'''
  This module aim in loading and writing files.
  Our files respect a specific format that 
  is not standard. This is why i hope these
  function make the read of file easier.
  
  For more information about the data, read
  the README file please.
  '''
  
  import sys
  
  def read_file(filepath):
      '''
      Read the file and return an array with pairs
      where each pair is composed by the metas and the 
      features.
      '''
      data = []
      with open(filepath, "r") as f:
          for line in f:
              splited = line.replace("
  ", "").split(" ")
              metas = splited[0].split(",")
              features = splited[1:]
              data.append((metas, features))
      return data
  
  
  def index_by(data, num_col):
      '''
      Allows the user to index data by number of columns.
      '''
      indexed = {}
      for line in data:
          metas = line[0]
          features = line[1]
          if metas[num_col] not in indexed:
              indexed[metas[num_col]] = []
          indexed[metas[num_col]].append((metas, features))
      return indexed
  
  
  def index_by_id(data):
      '''
      Allows the user to index data by id.
      Index data by id consists in indexing two times 
      because data have two keys. On with the language 
      and the other one with the id of the sentence.
      '''
      indexed = {}
      for line in data:
          metas = line[0]
          id_sen = metas[3]
          lang = metas[0]
          if lang not in indexed:
              indexed[lang] = {}
          indexed[lang][id_sen] = line
      return indexed
  
  
  def write_line(metas, features, f=sys.stdout):
      '''
      Just print the line. No need to specify a file.
  
      metas: meta information on list
      features: feature vector
      f: file to write it
      '''
      print(",".join(metas) + " " + " ".join(features), file=f)