package org.junit.rules;

import static org.junit.Assert.fail;

import java.io.File;
import java.io.IOException;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import org.junit.Rule;

The TemporaryFolder Rule allows creation of files and folders that should
be deleted when the test method finishes (whether it passes or
fails).
By default no exception will be thrown in case the deletion fails.
Example of usage:
public static class HasTempFolder {
 @Rule
 public TemporaryFolder folder= new TemporaryFolder();
 @Test
 public void testUsingTempFolder() throws IOException {
     File createdFile= folder.newFile("myfile.txt");
     File createdFolder= folder.newFolder("subfolder");
     // ...
    }
}

TemporaryFolder rule supports assured deletion mode, which will fail the test in case deletion fails with AssertionError. 
Creating TemporaryFolder with assured deletion:
 @Rule
 public TemporaryFolder folder= TemporaryFolder.builder().assureDeletion().build();

Since:
4.7/**
 * The TemporaryFolder Rule allows creation of files and folders that should
 * be deleted when the test method finishes (whether it passes or
 * fails).
 * By default no exception will be thrown in case the deletion fails.
 *
 * <p>Example of usage:
 * <pre>
 * public static class HasTempFolder {
 *  &#064;Rule
 *  public TemporaryFolder folder= new TemporaryFolder();
 *
 *  &#064;Test
 *  public void testUsingTempFolder() throws IOException {
 *      File createdFile= folder.newFile(&quot;myfile.txt&quot;);
 *      File createdFolder= folder.newFolder(&quot;subfolder&quot;);
 *      // ...
 *     }
 * }
 * </pre>
 *
 * <p>TemporaryFolder rule supports assured deletion mode, which
 * will fail the test in case deletion fails with {@link AssertionError}.
 *
 * <p>Creating TemporaryFolder with assured deletion:
 * <pre>
 *  &#064;Rule
 *  public TemporaryFolder folder= TemporaryFolder.builder().assureDeletion().build();
 * </pre>
 *
 * @since 4.7
 */
public class TemporaryFolder extends ExternalResource {
    private final File parentFolder;
    private final boolean assureDeletion;
    private File folder;

    private static final int TEMP_DIR_ATTEMPTS = 10000;
    private static final String TMP_PREFIX = "junit";

    
Create a temporary folder which uses system default temporary-file 
directory to create temporary resources.
/**
     * Create a temporary folder which uses system default temporary-file 
     * directory to create temporary resources.
     */
    public TemporaryFolder() {
        this((File) null);
    }

    
Create a temporary folder which uses the specified directory to create
temporary resources.
Params:
parentFolder – folder where temporary resources will be created. If null then system default temporary-file directory is used./**
     * Create a temporary folder which uses the specified directory to create
     * temporary resources.
     *
     * @param parentFolder folder where temporary resources will be created.
     * If {@code null} then system default temporary-file directory is used.
     */
    public TemporaryFolder(File parentFolder) {
        this.parentFolder = parentFolder;
        this.assureDeletion = false;
    }

    
Create a TemporaryFolder initialized with values from a builder. /**
     * Create a {@link TemporaryFolder} initialized with
     * values from a builder.
     */
    protected TemporaryFolder(Builder builder) {
        this.parentFolder = builder.parentFolder;
        this.assureDeletion = builder.assureDeletion;
    }

    
Returns a new builder for building an instance of TemporaryFolder. 
Since:
4.13/**
     * Returns a new builder for building an instance of {@link TemporaryFolder}.
     *
     * @since 4.13
     */
    public static Builder builder() {
        return new Builder();
    }

    
Builds an instance of TemporaryFolder. 
Since:
4.13/**
     * Builds an instance of {@link TemporaryFolder}.
     * 
     * @since 4.13
     */
    public static class Builder {
        private File parentFolder;
        private boolean assureDeletion;

        protected Builder() {}

        
Specifies which folder to use for creating temporary resources. If null then system default temporary-file directory is used. 
Returns:
this/**
         * Specifies which folder to use for creating temporary resources.
         * If {@code null} then system default temporary-file directory is
         * used.
         *
         * @return this
         */
        public Builder parentFolder(File parentFolder) {
            this.parentFolder = parentFolder;
            return this;
        }

