use strict;
use warnings;

=head1 NAME

Speech recognition in Windows using the MS Speech API

=head1 DESCRIPTION

This is an example of using the Microsoft Speech SDK 5.1 under Windows for command and control speech recognition in Perl.

Ported to perl from http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/93025
but B<not tested yet>.

Sample code for using the Microsoft Speech SDK 5.1 via COM (aka Win32::OLE) in Perl.

Requires that the SDK be installed; it's a free download from
http://microsoft.com/speech


After running this, then saying "One", "Two", "Three" or "Four" should
display "You said One" etc on the console. The recognition can be a bit
shaky at first until you've trained it (via the Speech entry in the Windows
Control Panel.

=head1 Classes

=cut

use Win32::OLE qw(EVENTS);
use Win32::SAPI5;

package SpeechRecognition;

=head2 SpeechRecognition

Initialize the speech recognition with the passed in list of words

=head3 C<< SpeechRecognition->new(qw[ words to add ]) >>

Initialize the speech recognition with the passed in list of words

=cut

sub new {
    my($self, @wordsToAdd)=@_;
    $self = bless {}, $self;     

    # For text-to-speech
    $self->{speaker} = Win32::SAPI5::SpVoice->new()
        or die "      \$^E => $^E\nLastError => ".Win32::OLE->LastError() ;

    # For speech recognition - first create a listener
    $self->{listener} = Win32::SAPI5::SpSharedRecognizer->new()
        or die "      \$^E => $^E\nLastError => ".Win32::OLE->LastError() ;

    # Then a recognition context
    $self->{context} = $self->{listener}->CreateRecoContext()
        or die "      \$^E => $^E\nLastError => ".Win32::OLE->LastError() ;
    
    # which has an associated grammar
    $self->{grammar} = $self->{context}->CreateGrammar()
        or die "      \$^E => $^E\nLastError => ".Win32::OLE->LastError() ;

    # Do not allow free word recognition - only command and control
    # recognizing the words in the grammar only

    $self->{grammar}->DictationSetState(0);
    # Create a new rule for the grammar, that is top level (so it begins
    # a recognition) and dynamic (ie we can change it at runtime)

    use constant SRATopLevel => 1; #from Enum SpeechRuleAttributes
    use constant SRADynamic => 32;

    $self->{wordsRule} = $self->{grammar}->{Rules}->Add(
        "wordsRule" =>  SRATopLevel +  SRADynamic,
        0,
    );
    # Clear the rule (not necessary first time, but if we're changing it
    # dynamically then it's useful)
    $self->{wordsRule}->Clear();

    # And go through the list of words, adding each to the rule
    $self->{wordsRule}->{InitialState}->AddWordTransition(undef, $_)
        for @wordsToAdd;

    # Set the wordsRule to be active
    $self->{grammar}->{Rules}->Commit();
    $self->{grammar}->CmdSetRuleState("wordsRule", 1);

    # Commit the changes to the grammar;
    $self->{grammar}->{Rules}->Commit();

    # And add an event handler that's called back when recognition occurs

# this part is different with Win32::OLE, needs testing
    $self->{eventHandler} = ContextEvents->new($self->{context});
    $self->{context}->WithEvents('ContextEvents');
#    $self->{context}->WithEvents( $self->{eventHandler} );

    # Announce we've started using speech synthesis
    $self->say("Started successfully");
}

=head3 C<< $self->say($phrase) >>

Speak a word or phrase

=cut

sub say {
    my($self,$phrase)=@_;
    $self->{speaker}->Speak($phrase);
}


=head2 ContextEvents

The callback class that handles the events raised by the speech object.
See "Automation | SpSharedRecoContext (Events)" in the MS Speech SDK
online help for documentation of the other events supported.

@ContextEvents::ISA = Win32::SAPI5::SpSharedRecoContext

=cut

package ContextEvents;

use base qw[ Win32::SAPI5::SpSharedRecoContext ];


=head3 C<< $self->OnRecognition(StreamNumber, StreamPosition, RecognitionType, Result) >>

Called when a word/phrase is successfully recognized  -
ie it is found in a currently open grammar with a sufficiently high
confidence

=cut

sub  OnRecognition {
    my($self, $StreamNumber, $StreamPosition, $RecognitionType, $Result) = @_;
    my $newResult = $self->{speaker}->Invoke('Dispatch', $Result);
    print "You said: ", $newResult->{PhraseInfo}->GetText();
}

sub Recognition { goto &OnRecognition }

1;
package main;

unless(caller){
    my $speechReco = SpeechRecognition->new( "One", "Two", "Three", "Four" );
    while(1){
    # not quite sure which one is the equivalent of #pythoncom.PumpWaitingMessages()
#        Win32::OLE->MessageLoop();
        Win32::OLE->SpinMessageLoop();
    }
}