/*
 * Copyright 2002-2019 the original author or authors.
 *
 * Licensed 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
 *
 *      https://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.
 */

package org.springframework.http.codec.support;

import java.nio.charset.StandardCharsets;
import java.time.Duration;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

import org.junit.jupiter.api.Test;
import reactor.core.publisher.Flux;

import org.springframework.core.ResolvableType;
import org.springframework.core.codec.ByteArrayDecoder;
import org.springframework.core.codec.ByteArrayEncoder;
import org.springframework.core.codec.ByteBufferDecoder;
import org.springframework.core.codec.ByteBufferEncoder;
import org.springframework.core.codec.CharSequenceEncoder;
import org.springframework.core.codec.DataBufferDecoder;
import org.springframework.core.codec.DataBufferEncoder;
import org.springframework.core.codec.Decoder;
import org.springframework.core.codec.Encoder;
import org.springframework.core.codec.StringDecoder;
import org.springframework.core.io.buffer.DefaultDataBufferFactory;
import org.springframework.http.MediaType;
import org.springframework.http.codec.ClientCodecConfigurer;
import org.springframework.http.codec.DecoderHttpMessageReader;
import org.springframework.http.codec.EncoderHttpMessageWriter;
import org.springframework.http.codec.FormHttpMessageReader;
import org.springframework.http.codec.HttpMessageReader;
import org.springframework.http.codec.HttpMessageWriter;
import org.springframework.http.codec.ResourceHttpMessageReader;
import org.springframework.http.codec.ResourceHttpMessageWriter;
import org.springframework.http.codec.ServerSentEventHttpMessageReader;
import org.springframework.http.codec.json.Jackson2JsonDecoder;
import org.springframework.http.codec.json.Jackson2JsonEncoder;
import org.springframework.http.codec.json.Jackson2SmileDecoder;
import org.springframework.http.codec.json.Jackson2SmileEncoder;
import org.springframework.http.codec.multipart.MultipartHttpMessageWriter;
import org.springframework.http.codec.protobuf.ProtobufDecoder;
import org.springframework.http.codec.protobuf.ProtobufHttpMessageWriter;
import org.springframework.http.codec.xml.Jaxb2XmlDecoder;
import org.springframework.http.codec.xml.Jaxb2XmlEncoder;
import org.springframework.util.MimeTypeUtils;

import static org.assertj.core.api.Assertions.assertThat;
import static org.springframework.core.ResolvableType.forClass;

/**
 * Unit tests for {@link ClientCodecConfigurer}.
 *
 * @author Rossen Stoyanchev
 */
public class ClientCodecConfigurerTests {

	private final ClientCodecConfigurer configurer = new DefaultClientCodecConfigurer();

	private final AtomicInteger index = new AtomicInteger(0);


	@Test
	public void defaultReaders() {
		List<HttpMessageReader<?>> readers = this.configurer.getReaders();
		assertThat(readers.size()).isEqualTo(12);
		assertThat(getNextDecoder(readers).getClass()).isEqualTo(ByteArrayDecoder.class);
		assertThat(getNextDecoder(readers).getClass()).isEqualTo(ByteBufferDecoder.class);
		assertThat(getNextDecoder(readers).getClass()).isEqualTo(DataBufferDecoder.class);
		assertThat(readers.get(this.index.getAndIncrement()).getClass()).isEqualTo(ResourceHttpMessageReader.class);
		assertStringDecoder(getNextDecoder(readers), true);
		assertThat(getNextDecoder(readers).getClass()).isEqualTo(ProtobufDecoder.class);
		// SPR-16804
		assertThat(readers.get(this.index.getAndIncrement()).getClass()).isEqualTo(FormHttpMessageReader.class);
		assertThat(getNextDecoder(readers).getClass()).isEqualTo(Jackson2JsonDecoder.class);
		assertThat(getNextDecoder(readers).getClass()).isEqualTo(Jackson2SmileDecoder.class);
		assertThat(getNextDecoder(readers).getClass()).isEqualTo(Jaxb2XmlDecoder.class);
		assertSseReader(readers);
		assertStringDecoder(getNextDecoder(readers), false);
	}

