package com.imyeyu.compress;

import com.imyeyu.io.IO;
import org.apache.commons.compress.archivers.sevenz.SevenZArchiveEntry;
import org.apache.commons.compress.archivers.sevenz.SevenZFile;

import java.io.File;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Path;

/**
 * 7z 解压器
 *
 * @author 夜雨
 * @version 2024-06-30 19:42
 */
public class Z7Decompressor extends Decompressor {

	@Override
	public void run(File fromFile, String toPath) throws Exception {
		initByteProgress(readTotalSize(fromFile));
		try {
			super.run(fromFile, toPath);
		} finally {
			resetProgress();
		}
	}

	@Override
	public void run(InputStream fromStream, String toPath) throws Exception {
		Path tempFile = writeTempFile(fromStream);
		try (SevenZFile file = SevenZFile.builder().setFile(tempFile.toFile()).get()) {
			SevenZArchiveEntry entry;
			boolean processed = false;
			while ((entry = file.getNextEntry()) != null) {
				if (entry.isDirectory()) {
					IO.dir(IO.fitPath(toPath) + entry.getName());
				} else {
					File toFile = IO.file(IO.fitPath(toPath) + entry.getName());
					try (OutputStream outputStream = IO.getOutputStream(toFile)) {
						copySevenZEntry(file, entry, outputStream);
						outputStream.flush();
					}
					handleFile(toFile);
					processed = true;
				}
			}
			if (processed) {
				finishProgress();
			}
		} finally {
			Files.deleteIfExists(tempFile);
		}
	}

	/**
	 * 将输入流写入临时文件
	 *
	 * @param fromStream 输入流
	 * @return 临时文件路径
	 * @throws Exception 写入失败
	 */
	private Path writeTempFile(InputStream fromStream) throws Exception {
		Path tempFile = Files.createTempFile("timi-compress-", ".7z");
		try (OutputStream outputStream = Files.newOutputStream(tempFile)) {
			transfer(fromStream, outputStream, false);
			outputStream.flush();
		}
		return tempFile;
	}

	/**
	 * 复制当前 7z 条目数据
	 *
	 * @param file 7z 文件
	 * @param entry 当前条目
	 * @param toStream 输出流
	 * @throws Exception 复制失败
	 */
	private void copySevenZEntry(SevenZFile file, SevenZArchiveEntry entry, OutputStream toStream) throws Exception {
		byte[] buffer = new byte[8192];
		long remain = entry.getSize();
		while (0 < remain) {
			awaitIfPaused();
			ensureRunning();
			int length = file.read(buffer, 0, (int) Math.min(buffer.length, remain));
			if (length < 0) {
				break;
			}
			toStream.write(buffer, 0, length);
			remain -= length;
			handleTransferred(length);
		}
	}

	/**
	 * 读取压缩包解压总字节数
	 *
	 * @param fromFile 压缩文件
	 * @return 总字节数
	 * @throws Exception 读取失败
	 */
	private long readTotalSize(File fromFile) throws Exception {
		long totalSize = 0L;
		try (SevenZFile file = SevenZFile.builder().setFile(fromFile).get()) {
			SevenZArchiveEntry entry;
			while ((entry = file.getNextEntry()) != null) {
				if (!entry.isDirectory()) {
					totalSize += entry.getSize();
				}
			}
		}
		return totalSize;
	}
}