#!/usr/bin/env perl
use 5.010;
use strictures;
no warnings "uninitialized";
use LWP::UserAgent;
use Getopt::Long;
use Pod::Usage;
use open qw( :encoding(UTF-8) :std );
use Path::Tiny;

# use XML::LibXML; # For expansion... or XML::Rabbit

my $service = "http://query.yahooapis.com/v1/public/yql";
my %opt = ( text => undef,
            url  => undef,
            max  => 100 );

# These are, luckily, false by default for Yahoo, so we only care about true.
my %boolean = map {; $_ => 1 }
    qw/ related_entities show_metadata enable_categorizer /;

# What we compose to query, e.g. not "verbose" or "file."
my %sql = ( %opt, %boolean );

my $ok = GetOptions( \%opt,
                     "text=s", "file=s", "url=s", "max=i",
                     "verbose", "help", keys %boolean );

pod2usage( -verbose => 0,
           -exitval => 1,
           -message => "Options were not recognized." )
    unless $ok;

pod2usage( -verbose => 2 ) if $opt{help};

pod2usage( -verbose => 0,
           -exitval => 1,
           -message => "One of these, at most, allowed: text, url, file." )
    if 1 < grep defined, @opt{qw/ text url file /};

# Only one, text|file, is allowed by Getopt::Long.
$opt{text} ||= path($opt{file})->slurp if $opt{file};

unless ( $opt{url} || $opt{text} ) # Accept from STDIN.
{
    say "Type away. ^D to execute (on *nix anyway).";
    chomp( my @input = <> );
    $opt{text} = join " ", @input;
    die "Give some input!\n" unless $opt{text} =~ /\w/;
}

my @where;
for my $key ( keys %opt )
{
    next unless defined $opt{$key} and exists $sql{$key};
    $opt{$key} = "true" if $boolean{$key};
    $opt{$key} =~ s/([\\"'\0])/\\$1/g;
    push @where, sprintf "%s = '%s'", $key, $opt{$key};
}

my $q = sprintf "SELECT * FROM contentanalysis.analyze WHERE %s",
    join " AND ", @where;

say "SQL >> $q\n" if $opt{verbose};

my $ua = LWP::UserAgent->new;

my $response = $ua->post( $service, [ q => $q ] );

say $response->request->as_string if $opt{verbose};

say $opt{verbose} ?
    $response->as_string : $response->decoded_content();

exit ! $response->is_success;

__END__

=pod

=encoding utf8

=head1 Name

yahoo-content-analyzer - command-line to query it.

=head1 Synopsis

 yahoo-content-analyzer -text "Perl is a programming language."

    -text "{command line string}"
    -file (slurp and submit as text)
    -url
    -max [100 is default]
    -related_entities
    -show_metadata
    -enable_categorizer
    -verbose
    -help

=head1 Description

L<https://developer.yahoo.com/search/content/V2/contentAnalysis.html>

=head1 Code Repository

L<http://perlmonks.org/?node_id=1094394>

=head1 See Also

L<https://metacpan.org/search?q=YQL>.

=head1 Author and License

Your Mother, L<http://perlmonks.org/?node_id=248054>. You may
redistribute and modify this code under the same terms as Perl itself.

=head1 Disclaimer of Warranty

No warranty. No means no.

=cut