/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the "Elastic License
 * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
 * Public License v 1"; you may not use this file except in compliance with, at
 * your election, the "Elastic License 2.0", the "GNU Affero General Public
 * License v3.0 only", or the "Server Side Public License, v 1".
 */

package org.elasticsearch.action.ingest;

import org.elasticsearch.ElasticsearchException;
import org.elasticsearch.common.io.stream.BytesStreamOutput;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.test.AbstractXContentTestCase;
import org.elasticsearch.xcontent.ConstructingObjectParser;
import org.elasticsearch.xcontent.ParseField;
import org.elasticsearch.xcontent.XContentParser;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.StringJoiner;
import java.util.function.Predicate;
import java.util.function.Supplier;

import static org.elasticsearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
import static org.elasticsearch.ingest.IngestDocumentMatcher.assertIngestDocument;
import static org.elasticsearch.xcontent.ConstructingObjectParser.constructorArg;
import static org.hamcrest.CoreMatchers.equalTo;
import static org.hamcrest.CoreMatchers.instanceOf;
import static org.hamcrest.CoreMatchers.nullValue;

public class SimulatePipelineResponseTests extends AbstractXContentTestCase<SimulatePipelineResponse> {

    @SuppressWarnings("unchecked")
    private static final ConstructingObjectParser<SimulatePipelineResponse, Void> PARSER = new ConstructingObjectParser<>(
        "simulate_pipeline_response",
        true,
        a -> {
            List<SimulateDocumentResult> results = (List<SimulateDocumentResult>) a[0];
            boolean verbose = false;
            if (results.size() > 0) {
                if (results.get(0) instanceof SimulateDocumentVerboseResult) {
                    verbose = true;
                }
            }
            return new SimulatePipelineResponse(null, verbose, results);
        }
    );
    static {
        PARSER.declareObjectArray(constructorArg(), (parser, context) -> {
            XContentParser.Token token = parser.currentToken();
            ensureExpectedToken(XContentParser.Token.START_OBJECT, token, parser);
            SimulateDocumentResult result = null;
            while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
                ensureExpectedToken(XContentParser.Token.FIELD_NAME, token, parser);
                String fieldName = parser.currentName();
                token = parser.nextToken();
                if (token == XContentParser.Token.START_ARRAY) {
                    if (fieldName.equals(SimulateDocumentVerboseResult.PROCESSOR_RESULT_FIELD)) {
                        List<SimulateProcessorResult> results = new ArrayList<>();
                        while ((token = parser.nextToken()) == XContentParser.Token.START_OBJECT) {
                            results.add(SimulateProcessorResult.fromXContent(parser));
                        }
                        ensureExpectedToken(XContentParser.Token.END_ARRAY, token, parser);
                        result = new SimulateDocumentVerboseResult(results);
                    } else {
                        parser.skipChildren();
                    }
                } else if (token.equals(XContentParser.Token.START_OBJECT)) {
                    switch (fieldName) {
                        case WriteableIngestDocument.DOC_FIELD -> result = new SimulateDocumentBaseResult(
                            WriteableIngestDocument.INGEST_DOC_PARSER.apply(parser, null).getIngestDocument()
                        );
                        case "error" -> result = new SimulateDocumentBaseResult(ElasticsearchException.fromXContent(parser));
                        default -> parser.skipChildren();
                    }
                } // else it is a value skip it
            }
            assert result != null;
            return result;
        }, new ParseField(SimulatePipelineResponse.Fields.DOCUMENTS));
    }

    public void testSerialization() throws IOException {
        boolean isVerbose = randomBoolean();
        String id = randomBoolean() ? randomAlphaOfLengthBetween(1, 10) : null;

