package TAP::Parser::Source;

use strict;
use warnings;

use File::Basename qw( fileparse );
use base 'TAP::Object';

use constant BLK_SIZE => 512;

=head1 NAME

TAP::Parser::Source - a TAP source & meta data about it

=head1 VERSION

Version 3.50

=cut

our $VERSION = '3.50';

=head1 SYNOPSIS

  use TAP::Parser::Source;
  my $source = TAP::Parser::Source->new;
  $source->raw( \'reference to raw TAP source' )
         ->config( \%config )
         ->merge( $boolean )
         ->switches( \@switches )
         ->test_args( \@args )
         ->assemble_meta;

  do { ... } if $source->meta->{is_file};
  # see assemble_meta for a full list of data available

=head1 DESCRIPTION

A TAP I<source> is something that produces a stream of TAP for the parser to
consume, such as an executable file, a text file, an archive, an IO handle, a
database, etc.  C<TAP::Parser::Source>s encapsulate these I<raw> sources, and
provide some useful meta data about them.  They are used by
L<TAP::Parser::SourceHandler>s, which do whatever is required to produce &
capture a stream of TAP from the I<raw> source, and package it up in a
L<TAP::Parser::Iterator> for the parser to consume.

Unless you're writing a new L<TAP::Parser::SourceHandler>, a plugin or
subclassing L<TAP::Parser>, you probably won't need to use this module directly.

=head1 METHODS

=head2 Class Methods

=head3 C<new>

 my $source = TAP::Parser::Source->new;

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

=cut

# new() implementation supplied by TAP::Object

sub _initialize {
    my ($self) = @_;
    $self->meta(   {} );
    $self->config( {} );
    return $self;
}

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

=head2 Instance Methods

=head3 C<raw>

  my $raw = $source->raw;
  $source->raw( $some_value );

Chaining getter/setter for the raw TAP source.  This is a reference, as it may
contain large amounts of data (eg: raw TAP).

=head3 C<meta>

  my $meta = $source->meta;
  $source->meta({ %some_value });

Chaining getter/setter for meta data about the source.  This defaults to an
empty hashref.  See L</assemble_meta> for more info.

=head3 C<has_meta>

True if the source has meta data.

=head3 C<config>

  my $config = $source->config;
  $source->config({ %some_value });

Chaining getter/setter for the source's configuration, if any has been provided
by the user.  How it's used is up to you.  This defaults to an empty hashref.
See L</config_for> for more info.

=head3 C<merge>

  my $merge = $source->merge;
  $source->config( $bool );

Chaining getter/setter for the flag that dictates whether STDOUT and STDERR
should be merged (where appropriate).  Defaults to undef.

=head3 C<switches>

  my $switches = $source->switches;
  $source->config([ @switches ]);

Chaining getter/setter for the list of command-line switches that should be
passed to the source (where appropriate).  Defaults to undef.

=head3 C<test_args>

  my $test_args = $source->test_args;
  $source->config([ @test_args ]);

Chaining getter/setter for the list of command-line arguments that should be
passed to the source (where appropriate).  Defaults to undef.

=cut

sub raw {
    my $self = shift;
    return $self->{raw} unless @_;
    $self->{raw} = shift;
    return $self;
}

sub meta {
    my $self = shift;
    return $self->{meta} unless @_;
    $self->{meta} = shift;
    return $self;
}

sub has_meta {
    return scalar %{ shift->meta } ? 1 : 0;
}

sub config {
    my $self = shift;
    return $self->{config} unless @_;
    $self->{config} = shift;
    return $self;
}

sub merge {
    my $self = shift;
    return $self->{merge} unless @_;
    $self->{merge} = shift;
    return $self;
}

sub switches {
    my $self = shift;
    return $self->{switches} unless @_;
    $self->{switches} = shift;
    return $self;
}

sub test_args {
    my $self = shift;
    return $self->{test_args} unless @_;
    $self->{test_args} = shift;
    return $self;
}

=head3 C<assemble_meta>

  my $meta = $source->assemble_meta;

Gathers meta data about the L</raw> source, stashes it in L</meta> and returns
it as a hashref.  This is done so that the L<TAP::Parser::SourceHandler>s don't
have to repeat common checks.  Currently this includes:

    is_scalar => $bool,
    is_hash   => $bool,
    is_array  => $bool,

    # for scalars:
    length => $n
    has_newlines => $bool

    # only done if the scalar looks like a filename
    is_file => $bool,
    is_dir  => $bool,
    is_symlink => $bool,
    file => {
        # only done if the scalar looks like a filename
        basename => $string, # including ext
        dir      => $string,
        ext      => $string,
        lc_ext   => $string,
        # system checks
        exists  => $bool,
        stat    => [ ... ], # perldoc -f stat
        empty   => $bool,
        size    => $n,
        text    => $bool,
        binary  => $bool,
        read    => $bool,
        write   => $bool,
        execute => $bool,
        setuid  => $bool,
        setgid  => $bool,
        sticky  => $bool,
        is_file => $bool,
        is_dir  => $bool,
        is_symlink => $bool,
        # only done if the file's a symlink
        lstat      => [ ... ], # perldoc -f lstat
        # only done if the file's a readable text file
        shebang => $first_line,
    }

