allow deletion of partially-materialized statements, hence this is accurate
            : prototype.hasSubstatement(type);
    }

    @Override
    public <Y extends DeclaredStatement<QName>, Z extends SchemaTreeEffectiveStatement<Y>>
            StmtContext<QName, Y, Z> requestSchemaTreeChild(final QName qname) {
        if (substatements instanceof List) {
            // We have performed materialization, hence we have triggered creation of all our schema tree child
            // statements.
            return null;
        }

        final QName templateQName = qname.bindTo(StmtContextUtils.getRootModuleQName(prototype));
        LOG.debug("Materializing child {} from {}", qname, templateQName);

        final StmtContext<?, ?, ?> template;
        if (prototype instanceof InferredStatementContext) {
            // Note: we need to access namespace here, as the target statement may have already been populated, in which
            //       case we want to obtain the statement in local namespace storage.
            template = (StmtContext) ((InferredStatementContext<?, ?, ?>) prototype).getFromNamespace(
                SchemaTreeNamespace.class, templateQName);
        } else {
            template = prototype.allSubstatementsStream()
                .filter(stmt -> stmt.producesEffective(SchemaTreeEffectiveStatement.class)
                    && templateQName.equals(stmt.argument()))
                .findAny()
                .orElse(null);
        }

        if (template == null) {
            // We do not have a template, this child does not exist. It may be added later, but that is someone else's
            // responsibility.
            LOG.debug("Child {} does not have a template", qname);
            return null;
        }

        @SuppressWarnings("unchecked")
        final Mutable<QName, Y, Z> ret = (Mutable<QName, Y, Z>) copySubstatement((Mutable<?, ?, ?>) template)
            .orElseThrow(
                () -> new InferenceException(this, "Failed to materialize child %s template %s", qname, template));
        ensureCompletedPhase(ret);
        addMaterialized(template, ret);

        LOG.debug("Child {} materialized", qname);
        return ret;
    }

    // Instantiate this statement's effective substatements. Note this method has side-effects in namespaces and overall
    // BuildGlobalContext, hence it must be called at most once.
    private List<ReactorStmtCtx<?, ?, ?>> ensureEffectiveSubstatements() {
        accessSubstatements();
        return substatements instanceof List ? castEffective(substatements)
            : initializeSubstatements(castMaterialized(substatements));
    }

    @Override
    Iterator<ReactorStmtCtx<?, ?, ?>> effectiveChildrenToComplete() {
        // When we have not initialized, there are no statements to catch up: we will catch up when we are copying
        // from prototype (which is already at ModelProcessingPhase.EFFECTIVE_MODEL).
        if (substatements == null) {
            return Collections.emptyIterator();
        }
        accessSubstatements();
        if (substatements instanceof HashMap) {
            return castMaterialized(substatements).values().iterator();
        } else {
            return castEffective(substatements).iterator();
        }
    }

    @Override
    Stream<? extends @NonNull StmtContext<?, ?, ?>> streamDeclared() {
        return Stream.empty();
    }

    @Override
    Stream<? extends @NonNull StmtContext<?, ?, ?>> streamEffective() {
        return ensureEffectiveSubstatements().stream().filter(StmtContext::isSupportedToBuildEffective);
    }

    private void accessSubstatements() {
        if (substatements instanceof String) {
            throw new VerifyException("Access to " + substatements + " substatements of " + this);
        }
    }

    @Override
    void markNoParentRef() {
        final Object local = substatements;
        if (local != null) {
            markNoParentRef(castEffective(local));
        }
    }

    @Override
    int sweepSubstatements() {
        final Object local = substatements;
        substatements = SWEPT_SUBSTATEMENTS;
        int count = 0;
        if (local instanceof List) {
            final List<ReactorStmtCtx<?, ?, ?>> list = castEffective(local);
            sweep(list);
            count = countUnswept(list);
        }
        return count;
    }

    private List<ReactorStmtCtx<?, ?, ?>> initializeSubstatements(
            final Map<StmtContext<?, ?, ?>, ReactorStmtCtx<?, ?, ?>> materializedSchemaTree) {
        final Collection<? extends StatementContextBase<?, ?, ?>> declared = prototype.mutableDeclaredSubstatements();
        final Collection<? extends Mutable<?, ?, ?>> effective = prototype.mutableEffectiveSubstatements();

        final List<Mutable<?, ?, ?>> buffer = new ArrayList<>(declared.size() + effective.size());
        for (final Mutable<?, ?, ?> stmtContext : declared) {
            if (stmtContext.isSupportedByFeatures()) {
                copySubstatement(stmtContext, buffer, materializedSchemaTree);
            }
        }
        for (final Mutable<?, ?, ?> stmtContext : effective) {
            copySubstatement(stmtContext, buffer, materializedSchemaTree);
        }

        final List<ReactorStmtCtx<?, ?, ?>> ret = beforeAddEffectiveStatementUnsafe(ImmutableList.of(), buffer.size());
        ret.addAll((Collection) buffer);
        substatements = ret;
        setModified();

