/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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 org.apache.sshd.common.config;

import java.io.IOException;
import java.io.Reader;
import java.io.StreamCorruptedException;
import java.io.StringReader;
import java.net.URL;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Properties;
import java.util.function.Function;

import org.apache.sshd.common.BaseBuilder;
import org.apache.sshd.common.Closeable;
import org.apache.sshd.common.FactoryManager;
import org.apache.sshd.common.NamedFactory;
import org.apache.sshd.common.NamedResource;
import org.apache.sshd.common.PropertyResolverUtils;
import org.apache.sshd.common.cipher.BuiltinCiphers;
import org.apache.sshd.common.cipher.Cipher;
import org.apache.sshd.common.compression.BuiltinCompressions;
import org.apache.sshd.common.compression.Compression;
import org.apache.sshd.common.compression.CompressionFactory;
import org.apache.sshd.common.helpers.AbstractFactoryManager;
import org.apache.sshd.common.kex.BuiltinDHFactories;
import org.apache.sshd.common.mac.BuiltinMacs;
import org.apache.sshd.common.mac.Mac;
import org.apache.sshd.common.signature.BuiltinSignatures;
import org.apache.sshd.common.signature.Signature;
import org.apache.sshd.common.util.GenericUtils;
import org.apache.sshd.common.util.Transformer;
import org.apache.sshd.util.test.BaseTestSupport;
import org.junit.FixMethodOrder;
import org.junit.Test;
import org.junit.runners.MethodSorters;

/**
 * @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
 */
@FixMethodOrder(MethodSorters.NAME_ASCENDING)
public class SshConfigFileReaderTest extends BaseTestSupport {
    public SshConfigFileReaderTest() {
        super();
    }

    @Test
    public void testReadFromURL() throws IOException {
        URL url = getClass().getResource("sshd_config");
        assertNotNull("Cannot locate test file", url);

        Properties props = SshConfigFileReader.readConfigFile(url);
        assertFalse("No properties read", props.isEmpty());
        assertTrue("Unexpected commented property data", GenericUtils.isEmpty(props.getProperty("ListenAddress")));
        assertTrue("Unexpected non-existing property data", GenericUtils.isEmpty(props.getProperty(getCurrentTestName())));

        String keysList = props.getProperty("HostKey");
        assertFalse("No host keys", GenericUtils.isEmpty(keysList));

        String[] keys = GenericUtils.split(keysList, ',');
        assertTrue("No multiple keys", GenericUtils.length((Object[]) keys) > 1);
    }

    @Test
    public void testParseCiphersList() {
        List<? extends NamedResource> expected = BaseBuilder.DEFAULT_CIPHERS_PREFERENCE;
        Properties props = initNamedResourceProperties(SshConfigFileReader.CIPHERS_CONFIG_PROP, expected);
        BuiltinCiphers.ParseResult result = SshConfigFileReader.getCiphers(PropertyResolverUtils.toPropertyResolver(props));
        testParsedFactoriesList(expected, result.getParsedFactories(), result.getUnsupportedFactories());
    }

    @Test
    public void testParseMacsList() {
        List<? extends NamedResource> expected = BaseBuilder.DEFAULT_MAC_PREFERENCE;
        Properties props = initNamedResourceProperties(SshConfigFileReader.MACS_CONFIG_PROP, expected);
        BuiltinMacs.ParseResult result = SshConfigFileReader.getMacs(PropertyResolverUtils.toPropertyResolver(props));
        testParsedFactoriesList(expected, result.getParsedFactories(), result.getUnsupportedFactories());
    }

    @Test
    public void testParseSignaturesList() {
        List<? extends NamedResource> expected = BaseBuilder.DEFAULT_SIGNATURE_PREFERENCE;
        Properties props = initNamedResourceProperties(SshConfigFileReader.HOST_KEY_ALGORITHMS_CONFIG_PROP, expected);
        BuiltinSignatures.ParseResult result = SshConfigFileReader.getSignatures(PropertyResolverUtils.toPropertyResolver(props));
        testParsedFactoriesList(expected, result.getParsedFactories(), result.getUnsupportedFactories());
    }

    @Test
    public void testParseKexFactoriesList() {
        List<? extends NamedResource> expected = BaseBuilder.DEFAULT_KEX_PREFERENCE;
        Properties props = initNamedResourceProperties(SshConfigFileReader.KEX_ALGORITHMS_CONFIG_PROP, expected);
        BuiltinDHFactories.ParseResult result = SshConfigFileReader.getKexFactories(PropertyResolverUtils.toPropertyResolver(props));
        testParsedFactoriesList(expected, result.getParsedFactories(), result.getUnsupportedFactories());
    }

