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/*
 * Copyright (c) 2013 Univocity Software Pty Ltd. All rights reserved.
 * This file is subject to the terms and conditions defined in file
 * 'LICENSE.txt', which is part of this source code package.
 */

package com.univocity.api.io;

import com.univocity.api.common.*;

import java.io.*;
import java.nio.charset.*;

/**
 * A {@code FileProvider} validates and stores the minimum information required by univocity to locate and manipulate files.
 * System properties can be used as part of the file name, such as {user.home}.
 *
 * @author Univocity Software Pty Ltd - [email protected]
 */
public final class FileProvider {

	private final File file;
	private final Charset encoding;
	private final String filePath;

	/**
	 * Creates a provider for the file to be read/written using the default system encoding.
	 *
	 * @param file the File
	 */
	public FileProvider(File file) {
		this(file, (Charset) null);
	}

	/**
	 * Creates a provider for the file to be read/written using a given encoding
	 *
	 * @param file     the File to be used.
	 * @param encoding the name of the encoding that must be used to read from/write to the given file.
	 */
	public FileProvider(File file, String encoding) {
		this(file, getEncoding(encoding));
	}

	/**
	 * Creates a provider for the file to be read/written using a given encoding
	 *
	 * @param file     the File to be used.
	 * @param encoding the encoding that must be used to read from/write to the given file.
	 */
	public FileProvider(File file, Charset encoding) {
		if (file == null) {
			throw new IllegalArgumentException("File cannot be null");
		}
		this.encoding = getEncoding(encoding);
		this.file = file;
		this.filePath = file.getAbsolutePath();
	}

	/**
	 * Creates a provider for the file, represented by a path, to be read/written using the default system encoding.
	 * The path can contain system variables enclosed within { and } (e.g. {@code {user.home}/myapp/log"}).
	 *
	 * @param file the path to a file. It can either be the path to a file in the file system or a resource in the classpath.
	 */
	public FileProvider(String file) {
		this(file, (Charset) null);
	}

	/**
	 * Creates a provider for the file, represented by a path, to be read/written using the default system encoding.
	 * The path can contain system variables enclosed within { and } (e.g. {@code {user.home}/myapp/log"}).
	 *
	 * @param file     the path to a file. It can either be the path to a file in the file system or a resource in the classpath.
	 * @param encoding the name of the encoding that must be used to read from/write to the given file.
	 */
	public FileProvider(String file, String encoding) {
		this(file, getEncoding(encoding));
	}

	/**
	 * Creates a provider for the file, represented by a path, to be read/written using the default system encoding.
	 * The path can contain system variables enclosed within { and } (e.g. {@code {user.home}/myapp/log"}).
	 *
	 * @param filePath the path to a file. It can either be the path to a file in the file system or a resource in the classpath.
	 * @param encoding the encoding that must be used to read from/write to the given file.
	 */
	public FileProvider(String filePath, Charset encoding) {
		if (filePath == null || filePath.trim().isEmpty()) {
			throw new IllegalArgumentException("File path cannot be null or empty");
		}
		this.encoding = getEncoding(encoding);
		this.file = null;
		this.filePath = Args.replaceSystemProperties(filePath).replace('\\', '/');
	}

	private final static Charset getEncoding(String encoding) {
		if (encoding == null) {
			return Charset.defaultCharset();
		}
		return Charset.forName(encoding);
	}

	private final static Charset getEncoding(Charset encoding) {
		if (encoding == null) {
			return Charset.defaultCharset();
		}
		return encoding;
	}

	/**
	 * Returns the File instance given in the constructor of this class, or {@code null} if a path to a resource is being used.
	 *
	 * @return the File to be loaded by univocity, or null if a resource path should be used instead.
	 */
	public final File getFile() {
		return file;
	}

	/**
	 * Returns the encoding used to manipulate the provided file.
	 *
	 * @return encoding used to manipulate the provided file.
	 */
	public final Charset getEncoding() {
		return encoding;
	}

	/**
	 * Returns the resource path given in the constructor of this class, or null if a {@code File} is being used.
	 *
	 * @return the path to a resource to be loaded by univocity, or null if a {@code File} should be used instead.
	 */
	public final String getFilePath() {
		return filePath;
	}

	@Override
	public final String toString() {
		return filePath + " (" + encoding + ")";
	}

	@Override
	public boolean equals(Object o) {
		if (this == o) return true;
		if (o == null || getClass() != o.getClass()) return false;

		FileProvider that = (FileProvider) o;

		return filePath.equals(that.filePath);

	}

	@Override
	public int hashCode() {
		return filePath.hashCode();
	}
}