/*
 * 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.commons.vfs2;

import java.io.File;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.time.Instant;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;

import org.apache.commons.io.FileUtils;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.vfs2.impl.DefaultFileReplicator;
import org.apache.commons.vfs2.impl.DefaultFileSystemManager;
import org.apache.commons.vfs2.impl.PrivilegedFileReplicator;
import org.apache.commons.vfs2.provider.local.DefaultLocalFileProvider;
import org.junit.Assert;

import junit.extensions.TestSetup;
import junit.framework.Protectable;
import junit.framework.Test;
import junit.framework.TestResult;
import junit.framework.TestSuite;

/**
 * The suite of tests for a file system.
 */
public abstract class AbstractTestSuite extends TestSetup {

    private static final Thread[] EMPTY_THREAD_ARRAY = new Thread[0];
    public static final String WRITE_TESTS_FOLDER = "write-tests";
    public static final String READ_TESTS_FOLDER = "read-tests";

    private final ProviderTestConfig providerConfig;
    private final String prefix;
    private TestSuite testSuite;

    private FileObject baseFolder;
    private FileObject readFolder;
    private FileObject writeFolder;
    private DefaultFileSystemManager manager;
    private File tempDir;

    private Thread[] startThreadSnapshot;
    private Thread[] endThreadSnapshot;
    private final boolean addEmptyDir;

    protected AbstractTestSuite(final ProviderTestConfig providerConfig, final String prefix, final boolean nested)
        throws Exception {
        this(providerConfig, prefix, nested, false);
    }

    protected AbstractTestSuite(final ProviderTestConfig providerConfig, final String prefix, final boolean nested,
        final boolean addEmptyDir) throws Exception {
        super(new TestSuite());
        testSuite = (TestSuite) fTest;
        this.providerConfig = providerConfig;
        this.prefix = prefix;
        this.addEmptyDir = addEmptyDir;
        addBaseTests();
        if (!nested) {
            // Add nested tests
            // TODO - move nested jar and zip tests here
            // TODO - enable this again
            // testSuite.addTest( new ProviderTestSuite( new JunctionProviderConfig( providerConfig ), "junction.", true
            // ));
        }
    }

    /**
     * Adds base tests - excludes the nested test cases.
     */
    protected void addBaseTests() throws Exception {
    }

    /**
     * Adds the tests from a class to this suite. The supplied class must be a subclass of
     * {@link AbstractProviderTestCase} and have a public a no-args constructor. This method creates an instance of the
     * supplied class for each public 'testNnnn' method provided by the class.
     */
    public void addTests(final Class<?> testClass) throws Exception {
        // Verify the class
        if (!AbstractProviderTestCase.class.isAssignableFrom(testClass)) {
            throw new Exception("Test class " + testClass.getName() + " is not assignable to "
                + AbstractProviderTestCase.class.getName());
        }

        // Locate the test methods
        final Method[] methods = testClass.getMethods();
        for (final Method method2 : methods) {
            final Method method = method2;
            if (!method.getName().startsWith("test") || Modifier.isStatic(method.getModifiers())
                || method.getReturnType() != Void.TYPE || method.getParameterTypes().length != 0) {
                continue;
            }

            // Create instance
            final AbstractProviderTestCase testCase = (AbstractProviderTestCase) testClass.newInstance();
            testCase.setMethod(method);
            testCase.setName(prefix + method.getName());
            testCase.addEmptyDir(this.addEmptyDir);
            testSuite.addTest(testCase);
        }
    }

    @Override
    public void run(final TestResult result) {
        final Protectable p = () -> {
            setUp();
            basicRun(result);
            tearDown();
            validateThreadSnapshot();
        };
        result.runProtected(this, p);
    }

    @Override
    protected void setUp() throws Exception {
        startThreadSnapshot = createThreadSnapshot();

        // Locate the temp directory, and clean it up
        tempDir = AbstractVfsTestCase.getTestDirectory("temp");
        FileUtils.cleanDirectory(tempDir);
        checkTempDir("Temp dir not empty before test");

        // Create the file system manager
        manager = providerConfig.getDefaultFileSystemManager();
        manager.setFilesCache(providerConfig.getFilesCache());

        final DefaultFileReplicator replicator = new DefaultFileReplicator(tempDir);
        manager.setReplicator(new PrivilegedFileReplicator(replicator));
        manager.setTemporaryFileStore(replicator);

        providerConfig.prepare(manager);

        if (!manager.hasProvider("file")) {
            manager.addProvider("file", new DefaultLocalFileProvider());
        }

        manager.init();

        // Locate the base folders
        baseFolder = providerConfig.getBaseTestFolder(manager);
        readFolder = baseFolder.resolveFile(READ_TESTS_FOLDER);
        writeFolder = baseFolder.resolveFile(WRITE_TESTS_FOLDER);

        // Make some assumptions about the read folder
        Assert.assertTrue("Folder does not exist: " + readFolder, readFolder.exists());
        Assert.assertNotEquals(readFolder.getName().getPath(), FileName.ROOT_PATH);