  # for arrays:
  size => $n,

=cut

sub assemble_meta {
    my ($self) = @_;

    return $self->meta if $self->has_meta;

    my $meta = $self->meta;
    my $raw  = $self->raw;

    # rudimentary is object test - if it's blessed it'll
    # inherit from UNIVERSAL
    $meta->{is_object} = UNIVERSAL::isa( $raw, 'UNIVERSAL' ) ? 1 : 0;

    if ( $meta->{is_object} ) {
        $meta->{class} = ref($raw);
    }
    else {
        my $ref = lc( ref($raw) );
        $meta->{"is_$ref"} = 1;
    }

    if ( $meta->{is_scalar} ) {
        my $source = $$raw;
        $meta->{length} = length($$raw);
        $meta->{has_newlines} = $$raw =~ /\n/ ? 1 : 0;

        # only do file checks if it looks like a filename
        if ( !$meta->{has_newlines} and $meta->{length} < 1024 ) {
            my $file = {};
            $file->{exists} = -e $source ? 1 : 0;
            if ( $file->{exists} ) {
                $meta->{file} = $file;

                # avoid extra system calls (see `perldoc -f -X`)
                $file->{stat}    = [ stat(_) ];
                $file->{empty}   = -z _ ? 1 : 0;
                $file->{size}    = -s _;
                $file->{text}    = -T _ ? 1 : 0;
                $file->{binary}  = -B _ ? 1 : 0;
                $file->{read}    = -r _ ? 1 : 0;
                $file->{write}   = -w _ ? 1 : 0;
                $file->{execute} = -x _ ? 1 : 0;
                $file->{setuid}  = -u _ ? 1 : 0;
                $file->{setgid}  = -g _ ? 1 : 0;
                $file->{sticky}  = -k _ ? 1 : 0;

                $meta->{is_file} = $file->{is_file} = -f _ ? 1 : 0;
                $meta->{is_dir}  = $file->{is_dir}  = -d _ ? 1 : 0;

                # symlink check requires another system call
                $meta->{is_symlink} = $file->{is_symlink}
                  = -l $source ? 1 : 0;
                if ( $file->{is_symlink} ) {
                    $file->{lstat} = [ lstat(_) ];
                }

                # put together some common info about the file
                ( $file->{basename}, $file->{dir}, $file->{ext} )
                  = map { defined $_ ? $_ : '' }
                  fileparse( $source, qr/\.[^.]*/ );
                $file->{lc_ext} = lc( $file->{ext} );
                $file->{basename} .= $file->{ext} if $file->{ext};

                if ( !$file->{is_dir} && $file->{read} ) {
                    eval { $file->{shebang} = $self->shebang($$raw); };
                    if ( my $e = $@ ) {
                        warn $e;
                    }
                }
            }
        }
    }
    elsif ( $meta->{is_array} ) {
        $meta->{size} = $#$raw + 1;
    }
    elsif ( $meta->{is_hash} ) {
        ;    # do nothing
    }

    return $meta;
}

=head3 C<shebang>

Get the shebang line for a script file.

  my $shebang = TAP::Parser::Source->shebang( $some_script );

May be called as a class method

=cut

{

    # Global shebang cache.
    my %shebang_for;

    sub _read_shebang {
        my ( $class, $file ) = @_;
        open my $fh, '<', $file or die "Can't read $file: $!\n";

        # Might be a binary file - so read a fixed number of bytes.
        my $got = read $fh, my ($buf), BLK_SIZE;
        defined $got or die "I/O error: $!\n";
        return $1 if $buf =~ /(.*)/;
        return;
    }

    sub shebang {
        my ( $class, $file ) = @_;
        $shebang_for{$file} = $class->_read_shebang($file)
          unless exists $shebang_for{$file};
        return $shebang_for{$file};
    }
}

=head3 C<config_for>

  my $config = $source->config_for( $class );

Returns L</config> for the $class given.  Class names may be fully qualified
or abbreviated, eg:

  # these are equivalent
  $source->config_for( 'Perl' );
  $source->config_for( 'TAP::Parser::SourceHandler::Perl' );

If a fully qualified $class is given, its abbreviated version is checked first.

=cut

sub config_for {
    my ( $self, $class ) = @_;
    my ($abbrv_class) = ( $class =~ /(?:\:\:)?(\w+)$/ );
    my $config = $self->config->{$abbrv_class} || $self->config->{$class};
    return $config;
}

1;

__END__

=head1 AUTHORS

Steve Purkis.

=head1 SEE ALSO

L<TAP::Object>,
L<TAP::Parser>,
L<TAP::Parser::IteratorFactory>,
L<TAP::Parser::SourceHandler>

=cut
