package nettext.file;

import java.io.PrintWriter;
import java.io.IOException;
import java.io.FileOutputStream;

import nettext.document.Document;
import nettext.document.DocumentList;
import nettext.document.DocumentListIterator;

/**
 * Writer for the available list of Documents
 */
public class DocumentListWriter {
  /**
   * The Writer.
   */
  private PrintWriter oStream;

  /**
   * The Writee.
   */
  private String fileName;

  /**
   * Standard Initialization function that initializes all fields
   * to default values
   *@param fileN afilename
   *@return boolean
   */
  public boolean initialize(String fileN) {
    if (fileN == null) {
      return false;
    }

    this.fileName = fileN;

    //initialize the PrintWriter
    try {
      oStream = new PrintWriter(new FileOutputStream(fileName));
    } catch (IOException ioe) {
      System.err.println("Error initializing list writer:");
      System.err.println("\t" + ioe.getMessage());
      System.err.flush();
      return false;
    }

    return true;
  }

  /**
   * Flush/Close Buffers/Streams
   */
  public void cleanUp() {
    oStream.flush();
    oStream.close();

    oStream = null;
  }

  /**
   * Writes the document list if possible.
   *
   * @param list a <code>DocumentList</code> value
   * @return a <code>boolean</code> value
   */
  public boolean writeDocumentList(final DocumentList list) {
    DocumentListIterator dli = list.getIterator();

    if (oStream == null) {
      return false;
    }

    //Start file
    if (!startFile()) { return false; }

    //Start list
    if (!startList(list)) { return false; }

    //Write documents
    while (dli.hasNext()) {
      if (!writeDocument(dli.next())) { return false; }
    }

    //End list
    if (!endList()) { return false; }

    //End file
    if (!endFile()) { return false; }

    return true;
  }

  /**
   * Write the things at the start of the File
   *@return boolean
   */
  public boolean startFile() {
    try {
      //Print out the start of the document.
      this.writeOut("<?xml version='1.0'?>");
      this.nl();
      this.nl();
    } catch (IOException ioe) {
      System.err.println("IO EXCEPTION!!! BAD!!!!, startFile()-NTOH");
      return false;
    }

    return true;
  }

  /**
   * Write out the things related to ending the file
   * @return a <code>boolean</code> value
   */
  public boolean endFile() {
    return true;
  }

  /**
   * Writes the start of the document list into the file.
   *
   * @param list a <code>DocumentList</code> value
   * @return a <code>boolean</code> value
   */
  public boolean startList(final DocumentList list) {
    try {
      this.writeOut("<" + XMLSettings.DOCUMENT_LIST);
      this.writeOut(" numDocuments=\"" + list.size() + "\"");
      this.writeOut(">");
      this.nl();
    } catch (IOException ioe) {
      System.err.println("IO Exception!! startList() - NTOH");
      return false;
    }

    return true;
  }

  /**
   * Writes out the end of the document list into the file.
   *
   * @return a <code>boolean</code> value
   */
  public boolean endList() {
    try {
      this.writeOut("</" + XMLSettings.DOCUMENT_LIST + ">");
      this.nl();
    } catch (IOException ioe) {
      System.err.println("IO Exception!! endList() - NTOH");
      return false;
    }

    return true;
  }

  /**
   * Write out the document.
   * @param toWrite a <code>Document</code> value
   * @return a <code>boolean</code> value
   */
  public boolean writeDocument(Document toWrite) {
    try {
      //  Figure out the writeOut (the docName shouldn't be fileName!)
      this.writeOut("\t<"
                    + XMLSettings.DOCUMENT_KEY
                    + " name=\""
                    + toWrite.getDocumentName()
                    + "\" id=\""
                    + toWrite.getDocumentId()
                    + "\" />");
      this.nl();
    } catch (IOException ioe) {
      System.err.println("IO Exception!! startDocument() - NTOH");
      return false;
    }

    return true;
  }

  /**
   * Helper function
   * Writes the String toWrite to the stdOut
   *@param toWrite toWrite
   *@throws IOException exception
   */
  private void writeOut(String toWrite) throws IOException {
    oStream.print(toWrite);
    oStream.flush();
  }

  /**
   * Helper function
   *   Writes a newline to the file
   *@throws IOException exception
   */
  private void nl() throws IOException {
    //flush once for the bulk, twice for the left-overs
    oStream.print("\n");
    oStream.flush();
  }

}