        SimulatePipelineResponse response = createInstance(id, isVerbose, true);
        BytesStreamOutput out = new BytesStreamOutput();
        response.writeTo(out);
        StreamInput streamInput = out.bytes().streamInput();
        SimulatePipelineResponse otherResponse = new SimulatePipelineResponse(streamInput);

        assertThat(otherResponse.getPipelineId(), equalTo(response.getPipelineId()));
        assertThat(otherResponse.getResults().size(), equalTo(response.getResults().size()));

        Iterator<SimulateDocumentResult> expectedResultIterator = response.getResults().iterator();
        for (SimulateDocumentResult result : otherResponse.getResults()) {
            if (isVerbose) {
                SimulateDocumentVerboseResult expectedSimulateDocumentVerboseResult = (SimulateDocumentVerboseResult) expectedResultIterator
                    .next();
                assertThat(result, instanceOf(SimulateDocumentVerboseResult.class));
                SimulateDocumentVerboseResult simulateDocumentVerboseResult = (SimulateDocumentVerboseResult) result;
                assertThat(
                    simulateDocumentVerboseResult.getProcessorResults().size(),
                    equalTo(expectedSimulateDocumentVerboseResult.getProcessorResults().size())
                );
                Iterator<SimulateProcessorResult> expectedProcessorResultIterator = expectedSimulateDocumentVerboseResult
                    .getProcessorResults()
                    .iterator();
                for (SimulateProcessorResult simulateProcessorResult : simulateDocumentVerboseResult.getProcessorResults()) {
                    SimulateProcessorResult expectedProcessorResult = expectedProcessorResultIterator.next();
                    assertThat(simulateProcessorResult.getProcessorTag(), equalTo(expectedProcessorResult.getProcessorTag()));
                    if (simulateProcessorResult.getIngestDocument() != null) {
                        assertIngestDocument(simulateProcessorResult.getIngestDocument(), expectedProcessorResult.getIngestDocument());
                    }
                    if (expectedProcessorResult.getFailure() == null) {
                        assertThat(simulateProcessorResult.getFailure(), nullValue());
                    } else {
                        assertThat(simulateProcessorResult.getFailure(), instanceOf(IllegalArgumentException.class));
                        IllegalArgumentException e = (IllegalArgumentException) simulateProcessorResult.getFailure();
                        assertThat(e.getMessage(), equalTo("test"));
                    }
                }
            } else {
                SimulateDocumentBaseResult expectedSimulateDocumentBaseResult = (SimulateDocumentBaseResult) expectedResultIterator.next();
                assertThat(result, instanceOf(SimulateDocumentBaseResult.class));
                SimulateDocumentBaseResult simulateDocumentBaseResult = (SimulateDocumentBaseResult) result;
                if (simulateDocumentBaseResult.getIngestDocument() != null) {
                    assertIngestDocument(
                        simulateDocumentBaseResult.getIngestDocument(),
                        expectedSimulateDocumentBaseResult.getIngestDocument()
                    );
                }
                if (expectedSimulateDocumentBaseResult.getFailure() == null) {
                    assertThat(simulateDocumentBaseResult.getFailure(), nullValue());
                } else {
                    assertThat(simulateDocumentBaseResult.getFailure(), instanceOf(IllegalArgumentException.class));
                    IllegalArgumentException e = (IllegalArgumentException) simulateDocumentBaseResult.getFailure();
                    assertThat(e.getMessage(), equalTo("test"));
                }
            }
        }
    }

    static SimulatePipelineResponse createInstance(String pipelineId, boolean isVerbose, boolean withFailure) {
        int numResults = randomIntBetween(1, 5);
        List<SimulateDocumentResult> results = new ArrayList<>(numResults);
        for (int i = 0; i < numResults; i++) {
            if (isVerbose) {
                results.add(SimulateDocumentVerboseResultTests.createTestInstance(withFailure));
            } else {
                results.add(SimulateDocumentBaseResultTests.createTestInstance(withFailure && randomBoolean()));
            }
        }
        return new SimulatePipelineResponse(pipelineId, isVerbose, results);
    }

    private static SimulatePipelineResponse createTestInstanceWithFailures() {
        boolean isVerbose = randomBoolean();
        return createInstance(null, isVerbose, false);
    }

