/*
    * This file is part of ***  M y C o R e  ***
    * See http://www.mycore.de/ for details.
    *
    * MyCoRe is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    *
   * MyCoRe 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 General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with MyCoRe.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package org.mycore.datamodel.niofs.ifs2;
  
  import java.io.IOException;
  import java.nio.file.DirectoryNotEmptyException;
  import java.nio.file.FileAlreadyExistsException;
  import java.nio.file.FileStore;
  import java.nio.file.FileSystemException;
  import java.nio.file.Path;
  import java.util.Comparator;
  import java.util.Objects;
  
  import org.apache.logging.log4j.LogManager;
  import org.mycore.datamodel.ifs2.MCRDirectory;
  import org.mycore.datamodel.ifs2.MCRStore;
  import org.mycore.datamodel.ifs2.MCRStoreCenter;
  import org.mycore.datamodel.metadata.MCRObjectID;
  import org.mycore.datamodel.niofs.MCRAbstractFileSystem;
  import org.mycore.datamodel.niofs.MCRPath;
  
  /**
   * @author Thomas Scheffler (yagee)
   *
   */
  public class MCRIFSFileSystem extends MCRAbstractFileSystem {
  
      private MCRFileSystemProvider provider;
  
      MCRIFSFileSystem(MCRFileSystemProvider provider) {
          super();
          this.provider = provider;
      }
  
      /* (non-Javadoc)
       * @see java.nio.file.FileSystem#provider()
       */
      @Override
      public MCRFileSystemProvider provider() {
          return provider;
      }
  
      /* (non-Javadoc)
       * @see java.nio.file.FileSystem#getRootDirectories()
       */
      @Override
      public Iterable<Path> getRootDirectories() {
          return MCRStoreCenter.instance().getCurrentStores(org.mycore.datamodel.ifs2.MCRFileStore.class)
              .filter(s -> s.getID().startsWith(MCRFileSystemUtils.STORE_ID_PREFIX))
              .sorted(Comparator.comparing(MCRStore::getID))
              .flatMap(s -> s.getStoredIDs()
                  .mapToObj(
                      i -> MCRObjectID.formatID(s.getID().substring(MCRFileSystemUtils.STORE_ID_PREFIX.length()), i)))
              .map(owner -> MCRAbstractFileSystem.getPath(owner, "/", this))
              .map(Path.class::cast)::iterator;
      }
  
      /* (non-Javadoc)
       * @see java.nio.file.FileSystem#getFileStores()
       */
      @Override
      public Iterable<FileStore> getFileStores() {
          return MCRStoreCenter.instance().getCurrentStores(org.mycore.datamodel.ifs2.MCRFileStore.class)
              .filter(s -> s.getID().startsWith(MCRFileSystemUtils.STORE_ID_PREFIX))
              .sorted(Comparator.comparing(MCRStore::getID))
              .map(MCRStore::getID)
              .distinct()
              .map(storeId -> {
                  try {
                      return MCRFileStore.getInstance(storeId);
                  } catch (IOException e) {
                      LogManager.getLogger().error("Error while iterating FileStores.", e);
                      return null;
                  }
              })
              .filter(Objects::nonNull)
              .map(FileStore.class::cast)::iterator;
      }
  
      @Override
      public void createRoot(String owner) throws FileSystemException {
          MCRObjectID derId = MCRObjectID.getInstance(owner);
          org.mycore.datamodel.ifs2.MCRFileStore fileStore = MCRFileSystemUtils.getStore(derId.getBase());
         MCRPath rootPath = getPath(owner, "", this);
         try {
             if (fileStore.retrieve(derId.getNumberAsInteger()) != null) {
                 throw new FileAlreadyExistsException(rootPath.toString());
             }
             try {
                 fileStore.create(derId.getNumberAsInteger());
             } catch (RuntimeException e) {
                 LogManager.getLogger(getClass()).warn("Catched RuntimeException while creating new root directory.", e);
                 throw new FileSystemException(rootPath.toString(), null, e.getMessage());
             }
         } catch (FileSystemException e) {
             throw e;
         } catch (IOException e) {
             throw new FileSystemException(rootPath.toString(), null, e.getMessage());
         }
         LogManager.getLogger(getClass()).info("Created root directory: {}", rootPath);
     }
 
     @Override
     public void removeRoot(String owner) throws FileSystemException {
         MCRPath rootPath = getPath(owner, "", this);
         MCRDirectory rootDirectory = null;
         try {
             rootDirectory = MCRFileSystemUtils.getFileCollection(owner);
             if (rootDirectory.hasChildren()) {
                 throw new DirectoryNotEmptyException(rootPath.toString());
             }
             rootDirectory.delete();
         } catch (FileSystemException e) {
             throw e;
         } catch (IOException e) {
             throw new FileSystemException(rootPath.toString(), null, e.getMessage());
         } catch (RuntimeException e) {
             LogManager.getLogger(getClass()).warn("Catched RuntimeException while removing root directory.", e);
             throw new FileSystemException(rootPath.toString(), null, e.getMessage());
         }
         LogManager.getLogger(getClass()).info("Removed root directory: {}", rootPath);
     }
 
 }