ExcelToCsv::ExcelFile

require 'exceltocsv'

converter = ExcelToCsv::ExcelFile.new
converter.xl_to_csv( 'path/to/input.xls', 'path/to/output.csv' )

require 'exceltocsv'

desc "Update CSV files from XLS source"
task :update do
  plks = FileList['plk/xls/**/*.xls']

  # Pathmap string maps to csv dir with csv target file
  pm = "%{^plk/xls,plk/csv;.xls$,.csv;.xlsx$,.csv}p"
  # Remove any source files when the dest file exists and is newer.
  plks.delete_if do |s|
    # Downcase the path,
    d = s.pathmap( pm ).downcase
    # and snakecase the target filename.
    d = snakecase_filename(d)
    File.exists?(d) && File.stat(s).mtime <= File.stat(d).mtime
  end

  target_csvs = plks.pathmap( pm )

  # I want the target filenames normalized to lower case.
  target_csvs.each { |p| p.downcase! }

  # Create all target dirs
  target_dirs = target_csvs.pathmap("%d")
  target_dirs.uniq!
  mkdir_p target_dirs

  # Convert all newer XL files to CSVs.
  # Note that this method only converts the first sheet in the workbook.
  converter = ExcelToCsv::ExcelFile.new
  plks.each do |x|
    converter.xl_to_csv(x, snakecase_filename(x.pathmap(pm).downcase))
  end

  puts "All target files are up to date" if plks.empty?
end

def snakecase_filename(filepath)
  snake_file_path = File.join(filepath.pathmap("%d"), filepath.pathmap("%n").snakecase + filepath.pathmap("%x"))
end