////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2017 the original author or authors.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
////////////////////////////////////////////////////////////////////////////////

package com.puppycrawl.tools.checkstyle;

import static com.puppycrawl.tools.checkstyle.utils.CommonUtils.EMPTY_BYTE_ARRAY;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotEquals;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;
import static org.powermock.api.mockito.PowerMockito.mock;
import static org.powermock.api.mockito.PowerMockito.when;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLStreamHandler;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Set;

import org.junit.Test;
import org.mockito.Mockito;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;

import com.puppycrawl.tools.checkstyle.api.CheckstyleException;

/**
 * Enter a description of class PackageNamesLoaderTest.java.
 * @author Rick Giles
 * @author lkuehne
 */
public class PackageNamesLoaderTest {
    @Test
    public void testDefault()
            throws CheckstyleException {
        final Set<String> packageNames = PackageNamesLoader
                .getPackageNames(Thread.currentThread()
                        .getContextClassLoader());
        validatePackageNames(packageNames);
    }

    private static void validatePackageNames(Set<String> pkgNames) {
        final String[] checkstylePackages = {
            "com.puppycrawl.tools.checkstyle.",
            "com.puppycrawl.tools.checkstyle.checks.",
            "com.puppycrawl.tools.checkstyle.checks.annotation.",
            "com.puppycrawl.tools.checkstyle.checks.blocks.",
            "com.puppycrawl.tools.checkstyle.checks.coding.",
            "com.puppycrawl.tools.checkstyle.checks.design.",
            "com.puppycrawl.tools.checkstyle.checks.header.",
            "com.puppycrawl.tools.checkstyle.checks.imports.",
            "com.puppycrawl.tools.checkstyle.checks.indentation.",
            "com.puppycrawl.tools.checkstyle.checks.javadoc.",
            "com.puppycrawl.tools.checkstyle.checks.metrics.",
            "com.puppycrawl.tools.checkstyle.checks.modifier.",
            "com.puppycrawl.tools.checkstyle.checks.naming.",
            "com.puppycrawl.tools.checkstyle.checks.regexp.",
            "com.puppycrawl.tools.checkstyle.checks.sizes.",
            "com.puppycrawl.tools.checkstyle.checks.whitespace.",
            "com.puppycrawl.tools.checkstyle.filefilters.",
            "com.puppycrawl.tools.checkstyle.filters.",
        };

        assertEquals("pkgNames.length.", checkstylePackages.length,
            pkgNames.size());
        final Set<String> checkstylePackagesSet = new HashSet<>(Arrays.asList(checkstylePackages));
        assertEquals("names set.", checkstylePackagesSet, pkgNames);
    }

    @Test
    @SuppressWarnings("unchecked")
    public void testPackagesWithDots() throws Exception {

        final Constructor<PackageNamesLoader> constructor =
                PackageNamesLoader.class.getDeclaredConstructor();
        constructor.setAccessible(true);
        final PackageNamesLoader loader = constructor.newInstance();

        final Attributes attributes = mock(Attributes.class);
        when(attributes.getValue("name")).thenReturn("coding.");
        loader.startElement("", "", "package", attributes);
        loader.endElement("", "", "package");

        final Field field = PackageNamesLoader.class.getDeclaredField("packageNames");
        field.setAccessible(true);
        final Set<String> list = (Set<String>) field.get(loader);
        assertEquals("coding.", list.iterator().next());
    }

    @Test
    @SuppressWarnings("unchecked")
    public void testPackagesWithSaxException() throws Exception {

        final URLConnection mockConnection = Mockito.mock(URLConnection.class);
        when(mockConnection.getInputStream()).thenReturn(
                new ByteArrayInputStream(EMPTY_BYTE_ARRAY));

        final URL url = getMockUrl(mockConnection);

        final Enumeration<URL> enumeration = mock(Enumeration.class);
        when(enumeration.hasMoreElements()).thenReturn(true);
        when(enumeration.nextElement()).thenReturn(url);

        final ClassLoader classLoader = mock(ClassLoader.class);
        when(classLoader.getResources("checkstyle_packages.xml")).thenReturn(enumeration);

        try {
            PackageNamesLoader.getPackageNames(classLoader);
            fail("CheckstyleException is expected");
        }
        catch (CheckstyleException ex) {
            assertTrue(ex.getCause() instanceof SAXException);
        }
    }

    @Test
    @SuppressWarnings("unchecked")
    public void testPackagesWithIoException() throws Exception {

        final URLConnection mockConnection = Mockito.mock(URLConnection.class);
        when(mockConnection.getInputStream()).thenReturn(null);

        final URL url = getMockUrl(mockConnection);

        final Enumeration<URL> enumer = mock(Enumeration.class);
        when(enumer.hasMoreElements()).thenReturn(true);
        when(enumer.nextElement()).thenReturn(url);

        final ClassLoader classLoader = mock(ClassLoader.class);
        when(classLoader.getResources("checkstyle_packages.xml")).thenReturn(enumer);

        try {
            PackageNamesLoader.getPackageNames(classLoader);
            fail("CheckstyleException is expected");
        }
        catch (CheckstyleException ex) {
            assertTrue(ex.getCause() instanceof IOException);
            assertNotEquals("unable to get package file resources", ex.getMessage());
        }
    }

    @Test
    @SuppressWarnings("unchecked")
    public void testPackagesWithIoExceptionGetResources() throws Exception {

        final ClassLoader classLoader = mock(ClassLoader.class);
        when(classLoader.getResources("checkstyle_packages.xml")).thenThrow(IOException.class);

        try {
            PackageNamesLoader.getPackageNames(classLoader);
            fail("CheckstyleException is expected");
        }
        catch (CheckstyleException ex) {
            assertTrue(ex.getCause() instanceof IOException);
            assertEquals("unable to get package file resources", ex.getMessage());
        }
    }

    private static URL getMockUrl(final URLConnection connection) throws IOException {
        final URLStreamHandler handler = new URLStreamHandler() {
            @Override
            protected URLConnection openConnection(final URL url) {
                return connection;
            }
        };
        return new URL("http://foo.bar", "foo.bar", 80, "", handler);
    }

}
