class RubyXL::Workbook

def write(filepath=@filepath)
  validate_before_write
  if !(filepath =~ /(.+)\.xls(x|m)/)
    raise "Only xlsx and xlsm files are supported. Unsupported type for file: #{filepath}"
  end
  dirpath = ''
  extension = 'xls'
  if(filepath =~ /((.|\s)*)\.xls(x|m)$/)
    dirpath = $1.to_s()
    extension += $3.to_s
  end
  filename = ''
  if(filepath =~ /\/((.|\s)*)\/((.|\s)*)\.xls(x|m)$/)
    filename = $3.to_s()
  end
  #creates zip file, writes each type of file to zip folder
  #zips package and renames it to xlsx.
  zippath = File.join(dirpath, filename + '.zip')
  File.unlink(zippath) if File.exists?(zippath)
  FileUtils.mkdir_p(File.join(dirpath,zippath))
  Zip::ZipFile.open(zippath, Zip::ZipFile::CREATE) do |zipfile|
    writer = Writer::ContentTypesWriter.new(dirpath,self)
    zipfile.get_output_stream('[Content_Types].xml') {|f| f.puts(writer.write())}
    writer = Writer::RootRelsWriter.new(dirpath,self)
    zipfile.get_output_stream(File.join('_rels','.rels')) {|f| f.puts(writer.write())}
    writer = Writer::AppWriter.new(dirpath,self)
    zipfile.get_output_stream(File.join('docProps','app.xml')) {|f| f.puts(writer.write())}
    writer = Writer::CoreWriter.new(dirpath,self)
    zipfile.get_output_stream(File.join('docProps','core.xml')) {|f| f.puts(writer.write())}
    writer = Writer::ThemeWriter.new(dirpath,self)
    zipfile.get_output_stream(File.join('xl','theme','theme1.xml')) {|f| f.puts(writer.write())}
    writer = Writer::WorkbookRelsWriter.new(dirpath,self)
    zipfile.get_output_stream(File.join('xl','_rels','workbook.xml.rels')) {|f| f.puts(writer.write())}
    writer = Writer::WorkbookWriter.new(dirpath,self)
    zipfile.get_output_stream(File.join('xl','workbook.xml')) {|f| f.puts(writer.write())}
    writer = Writer::StylesWriter.new(dirpath,self)
    zipfile.get_output_stream(File.join('xl','styles.xml')) {|f| f.puts(writer.write())}
    unless @shared_strings.nil?
      writer = Writer::SharedStringsWriter.new(dirpath,self)
      zipfile.get_output_stream(File.join('xl','sharedStrings.xml')) {|f| f.puts(writer.write())}
    end
    #preserves external links (exactly, no modification allowed)
    unless @external_links.nil?
      #-1 because of rels
      1.upto(@external_links.size-1) do |i|
        zipfile.get_output_stream(
          File.join('xl','externalLinks',"externalLink#{i}.xml")) {|f|
            f.puts(@external_links[i])
          }
      end
      @external_links['rels'].each_index do |i|
        unless @external_links['rels'][i].nil?
          zipfile.get_output_stream(
            File.join('xl','externalLinks','_rels',"externalLink#{i}.xml.rels")) {|f|
              f.puts(@external_links['rels'][i])
            }
        end
      end
    end
    #preserves drawings (exactly, no modification allowed)
    unless @drawings.nil?
      1.upto(@drawings.size) do |i|
        zipfile.get_output_stream(
        File.join('xl','drawings',"vmlDrawing#{i}.vml")) {|f|
          f.puts(@drawings[i])
        }
      end
    end
    unless @printer_settings.nil?
      1.upto(@printer_settings.size) do |i|
        zipfile.get_output_stream(
        File.join('xl','printerSettings',"printerSettings#{i}.bin")) {|f|
          f.puts(@printer_settings[i])
        }
      end
    end
    unless @worksheet_rels.nil?
      1.upto(@worksheet_rels.size) do |i|
        zipfile.get_output_stream(
        File.join('xl','worksheets','_rels',"sheet#{i}.xml.rels")) {|f|
          f.puts(@worksheet_rels[i])
        }
      end
    end
    unless @macros.nil?
      zipfile.get_output_stream(File.join('xl','vbaProject.bin')) {|f| f.puts(@macros)}
    end
    @worksheets.each_with_index do |sheet,i|
      writer = Writer::WorksheetWriter.new(dirpath,self,i)
      zipfile.get_output_stream(File.join('xl','worksheets',"sheet#{i+1}.xml")) {|f| f.puts(writer.write())}
    end
  end
  FileUtils.cp(zippath,File.join(dirpath,filename+".#{extension}"))
  FileUtils.cp(File.join(dirpath,filename+".#{extension}"),filepath)
  if File.exist?(filepath)
    FileUtils.rm_rf(dirpath)
  end
  return filepath
end