import java.util.*;

public class FileSystem {
	CompoundFile dirs;
	CompoundFile current_dir;

		// constructor
	FileSystem(CompoundFile starter) {
		dirs = starter; 
		current_dir = starter;
	}

	public synchronized void exitSystem() {
			// exit shell
		System.exit(0);
	}

	public synchronized void MakeDirectory (String str) {
			//add the new file to the end of the compound file 
			//list , only if no file exist with the same name
		if (current_dir.isExist(str))
			System.out.println("mkdir:" + str + ":File exists");
		else{
			CompoundFile newFile=new CompoundFile(current_dir,str);
			current_dir.File_list.add(current_dir.File_list.size(),newFile);
		}
	} // end of MakeDirectory()


	public synchronized void ChangeDirectoryUp() {
		CompoundFile upper_dir 
			= (CompoundFile)(current_dir.getParentDir());

		if (upper_dir != null) 	// not under root directory
			current_dir = upper_dir;

	} // end of ChangeDirectoryUp()

	public synchronized void ChangeDirectoryDown(String name) {
		ArrayList tmpList = current_dir.File_list;

		if (current_dir.isExist(name)) {
			for (int k = 0; k < tmpList.size(); k ++) {
				File tmpFile = (File)(tmpList.get(k));
				String nameFound=tmpFile.getFileName().getI();
				if (nameFound.compareTo(name) == 0) {
					if (tmpFile.getDir() == null) {
						System.out.println(name + ": Not a directory.");
					}
					else {
					  current_dir = tmpFile.getDir();
					}
				}
			}
		}
		else 
		     System.out.println(name + ": No such file or directory.");

	} // end of  ChangeDirectoryDown(String)


	public synchronized void DiskUsage() {
		ArrayList tmpList = current_dir.File_list;
		String str = "./";
		if (tmpList.isEmpty()) 
			System.out.println(".");
		else {
			for (int k = 0; k < tmpList.size(); k ++) {
				File tmpFile = (File)(tmpList.get(k));
				tmpFile.print(str);
			}
			System.out.println(".");
		}
	} // end of DiskUsage()

	public synchronized void MakeLink(String a, String b){
	    ArrayList tmpList = current_dir.File_list;
	    if (!current_dir.isExist(b)) {
		if (current_dir.isExist(a)) {
			for (int k = 0; k < tmpList.size(); k ++) {
				File tmpFile = (File) tmpList.get(k);
				String nameFound = tmpFile.getFileName().getI();
				if (nameFound.compareTo(a) == 0) {
					Link newLink = new Link(tmpFile,b);
					current_dir.File_list.add(tmpList.size(),newLink);
				}
			}
		}
			// if both a and b don't exist, create a empty file b
		else {
			SimpleFile newFile = new SimpleFile(current_dir,b);
			current_dir.File_list.add(current_dir.File_list.size(),newFile);
		}
	    }
		// if there is already a file having name b, report the error
	    else 
		System.out.println("ln : cannot create "+b+":File exists");		
	} // end of MakeLink


	public synchronized void RemoveDir(String name){
		ArrayList tmpList = current_dir.File_list;
		if (current_dir.isExist(name)) {
			for (int k = 0; k < tmpList.size(); k ++ ) {
				File tmpFile = (File)(tmpList.get(k));
				String nameFound=tmpFile.getFileName().getI();
				if (nameFound.compareTo(name) == 0) {
					if ((tmpFile.getDir() == null) || (tmpFile.getLink() != null))
						System.out.println("rmdir: directory " + name + ": Path component not a directory");
					else
						current_dir.File_list.remove(k);
				}
			}	
		}
		else
			System.out.println("rmdir:directory "+name+": Directory does not exist");

	} // end of RemoveDir()


	public synchronized void RemoveSmFile(String name){
                ArrayList tmpList = current_dir.File_list;
                if (current_dir.isExist(name)) {
                        for (int k = 0; k < tmpList.size(); k ++ ) {
                                File tmpFile = (File)(tmpList.get(k));
                                String nameFound=tmpFile.getFileName().getI();
                                if (nameFound.compareTo(name) == 0) {
					if ((tmpFile.getLink()!=null) || (tmpFile.getDir() == null))
						current_dir.File_list.remove(k);
					else
						System.out.println("rm:" + name + " is a directory"); 
                                }
                        }
                }
                else
                        System.out.println(name +": No such file or directory");
	}// end of RemoveSmFile()


	public synchronized void CreatEmpFile(String name) {
		ArrayList tmpList = current_dir.File_list;
		if (!current_dir.isExist(name)) {
			SimpleFile newFile = new SimpleFile(current_dir,name);
			current_dir.File_list.add(current_dir.File_list.size(),newFile);
		}
		else 
			System.out.println("Creat-empty-file:"+name + ": File exists");
	} // end of CreatEmpFile( )

} // end of class FileSystem