/*
 * 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.index.get;

import org.opensearch.common.Strings;
import org.opensearch.core.common.bytes.BytesArray;
import org.opensearch.core.common.bytes.BytesReference;
import org.opensearch.common.collect.Tuple;
import org.opensearch.common.document.DocumentField;
import org.opensearch.common.io.stream.BytesStreamOutput;
import org.opensearch.core.xcontent.ToXContent;
import org.opensearch.common.xcontent.XContentHelper;
import org.opensearch.core.xcontent.XContentParser;
import org.opensearch.common.xcontent.XContentType;
import org.opensearch.index.mapper.IdFieldMapper;
import org.opensearch.index.mapper.IndexFieldMapper;
import org.opensearch.index.mapper.SeqNoFieldMapper;
import org.opensearch.index.mapper.SourceFieldMapper;
import org.opensearch.index.mapper.VersionFieldMapper;
import org.opensearch.test.OpenSearchTestCase;
import org.opensearch.test.RandomObjects;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.function.Predicate;
import java.util.function.Supplier;

import static java.util.Collections.singletonList;
import static java.util.Collections.singletonMap;
import static org.opensearch.common.xcontent.XContentHelper.toXContent;
import static org.opensearch.core.xcontent.XContentParserUtils.ensureExpectedToken;
import static org.opensearch.index.get.DocumentFieldTests.randomDocumentField;
import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_PRIMARY_TERM;
import static org.opensearch.index.seqno.SequenceNumbers.UNASSIGNED_SEQ_NO;
import static org.opensearch.test.EqualsHashCodeTestUtils.checkEqualsAndHashCode;
import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertToXContentEquivalent;

public class GetResultTests extends OpenSearchTestCase {

    public void testToAndFromXContent() throws Exception {
        XContentType xContentType = randomFrom(XContentType.values());
        Tuple<GetResult, GetResult> tuple = randomGetResult(xContentType);
        GetResult getResult = tuple.v1();
        GetResult expectedGetResult = tuple.v2();
        boolean humanReadable = randomBoolean();
        BytesReference originalBytes = toShuffledXContent(getResult, xContentType, ToXContent.EMPTY_PARAMS, humanReadable, "_source");
        // test that we can parse what we print out
        GetResult parsedGetResult;
        try (XContentParser parser = createParser(xContentType.xContent(), originalBytes)) {
            parsedGetResult = GetResult.fromXContent(parser);
            assertNull(parser.nextToken());
        }
        assertEquals(expectedGetResult, parsedGetResult);
        // print the parsed object out and test that the output is the same as the original output
        BytesReference finalBytes = toXContent(parsedGetResult, xContentType, humanReadable);
        assertToXContentEquivalent(originalBytes, finalBytes, xContentType);
        // check that the source stays unchanged, no shuffling of keys nor anything like that
        assertEquals(expectedGetResult.sourceAsString(), parsedGetResult.sourceAsString());
    }

    public void testToXContent() throws IOException {
        {
            GetResult getResult = new GetResult(
                "index",
                "id",
                0,
                1,
                1,
                true,
                new BytesArray("{ \"field1\" : " + "\"value1\", \"field2\":\"value2\"}"),
                singletonMap("field1", new DocumentField("field1", singletonList("value1"))),
                singletonMap("field1", new DocumentField("metafield", singletonList("metavalue")))
            );
            String output = Strings.toString(XContentType.JSON, getResult);
            assertEquals(
                "{\"_index\":\"index\",\"_id\":\"id\",\"_version\":1,\"_seq_no\":0,\"_primary_term\":1,"
                    + "\"metafield\":\"metavalue\",\"found\":true,\"_source\":{ \"field1\" : \"value1\", \"field2\":\"value2\"},"
                    + "\"fields\":{\"field1\":[\"value1\"]}}",
                output
            );
        }
        {
            GetResult getResult = new GetResult("index", "id", UNASSIGNED_SEQ_NO, 0, 1, false, null, null, null);
            String output = Strings.toString(XContentType.JSON, getResult);
            assertEquals("{\"_index\":\"index\",\"_id\":\"id\",\"found\":false}", output);
        }
    }

    public void testToAndFromXContentEmbedded() throws Exception {
        XContentType xContentType = randomFrom(XContentType.values());
        Tuple<GetResult, GetResult> tuple = randomGetResult(xContentType);
        GetResult getResult = tuple.v1();
        // We don't expect to retrieve the index/type/id of the GetResult because they are not rendered
        // by the toXContentEmbedded method.
        GetResult expectedGetResult = new GetResult(
            null,
            null,
            tuple.v2().getSeqNo(),
            tuple.v2().getPrimaryTerm(),
            -1,
            tuple.v2().isExists(),
            tuple.v2().sourceRef(),
            tuple.v2().getDocumentFields(),
            tuple.v2().getMetadataFields()
        );

        boolean humanReadable = randomBoolean();
        BytesReference originalBytes = toXContentEmbedded(getResult, xContentType, humanReadable);

