/*******************************************************************************
 * Copyright (C) 2026, Leo Galambos
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
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 * 3. All advertising materials mentioning features or use of this software must
 *    display the following acknowledgement:
 *    This product includes software developed by the Egothor project.
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 *    may be used to endorse or promote products derived from this software without
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package zeroecho.pki.server.http;

import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.Objects;
import java.util.ServiceLoader;

import javax.net.ssl.X509TrustManager;

import zeroecho.pki.server.spi.PkiServerClientTrustProvider;
import zeroecho.pki.spi.ProviderConfig;

/** Deterministic explicit provider resolver for forwarded-client trust. */
@SuppressWarnings({ "PMD.AvoidCatchingGenericException", "PMD.PreserveStackTrace" })
final class ClientTrustProviders {
    private ClientTrustProviders() {
    }

    /* default */ static X509TrustManager create(ProviderConfig configuration, ClassLoader loader) {
        ProviderConfig exact = Objects.requireNonNull(configuration, "configuration");
        List<PkiServerClientTrustProvider> providers = new ArrayList<>();
        ServiceLoader.load(PkiServerClientTrustProvider.class, Objects.requireNonNull(loader, "loader"))
                .forEach(providers::add);
        providers.sort(Comparator.comparing(PkiServerClientTrustProvider::id));
        if (providers.stream().map(PkiServerClientTrustProvider::id).distinct().count() != providers.size()) {
            throw new IllegalStateException("Administrative-client trust provider identities are ambiguous");
        }
        PkiServerClientTrustProvider selected = providers.stream()
                .filter(provider -> provider.id().equals(exact.backendId())).findFirst()
                .orElseThrow(() -> new IllegalArgumentException(
                        "Administrative-client trust provider is unavailable"));
        try {
            return Objects.requireNonNull(selected.create(exact),
                    "Administrative-client trust provider returned no trust manager");
        } catch (RuntimeException failure) {
            throw failure;
        } catch (Exception failure) {
            throw new IllegalStateException("Administrative-client trust initialization failed");
        }
    }
}