        
Setting this flag assures that no resources are left undeleted. Failure to fulfill the assurance results in failure of tests with an AssertionError. 
Returns:
this/**
         * Setting this flag assures that no resources are left undeleted. Failure
         * to fulfill the assurance results in failure of tests with an
         * {@link AssertionError}.
         *
         * @return this
         */
        public Builder assureDeletion() {
            this.assureDeletion = true;
            return this;
        }

        
Builds a TemporaryFolder instance using the values in this builder. /**
         * Builds a {@link TemporaryFolder} instance using the values in this builder.
         */
        public TemporaryFolder build() {
            return new TemporaryFolder(this);
        }
    }

    @Override
    protected void before() throws Throwable {
        create();
    }

    @Override
    protected void after() {
        delete();
    }

    // testing purposes only

    
for testing purposes only. Do not use.
/**
     * for testing purposes only. Do not use.
     */
    public void create() throws IOException {
        folder = createTemporaryFolderIn(parentFolder);
    }

    
Returns a new fresh file with the given name under the temporary folder.
/**
     * Returns a new fresh file with the given name under the temporary folder.
     */
    public File newFile(String fileName) throws IOException {
        File file = new File(getRoot(), fileName);
        if (!file.createNewFile()) {
            throw new IOException(
                    "a file with the name \'" + fileName + "\' already exists in the test folder");
        }
        return file;
    }

    
Returns a new fresh file with a random name under the temporary folder.
/**
     * Returns a new fresh file with a random name under the temporary folder.
     */
    public File newFile() throws IOException {
        return File.createTempFile(TMP_PREFIX, null, getRoot());
    }

    
Returns a new fresh folder with the given path under the temporary
folder.
/**
     * Returns a new fresh folder with the given path under the temporary
     * folder.
     */
    public File newFolder(String path) throws IOException {
        return newFolder(new String[]{path});
    }

    
Returns a new fresh folder with the given paths under the temporary folder. For example, if you pass in the strings "parent" and "child" then a directory named "parent" will be created under the temporary folder and a directory named "child" will be created under the newly-created "parent" directory. /**
     * Returns a new fresh folder with the given paths under the temporary
     * folder. For example, if you pass in the strings {@code "parent"} and {@code "child"}
     * then a directory named {@code "parent"} will be created under the temporary folder
     * and a directory named {@code "child"} will be created under the newly-created
     * {@code "parent"} directory.
     */
    public File newFolder(String... paths) throws IOException {
        if (paths.length == 0) {
            throw new IllegalArgumentException("must pass at least one path");
        }

        /*
         * Before checking if the paths are absolute paths, check if create() was ever called,
         * and if it wasn't, throw IllegalStateException.
         */
        File root = getRoot();
        for (String path : paths) {
            if (new File(path).isAbsolute()) {
                throw new IOException("folder path \'" + path + "\' is not a relative path");
            }
        }

        File relativePath = null;
        File file = root;
        boolean lastMkdirsCallSuccessful = true;
        for (String path : paths) {
            relativePath = new File(relativePath, path);
            file = new File(root, relativePath.getPath());

            lastMkdirsCallSuccessful = file.mkdirs();
            if (!lastMkdirsCallSuccessful && !file.isDirectory()) {
                if (file.exists()) {
                    throw new IOException(
                            "a file with the path \'" + relativePath.getPath() + "\' exists");
                } else {
                    throw new IOException(
                            "could not create a folder with the path \'" + relativePath.getPath() + "\'");
                }
            }
        }
        if (!lastMkdirsCallSuccessful) {
            throw new IOException(
                    "a folder with the path \'" + relativePath.getPath() + "\' already exists");
        }
        return file;
    }