        // Test that we can parse the result of toXContentEmbedded()
        GetResult parsedEmbeddedGetResult;
        try (XContentParser parser = createParser(xContentType.xContent(), originalBytes)) {
            ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser);
            parsedEmbeddedGetResult = GetResult.fromXContentEmbedded(parser);
            assertNull(parser.nextToken());
        }
        assertEquals(expectedGetResult, parsedEmbeddedGetResult);
        // print the parsed object out and test that the output is the same as the original output
        BytesReference finalBytes = toXContentEmbedded(parsedEmbeddedGetResult, xContentType, humanReadable);
        assertToXContentEquivalent(originalBytes, finalBytes, xContentType);
        // check that the source stays unchanged, no shuffling of keys nor anything like that
        assertEquals(expectedGetResult.sourceAsString(), parsedEmbeddedGetResult.sourceAsString());
    }

    public void testToXContentEmbedded() throws IOException {
        Map<String, DocumentField> fields = new HashMap<>();
        fields.put("foo", new DocumentField("foo", singletonList("bar")));
        fields.put("baz", new DocumentField("baz", Arrays.asList("baz_0", "baz_1")));

        GetResult getResult = new GetResult(
            "index",
            "id",
            0,
            1,
            2,
            true,
            new BytesArray("{\"foo\":\"bar\",\"baz\":[\"baz_0\",\"baz_1\"]}"),
            fields,
            null
        );

        BytesReference originalBytes = toXContentEmbedded(getResult, XContentType.JSON, false);
        assertEquals(
            "{\"_seq_no\":0,\"_primary_term\":1,\"found\":true,\"_source\":{\"foo\":\"bar\",\"baz\":[\"baz_0\",\"baz_1\"]},"
                + "\"fields\":{\"foo\":[\"bar\"],\"baz\":[\"baz_0\",\"baz_1\"]}}",
            originalBytes.utf8ToString()
        );
    }

    public void testToXContentEmbeddedNotFound() throws IOException {
        GetResult getResult = new GetResult("index", "id", UNASSIGNED_SEQ_NO, 0, 1, false, null, null, null);

        BytesReference originalBytes = toXContentEmbedded(getResult, XContentType.JSON, false);
        assertEquals("{\"found\":false}", originalBytes.utf8ToString());
    }

    public void testSerializationNotFound() throws IOException {
        // serializes and deserializes with streamable, then prints back to xcontent
        GetResult getResult = new GetResult("index", "id", UNASSIGNED_SEQ_NO, 0, 1, false, null, null, null);

        BytesStreamOutput out = new BytesStreamOutput();
        getResult.writeTo(out);
        getResult = new GetResult(out.bytes().streamInput());

        BytesReference originalBytes = toXContentEmbedded(getResult, XContentType.JSON, false);
        assertEquals("{\"found\":false}", originalBytes.utf8ToString());
    }

    public void testGetSourceAsBytes() {
        XContentType xContentType = randomFrom(XContentType.values());
        Tuple<GetResult, GetResult> tuple = randomGetResult(xContentType);
        GetResult getResult = tuple.v1();
        if (getResult.isExists() && getResult.isSourceEmpty() == false) {
            assertNotNull(getResult.sourceRef());
        } else {
            assertNull(getResult.sourceRef());
        }
    }

    public void testEqualsAndHashcode() {
        checkEqualsAndHashCode(randomGetResult(XContentType.JSON).v1(), GetResultTests::copyGetResult, GetResultTests::mutateGetResult);
    }

    public static GetResult copyGetResult(GetResult getResult) {
        return new GetResult(
            getResult.getIndex(),
            getResult.getId(),
            getResult.getSeqNo(),
            getResult.getPrimaryTerm(),
            getResult.getVersion(),
            getResult.isExists(),
            getResult.internalSourceRef(),
            getResult.getDocumentFields(),
            getResult.getMetadataFields()
        );
    }

