'''
Task Coach - Your friendly task manager
Copyright (C) 2004-2015 Task Coach developers <developers@taskcoach.org>

Task Coach is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Task Coach is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
'''

from taskcoachlib import operating_system, patterns
import subprocess
import wx


if operating_system.isWindows():
    
    class Speaker(object):
        ''' No-op class since we don't support speech on Windows yet. '''
        
        def say(self, text):
            ''' Simply ignore the method call. '''
            pass
        
else:
    
    class Speaker(object):
        ''' Class for letting the computer speak texts. Currently 'say' is
            supported on Mac OS X and 'espeak' on Linux. '''
        
        # Since speech is just one output channel, make this class a singleton.
        __metaclass__ = patterns.Singleton
        
        def __init__(self):
            if operating_system.isMac():
                self.__binary = 'say'
            elif operating_system.isGTK():
                self.__binary = 'espeak'
            self.__texts_to_say = []
            self.__current_speech_process = None
                
        def say(self, text):
            ''' Schedule the text for speaking. '''
            self.__texts_to_say.append(text)
            self.__say_next_text()
                    
        def __say_next_text(self):
            ''' Say the next text if there is no speech process currently 
                running. If there is, try again in one second. '''
            if self.__is_speaking():
                wx.CallLater(1000, self.__say_next_text)
                return
            if not self.__texts_to_say:
                return
            text = self.__texts_to_say.pop()
            self.__current_speech_process = subprocess.Popen((self.__binary, 
                                                              text))

        def __is_speaking(self):
            ''' Return whether the computer is currently speaking. '''
            process = self.__current_speech_process
            return process and process.poll() is None
            