class EacRubyUtils::StringDelimited

def after_end_index
  end_index.if_present { |v| v + end_delimiter.length }
end

def begin_index
  string.index(begin_delimiter)
end

def between_indexes(a_begin_index, a_end_index)
  a_begin_index && a_end_index ? string[a_begin_index, a_end_index - a_begin_index] : nil
end

def content_index
  begin_index.if_present { |v| v + begin_delimiter.length }
end

def end_index
  content_index.if_present { |_v| string.index(end_delimiter, content_index) }
end

def eos_index
  string.length
end

def initialize(string, begin_delimiter, end_delimiter)
  @string = string
  @begin_delimiter = begin_delimiter
  @end_delimiter = end_delimiter
end

def inner
  between_indexes(content_index, end_index).to_s
end

def outer
  between_indexes(begin_index, after_end_index).to_s
end

def sos_index
  0
end

def without_inner
  without_join(
    between_indexes(sos_index, content_index), between_indexes(end_index, eos_index)
  )
end

def without_join(*strings)
  return string if strings.any?(&:nil?)
  strings.join
end

def without_outer
  without_join(
    between_indexes(sos_index, begin_index),
    between_indexes(after_end_index, eos_index)
  )
end