/**
 * Copyright (C) 2010-2017 Gordon Fraser, Andrea Arcuri and EvoSuite
 * contributors
 *
 * This file is part of EvoSuite.
 *
 * EvoSuite is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3.0 of the License, or
 * (at your option) any later version.
 *
 * EvoSuite is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with EvoSuite. If not, see <http://www.gnu.org/licenses/>.
 */
package org.evosuite.runtime.testdata;

import org.evosuite.runtime.vfs.FSObject;
import org.evosuite.runtime.vfs.VFile;
import org.evosuite.runtime.vfs.VirtualFileSystem;

/**
 * This class is used create files as test data
 * in the test cases.
 * 
 * <p>
 * The methods in this class are the main ones that are going
 * to be used in the generated JUnit files to manipulate
 * the virtual file system.
 * Note: if SUT takes as input a {@code File}, then it can happen
 * that mock {@code java.io} objects manipulating the VFS will appear in the test
 * cases.
 * 
 * @author arcuri
 *
 */
public class FileSystemHandling {

	/**
	 * Append a string to the given file.
	 * If the file does not exist, it will be created.
	 * 
	 * @return
	 */
	public static boolean appendStringToFile(EvoSuiteFile file, String value){
		
		if(file==null || value==null){
			return false;
		}
		
		return appendDataToFile(file,value.getBytes()); 
	}

	/**
	 * Append a string to the given file, and then move cursor
	 * to the next line.
	 * If the file does not exist, it will be created.
	 * 
	 * @return
	 */
	public static boolean appendLineToFile(EvoSuiteFile file, String line){
		
		if(file==null || line==null){
			return false;
		}
		
		return appendStringToFile(file, line + "\n"); 
	}
	
	
	
	/**
	 * Append a byte array to the given file.
	 * If the file does not exist, it will be created.
	 * 
	 * @param data
	 * @return
	 */
	public static boolean appendDataToFile(EvoSuiteFile file, byte[] data){
		
		if(file==null || data==null){
			return false;
		}
		
		FSObject target = VirtualFileSystem.getInstance().findFSObject(file.getPath());
		//can we write to it?
		if(target!=null && (target.isFolder() || !target.isWritePermission())){
			return false;
		}
		
		if(target==null){
			//if it does not exist, let's create it
			boolean created = VirtualFileSystem.getInstance().createFile(file.getPath());
			if(!created){
				return false;
			}
			target = VirtualFileSystem.getInstance().findFSObject(file.getPath());
			assert target != null;
		}
		
		VFile vf = (VFile) target;
		vf.writeBytes(data, 0, data.length);
		
		return true;
	}
	
	
	public static boolean createFolder(EvoSuiteFile file){		
		
		if(file==null){
			return false;
		}
		
		return VirtualFileSystem.getInstance().createFolder(file.getPath());
	}
	
	/**
	 * Set read/write/execute permissions to the given file
	 * 
	 * @param file
	 * @param isReadable
	 * @param isWritable
	 * @param isExecutable
	 * @return
	 */
	public static boolean setPermissions(EvoSuiteFile file, boolean isReadable, boolean isWritable, boolean isExecutable){
		if(file==null){
			return false;
		}
		FSObject target = VirtualFileSystem.getInstance().findFSObject(file.getPath());
		if(target == null){
			return false; 
		}
		
		target.setExecutePermission(isReadable);
		target.setWritePermission(isWritable);
		target.setExecutePermission(isExecutable);
		return true;
	}
	
	/**
	 * All operations on the given {@code file} will throw an IOException if that
	 * appears in their method signature
	 * 
	 * @param file
	 * @return
	 */
	public static boolean shouldThrowIOException(EvoSuiteFile file){
		if(file==null){
			return false;
		}
		return VirtualFileSystem.getInstance().setShouldThrowIOException(file); 
	}

	/**
	 * All operations in the entire VFS will throw an IOException if that
	 * appears in their method signature
	 */
	public static boolean shouldAllThrowIOExceptions(){
		return VirtualFileSystem.getInstance().setShouldAllThrowIOExceptions(); 
	}
}