# Module to handle sound playback

#------------------------------------------------------------------------------

import os
import traceback

#------------------------------------------------------------------------------

if os.name=="nt":
    import time
    import threading
    from ctypes import windll, c_buffer

    class MCIException(Exception):
        """MCI exception."""
        def __init__(self, mci, command, errorCode):
            """Construct an MCI exception for the given error code."""
            message = "MCI error: %s: %s" % (command, mci.getErrorString(errorCode))
            super(MCIException, self).__init__(message)

    class MCI:
        """Interface for the Media Control Interface."""
        def __init__(self):
            """Construct the interface."""
            self.w32mci = windll.winmm.mciSendStringA
            self.w32mcierror = windll.winmm.mciGetErrorStringA

        def send(self, command):
            """Send the given command to the MCI."""
            buffer = c_buffer(255)
            errorCode = self.w32mci(str(command), buffer, 254, 0)
            if errorCode:
                raise MCIException(self, command, errorCode)
            else:
                return buffer.value

        def getErrorString(self, errorCode):
            """Get the string representation of the given error code."""
            buffer = c_buffer(255)
            self.w32mcierror(int(errorCode), buffer, 254)
            return buffer.value

    class SoundThread(threading.Thread):
        """The thread controlling the playback of sounds."""
        def __init__(self, soundsDirectory):
            threading.Thread.__init__(self)

            self._soundsDirectory = soundsDirectory
            self._mci = MCI()

            self._requestCondition = threading.Condition()
            self._requests = []
            self._pending = []
            self._count = 0

            self.daemon = True

        def requestSound(self, name, finishCallback = None, extra = None):
            """Request the playback of the sound with the given name."""
            path = os.path.join(self._soundsDirectory, name)
            with self._requestCondition:
                self._requests.append((path, (finishCallback, extra)))
                self._requestCondition.notify()

        def run(self):
            """Perform the operation of the thread.

            It waits for a request or a timeout. If a request is received, that
            is started to be played back. If a timeout occurs, the file is
            closed."""

            while True:
                with self._requestCondition:
                    if not self._requests:
                        if self._pending:
                            timeout = max(time.time() - self._pending[0][0],
                                          0.0)
                        else:
                            timeout = 10.0
                            
                        self._requestCondition.wait(timeout)

                    requests = []
                    for (path, finishData) in self._requests:
                        requests.append((path, finishData, self._count))
                        self._count += 1
                    self._requests = []

                    now = time.time()
                    toClose = []
                    while self._pending and \
                          self._pending[0][0]<=now:
                        toClose.append(self._pending[0][1])
                        del self._pending[0]

                for (alias, (finishCallback, extra)) in toClose:
                    success = True
                    try:
                        print "Closing", alias
                        self._mci.send("close " + alias)
                        print "Closed", alias
                    except Exception, e:
                        print "Failed closing " + alias + ":", str(e)
                        success = False

                    if finishCallback is not None:
                        try:
                            finishCallback(success, extra)
                        except:
                            traceback.print_exc()

                for (path, finishData, counter) in requests:
                    try:
                        alias = "mlxsound%d" % (counter,)
                        print "Starting to play", path, "as", alias
                        self._mci.send("open \"%s\" alias %s" % \
                                       (path, alias))
                        self._mci.send("set %s time format milliseconds" % \
                                       (alias,))
                        lengthBuffer = self._mci.send("status %s length" % \
                                                      (alias,))
                        self._mci.send("play %s from 0 to %s" % \
                                       (alias, lengthBuffer))
                        length = int(lengthBuffer)
                        timeout = time.time() + length / 1000.0
                        with self._requestCondition:
                            self._pending.append((timeout, (alias, finishData)))
                            self._pending.sort()
                        print "Started to play", path
                    except Exception, e:
                        print "Failed to start playing " + path + ":", str(e)                        
                        (finishCallback, extra) = finishData
                        if finishCallback is not None:
                            try:
                                finishCallback(None, extra)
                            except:
                                traceback.print_exc()

    _thread = None

    def initializeSound(soundsDirectory):
        """Initialize the sound handling with the given directory containing
        the sound files."""
        global _thread
        _thread = SoundThread(soundsDirectory)
        _thread.start()

    def startSound(name, finishCallback = None, extra = None):
        """Start playing back the given sound.
        
        name should be the name of a sound file relative to the sound directory
        given in initializeSound."""
        _thread.requestSound(name, finishCallback = finishCallback,
                             extra = extra)
        
#------------------------------------------------------------------------------

else: # os.name!="nt"
    def initializeSound(soundsDirectory):
        """Initialize the sound handling with the given directory containing
        the sound files."""
        pass

    def startSound(name, finishCallback = None, extra = None):
        """Start playing back the given sound.

        FIXME: it does not do anything currently, but it should."""
        pass

#------------------------------------------------------------------------------
#------------------------------------------------------------------------------

if __name__ == "__main__":
    def callback(result, extra):
        print "callback", result, extra
    
    initializeSound("e:\\home\\vi\\tmp")
    startSound("malev.mp3", finishCallback = callback, extra="malev.mp3")
    time.sleep(5)
    startSound("ding.wav", finishCallback = callback, extra="ding1.wav")
    time.sleep(5)
    startSound("ding.wav", finishCallback = callback, extra="ding2.wav")
    time.sleep(5)
    startSound("ding.wav", finishCallback = callback, extra="ding3.wav")
    time.sleep(50)

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