/*
 * Copyright 2014-2018 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
 *
 *     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.
 */

package de.codecentric.boot.admin.server.cloud;

import de.codecentric.boot.admin.server.config.EnableAdminServer;
import reactor.core.publisher.Flux;
import reactor.test.StepVerifier;

import java.net.URI;
import java.time.Duration;
import java.util.List;
import java.util.concurrent.atomic.AtomicReference;
import org.json.JSONObject;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.boot.WebApplicationType;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.client.discovery.event.InstanceRegisteredEvent;
import org.springframework.cloud.client.discovery.simple.SimpleDiscoveryProperties;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.http.MediaType;
import org.springframework.http.codec.json.Jackson2JsonDecoder;
import org.springframework.http.codec.json.Jackson2JsonEncoder;
import org.springframework.security.config.annotation.web.reactive.EnableWebFluxSecurity;
import org.springframework.security.config.web.server.ServerHttpSecurity;
import org.springframework.security.web.server.SecurityWebFilterChain;
import org.springframework.test.web.reactive.server.WebTestClient;
import org.springframework.web.reactive.function.client.ExchangeStrategies;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.datatype.jsonorg.JsonOrgModule;

import static java.util.Collections.singletonList;
import static org.assertj.core.api.Assertions.assertThat;


public class AdminApplicationDiscoveryTest {
    private ConfigurableApplicationContext instance;
    private SimpleDiscoveryProperties simpleDiscovery;
    private WebTestClient webClient;
    private int port;

    @Before
    public void setUp() {
        instance = new SpringApplicationBuilder().sources(TestAdminApplication.class)
                                                 .web(WebApplicationType.REACTIVE)
                                                 .run("--server.port=0", "--management.endpoints.web.base-path=/mgmt",
                                                     "--endpoints.health.enabled=true", "--info.test=foobar",
                                                     "--eureka.client.enabled=false");

        simpleDiscovery = instance.getBean(SimpleDiscoveryProperties.class);

        this.port = instance.getEnvironment().getProperty("local.server.port", Integer.class, 0);
        this.webClient = createWebClient(this.port);
    }

    @Test
    public void lifecycle() {
        AtomicReference<URI> location = new AtomicReference<>();

        StepVerifier.create(getEventStream().log())
                    .expectSubscription()
                    .then(() -> {
                        listEmptyInstances();
                        location.set(registerInstance());
                    })
                    .assertNext((event) -> assertThat(event.opt("type")).isEqualTo("REGISTERED"))
                    .assertNext((event) -> assertThat(event.opt("type")).isEqualTo("STATUS_CHANGED"))
                    .assertNext((event) -> assertThat(event.opt("type")).isEqualTo("ENDPOINTS_DETECTED"))
                    .assertNext((event) -> assertThat(event.opt("type")).isEqualTo("INFO_CHANGED"))
                    .then(() -> {
                        getInstance(location.get());
                        listInstances();
                        deregisterInstance();
                    })
                    .assertNext((event) -> assertThat(event.opt("type")).isEqualTo("DEREGISTERED"))
                    .then(this::listEmptyInstances)
                    .thenCancel()
                    .verify(Duration.ofSeconds(60));
    }

    private URI registerInstance() {
        //We register the instance by setting static values for the SimpleDiscoveryClient and issuing a
        //InstanceRegisteredEvent that makes sure the instance gets registered.
        SimpleDiscoveryProperties.SimpleServiceInstance serviceInstance = new SimpleDiscoveryProperties.SimpleServiceInstance();
        serviceInstance.setServiceId("Test-Instance");
        serviceInstance.setUri(URI.create("http://localhost:" + port));
        serviceInstance.getMetadata().put("management.context-path", "/mgmt");
        simpleDiscovery.getInstances().put("Test-Application", singletonList(serviceInstance));

        instance.publishEvent(new InstanceRegisteredEvent<>(new Object(), null));

        //To get the location of the registered instances we fetch the instance with the name.
        List<JSONObject> applications = webClient.get()
                                                 .uri("/instances?name=Test-Instance")
                                                 .accept(MediaType.APPLICATION_JSON)
                                                 .exchange()
                                                 .expectStatus()
                                                 .isOk()
                                                 .returnResult(JSONObject.class)
                                                 .getResponseBody()
                                                 .collectList()
                                                 .block();
        assertThat(applications).hasSize(1);
        return URI.create("http://localhost:" + port + "/instances/" + applications.get(0).optString("id"));
    }

    private void deregisterInstance() {
        simpleDiscovery.getInstances().clear();
        instance.publishEvent(new InstanceRegisteredEvent<>(new Object(), null));
    }


    private Flux<JSONObject> getEventStream() {
        //@formatter:off
        return webClient.get().uri("/instances/events").accept(MediaType.TEXT_EVENT_STREAM)
                        .exchange()
                        .expectStatus().isOk()
                        .expectHeader().contentTypeCompatibleWith(MediaType.TEXT_EVENT_STREAM)
                        .returnResult(JSONObject.class).getResponseBody();
        //@formatter:on
    }

    private void getInstance(URI uri) {
        //@formatter:off
        webClient.get().uri(uri).accept(MediaType.APPLICATION_JSON_UTF8)
                .exchange()
                .expectStatus().isOk()
                .expectBody()
                .jsonPath("$.registration.name").isEqualTo("Test-Instance")
                .jsonPath("$.statusInfo.status").isEqualTo("UP")
                .jsonPath("$.info.test").isEqualTo("foobar");
        //@formatter:on
    }

    private void listInstances() {
        //@formatter:off
        webClient.get().uri("/instances").accept(MediaType.APPLICATION_JSON_UTF8)
                .exchange()
                .expectStatus().isOk()
                .expectBody()
                    .jsonPath("$[0].registration.name").isEqualTo("Test-Instance")
                    .jsonPath("$[0].statusInfo.status").isEqualTo("UP")
                    .jsonPath("$[0].info.test").isEqualTo("foobar");
        //@formatter:on
    }

    private void listEmptyInstances() {
        //@formatter:off
        webClient.get().uri("/instances").accept(MediaType.APPLICATION_JSON_UTF8)
                .exchange()
                .expectStatus().isOk()
                .expectBody().json("[]");
        //@formatter:on
    }

    private WebTestClient createWebClient(int port) {
        ObjectMapper mapper = new ObjectMapper().registerModule(new JsonOrgModule());
        return WebTestClient.bindToServer()
                            .baseUrl("http://localhost:" + port)
                            .exchangeStrategies(ExchangeStrategies.builder().codecs((configurer) -> {
                                configurer.defaultCodecs().jackson2JsonDecoder(new Jackson2JsonDecoder(mapper));
                                configurer.defaultCodecs().jackson2JsonEncoder(new Jackson2JsonEncoder(mapper));
                            }).build())
                            .build();
    }

    @After
    public void shutdown() {
        instance.close();
    }

    @EnableAdminServer
    @EnableAutoConfiguration
    @SpringBootConfiguration
    @EnableWebFluxSecurity
    public static class TestAdminApplication {
        @Bean
        SecurityWebFilterChain securityWebFilterChain(ServerHttpSecurity http) {
            return http.authorizeExchange().anyExchange().permitAll()//
                       .and().csrf().disable()//
                       .build();
        }
    }
}