	@Test
	public void defaultWriters() {
		List<HttpMessageWriter<?>> writers = this.configurer.getWriters();
		assertThat(writers.size()).isEqualTo(11);
		assertThat(getNextEncoder(writers).getClass()).isEqualTo(ByteArrayEncoder.class);
		assertThat(getNextEncoder(writers).getClass()).isEqualTo(ByteBufferEncoder.class);
		assertThat(getNextEncoder(writers).getClass()).isEqualTo(DataBufferEncoder.class);
		assertThat(writers.get(index.getAndIncrement()).getClass()).isEqualTo(ResourceHttpMessageWriter.class);
		assertStringEncoder(getNextEncoder(writers), true);
		assertThat(writers.get(this.index.getAndIncrement()).getClass()).isEqualTo(MultipartHttpMessageWriter.class);
		assertThat(writers.get(index.getAndIncrement()).getClass()).isEqualTo(ProtobufHttpMessageWriter.class);
		assertThat(getNextEncoder(writers).getClass()).isEqualTo(Jackson2JsonEncoder.class);
		assertThat(getNextEncoder(writers).getClass()).isEqualTo(Jackson2SmileEncoder.class);
		assertThat(getNextEncoder(writers).getClass()).isEqualTo(Jaxb2XmlEncoder.class);
		assertStringEncoder(getNextEncoder(writers), false);
	}

	@Test
	public void jackson2EncoderOverride() {
		Jackson2JsonDecoder decoder = new Jackson2JsonDecoder();
		this.configurer.defaultCodecs().jackson2JsonDecoder(decoder);

		assertThat(this.configurer.getReaders().stream()
				.filter(reader -> ServerSentEventHttpMessageReader.class.equals(reader.getClass()))
				.map(reader -> (ServerSentEventHttpMessageReader) reader)
				.findFirst()
				.map(ServerSentEventHttpMessageReader::getDecoder)
				.filter(e -> e == decoder).orElse(null)).isSameAs(decoder);
	}


	private Decoder<?> getNextDecoder(List<HttpMessageReader<?>> readers) {
		HttpMessageReader<?> reader = readers.get(this.index.getAndIncrement());
		assertThat(reader.getClass()).isEqualTo(DecoderHttpMessageReader.class);
		return ((DecoderHttpMessageReader<?>) reader).getDecoder();
	}

	private Encoder<?> getNextEncoder(List<HttpMessageWriter<?>> writers) {
		HttpMessageWriter<?> writer = writers.get(this.index.getAndIncrement());
		assertThat(writer.getClass()).isEqualTo(EncoderHttpMessageWriter.class);
		return ((EncoderHttpMessageWriter<?>) writer).getEncoder();
	}

	@SuppressWarnings("unchecked")
	private void assertStringDecoder(Decoder<?> decoder, boolean textOnly) {
		assertThat(decoder.getClass()).isEqualTo(StringDecoder.class);
		assertThat(decoder.canDecode(forClass(String.class), MimeTypeUtils.TEXT_PLAIN)).isTrue();
		Object expected = !textOnly;
		assertThat(decoder.canDecode(forClass(String.class), MediaType.TEXT_EVENT_STREAM)).isEqualTo(expected);

		Flux<String> decoded = (Flux<String>) decoder.decode(
				Flux.just(new DefaultDataBufferFactory().wrap("line1\nline2".getBytes(StandardCharsets.UTF_8))),
				ResolvableType.forClass(String.class), MimeTypeUtils.TEXT_PLAIN, Collections.emptyMap());

		assertThat(decoded.collectList().block(Duration.ZERO)).isEqualTo(Arrays.asList("line1", "line2"));
	}

	private void assertStringEncoder(Encoder<?> encoder, boolean textOnly) {
		assertThat(encoder.getClass()).isEqualTo(CharSequenceEncoder.class);
		assertThat(encoder.canEncode(forClass(String.class), MimeTypeUtils.TEXT_PLAIN)).isTrue();
		Object expected = !textOnly;
		assertThat(encoder.canEncode(forClass(String.class), MediaType.TEXT_EVENT_STREAM)).isEqualTo(expected);
	}

	private void assertSseReader(List<HttpMessageReader<?>> readers) {
		HttpMessageReader<?> reader = readers.get(this.index.getAndIncrement());
		assertThat(reader.getClass()).isEqualTo(ServerSentEventHttpMessageReader.class);
		Decoder<?> decoder = ((ServerSentEventHttpMessageReader) reader).getDecoder();
		assertThat(decoder).isNotNull();
		assertThat(decoder.getClass()).isEqualTo(Jackson2JsonDecoder.class);
	}

}
