/*
 * 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.data.impl.codec;

import static com.google.common.base.Preconditions.checkArgument;

import com.google.common.annotations.Beta;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableSet;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import org.opendaylight.yangtools.yang.data.api.codec.BitsCodec;
import org.opendaylight.yangtools.yang.model.api.type.BitsTypeDefinition;
import org.opendaylight.yangtools.yang.model.api.type.BitsTypeDefinition.Bit;

/**
 * Do not use this class outside of yangtools, its presence does not fall into the API stability contract.
 */
@Beta
public final class BitsStringCodec extends TypeDefinitionAwareCodec<Set<String>, BitsTypeDefinition>
        implements BitsCodec<String> {
    private static final Joiner JOINER = Joiner.on(" ").skipNulls();
    private static final Splitter SPLITTER = Splitter.on(' ').omitEmptyStrings().trimResults();

    private final ImmutableSet<String> validBits;

    @SuppressWarnings("unchecked")
    private BitsStringCodec(final BitsTypeDefinition typeDef) {
        super((Class<Set<String>>) (Class<?>) Set.class, typeDef);
        validBits = typeDef.getBits().stream()
            .map(Bit::getName)
            .collect(ImmutableSet.toImmutableSet());
    }

    public static BitsStringCodec from(final BitsTypeDefinition type) {
        return new BitsStringCodec(type);
    }

    @Override
    protected Set<String> deserializeImpl(final String product) {
        final Set<String> strings = ImmutableSet.copyOf(SPLITTER.split(product));

        // Normalize strings to schema first, retaining definition order
        final List<String> sorted = new ArrayList<>(strings.size());
        for (final String bit : validBits) {
            if (strings.contains(bit)) {
                sorted.add(bit);
            }
        }

        // Check sizes, if the normalized set does not match non-normalized size, non-normalized strings contain
        // an invalid bit.
        if (sorted.size() != strings.size()) {
            for (final String bit : strings) {
                checkArgument(validBits.contains(bit), "Invalid value '%s' for bits type. Allowed values are: %s", bit,
                    validBits);
            }
        }

        // In case all valid bits have been specified, retain the set we have created for this codec
        return sorted.size() == validBits.size() ? validBits : ImmutableSet.copyOf(sorted);
    }

    @Override
    protected String serializeImpl(final Set<String> input) {
        return JOINER.join(input);
    }
}