class PollySpeech

# File lib/pollyspeech.rb, line 16
def initialize(access_key: '', secret_key: '', region: 'us-east-1', 
                voice_id: 'Emma', cache_filepath: 'cache', debug: false)

  @debug = debug
  
  @polly = Aws::Polly::Client.new(region: region, 
    credentials: Aws::Credentials.new(access_key, secret_key))
  @voice_id = voice_id
  @cache_filepath = File.join(cache_filepath, voice_id)

end

# File lib/pollyspeech.rb, line 28
def tts(text='', audiofile_out='/tmp/polly.ogg')

  ext = File.extname(audiofile_out)
  out_format = {'.ogg' => 'ogg_vorbis', '.mp3' => 'mp3'}[ext]

  FileUtils.mkdir_p @cache_filepath
  
  h = Digest::MD5.new << text
  filename = File.join(@cache_filepath, h.to_s + ext)
  
  
  # attempts to find the audio file from a local cache instead of
  # making a relatively expensive request through the web API
  
  if not File.exists? filename then
          
    params = {response_target: filename, text: text, 
      output_format: out_format,  voice_id: @voice_id}
    params.merge!({text_type: 'ssml'}) if text.lstrip =~ /^<speak/
    @polly.synthesize_speech(params)

  end    
  
  puts ('audiofile_out' + audiofile_out.inspect).debug if @debug
  FileX.cp filename, audiofile_out        

end