/*
 * Copyright (c) 2017 Pantheon Technologies, 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.rfc7950.stmt.key;

import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.ImmutableSet.Builder;
import java.util.Collection;
import org.opendaylight.yangtools.yang.common.QName;
import org.opendaylight.yangtools.yang.common.QNameModule;
import org.opendaylight.yangtools.yang.model.api.YangStmtMapping;
import org.opendaylight.yangtools.yang.model.api.meta.EffectiveStatement;
import org.opendaylight.yangtools.yang.model.api.stmt.KeyStatement;
import org.opendaylight.yangtools.yang.model.api.stmt.SchemaNodeIdentifier;
import org.opendaylight.yangtools.yang.parser.spi.meta.AbstractStatementSupport;
import org.opendaylight.yangtools.yang.parser.spi.meta.QNameCacheNamespace;
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.meta.SubstatementValidator;
import org.opendaylight.yangtools.yang.parser.spi.source.SourceException;

public final class KeyStatementSupport
        extends AbstractStatementSupport<Collection<SchemaNodeIdentifier>, KeyStatement,
                EffectiveStatement<Collection<SchemaNodeIdentifier>, KeyStatement>> {
    private static final Splitter LIST_KEY_SPLITTER = Splitter.on(' ').omitEmptyStrings().trimResults();
    private static final SubstatementValidator SUBSTATEMENT_VALIDATOR = SubstatementValidator.builder(
        YangStmtMapping.KEY)
        .build();
    private static final KeyStatementSupport INSTANCE = new KeyStatementSupport();

    private KeyStatementSupport() {
        super(YangStmtMapping.KEY);
    }

    public static KeyStatementSupport getInstance() {
        return INSTANCE;
    }

    @Override
    public Collection<SchemaNodeIdentifier> parseArgumentValue(final StmtContext<?, ?, ?> ctx, final String value) {
        final Builder<SchemaNodeIdentifier> builder = ImmutableSet.builder();
        int tokens = 0;
        for (String keyToken : LIST_KEY_SPLITTER.split(value)) {
            builder.add(SchemaNodeIdentifier.SAME.createChild(StmtContextUtils.qnameFromArgument(ctx, keyToken)));
            tokens++;
        }

        // Throws NPE on nulls, retains first inserted value, cannot be modified
        final Collection<SchemaNodeIdentifier> ret = builder.build();
        SourceException.throwIf(ret.size() != tokens, ctx.getStatementSourceReference(),
                "Key argument '%s' contains duplicates", value);
        return ret;
    }

    @Override
    public Collection<SchemaNodeIdentifier> adaptArgumentValue(
            final StmtContext<Collection<SchemaNodeIdentifier>, KeyStatement,
                EffectiveStatement<Collection<SchemaNodeIdentifier>, KeyStatement>> ctx,
            final QNameModule targetModule) {
        final Builder<SchemaNodeIdentifier> builder = ImmutableSet.builder();
        boolean replaced = false;
        for (final SchemaNodeIdentifier arg : ctx.getStatementArgument()) {
            final QName qname = arg.getLastComponent();
            if (!targetModule.equals(qname.getModule())) {
                final QName newQname = ctx.getFromNamespace(QNameCacheNamespace.class,
                        QName.create(targetModule, qname.getLocalName()));
                builder.add(SchemaNodeIdentifier.SAME.createChild(newQname));
                replaced = true;
            } else {
                builder.add(arg);
            }
        }

        // This makes sure we reuse the collection when a grouping is
        // instantiated in the same module
        return replaced ? builder.build() : ctx.getStatementArgument();
    }

    @Override
    public KeyStatement createDeclared(final StmtContext<Collection<SchemaNodeIdentifier>, KeyStatement, ?> ctx) {
        return new KeyStatementImpl(ctx);
    }

    @Override
    public EffectiveStatement<Collection<SchemaNodeIdentifier>, KeyStatement> createEffective(
            final StmtContext<Collection<SchemaNodeIdentifier>, KeyStatement,
                    EffectiveStatement<Collection<SchemaNodeIdentifier>, KeyStatement>> ctx) {
        return new KeyEffectiveStatementImpl(ctx);
    }

    @Override
    protected SubstatementValidator getSubstatementValidator() {
        return SUBSTATEMENT_VALIDATOR;
    }
}