/*
 * Copyright (c) 2016 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.restconf.nb.rfc8040.jersey.providers;

import com.google.gson.stream.JsonWriter;
import java.io.IOException;
import java.io.OutputStream;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.ext.Provider;
import org.eclipse.jdt.annotation.Nullable;
import org.opendaylight.restconf.api.MediaTypes;
import org.opendaylight.restconf.api.query.PrettyPrintParam;
import org.opendaylight.restconf.nb.rfc8040.legacy.WriterParameters;
import org.opendaylight.restconf.server.spi.FormattableBodySupport;
import org.opendaylight.yangtools.yang.common.XMLNamespace;
import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeIdentifier;
import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode;
import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
import org.opendaylight.yangtools.yang.data.codec.gson.JSONCodecFactorySupplier;
import org.opendaylight.yangtools.yang.data.codec.gson.JSONNormalizedNodeStreamWriter;
import org.opendaylight.yangtools.yang.data.spi.node.ImmutableNodes;
import org.opendaylight.yangtools.yang.model.util.SchemaInferenceStack;
import org.opendaylight.yangtools.yang.model.util.SchemaInferenceStack.Inference;

@Provider
@Produces({ MediaTypes.APPLICATION_YANG_DATA_JSON, MediaType.APPLICATION_JSON })
public final class JsonNormalizedNodeBodyWriter extends AbstractNormalizedNodeBodyWriter {
    @Override
    void writeData(final SchemaInferenceStack stack, final NormalizedNode data, final WriterParameters writerParameters,
            final PrettyPrintParam prettyPrint, final OutputStream out) throws IOException {
        if (!stack.isEmpty()) {
            stack.exit();
        }

        // RESTCONF allows returning one list item. We need to wrap it in map node in order to serialize it properly
        final var toSerialize = data instanceof MapEntryNode mapEntry
            ? ImmutableNodes.newSystemMapBuilder()
                .withNodeIdentifier(new NodeIdentifier(data.name().getNodeType()))
                .withChild(mapEntry)
                .build()
                : data;

        try (var jsonWriter = FormattableBodySupport.createJsonWriter(out, prettyPrint)) {
            jsonWriter.beginObject();

            final var nnWriter = createNormalizedNodeWriter(stack.toInference(), jsonWriter, writerParameters, null);
            nnWriter.write(toSerialize);
            nnWriter.flush();

            jsonWriter.endObject().flush();
        }
    }

    private static RestconfNormalizedNodeWriter createNormalizedNodeWriter(final Inference inference,
            final JsonWriter jsonWriter, final WriterParameters writerParameters,
            final @Nullable XMLNamespace initialNamespace) {
        // TODO: Performance: Cache JSON Codec factory and schema context
        final var codecs = JSONCodecFactorySupplier.RFC7951.getShared(inference.modelContext());
        return RestconfNormalizedNodeWriter.forStreamWriter(
            JSONNormalizedNodeStreamWriter.createNestedWriter(codecs, inference,
                initialNamespace, jsonWriter), writerParameters.depth(), writerParameters.fields());
    }
}