package TAP::Parser::Source::Perl;

use strict;
use vars qw($VERSION @ISA);

use constant IS_WIN32 => ( $^O =~ /^(MS)?Win32$/ );
use constant IS_MACOS => ( $^O eq 'MacOS' );
use constant IS_VMS   => ( $^O eq 'VMS' );

use TAP::Parser::Source;
@ISA = 'TAP::Parser::Source';

=head1 NAME

TAP::Parser::Source::Perl - Stream Perl output

=head1 VERSION

Version 2.99_01

=cut

$VERSION = '2.99_01';

=head1 DESCRIPTION

Takes a filename and hopefully returns a stream from it.  The filename should
be the name of a Perl program.

Note that this is a subclass of L<TAP::Parser::Source>.  See that module for
more methods.

=head1 SYNOPSIS

 use TAP::Parser::Source::Perl;
 my $perl   = TAP::Parser::Source::Perl->new;
 my $stream = $perl->source_file($filename)->get_stream;

=head1 METHODS

=head2 Class Methods

=head3 C<new>

 my $perl = TAP::Parser::Source::Perl->new;

Returns a new C<TAP::Parser::Source::Perl> object.

=head2 Instance Methods

=head3 C<source_file>

 my $perl = $source->source;
 $perl->source_file($filename);

Getter/setter for the source filename.  Will C<croak> if the C<$filename> does
not appear to be a file.

=cut

sub source_file {
    my $self = shift;
    return $self->{source_file} unless @_;
    my $filename = shift;
    unless ( -f $filename ) {
        $self->_croak("Cannot find ($filename)");
    }
    $self->{source_file} = $filename;
    return $self;
}

=head3 C<switches>

 my $switches = $perl->switches;
 my @switches = $perl->switches;
 $perl->switches(\@switches);

Getter/setter for the additional switches to pass to the perl executable.  One
common switch would be to set an include directory:

 $perl->switches('-Ilib');

=cut

sub switches {
    my $self = shift;
    unless (@_) {
        return wantarray ? @{ $self->{switches} } : $self->{switches};
    }
    my $switches = shift;
    $self->{switches} = [@$switches];    # force a copy
    return $self;
}

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

=head3 C<get_stream>

 my $stream = $source->get_stream;

Returns a stream of the output generated by executing C<source_file>.

=cut

sub get_stream {
    my $self     = shift;
    my @switches = $self->_switches;

    my @command = $self->_get_command_for_switches(@switches)
      or $self->_croak("No command found!");

    # Nasty kludge. It might be nicer if we got the libs separately
    # although at least this way we find any -I switches that were
    # supplied other then as explicit libs.
    # We filter out any names containing colons because they will break
    # PERL5LIB
    my @libs;
    for ( grep { $_ !~ /:/ } @switches ) {
        push @libs, $1 if / ^ -I (.*) $ /x;
    }

    my $previous = $ENV{PERL5LIB};
    if ($previous) {
        push @libs, split( /:/, $previous );
    }

    my $setup = sub {
        if (@libs) {
            $ENV{PERL5LIB} = join( ':', @libs );
        }
    };

    # Cargo culted from comments seen elsewhere about VMS / environment
    # variables. I don't know if this is actually necessary.
    my $teardown = sub {
        if ($previous) {
            $ENV{PERL5LIB} = $previous;
        }
        else {
            delete $ENV{PERL5LIB};
        }
    };

    return TAP::Parser::Iterator->new(
        {   command  => \@command,
            merge    => $self->merge,
            setup    => $setup,
            teardown => $teardown,
        }
    );
}

sub _get_command_for_switches {
    my $self     = shift;
    my @switches = @_;
    my $file     = $self->source_file;
    my $command  = $self->_get_perl;

    $file = qq["$file"] if ( $file =~ /\s/ ) && ( $file !~ /^".*"$/ );
    my @command = ( $command, @switches, $file );
    return @command;
}

sub _get_command {
    my $self = shift;
    return $self->_get_command_for_switches( $self->_switches );
}

sub _switches {
    my $self     = shift;
    my $file     = $self->source_file;
    my @switches = (
        $self->switches,
    );

    local *TEST;
    open( TEST, $file ) or print "can't open $file. $!\n";
    my $shebang = <TEST>;
    close(TEST) or print "can't close $file. $!\n";

    $self->_croak("Script $file is empty") unless defined $shebang;

    my $taint = ( $shebang =~ /^#!.*\bperl.*\s-\w*([Tt]+)/ );
    push( @switches, "-$1" ) if $taint;

    push @switches, map {"-I$_"} $self->_filtered_inc;

    # Quote the argument if there's any whitespace in it, or if
    # we're VMS, since VMS requires all parms quoted.  Also, don't quote
    # it if it's already quoted.
    for (@switches) {
        $_ = qq["$_"] if ( ( /\s/ || IS_VMS ) && !/^".*"$/ );
    }

    my %found_switch = map { $_ => 0 } @switches;

    # remove duplicate switches
    @switches
      = grep { defined $_ && $_ ne '' && !$found_switch{$_}++ } @switches;
    return @switches;
}

sub _filtered_inc {
    my $self = shift;
    my @inc  = @_;
    @inc = @INC unless @inc;

    if (IS_VMS) {

        # VMS has a 255-byte limit on the length of %ENV entries, so
        # toss the ones that involve perl_root, the install location
        @inc = grep !/perl_root/i, @inc;

    }
    elsif (IS_WIN32) {

        # Lose any trailing backslashes in the Win32 paths
        s/[\\\/+]$// foreach @inc;
    }

    my %seen;
    $seen{$_}++ foreach $self->_default_inc;
    @inc = grep !$seen{$_}++, @inc;

    return @inc;
}

{

    # cache this to avoid repeatedly shelling out to Perl.  This really speeds
    # up TAP::Parser.
    my @inc;

    sub _default_inc {
        return @inc if @inc;
        my $proto = shift;
        local $ENV{PERL5LIB};
        local $ENV{PERLLIB};    # [12030] fix untested
        my $perl = $proto->_get_perl;
        chomp( @inc = `$perl -le "print join qq[\\n], \@INC"` );
        return @inc;
    }
}

sub _get_perl {
    my $proto = shift;
    return $ENV{HARNESS_PERL}           if defined $ENV{HARNESS_PERL};
    return Win32::GetShortPathName($^X) if IS_WIN32;
    return $^X;
}

1;