    @Test
    public void testGetCompression() {
        Properties props = new Properties();
        for (CompressionConfigValue expected : CompressionConfigValue.VALUES) {
            props.setProperty(SshConfigFileReader.COMPRESSION_PROP, expected.name().toLowerCase());

            NamedResource actual = SshConfigFileReader.getCompression(PropertyResolverUtils.toPropertyResolver(props));
            assertNotNull("No match for " + expected.name(), actual);
            assertEquals(expected.name(), expected.getName(), actual.getName());
        }
    }

    @Test
    public void testConfigureAbstractFactoryManagerWithDefaults() {
        Properties props = new Properties();   // empty means use defaults
        AbstractFactoryManager expected = new AbstractFactoryManager() {
            @Override
            protected Closeable getInnerCloseable() {
                return null;
            }
        };
        // must be lenient since we do not cover the full default spectrum
        AbstractFactoryManager actual = SshConfigFileReader.configure(expected, PropertyResolverUtils.toPropertyResolver(props), true, true);
        assertSame("Mismatched configured result", expected, actual);
        validateAbstractFactoryManagerConfiguration(expected, props, true);
    }

    @Test(expected = IllegalArgumentException.class)
    public void testNonLenientCiphersConfiguration() {
        FactoryManager manager = SshConfigFileReader.configureCiphers(
                new AbstractFactoryManager() {
                    @Override
                    protected Closeable getInnerCloseable() {
                        return null;
                    }
                },
                getCurrentTestName(),
                false,
                true);
        fail("Unexpected success: " + NamedResource.getNames(manager.getCipherFactories()));
    }

    @Test(expected = IllegalArgumentException.class)
    public void testNonLenientSignaturesConfiguration() {
        FactoryManager manager = SshConfigFileReader.configureSignatures(
                new AbstractFactoryManager() {
                    @Override
                    protected Closeable getInnerCloseable() {
                        return null;
                    }
                },
                getCurrentTestName(),
                false,
                true);
        fail("Unexpected success: " + NamedResource.getNames(manager.getSignatureFactories()));
    }

    @Test(expected = IllegalArgumentException.class)
    public void testNonLenientMacsConfiguration() {
        FactoryManager manager = SshConfigFileReader.configureMacs(
                new AbstractFactoryManager() {
                    @Override
                    protected Closeable getInnerCloseable() {
                        return null;
                    }
                },
                getCurrentTestName(),
                false,
                true);
        fail("Unexpected success: " + NamedResource.getNames(manager.getMacFactories()));
    }

    @Test
    public void testConfigureCompressionFromStringAcceptsCombinedValues() {
        testConfigureCompressionFromStringAcceptsCombinedValues(CompressionConfigValue.class, Transformer.ENUM_NAME_EXTRACTOR);
        testConfigureCompressionFromStringAcceptsCombinedValues(BuiltinCompressions.class, NamedResource.NAME_EXTRACTOR);
    }

    @Test(expected = StreamCorruptedException.class)
    public void testInvalidDelimiter() throws IOException {
        String line = getClass().getSimpleName() + "+" + getCurrentTestName();
        try (Reader rdr = new StringReader(line)) {
            Properties props = SshConfigFileReader.readConfigFile(rdr, true);
            fail("Unexpected success: " + props);
        }
    }

    @Test   // SSHD-774
    public void testTabDelimiter() throws IOException {
        String name = getClass().getSimpleName();
        String expected = getCurrentTestName();
        Properties props;
        try (Reader rdr = new StringReader(name + "\t" + expected)) {
            props = SshConfigFileReader.readConfigFile(rdr, true);
        }

        String actual = props.getProperty(name);
        assertEquals("Mismatched read configuration value", expected, actual);
    }

    private static <E extends Enum<E> & CompressionFactory> void testConfigureCompressionFromStringAcceptsCombinedValues(
            Class<E> facs, Function<? super E, String> configValueXformer) {
        for (E expected : facs.getEnumConstants()) {
            String value = configValueXformer.apply(expected);
            String prefix = facs.getSimpleName() + "[" + expected.name() + "][" + value + "]";
            FactoryManager manager = SshConfigFileReader.configureCompression(
                    new AbstractFactoryManager() {
                        @Override
                        protected Closeable getInnerCloseable() {
                            return null;
                        }
                    },
                    value,
                    false,
                    true);
            List<NamedFactory<Compression>> compressions = manager.getCompressionFactories();
            assertEquals(prefix + "(size)", 1, GenericUtils.size(compressions));
            assertSame(prefix + "[instance]", expected, compressions.get(0));
        }
    }

