/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 */

/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch licenses this file to you under
 * the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.common.xcontent.support;

import org.opensearch.common.compress.CompressedXContent;
import org.opensearch.common.xcontent.XContentHelper;
import org.opensearch.common.xcontent.XContentType;
import org.opensearch.core.common.bytes.BytesReference;
import org.opensearch.core.xcontent.DeprecationHandler;
import org.opensearch.core.xcontent.MediaTypeRegistry;
import org.opensearch.core.xcontent.NamedXContentRegistry;
import org.opensearch.core.xcontent.ToXContent;
import org.opensearch.core.xcontent.ToXContentObject;
import org.opensearch.core.xcontent.XContentBuilder;
import org.opensearch.core.xcontent.XContentParser;
import org.opensearch.test.OpenSearchTestCase;
import org.hamcrest.Matchers;

import java.io.IOException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class XContentHelperTests extends OpenSearchTestCase {

    Map<String, Object> getMap(Object... keyValues) {
        Map<String, Object> map = new HashMap<>();
        for (int i = 0; i < keyValues.length; i++) {
            map.put((String) keyValues[i], keyValues[++i]);
        }
        return map;
    }

    Map<String, Object> getNamedMap(String name, Object... keyValues) {
        Map<String, Object> map = getMap(keyValues);

        Map<String, Object> namedMap = new HashMap<>(1);
        namedMap.put(name, map);
        return namedMap;
    }

    List<Object> getList(Object... values) {
        return Arrays.asList(values);
    }

    public void testMergingListValuesAreMapsOfOne() {
        Map<String, Object> defaults = getMap("test", getList(getNamedMap("name1", "t1", "1"), getNamedMap("name2", "t2", "2")));
        Map<String, Object> content = getMap("test", getList(getNamedMap("name2", "t3", "3"), getNamedMap("name4", "t4", "4")));
        Map<String, Object> expected = getMap(
            "test",
            getList(getNamedMap("name2", "t2", "2", "t3", "3"), getNamedMap("name4", "t4", "4"), getNamedMap("name1", "t1", "1"))
        );

        XContentHelper.mergeDefaults(content, defaults);

        assertThat(content, Matchers.equalTo(expected));
    }

    public void testToXContent() throws IOException {
        final XContentType xContentType = randomFrom(XContentType.values());
        final ToXContent toXContent;
        final boolean error;
        if (randomBoolean()) {
            if (randomBoolean()) {
                error = false;
                toXContent = (builder, params) -> builder.field("field", "value");
            } else {
                error = true;
                toXContent = (builder, params) -> builder.startObject().field("field", "value").endObject();
            }
        } else {
            if (randomBoolean()) {
                error = false;
                toXContent = (ToXContentObject) (builder, params) -> builder.startObject().field("field", "value").endObject();
            } else {
                error = true;
                toXContent = (ToXContentObject) (builder, params) -> builder.field("field", "value");
            }
        }
        if (error) {
            expectThrows(IOException.class, () -> XContentHelper.toXContent(toXContent, xContentType, randomBoolean()));
        } else {
            BytesReference bytes = XContentHelper.toXContent(toXContent, xContentType, randomBoolean());
            try (
                XContentParser parser = xContentType.xContent()
                    .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, bytes.streamInput())
            ) {
                assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
                assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
                assertTrue(parser.nextToken().isValue());
                assertEquals("value", parser.text());
                assertEquals(XContentParser.Token.END_OBJECT, parser.nextToken());
                assertNull(parser.nextToken());
            }
        }
    }

    public void testChildBytes() throws IOException {

        for (XContentType xContentType : XContentType.values()) {

            XContentBuilder builder = XContentBuilder.builder(xContentType.xContent());
            builder.startObject().startObject("level1");
            builder.startObject("level2")
                .startObject("object")
                .field("text", "string")
                .field("number", 10)
                .endObject()
                .startObject("object2")
                .field("boolean", true)
                .nullField("null")
                .startArray("array_of_strings")
                .value("string1")
                .value("string2")
                .endArray()
                .endObject()
                .endObject();
            builder.field("field", "value");
            builder.endObject().endObject();
            BytesReference input = BytesReference.bytes(builder);

