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package Crypt::OTR;

use 5.010000;
use strict;
use warnings;
use Carp qw/croak/;
use Crypt::OTR::PublicKey;
use AutoLoader;

our $VERSION = '0.08';

sub AUTOLOAD {
    # This AUTOLOAD is used to 'autoload' constants from the constant()
    # XS function.

    my $constname;
    our $AUTOLOAD;
    ($constname = $AUTOLOAD) =~ s/.*:://;
    croak "&Crypt::OTR::constant not defined" if $constname eq 'constant';
    my ($error, $val) = constant($constname);
    if ($error) { croak $error; }
    {
	no strict 'refs';
	# Fixed between 5.005_53 and 5.005_61
#XXX	if ($] >= 5.00561) {
#XXX	    *$AUTOLOAD = sub () { $val };
#XXX	}
#XXX	else {
	    *$AUTOLOAD = sub { $val };
#XXX	}
    }
    goto &$AUTOLOAD;
}

require XSLoader;
XSLoader::load('Crypt::OTR', $VERSION);

#########################

=head1 NAME

Crypt::OTR - Off-The-Record encryption library for secure instant
messaging applications

=head1 SYNOPSIS

    use Crypt::OTR;
    
    # call near the beginning of your program
    Crypt::OTR->init;

    # create OTR object, set up callbacks
    my $otr = new Crypt::OTR(
        account_name     => "alice",            # name of account associated with this keypair
        protocol_name    => "my_protocol_name", # e.g. 'AIM'
        max_message_size => 1024,               # how much to fragment
    );
    $otr->set_callback('inject' => \&otr_inject);
    $otr->set_callback('otr_message' => \&otr_system_message);
    $otr->set_callback('verified' => \&otr_verified);
    $otr->set_callback('unverified' => \&otr_unverified);

    # create a context for user "bob"
    $otr->establish("bob");  # calls otr_inject($account_name, $protocol, $dest_account, $message)

    # send a message to bob
    my $plaintext = "hello, bob! this is a message from alice";
    if (my $ciphertext = $otr->encrypt("bob", $plaintext)) {
        $my_app->send_message_to_user("bob", $ciphertext);
    } else {
        warn "Your message was not sent - no encrypted conversation is established\n";
    }

    # called from bob's end
    if (my $plaintext = $otr->decrypt("alice", $ciphertext)) {
        print "alice: $plaintext\n";
    } else {
        warn "We received an encrypted message from alice but were unable to decrypt it\n";
    }

    # done with chats
    $otr->finish("bob");
    
    # CALLBACKS 

    # called when OTR is ready to send a message after massaging it.
    # this method should actually transmit $message to $dest_account
    sub otr_inject {
        my ($self, $account_name, $protocol, $dest_account, $message) = @_;
        $my_app->send_message_to_user($dest_account, $message);
    }

    # called to display an OTR control message for a particular user or protocol
    sub otr_system_message {
        my ($self, $account_name, $protocol, $other_user, $otr_message) = @_;
        warn "OTR says: $otr_message\n";
        return 1;
    }

    # called when a verified conversation is established with $from_account
    sub verified {
        my ($self, $from_account) = @_;
        print "Started verified conversation with $from_account\n";
    }

    # called when an unverified conversation is established with $from_account
    sub unverified {
        my ($self, $from_account) = @_;
        print "Started unverified conversation with $from_account\n";
    }