    private static <M extends FactoryManager> M validateAbstractFactoryManagerConfiguration(M manager, Properties props, boolean lenient) {
        validateFactoryManagerCiphers(manager, props);
        validateFactoryManagerSignatures(manager, props);
        validateFactoryManagerMacs(manager, props);
        validateFactoryManagerCompressions(manager, props, lenient);
        return manager;
    }

    private static <M extends FactoryManager> M validateFactoryManagerCiphers(M manager, Properties props) {
        return validateFactoryManagerCiphers(manager, props.getProperty(SshConfigFileReader.CIPHERS_CONFIG_PROP, SshConfigFileReader.DEFAULT_CIPHERS));
    }

    private static <M extends FactoryManager> M validateFactoryManagerCiphers(M manager, String value) {
        BuiltinCiphers.ParseResult result = BuiltinCiphers.parseCiphersList(value);
        validateFactoryManagerFactories(Cipher.class, result.getParsedFactories(), manager.getCipherFactories());
        return manager;
    }

    private static <M extends FactoryManager> M validateFactoryManagerSignatures(M manager, Properties props) {
        return validateFactoryManagerSignatures(manager, props.getProperty(SshConfigFileReader.HOST_KEY_ALGORITHMS_CONFIG_PROP, SshConfigFileReader.DEFAULT_HOST_KEY_ALGORITHMS));
    }

    private static <M extends FactoryManager> M validateFactoryManagerSignatures(M manager, String value) {
        BuiltinSignatures.ParseResult result = BuiltinSignatures.parseSignatureList(value);
        validateFactoryManagerFactories(Signature.class, result.getParsedFactories(), manager.getSignatureFactories());
        return manager;
    }

    private static <M extends FactoryManager> M validateFactoryManagerMacs(M manager, Properties props) {
        return validateFactoryManagerMacs(manager, props.getProperty(SshConfigFileReader.MACS_CONFIG_PROP, SshConfigFileReader.DEFAULT_MACS));
    }

    private static <M extends FactoryManager> M validateFactoryManagerMacs(M manager, String value) {
        BuiltinMacs.ParseResult result = BuiltinMacs.parseMacsList(value);
        validateFactoryManagerFactories(Mac.class, result.getParsedFactories(), manager.getMacFactories());
        return manager;
    }

    private static <M extends FactoryManager> M validateFactoryManagerCompressions(M manager, Properties props, boolean lenient) {
        return validateFactoryManagerCompressions(manager, props.getProperty(SshConfigFileReader.COMPRESSION_PROP, SshConfigFileReader.DEFAULT_COMPRESSION), lenient);
    }

    private static <M extends FactoryManager> M validateFactoryManagerCompressions(M manager, String value, boolean lenient) {
        NamedFactory<Compression> factory = CompressionConfigValue.fromName(value);
        assertTrue("Unknown compression: " + value, lenient || (factory != null));
        if (factory != null) {
            validateFactoryManagerFactories(Compression.class, Collections.singletonList(factory), manager.getCompressionFactories());
        }
        return manager;
    }

    private static <T, F extends NamedFactory<T>> void validateFactoryManagerFactories(Class<T> type, List<? extends F> expected, List<? extends F> actual) {
        validateFactoryManagerSettings(type, expected, actual);
    }

    private static <R extends NamedResource> void validateFactoryManagerSettings(Class<?> type, List<? extends R> expected, List<? extends R> actual) {
        validateFactoryManagerSettings(type.getSimpleName(), expected, actual);
    }

    private static <R extends NamedResource> void validateFactoryManagerSettings(String type, List<? extends R> expected, List<? extends R> actual) {
        assertListEquals(type, expected, actual);
    }

    private static <T extends NamedResource> List<T> testParsedFactoriesList(
            List<? extends NamedResource> expected, List<T> actual, Collection<String> unsupported) {
        assertTrue("Unexpected unsupported factories: " + unsupported, GenericUtils.isEmpty(unsupported));
        assertEquals("Mismatched list size", expected.size(), GenericUtils.size(actual));
        for (int index = 0; index < expected.size(); index++) {
            NamedResource e = expected.get(index);
            String n1 = e.getName();
            NamedResource a = actual.get(index);
            String n2 = a.getName();
            assertEquals("Mismatched name at index=" + index, n1, n2);
        }

        return actual;
    }

    private static <R extends NamedResource> Properties initNamedResourceProperties(String key, Collection<? extends R> values) {
        return initProperties(key, NamedResource.getNames(values));
    }

    private static Properties initProperties(String key, String value) {
        Properties props = new Properties();
        props.setProperty(key, value);
        return props;
    }
}
