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/*
 * Copyright 2023 the original author or authors.
 * 
 * Licensed 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
 * 

 * https://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 de.cuioss.tools.io;

import static de.cuioss.tools.base.Preconditions.checkArgument;
import static de.cuioss.tools.string.MoreStrings.isEmpty;
import static java.util.Objects.requireNonNull;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.StringWriter;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;

import lombok.AccessLevel;
import lombok.NoArgsConstructor;

/**
 * Utility class for dealing with generic / classpath related file access.
 *
 * @author Oliver Wolff
 */
@NoArgsConstructor(access = AccessLevel.PRIVATE)
public final class FileLoaderUtility {

    /**
     * Returns an implementation of {@link FileLoader} matching to the given path.
     *
     * @param pathName must not be null or empty.
     * @return a configured implementation of {@link FileLoader}. In case the
     *         pathName is prefixed with {@link FileTypePrefix#CLASSPATH} it returns
     *         a {@link ClassPathLoader}. If prefixed with
     *         {@link FileTypePrefix#URL} it returns a {@link UrlLoader}. Otherwise,
     *         it returns a {@link FileSystemLoader}.
     */
    public static FileLoader getLoaderForPath(final String pathName) {
        if (isEmpty(pathName)) {
            throw new IllegalArgumentException("pathName must not be null nor empty");
        }
        if (pathName.startsWith(FileTypePrefix.CLASSPATH.getPrefix())) {
            return new ClassPathLoader(pathName);
        }
        if (pathName.startsWith(FileTypePrefix.URL.getPrefix())) {
            return new UrlLoader(pathName);
        }
        return new FileSystemLoader(pathName);
    }

    /**
     * Helper class that copies the content of a {@link FileLoader} to the
     * temp-folder and references it
     * 
Caution: Security-Impact Creating a temp-file might introduce a
     * security issue. Never ever use this location for sensitive information that
     * might be of interest for an attacker
     *
     * @param source           must not be null and represent an accessible file,
     *                         saying {@link FileLoader#isReadable()}
     * @param markDeleteOnExit if true the file will be marked to
     *                         delete on Exit.
     * @return a reference on a file copied in the temp folder
     * @throws IOException
     */
    @SuppressWarnings("java:S5443") // owolff: See hint Caution: Security-Impact
    public static Path copyFileToTemp(final FileLoader source, final boolean markDeleteOnExit) throws IOException {
        checkArgument(null != source, "Attribute with name source must not be null");
        checkArgument(source.isReadable(), "Source must be readable");

        final var target = Files.createTempFile(source.getFileName().getNamePart(), source.getFileName().getSuffix());

        try (final var inputStream = source.inputStream()) {
            Files.copy(new BufferedInputStream(inputStream), target, StandardCopyOption.REPLACE_EXISTING);
        }
        if (markDeleteOnExit) {
            target.toFile().deleteOnExit();
        }
        return target;
    }

    /**
     * Convenience method for reading the content from a given {@link FileLoader}
     * into a String
     *
     * @param fileLoader must not be null
     * @param charset    must not be null
     * @return The String content of the File represented by the given
     *         {@link FileLoader}
     * @throws IOException
     */
    public static String toString(final FileLoader fileLoader, final Charset charset) throws IOException {
        requireNonNull(fileLoader);
        final var writer = new StringWriter();
        try (final var inputStream = fileLoader.inputStream()) {
            IOStreams.copy(inputStream, writer, charset);
        }
        return writer.toString();
    }

    /**
     * Convenience method for reading the content from a given {@link FileLoader}
     * into a String read as UTF-8 String
     *
     * @param fileLoader must not be null
     * @return The String content of the File represented by the given
     *         {@link FileLoader}
     * @throws IOException
     */
    public static String toString(final FileLoader fileLoader) throws IOException {
        return toString(fileLoader, StandardCharsets.UTF_8);
    }

    /**
     * Convenience method for reading the content from a given {@link FileLoader}
     * into a String read as UTF-8 String
     *
     * @param fileLoader must not be null
     * @return The String content of the File represented by the given
     *         {@link FileLoader}
     * @throws IllegalArgumentException masking the actual {@link IOException}
     * @throws NullPointerException     if fileLoader is null
     */
    public static String toStringUnchecked(final FileLoader fileLoader) {
        requireNonNull(fileLoader);
        try {
            return toString(fileLoader);
        } catch (final IOException | IllegalStateException e) {
            throw new IllegalArgumentException("Unable to read from Path " + fileLoader.getFileName(), e);
        }
    }
}