/**
 * 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.hadoop.hdfs.server.namenode;

import java.io.File;
import java.io.IOException;

import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.fs.permission.PermissionStatus;
import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.hdfs.server.common.GenerationStamp;
import org.apache.hadoop.hdfs.server.common.Storage;
import org.apache.hadoop.hdfs.server.namenode.BlocksMap.BlockInfo;

/**
 * 
 * CreateEditsLog Synopsis: CreateEditsLog -f numFiles StartingBlockId
 * numBlocksPerFile [-r replicafactor] [-d editsLogDirectory] Default
 * replication factor is 1 Default edits log directory is /tmp/EditsLogOut
 * 
 * Create a name node's edits log in /tmp/EditsLogOut. The file
 * /tmp/EditsLogOut/current/edits can be copied to a name node's
 * dfs.name.dir/current direcotry and the name node can be started as usual.
 * 
 * The files are created in /createdViaInjectingInEditsLog The file names
 * contain the starting and ending blockIds; hence once can create multiple
 * edits logs using this command using non overlapping block ids and feed the
 * files to a single name node.
 * 
 * See Also @link #DataNodeCluster for injecting a set of matching blocks
 * created with this command into a set of simulated data nodes.
 * 
 */

public class CreateEditsLog {
	static final String BASE_PATH = "/createdViaInjectingInEditsLog";
	static final String EDITS_DIR = "/tmp/EditsLogOut";
	static String edits_dir = EDITS_DIR;
	static final public long BLOCK_GENERATION_STAMP = GenerationStamp.FIRST_VALID_STAMP;

	static void addFiles(FSEditLog editLog, int numFiles, short replication,
			int blocksPerFile, long startingBlockId,
			FileNameGenerator nameGenerator) {

		PermissionStatus p = new PermissionStatus("joeDoe", "people",
				new FsPermission((short) 0777));
		INodeDirectory dirInode = new INodeDirectory(p, 0L);
		editLog.logMkDir(BASE_PATH, dirInode);
		long blockSize = 10;
		BlockInfo[] blocks = new BlockInfo[blocksPerFile];
		for (int iB = 0; iB < blocksPerFile; ++iB) {
			blocks[iB] = new BlockInfo(new Block(0, blockSize,
					BLOCK_GENERATION_STAMP), replication);
		}

		long currentBlockId = startingBlockId;
		long bidAtSync = startingBlockId;

		for (int iF = 0; iF < numFiles; iF++) {
			for (int iB = 0; iB < blocksPerFile; ++iB) {
				blocks[iB].setBlockId(currentBlockId++);
			}

			try {

				INodeFileUnderConstruction inode = new INodeFileUnderConstruction(
						null, replication, 0, blockSize, blocks, p, "", "",
						null);
				// Append path to filename with information about blockIDs
				String path = "_" + iF + "_B" + blocks[0].getBlockId()
						+ "_to_B" + blocks[blocksPerFile - 1].getBlockId()
						+ "_";
				String filePath = nameGenerator.getNextFileName("");
				filePath = filePath + path;
				// Log the new sub directory in edits
				if ((iF % nameGenerator.getFilesPerDirectory()) == 0) {
					String currentDir = nameGenerator.getCurrentDir();
					dirInode = new INodeDirectory(p, 0L);
					editLog.logMkDir(currentDir, dirInode);
				}
				editLog.logOpenFile(filePath, inode);
				editLog.logCloseFile(filePath, inode);

				if (currentBlockId - bidAtSync >= 2000) { // sync every 2K
					// blocks
					editLog.logSync();
					bidAtSync = currentBlockId;
				}
			} catch (IOException e) {
				System.out.println("Creating trascation for file " + iF
						+ " encountered exception " + e);
			}
		}
		System.out.println("Created edits log in directory " + edits_dir);
		System.out.println(" containing " + numFiles
				+ " File-Creates, each file with " + blocksPerFile + " blocks");
		System.out.println(" blocks range: " + startingBlockId + " to "
				+ (currentBlockId - 1));
	}

	static String usage = "Usage: createditlogs "
			+ " -f  numFiles startingBlockIds NumBlocksPerFile  [-r replicafactor] "
			+ "[-d editsLogDirectory]\n"
			+ "      Default replication factor is 1\n"
			+ "      Default edits log direcory is " + EDITS_DIR + "\n";

	static void printUsageExit() {
		System.out.println(usage);
		System.exit(-1);
	}

	static void printUsageExit(String err) {
		System.out.println(err);
		printUsageExit();
	}

	/**
	 * @param args
	 * @throws IOException
	 */
	public static void main(String[] args) throws IOException {

		long startingBlockId = 1;
		int numFiles = 0;
		short replication = 1;
		int numBlocksPerFile = 0;

		if (args.length == 0) {
			printUsageExit();
		}

		for (int i = 0; i < args.length; i++) { // parse command line
			if (args[i].equals("-h"))
				printUsageExit();
			if (args[i].equals("-f")) {
				if (i + 3 >= args.length || args[i + 1].startsWith("-")
						|| args[i + 2].startsWith("-")
						|| args[i + 3].startsWith("-")) {
					printUsageExit("Missing num files, starting block and/or number of blocks");
				}
				numFiles = Integer.parseInt(args[++i]);
				startingBlockId = Integer.parseInt(args[++i]);
				numBlocksPerFile = Integer.parseInt(args[++i]);
				if (numFiles <= 0 || numBlocksPerFile <= 0) {
					printUsageExit("numFiles and numBlocksPerFile most be greater than 0");
				}
			} else if (args[i].equals("-r") || args[i + 1].startsWith("-")) {
				if (i + 1 >= args.length) {
					printUsageExit("Missing num files, starting block and/or number of blocks");
				}
				replication = Short.parseShort(args[++i]);
			} else if (args[i].equals("-d")) {
				if (i + 1 >= args.length || args[i + 1].startsWith("-")) {
					printUsageExit("Missing edits logs directory");
				}
				edits_dir = args[++i];
			} else {
				printUsageExit();
			}
		}

		File editsLogDir = new File(edits_dir);
		File subStructureDir = new File(edits_dir + "/"
				+ Storage.STORAGE_DIR_CURRENT);
		if (!editsLogDir.exists()) {
			if (!editsLogDir.mkdir()) {
				System.out.println("cannot create " + edits_dir);
				System.exit(-1);
			}
		}
		if (!subStructureDir.exists()) {
			if (!subStructureDir.mkdir()) {
				System.out.println("cannot create subdirs of " + edits_dir);
				System.exit(-1);
			}
		}

		FSImage fsImage = new FSImage(new File(edits_dir));
		FileNameGenerator nameGenerator = new FileNameGenerator(BASE_PATH, 100);

		FSEditLog editLog = fsImage.getEditLog();
		editLog.createEditLogFile(fsImage.getFsEditName());
		editLog.open();
		addFiles(editLog, numFiles, replication, numBlocksPerFile,
				startingBlockId, nameGenerator);
		editLog.logSync();
		editLog.close();
	}
}
