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 * regarding copyright ownership.  The ASF licenses this file   *
 * to you under the Apache License, Version 2.0 (the            *
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 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
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package org.apache.james;

import static io.restassured.RestAssured.when;
import static io.restassured.config.EncoderConfig.encoderConfig;
import static io.restassured.config.RestAssuredConfig.newConfig;

import java.nio.charset.StandardCharsets;
import java.util.concurrent.CountDownLatch;

import javax.annotation.PreDestroy;
import javax.inject.Inject;

import org.apache.james.utils.WebAdminGuiceProbe;
import org.apache.james.webadmin.WebAdminConfiguration;
import org.apache.james.webadmin.WebAdminServer;
import org.eclipse.jetty.http.HttpStatus;
import org.junit.jupiter.api.Nested;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.RegisterExtension;

import io.restassured.RestAssured;
import io.restassured.builder.RequestSpecBuilder;
import io.restassured.http.ContentType;
import reactor.core.publisher.Mono;
import reactor.core.publisher.MonoProcessor;
import reactor.core.scheduler.Schedulers;

class GuiceLifecycleHeathCheckTest {
    private static JamesServerBuilder extensionBuilder() {
        return new JamesServerBuilder<>(JamesServerBuilder.defaultConfigurationProvider())
            .server(configuration -> MemoryJamesServerMain.createServer(configuration)
                .overrideWith(binder -> binder.bind(WebAdminConfiguration.class)
                    .toInstance(WebAdminConfiguration.TEST_CONFIGURATION)));
    }

    private static void configureRequestSpecification(GuiceJamesServer server) {
        WebAdminGuiceProbe webAdminGuiceProbe = server.getProbe(WebAdminGuiceProbe.class);

        RestAssured.requestSpecification = new RequestSpecBuilder()
                .setContentType(ContentType.JSON)
                .setAccept(ContentType.JSON)
                .setConfig(newConfig().encoderConfig(encoderConfig().defaultContentCharset(StandardCharsets.UTF_8)))
                .setPort(webAdminGuiceProbe.getWebAdminPort().getValue())
                .build();
    }

    @Nested
    class Healthy {
        @RegisterExtension
        JamesServerExtension jamesServerExtension = extensionBuilder().build();

        @Test
        void startedJamesServerShouldBeHealthy(GuiceJamesServer server) {
            configureRequestSpecification(server);

            when()
                .get("/healthcheck")
                .then()
                .statusCode(HttpStatus.OK_200);
        }
    }

    static class DestroyedBeforeWebAdmin {
        WebAdminServer webAdminServer;
        CountDownLatch latch;

        @Inject
        DestroyedBeforeWebAdmin(WebAdminServer webAdminServer, CountDownLatch latch) {
            this.webAdminServer = webAdminServer;
            this.latch = latch;
        }

        @PreDestroy
        void cleanup() {
            try {
                latch.await();
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
        }
    }

    @Nested
    class Unhealthy {
        CountDownLatch latch = new CountDownLatch(1);

        @RegisterExtension
        JamesServerExtension jamesServerExtension = extensionBuilder()
            .overrideServerModule(binder -> binder.bind(CountDownLatch.class).toInstance(latch))
            .overrideServerModule(binder -> binder.bind(DestroyedBeforeWebAdmin.class).asEagerSingleton())
            .build();

        @Test
        void stoppingJamesServerShouldBeUnhealthy(GuiceJamesServer server) {
            Mono<Void> stopMono = Mono.fromRunnable(() -> { });
            try {
                configureRequestSpecification(server);

                stopMono = Mono.fromRunnable(server::stop);
                stopMono
                    .publishOn(Schedulers.elastic())
                    .subscribeWith(MonoProcessor.create());

                when()
                    .get("/healthcheck")
                    .then()
                    .statusCode(HttpStatus.SERVICE_UNAVAILABLE_503);
            } finally {
                latch.countDown();
                stopMono.block();
            }
        }
    }
}