    @Override
    protected SimulatePipelineResponse createTestInstance() {
        boolean isVerbose = randomBoolean();
        // since the pipeline id is not serialized with XContent we set it to null for equality tests.
        // we test failures separately since comparing XContent is not possible with failures
        return createInstance(null, isVerbose, false);
    }

    @Override
    protected SimulatePipelineResponse doParseInstance(XContentParser parser) {
        return PARSER.apply(parser, null);
    }

    @Override
    protected boolean supportsUnknownFields() {
        return true;
    }

    @Override
    protected void assertEqualInstances(SimulatePipelineResponse response, SimulatePipelineResponse parsedResponse) {
        assertEquals(response.getPipelineId(), parsedResponse.getPipelineId());
        assertEquals(response.isVerbose(), parsedResponse.isVerbose());
        assertEquals(response.getResults().size(), parsedResponse.getResults().size());
        for (int i = 0; i < response.getResults().size(); i++) {
            if (response.isVerbose()) {
                assertThat(response.getResults().get(i), instanceOf(SimulateDocumentVerboseResult.class));
                assertThat(parsedResponse.getResults().get(i), instanceOf(SimulateDocumentVerboseResult.class));
                SimulateDocumentVerboseResult responseResult = (SimulateDocumentVerboseResult) response.getResults().get(i);
                SimulateDocumentVerboseResult parsedResult = (SimulateDocumentVerboseResult) parsedResponse.getResults().get(i);
                SimulateDocumentVerboseResultTests.assertEqualDocs(responseResult, parsedResult);
            } else {
                assertThat(response.getResults().get(i), instanceOf(SimulateDocumentBaseResult.class));
                assertThat(parsedResponse.getResults().get(i), instanceOf(SimulateDocumentBaseResult.class));
                SimulateDocumentBaseResult responseResult = (SimulateDocumentBaseResult) response.getResults().get(i);
                SimulateDocumentBaseResult parsedResult = (SimulateDocumentBaseResult) parsedResponse.getResults().get(i);
                SimulateDocumentBaseResultTests.assertEqualDocs(responseResult, parsedResult);
            }
        }
    }

    @Override
    protected Predicate<String> getRandomFieldsExcludeFilter() {
        // We cannot have random fields in the _source field and _ingest field
        return field -> field.contains(
            new StringJoiner(".").add(WriteableIngestDocument.DOC_FIELD).add(WriteableIngestDocument.SOURCE_FIELD).toString()
        )
            || field.contains(
                new StringJoiner(".").add(WriteableIngestDocument.DOC_FIELD).add(WriteableIngestDocument.INGEST_FIELD).toString()
            );
    }

    /**
     * Test parsing {@link SimulatePipelineResponse} with inner failures as they don't support asserting on xcontent equivalence, given that
     * exceptions are not parsed back as the same original class. We run the usual {@link AbstractXContentTestCase#testFromXContent()}
     * without failures, and this other test with failures where we disable asserting on xcontent equivalence at the end.
     */
    public void testFromXContentWithFailures() throws IOException {
        Supplier<SimulatePipelineResponse> instanceSupplier = SimulatePipelineResponseTests::createTestInstanceWithFailures;
        // exceptions are not of the same type whenever parsed back
        boolean assertToXContentEquivalence = false;
        AbstractXContentTestCase.testFromXContent(
            NUMBER_OF_TEST_RUNS,
            instanceSupplier,
            supportsUnknownFields(),
            getShuffleFieldsExceptions(),
            getRandomFieldsExcludeFilter(),
            this::createParser,
            this::doParseInstance,
            this::assertEqualInstances,
            assertToXContentEquivalence,
            getToXContentParams()
        );
    }
}