package I18N::Japanese;

use Encode 'encode';
use Symbol 'qualify_to_ref';

# eventually, determine this dynamically
my $encoding = "cp932";

# this is meant to take effect for whoever uses us
require encoding; encoding->import($encoding);

# override/wrap Perl built-ins that take or return filenames

# (... snippage of all but open()-wrapper)

*CORE::GLOBAL::open = sub (*@) {
    my $fhref = \$_[0];
    my $autov = !defined $_[0];
    my $fh = qualify_to_ref(shift, scalar caller);
    # pass filehandle up to caller when "open my $f, ..."
    $$fhref = $fh if $autov;

    my ($arg2, $arg3, @args) = convert_encoding(@_);

    # need to handle the different prototypes seperately
    if (@_ >= 3) {
        CORE::open $fh, $arg2, $arg3, @args;
    } elsif (@_ == 2) {
        if (defined $arg3) {
            CORE::open $fh, $arg2, $arg3;
        } else {
            # must be undef _syntactically_
            CORE::open $fh, $arg2, undef;
        }
    } elsif (@_ == 1) {
        CORE::open $fh, $arg2;
    } else {
        CORE::open $fh;
    }
};

sub convert_encoding {
    return ( map ref(\$_) eq 'SCALAR' ? encode($encoding, $_) : $_, @_ );
}

1;