    public static GetResult mutateGetResult(GetResult getResult) {
        List<Supplier<GetResult>> mutations = new ArrayList<>();
        mutations.add(
            () -> new GetResult(
                randomUnicodeOfLength(15),
                getResult.getId(),
                getResult.getSeqNo(),
                getResult.getPrimaryTerm(),
                getResult.getVersion(),
                getResult.isExists(),
                getResult.internalSourceRef(),
                getResult.getFields(),
                null
            )
        );
        mutations.add(
            () -> new GetResult(
                getResult.getIndex(),
                randomUnicodeOfLength(15),
                getResult.getSeqNo(),
                getResult.getPrimaryTerm(),
                getResult.getVersion(),
                getResult.isExists(),
                getResult.internalSourceRef(),
                getResult.getFields(),
                null
            )
        );
        mutations.add(
            () -> new GetResult(
                getResult.getIndex(),
                getResult.getId(),
                getResult.getSeqNo(),
                getResult.getPrimaryTerm(),
                randomNonNegativeLong(),
                getResult.isExists(),
                getResult.internalSourceRef(),
                getResult.getFields(),
                null
            )
        );
        mutations.add(
            () -> new GetResult(
                getResult.getIndex(),
                getResult.getId(),
                getResult.isExists() ? UNASSIGNED_SEQ_NO : getResult.getSeqNo(),
                getResult.isExists() ? 0 : getResult.getPrimaryTerm(),
                getResult.getVersion(),
                getResult.isExists() == false,
                getResult.internalSourceRef(),
                getResult.getFields(),
                null
            )
        );
        mutations.add(
            () -> new GetResult(
                getResult.getIndex(),
                getResult.getId(),
                getResult.getSeqNo(),
                getResult.getPrimaryTerm(),
                getResult.getVersion(),
                getResult.isExists(),
                RandomObjects.randomSource(random()),
                getResult.getFields(),
                null
            )
        );
        mutations.add(
            () -> new GetResult(
                getResult.getIndex(),
                getResult.getId(),
                getResult.getSeqNo(),
                getResult.getPrimaryTerm(),
                getResult.getVersion(),
                getResult.isExists(),
                getResult.internalSourceRef(),
                randomDocumentFields(XContentType.JSON, randomBoolean()).v1(),
                null
            )
        );
        return randomFrom(mutations).get();
    }

    public static Tuple<GetResult, GetResult> randomGetResult(XContentType xContentType) {
        final String index = randomAlphaOfLengthBetween(3, 10);
        final String type = randomAlphaOfLengthBetween(3, 10);
        final String id = randomAlphaOfLengthBetween(3, 10);
        final long version;
        final long seqNo;
        final long primaryTerm;
        final boolean exists;
        BytesReference source = null;
        Map<String, DocumentField> docFields = null;
        Map<String, DocumentField> expectedDocFields = null;
        Map<String, DocumentField> metaFields = null;
        Map<String, DocumentField> expectedMetaFields = null;
        if (frequently()) {
            version = randomNonNegativeLong();
            seqNo = randomNonNegativeLong();
            primaryTerm = randomLongBetween(1, 100);
            exists = true;
            if (frequently()) {
                source = RandomObjects.randomSource(random());
            }
            if (randomBoolean()) {
                Tuple<Map<String, DocumentField>, Map<String, DocumentField>> tuple = randomDocumentFields(xContentType, false);
                docFields = tuple.v1();
                expectedDocFields = tuple.v2();

                tuple = randomDocumentFields(xContentType, true);
                metaFields = tuple.v1();
                expectedMetaFields = tuple.v2();
            }
        } else {
            seqNo = UNASSIGNED_SEQ_NO;
            primaryTerm = UNASSIGNED_PRIMARY_TERM;
            version = -1;
            exists = false;
        }
        GetResult getResult = new GetResult(index, id, seqNo, primaryTerm, version, exists, source, docFields, metaFields);
        GetResult expectedGetResult = new GetResult(
            index,
            id,
            seqNo,
            primaryTerm,
            version,
            exists,
            source,
            expectedDocFields,
            expectedMetaFields
        );
        return Tuple.tuple(getResult, expectedGetResult);
    }

    public static Tuple<Map<String, DocumentField>, Map<String, DocumentField>> randomDocumentFields(
        XContentType xContentType,
        boolean isMetaFields
    ) {
        int numFields = isMetaFields ? randomIntBetween(1, 3) : randomIntBetween(2, 10);
        Map<String, DocumentField> fields = new HashMap<>(numFields);
        Map<String, DocumentField> expectedFields = new HashMap<>(numFields);
        // As we are using this to construct a GetResult object that already contains
        // index, id, version, seqNo, and source fields, we need to exclude them from random fields
        Predicate<String> excludeMetaFieldFilter = field -> field.equals(IndexFieldMapper.NAME)
            || field.equals(IdFieldMapper.NAME)
            || field.equals(VersionFieldMapper.NAME)
            || field.equals(SourceFieldMapper.NAME)
            || field.equals(SeqNoFieldMapper.NAME);
        while (fields.size() < numFields) {
            Tuple<DocumentField, DocumentField> tuple = randomDocumentField(xContentType, isMetaFields, excludeMetaFieldFilter);
            DocumentField getField = tuple.v1();
            DocumentField expectedGetField = tuple.v2();
            if (fields.putIfAbsent(getField.getName(), getField) == null) {
                assertNull(expectedFields.putIfAbsent(expectedGetField.getName(), expectedGetField));
            }
        }
        return Tuple.tuple(fields, expectedFields);
    }

    private static BytesReference toXContentEmbedded(GetResult getResult, XContentType xContentType, boolean humanReadable)
        throws IOException {
        return XContentHelper.toXContent(getResult::toXContentEmbedded, xContentType, humanReadable);
    }
}