/*
 * 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.juneau.commons.utils;

import static org.apache.juneau.commons.utils.AssertionUtils.*;
import static org.apache.juneau.commons.utils.IoUtils.*;
import static org.apache.juneau.commons.utils.StringUtils.*;
import static org.apache.juneau.commons.utils.ThrowableUtils.*;
import static org.apache.juneau.commons.utils.Utils.*;

import java.io.*;
import java.nio.file.*;

/**
 * File utilities.
 *
 */
public class FileUtils {

   /**
    * Creates a file if it doesn't already exist using {@link File#createNewFile()}.
    *
    * <p>
    * Throws a {@link RuntimeException} if the file could not be created.
    *
    * @param f The file to create.
    */
   public static void create(File f) {
      if (f.exists())
         return;
      safe(() -> {
         opt(f.createNewFile()).filter(x -> x).orElseThrow(() -> rex("Could not create file ''{0}''", f.getAbsolutePath()));
      });
   }

   /**
    * Create a temporary file with the specified name.
    *
    * <p>
    * The name is broken into file name and suffix, and the parts are passed to
    * {@link File#createTempFile(String, String)}.
    *
    * <p>
    * {@link File#deleteOnExit()} is called on the resulting file before being returned by this method.
    *
    * @param name The file name
    * @return A newly-created temporary file.
    * @throws IOException Thrown by underlying stream.
    */
   public static File createTempFile(String name) throws IOException {
      var parts = name.split("\\.");
      var f = File.createTempFile(parts[0], "." + parts[1]);
      f.deleteOnExit();
      return f;
   }

   /**
    * Create a temporary file with the specified name and specified contents.
    *
    * <p>
    * The name is broken into file name and suffix, and the parts are passed to
    * {@link File#createTempFile(String, String)}.
    *
    * <p>
    * {@link File#deleteOnExit()} is called on the resulting file before being returned by this method.
    *
    * @param name The file name
    * @param contents The file contents.
    * @return A newly-created temporary file.
    * @throws IOException Thrown by underlying stream.
    */
   public static File createTempFile(String name, String contents) throws IOException {
      var f = createTempFile(name);
      if (contents != null) {
         try (var r = new StringReader(contents); Writer w = new FileWriter(f)) {
            pipe(r, w);
            w.flush();
         }
      }
      // If contents is null, create an empty file
      return f;
   }

   /**
    * Recursively deletes a file or directory.
    *
    * @param f The file or directory to delete.
    * @return <jk>true</jk> if file or directory was successfully deleted.
    */
   public static boolean deleteFile(File f) {
      if (f == null)
         return true;
      if (f.isDirectory()) {
         var cf = f.listFiles();
         if (nn(cf))
            for (var c : cf)
               deleteFile(c);
      }
      return f.delete();
   }

   /**
    * Returns <jk>true</jk> if the specified file exists in the specified directory.
    *
    * @param dir The directory.
    * @param fileName The file name.
    * @return <jk>true</jk> if the specified file exists in the specified directory.
    */
   public static boolean fileExists(File dir, String fileName) {
      if (dir == null || fileName == null)
         return false;
      return Files.exists(dir.toPath().resolve(fileName));
   }

   /**
    * Strips the extension from a file name.
    *
    * @param name The file name.
    * @return The file name without the extension, or <jk>null</jk> if name was <jk>null</jk>.
    */
   public static String getBaseName(String name) {
      if (name == null)
         return null;
      var i = name.lastIndexOf('.');
      if (i == -1)
         return name;
      return name.substring(0, i);
   }

   /**
    * Returns the extension from a file name.
    *
    * @param name The file name.
    * @return The the extension, or <jk>null</jk> if name was <jk>null</jk>.
    */
   public static String getFileExtension(String name) {
      if (name == null)
         return null;
      var i = name.lastIndexOf('.');
      if (i == -1)
         return "";
      return name.substring(i + 1);
   }

   /**
    * Given an arbitrary path, returns the file name portion of that path.
    *
    * @param path The path to check.
    * @return The file name.
    */
   public static String getFileName(String path) {
      if (isEmpty(path))
         return null;
      path = trimTrailingSlashes(path);
      if (isEmpty(path))
         return null;  // Path contained only slashes
      // Handle both forward slashes (Unix) and backslashes (Windows)
      var i = Math.max(path.lastIndexOf('/'), path.lastIndexOf('\\'));
      return i == -1 ? path : path.substring(i + 1);
   }

   /**
    * Returns <jk>true</jk> if the specified file name contains the specified extension.
    *
    * @param name The file name.
    * @param ext The extension.
    * @return <jk>true</jk> if the specified file name contains the specified extension.
    */
   public static boolean hasExtension(String name, String ext) {
      if (name == null || ext == null)
         return false;
      return ext.equals(getFileExtension(name));
   }

   /**
    * Same as {@link File#mkdirs()} except throws a RuntimeExeption if directory could not be created.
    *
    * @param f The directory to create.  Must not be <jk>null</jk>.
    * @param clean If <jk>true</jk>, deletes the contents of the directory if it already exists.
    * @return The same file.
    * @throws RuntimeException if directory could not be created.
    */
   public static File mkdirs(File f, boolean clean) {
      assertArgNotNull("f", f);
      if (f.exists()) {
         if (clean) {
            opt(deleteFile(f)).filter(x -> x).orElseThrow(() -> rex("Could not clean directory ''{0}''", f.getAbsolutePath()));
         } else {
            return f;
         }
      }
      opt(f.mkdirs()).filter(x -> x).orElseThrow(() -> rex("Could not create directory ''{0}''", f.getAbsolutePath()));
      return f;
   }

   /**
    * Same as {@link #mkdirs(String, boolean)} but uses String path.
    *
    * @param path The path of the directory to create.  Must not be <jk>null</jk>
    * @param clean If <jk>true</jk>, deletes the contents of the directory if it already exists.
    * @return The directory.
    */
   public static File mkdirs(String path, boolean clean) {
      assertArgNotNull("path", path);
      return mkdirs(new File(path), clean);
   }

   /**
    * Updates the modified timestamp on the specified file.
    *
    * <p>
    * Method ensures that the timestamp changes even if it's been modified within the past millisecond.
    *
    * @param f The file to modify the modified timestamp on.
    */
   public static void modifyTimestamp(File f) {
      var lm = f.lastModified();
      var l = System.currentTimeMillis();
      if (lm == l)
         l++;
      opt(f.setLastModified(l)).filter(x -> x).orElseThrow(() -> rex("Could not modify timestamp on file ''{0}''", f.getAbsolutePath()));

      // Linux only gives 1s precision, so set the date 1s into the future.
      if (lm == f.lastModified())
         opt(f.setLastModified(l + 1000)).filter(x -> x).orElseThrow(() -> rex("Could not modify timestamp on file ''{0}''", f.getAbsolutePath()));
   }
}