            BytesReference bytes;
            try (
                XContentParser parser = xContentType.xContent()
                    .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, input.streamInput())
            ) {

                assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
                assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
                assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
                assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
                assertEquals("level2", parser.currentName());
                // Extract everything under 'level2' as a bytestream
                bytes = XContentHelper.childBytes(parser);
                assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
                assertEquals("field", parser.currentName());
            }

            // now parse the contents of 'level2'
            try (
                XContentParser parser = xContentType.xContent()
                    .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, bytes.streamInput())
            ) {
                assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
                assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
                assertEquals("object", parser.currentName());
                assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
                assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
                assertEquals("text", parser.currentName());
                assertEquals(XContentParser.Token.VALUE_STRING, parser.nextToken());
                assertEquals("string", parser.text());
                assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
                assertEquals("number", parser.currentName());
                assertEquals(XContentParser.Token.VALUE_NUMBER, parser.nextToken());
                assertEquals(10, parser.numberValue());
                assertEquals(XContentParser.Token.END_OBJECT, parser.nextToken());
                assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
                assertEquals("object2", parser.currentName());
                assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
                assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
                assertEquals("boolean", parser.currentName());
                assertEquals(XContentParser.Token.VALUE_BOOLEAN, parser.nextToken());
                assertTrue(parser.booleanValue());
                assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
                assertEquals("null", parser.currentName());
                assertEquals(XContentParser.Token.VALUE_NULL, parser.nextToken());
                assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
                assertEquals("array_of_strings", parser.currentName());
                assertEquals(XContentParser.Token.START_ARRAY, parser.nextToken());
                assertEquals(XContentParser.Token.VALUE_STRING, parser.nextToken());
                assertEquals("string1", parser.text());
                assertEquals(XContentParser.Token.VALUE_STRING, parser.nextToken());
                assertEquals("string2", parser.text());
                assertEquals(XContentParser.Token.END_ARRAY, parser.nextToken());
                assertEquals(XContentParser.Token.END_OBJECT, parser.nextToken());
                assertEquals(XContentParser.Token.END_OBJECT, parser.nextToken());
                assertNull(parser.nextToken());
            }

        }
    }

    public void testEmbeddedObject() throws IOException {
        // Need to test this separately as MediaTypeRegistry.JSON never produces VALUE_EMBEDDED_OBJECT
        XContentBuilder builder = XContentBuilder.builder(XContentType.CBOR.xContent());
        builder.startObject().startObject("root");
        CompressedXContent embedded = new CompressedXContent("{\"field\":\"value\"}");
        builder.field("bytes", embedded.compressed());
        builder.endObject().endObject();
        BytesReference bytes = BytesReference.bytes(builder);

        BytesReference inner;
        try (
            XContentParser parser = XContentType.CBOR.xContent()
                .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, bytes.streamInput())
        ) {

            assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
            assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
            inner = XContentHelper.childBytes(parser);
            assertEquals(XContentParser.Token.END_OBJECT, parser.nextToken());
            assertNull(parser.nextToken());
        }

        try (
            XContentParser parser = XContentType.CBOR.xContent()
                .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, inner.streamInput())
        ) {

            assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
            assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
            assertEquals("bytes", parser.currentName());
            assertEquals(XContentParser.Token.VALUE_EMBEDDED_OBJECT, parser.nextToken());
            assertEquals(embedded, new CompressedXContent(parser.binaryValue()));
            assertEquals(XContentParser.Token.END_OBJECT, parser.nextToken());
            assertNull(parser.nextToken());

        }
    }

    public void testEmptyChildBytes() throws IOException {

        String inputJson = "{ \"mappings\" : {} }";
        try (
            XContentParser parser = MediaTypeRegistry.JSON.xContent()
                .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, inputJson)
        ) {

            assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
            assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
            BytesReference bytes = XContentHelper.childBytes(parser);
            assertEquals(XContentParser.Token.END_OBJECT, parser.nextToken());
            assertNull(parser.nextToken());

            assertEquals("{}", bytes.utf8ToString());

        }

    }
}