        prototype.decRef();
        return ret;
    }

    //
    // Statement copy mess starts here. As it turns out, it's not that much of a mess, but it does make your head spin
    // sometimes. Tread softly because you tread on my dreams.
    //

    private EffectiveCopy effectiveCopy(final ReactorStmtCtx<?, ?, ?> stmt) {
        final ReactorStmtCtx<?, ?, ?> effective = stmt.asEffectiveChildOf(this, childCopyType(), targetModule);
        return effective == null ? null : new EffectiveCopy(stmt, effective);
    }

    private void copySubstatement(final Mutable<?, ?, ?> substatement, final Collection<Mutable<?, ?, ?>> buffer,
            final Map<StmtContext<?, ?, ?>, ReactorStmtCtx<?, ?, ?>> materializedSchemaTree) {
        // Consult materialized substatements. We are in a copy operation and will end up throwing materialized
        // statements away -- hence we do not perform Map.remove() to save ourselves a mutation operation.
        //
        // We could also perform a Map.containsKey() and perform a bulk add, but that would mean the statement order
        // against parent would change -- and we certainly do not want that to happen.
        final ReactorStmtCtx<?, ?, ?> materialized = findMaterialized(materializedSchemaTree, substatement);
        if (materialized == null) {
            copySubstatement(substatement).ifPresent(copy -> {
                ensureCompletedPhase(copy);
                buffer.add(copy);
            });
        } else {
            buffer.add(materialized);
        }
    }

    private Optional<? extends Mutable<?, ?, ?>> copySubstatement(final Mutable<?, ?, ?> substatement) {
        return substatement.copyAsChildOf(this, childCopyType(), targetModule);
    }

    private void addMaterialized(final StmtContext<?, ?, ?> template, final Mutable<?, ?, ?> copy) {
        final HashMap<StmtContext<?, ?, ?>, ReactorStmtCtx<?, ?, ?>> materializedSchemaTree;
        if (substatements == null) {
            // Lazy initialization of backing map. We do not expect this to be used often or multiple times -- each hit
            // here means an inference along schema tree, such as deviate/augment. HashMap requires power-of-two and
            // defaults to 0.75 load factor -- we therefore size it to 4, i.e. next two inserts will not cause a
            // resizing operation.
            materializedSchemaTree = new HashMap<>(4);
            substatements = materializedSchemaTree;
            setModified();
        } else {
            verify(substatements instanceof HashMap, "Unexpected substatements %s", substatements);
            materializedSchemaTree = castMaterialized(substatements);
        }

        final StmtContext<?, ?, ?> existing = materializedSchemaTree.put(template,
            (StatementContextBase<?, ?, ?>) copy);
        if (existing != null) {
            throw new VerifyException(
                "Unexpected duplicate request for " + copy.argument() + " previous result was " + existing);
        }
    }

    private static @Nullable ReactorStmtCtx<?, ?, ?> findMaterialized(
            final Map<StmtContext<?, ?, ?>, ReactorStmtCtx<?, ?, ?>> materializedSchemaTree,
            final StmtContext<?, ?, ?> template) {
        return materializedSchemaTree == null ? null : materializedSchemaTree.get(template);
    }

    @SuppressWarnings("unchecked")
    private static List<ReactorStmtCtx<?, ?, ?>> castEffective(final Object substatements) {
        return (List<ReactorStmtCtx<?, ?, ?>>) substatements;
    }

    @SuppressWarnings("unchecked")
    private static HashMap<StmtContext<?, ?, ?>, ReactorStmtCtx<?, ?, ?>> castMaterialized(final Object substatements) {
        return (HashMap<StmtContext<?, ?, ?>, ReactorStmtCtx<?, ?, ?>>) substatements;
    }

    // Statement copy mess ends here

    /*
     * KEEP THINGS ORGANIZED!
     *
     * below methods exist in the same form in SubstatementContext. If any adjustment is made here, make sure it is
     * properly updated there.
     */
    @Override
    public A argument() {
        return argument;
    }

    @Override
    public StatementContextBase<?, ?, ?> getParentContext() {
        return parent;
    }

    @Override
    public StorageNodeType getStorageNodeType() {
        return StorageNodeType.STATEMENT_LOCAL;
    }

    @Override
    public StatementContextBase<?, ?, ?> getParentNamespaceStorage() {
        return parent;
    }

    @Override
    public RootStatementContext<?, ?, ?> getRoot() {
        return parent.getRoot();
    }

    @Override
    public EffectiveConfig effectiveConfig() {
        return effectiveConfig(parent);
    }

    @Override
    protected boolean isIgnoringIfFeatures() {
        return isIgnoringIfFeatures(parent);
    }

    @Override
    protected boolean isIgnoringConfig() {
        return isIgnoringConfig(parent);
    }

    @Override
    protected boolean isParentSupportedByFeatures() {
        return parent.isSupportedByFeatures();
    }
}