        // Configure the tests
        final Enumeration<Test> tests = testSuite.tests();
        if (!tests.hasMoreElements()) {
            Assert.fail("No tests.");
        }
        while (tests.hasMoreElements()) {
            final Test test = tests.nextElement();
            if (test instanceof AbstractProviderTestCase) {
                final AbstractProviderTestCase providerTestCase = (AbstractProviderTestCase) test;
                providerTestCase.setConfig(manager, providerConfig, baseFolder, readFolder, writeFolder);
            }
        }
    }

    @Override
    protected void tearDown() throws Exception {
        readFolder.close();
        writeFolder.close();
        baseFolder.close();

        readFolder = null;
        writeFolder = null;
        baseFolder = null;
        testSuite = null;

        // Suggest to threads (SoftRefFilesCache) to free all files.
        System.gc();
        Thread.sleep(1000);
        System.gc();
        Thread.sleep(1000);
        System.gc();
        Thread.sleep(1000);
        System.gc();
        Thread.sleep(1000);

        manager.freeUnusedResources();
        manager.close();
        // Give a chance for any threads to end.
        Thread.sleep(20);

        // Make sure temp directory is empty or gone
        checkTempDir("Temp dir not empty after test");
        VFS.close();
    }

    private void validateThreadSnapshot() {
        endThreadSnapshot = createThreadSnapshot();

        final Thread[] diffThreadSnapshot = diffThreadSnapshot(startThreadSnapshot, endThreadSnapshot);
        if (diffThreadSnapshot.length > 0) {
            final String message = dumpThreadSnapshot(diffThreadSnapshot);
            /*
             * if (providerConfig.checkCleanThreadState()) { // close the manager to do a "not thread safe" release of
             * all resources // and allow the vm to shutdown manager.close(); fail(message); } else {
             */
            System.out.print(message);
            // }
        }
        // System.in.read();
    }

    /**
     * Asserts that the temp dir is empty or gone.
     */
    private void checkTempDir(final String assertMsg) {
        if (tempDir.exists()) {
            Assert.assertTrue(assertMsg + " (" + tempDir.getAbsolutePath() + ")",
                tempDir.isDirectory() && ArrayUtils.isEmpty(tempDir.list()));
        }
    }

    private String dumpThreadSnapshot(final Thread[] threadSnapshot) {
        if (ArrayUtils.isEmpty(threadSnapshot)) {
            return StringUtils.EMPTY;
        }
        final StringBuffer sb = new StringBuffer(256);
        sb.append("Threads still running (" + threadSnapshot.length + ") at " + Instant.now() + ", live threads:");
        sb.append(System.lineSeparator());

        Field threadTargetField = null;
        try {
            threadTargetField = Thread.class.getDeclaredField("target");
            threadTargetField.setAccessible(true);
        } catch (final Exception e) {
            System.err.println("Test suite cannot show you a thread snapshot: " + e);
        }

        int liveCount = 0;
        for (int index = 0; index < threadSnapshot.length; index++) {
            final Thread thread = threadSnapshot[index];
            if (thread != null && thread.isAlive()) {
                liveCount++;
                sb.append("\tThread[");
                sb.append(index);
                sb.append("] ");
                sb.append(" ID ");
                sb.append(thread.getId());
                sb.append(", ");
                // prints [name,priority,group]
                sb.append(thread);
                sb.append(",\t");
                sb.append(thread.getState());
                sb.append(",\t");
                if (!thread.isDaemon()) {
                    sb.append("non_");
                }
                sb.append("daemon");

                if (threadTargetField != null) {
                    sb.append(",\t");
                    try {
                        final Object threadTarget = threadTargetField.get(thread);
                        if (threadTarget != null) {
                            sb.append(threadTarget.getClass().getCanonicalName());
                        } else {
                            sb.append("null");
                        }
                    } catch (final IllegalAccessException e) {
                        sb.append("unknown (");
                        sb.append(e);
                        sb.append(")");
                    }
                }

                sb.append(System.lineSeparator());
//              Stream.of(thread.getStackTrace()).forEach(e -> {
//                  sb.append('\t');
//                  sb.append(e);
//                  sb.append(System.lineSeparator());
//              });
            }
        }
        return liveCount == 0 ? StringUtils.EMPTY : sb.toString();
    }

    private Thread[] diffThreadSnapshot(final Thread[] startThreadSnapshot, final Thread[] endThreadSnapshot) {
        final List<Thread> diff = new ArrayList<>(10);

        nextEnd: for (final Thread element : endThreadSnapshot) {
            for (final Thread element2 : startThreadSnapshot) {
                if (element2 == element) {
                    continue nextEnd;
                }
            }

            diff.add(element);
        }

        return diff.toArray(EMPTY_THREAD_ARRAY);
    }

    private Thread[] createThreadSnapshot() {
        ThreadGroup tg = Thread.currentThread().getThreadGroup();
        while (tg.getParent() != null) {
            tg = tg.getParent();
        }

        final Thread snapshot[] = new Thread[200];
        tg.enumerate(snapshot, true);

        return snapshot;
    }
}