package ca.uhn.hl7v2.conf.store;
   
   import java.io.BufferedReader;
   import java.io.BufferedWriter;
   import java.io.File;
   import java.io.FileReader;
   import java.io.FileWriter;
   import java.io.IOException;
   
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Stores profiles in a local directory.  Profiles are stored as text
   * in files named ID.xml (where ID is the profile ID).
   * 
   * @author Bryan Tripp
   */
  public class FileProfileStore implements ProfileStore {
      
      private final File root;
      private static final Logger log = LoggerFactory.getLogger(FileProfileStore.class);
      
      /** Creates a new instance of FileProfileStore */
      public FileProfileStore(String theFile) {
          root = new File(theFile);
          if (root.exists()) {
  	        if (!root.isDirectory()) {
  	            log.warn("Profile store is not a directory (won't be able to retrieve any profiles): {}", theFile);
  	        }
          } else {
          	log.debug("Profile store directory doesn't exist: {}", theFile);
          }
      }
      
      /**
       * Retrieves profile from persistent storage (by ID).  Returns null
       * if the profile isn't found.
       */
      public String getProfile(String theID) throws IOException {
          String profile = null;
          
          String fileName = getFileName(theID);
  		File source = new File(fileName);
          if (!source.exists()) {
          	log.debug("File for profile {} doesn't exist: {}", theID, fileName);
          } else if (source.isFile()) {
              BufferedReader in = new BufferedReader(new FileReader(source));
              char[] buf = new char[(int) source.length()];
              int check = in.read(buf, 0, buf.length);
              in.close();
              if (check != buf.length)
                  throw new IOException("Only read " + check + " of " + buf.length
                  + " bytes of file " + source.getAbsolutePath());
              profile = new String(buf);
              log.debug("Got profile {}: \r\n {}", theID, profile);
          }
          return profile;
      }
      
      /**
       * Stores profile in persistent storage with given ID.
       */
      public void persistProfile(String ID, String profile) throws IOException {
          if (!root.exists()) {
          	throw new IOException("Can't persist profile. Directory doesn't exist: " + root.getAbsolutePath());
          }
          if (!root.isDirectory()) {
          	throw new IOException("Can't persist profile. Not a directory: " + root.getAbsolutePath());
          }
      	
      	File dest = new File(getFileName(ID));
          BufferedWriter out = new BufferedWriter(new FileWriter(dest));
          out.write(profile);
          out.flush();
          out.close();
      }
      
      private String getFileName(String ID) {
          return root.getAbsolutePath() + "/" + ID + ".xml";
      }
  }