""" from https://github.com/keithito/tacotron """
import re
from text import cleaners

# Regular expression matching text enclosed in curly braces:
_curly_re = re.compile(r'(.*?)\{(.+?)\}(.*)')


def get_arpabet(word, dictionary):
  word_arpabet = dictionary.lookup(word)
  if word_arpabet is not None:
    return "{" + word_arpabet[0] + "}"
  else:
    return word


def text_to_sequence(text, symbols, cleaner_names, dictionary=None):
  '''Converts a string of text to a sequence of IDs corresponding to the symbols in the text.

    The text can optionally have ARPAbet sequences enclosed in curly braces embedded
    in it. For example, "Turn left on {HH AW1 S S T AH0 N} Street."

    Args:
      text: string to convert to a sequence
      cleaner_names: names of the cleaner functions to run the text through
      dictionary: arpabet class with arpabet dictionary

    Returns:
      List of integers corresponding to the symbols in the text
  '''
  # Mappings from symbol to numeric ID and vice versa:
  global _id_to_symbol, _symbol_to_id
  _symbol_to_id = {s: i for i, s in enumerate(symbols)}
  _id_to_symbol = {i: s for i, s in enumerate(symbols)}

  sequence = []

  space = _symbols_to_sequence(' ')
  # Check for curly braces and treat their contents as ARPAbet:
  while len(text):
    m = _curly_re.match(text)
    if not m:
      clean_text = _clean_text(text, cleaner_names)
      if dictionary is not None:
        clean_text = [get_arpabet(w, dictionary) for w in clean_text.split(" ")]
        for i in range(len(clean_text)):
          t = clean_text[i]
          if t.startswith("{"):
            sequence += _arpabet_to_sequence(t[1:-1])
          else:
            sequence += _symbols_to_sequence(t)
          sequence += space
      else:
        sequence += _symbols_to_sequence(clean_text)
      break
    sequence += _symbols_to_sequence(_clean_text(m.group(1), cleaner_names))
    sequence += _arpabet_to_sequence(m.group(2))
    text = m.group(3)
  
  # remove trailing space
  if dictionary is not None:
    sequence = sequence[:-1] if sequence[-1] == space[0] else sequence
  return sequence


def _clean_text(text, cleaner_names):
  for name in cleaner_names:
    cleaner = getattr(cleaners, name)
    if not cleaner:
      raise Exception('Unknown cleaner: %s' % name)
    text = cleaner(text)
  return text


def _symbols_to_sequence(symbols):
  return [_symbol_to_id[s] for s in symbols if _should_keep_symbol(s)]


def _arpabet_to_sequence(text):
  return _symbols_to_sequence(['@' + s for s in text.split()])


def _should_keep_symbol(s):
  return s in _symbol_to_id and s is not '_' and s is not '~'