    
Returns a new fresh folder with a random name under the temporary folder.
/**
     * Returns a new fresh folder with a random name under the temporary folder.
     */
    public File newFolder() throws IOException {
        return createTemporaryFolderIn(getRoot());
    }

    private static File createTemporaryFolderIn(File parentFolder) throws IOException {
        try {
            return createTemporaryFolderWithNioApi(parentFolder);
        } catch (ClassNotFoundException ignore) {
            // Fallback for Java 5 and 6
            return createTemporaryFolderWithFileApi(parentFolder);
        } catch (InvocationTargetException e) {
            Throwable cause = e.getCause();
            if (cause instanceof IOException) {
                throw (IOException) cause;
            }
            if (cause instanceof RuntimeException) {
                throw (RuntimeException) cause;
            }
            IOException exception = new IOException("Failed to create temporary folder in " + parentFolder);
            exception.initCause(cause);
            throw exception;
        } catch (Exception e) {
            throw new RuntimeException("Failed to create temporary folder in " + parentFolder, e);
        }
    }

    private static File createTemporaryFolderWithNioApi(File parentFolder) throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        Class<?> filesClass = Class.forName("java.nio.file.Files");
        Object fileAttributeArray = Array.newInstance(Class.forName("java.nio.file.attribute.FileAttribute"), 0);
        Class<?> pathClass = Class.forName("java.nio.file.Path");
        Object tempDir;
        if (parentFolder != null) {
            Method createTempDirectoryMethod = filesClass.getDeclaredMethod("createTempDirectory", pathClass, String.class, fileAttributeArray.getClass());
            Object parentPath = File.class.getDeclaredMethod("toPath").invoke(parentFolder);
            tempDir = createTempDirectoryMethod.invoke(null, parentPath, TMP_PREFIX, fileAttributeArray);
        } else {
            Method createTempDirectoryMethod = filesClass.getDeclaredMethod("createTempDirectory", String.class, fileAttributeArray.getClass());
            tempDir = createTempDirectoryMethod.invoke(null, TMP_PREFIX, fileAttributeArray);
        }
        return (File) pathClass.getDeclaredMethod("toFile").invoke(tempDir);
    }

    private static File createTemporaryFolderWithFileApi(File parentFolder) throws IOException {
        File createdFolder = null;
        for (int i = 0; i < TEMP_DIR_ATTEMPTS; ++i) {
            // Use createTempFile to get a suitable folder name.
            String suffix = ".tmp";
            File tmpFile = File.createTempFile(TMP_PREFIX, suffix, parentFolder);
            String tmpName = tmpFile.toString();
            // Discard .tmp suffix of tmpName.
            String folderName = tmpName.substring(0, tmpName.length() - suffix.length());
            createdFolder = new File(folderName);
            if (createdFolder.mkdir()) {
                tmpFile.delete();
                return createdFolder;
            }
            tmpFile.delete();
        }
        throw new IOException("Unable to create temporary directory in: "
            + parentFolder.toString() + ". Tried " + TEMP_DIR_ATTEMPTS + " times. "
            + "Last attempted to create: " + createdFolder.toString());
    }

    
Returns:
the location of this temporary folder./**
     * @return the location of this temporary folder.
     */
    public File getRoot() {
        if (folder == null) {
            throw new IllegalStateException(
                    "the temporary folder has not yet been created");
        }
        return folder;
    }

    
Delete all files and folders under the temporary folder. Usually not called directly, since it is automatically applied by the Rule. 
Throws:
AssertionError – if unable to clean up resources
and deletion of resources is assured./**
     * Delete all files and folders under the temporary folder. Usually not
     * called directly, since it is automatically applied by the {@link Rule}.
     *
     * @throws AssertionError if unable to clean up resources
     * and deletion of resources is assured.
     */
    public void delete() {
        if (!tryDelete()) {
            if (assureDeletion) {
                fail("Unable to clean up temporary folder " + folder);
            }
        }
    }

    
Tries to delete all files and folders under the temporary folder and
returns whether deletion was successful or not.
Returns:
true if all resources are deleted successfully, false otherwise./**
     * Tries to delete all files and folders under the temporary folder and
     * returns whether deletion was successful or not.
     *
     * @return {@code true} if all resources are deleted successfully,
     *         {@code false} otherwise.
     */
    private boolean tryDelete() {
        if (folder == null) {
            return true;
        }
        
        return recursiveDelete(folder);
    }

    private boolean recursiveDelete(File file) {
        // Try deleting file before assuming file is a directory
        // to prevent following symbolic links.
        if (file.delete()) {
            return true;
        }
        File[] files = file.listFiles();
        if (files != null) {
            for (File each : files) {
                if (!recursiveDelete(each)) {
                    return false;
                }
            }
        }
        return file.delete();
    }
}