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package org.apache.james.mailrepository.api;

import org.apache.james.core.healthcheck.ComponentName;
import org.apache.james.core.healthcheck.HealthCheck;
import org.apache.james.core.healthcheck.Result;
import org.apache.james.util.FunctionalUtils;

import com.github.fge.lambdas.Throwing;

import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

public class EmptyErrorMailRepositoryHealthCheck implements HealthCheck {
    public static final ComponentName COMPONENT_NAME = new ComponentName("EmptyErrorMailRepository");
    private final MailRepositoryStore repositoryStore;
    private final MailRepositoryPath errorRepositoryPath;

    public EmptyErrorMailRepositoryHealthCheck(MailRepositoryPath errorRepositoryPath, MailRepositoryStore repositoryStore) {
        this.repositoryStore = repositoryStore;
        this.errorRepositoryPath = errorRepositoryPath;
    }

    @Override
    public ComponentName componentName() {
        return COMPONENT_NAME;
    }

    @Override
    public Mono<Result> check() {
        // TODO: use .sizeReactive of https://github.com/apache/james-project/pull/1049/
        return Flux.fromStream(Throwing.supplier(() -> repositoryStore.getByPath(errorRepositoryPath)))
            .any(Throwing.predicate(repository -> repository.size() > 0))
            .filter(FunctionalUtils.identityPredicate())
            .map(hasSize -> Result.degraded(COMPONENT_NAME, "MailRepository is not empty"))
            .switchIfEmpty(Mono.just(Result.healthy(COMPONENT_NAME)));
    }
}
