use strict;
use warnings;
use utf8;
use constant IN_IPERL => !! $ENV{PERL_IPERL_RUNNING};
no if IN_IPERL, warnings => 'redefine'; # fewer messages when re-running cells

use feature qw(say state postderef);
use Syntax::Construct qw(each-array);

use lib::projectroot qw(lib);

BEGIN {
    if( IN_IPERL ) {
        $ENV{TF_CPP_MIN_LOG_LEVEL} = 3;
    }
    require AI::TensorFlow::Libtensorflow;
}

use URI ();
use HTTP::Tiny ();
use Path::Tiny qw(path);

use File::Which ();

use List::Util 1.56 qw(mesh);

use Data::Printer ( output => 'stderr', return_value => 'void', filters => ['PDL'] );
use Data::Printer::Filter::PDL ();
use Text::Table::Tiny qw(generate_table);

use Imager;

my $s = AI::TensorFlow::Libtensorflow::Status->New;
sub AssertOK {
    die "Status $_[0]: " . $_[0]->Message
        unless $_[0]->GetCode == AI::TensorFlow::Libtensorflow::Status::OK;
    return;
}
AssertOK($s);

use PDL;
use AI::TensorFlow::Libtensorflow::DataType qw(FLOAT UINT8);

use FFI::Platypus::Memory qw(memcpy);
use FFI::Platypus::Buffer qw(scalar_to_pointer);

sub FloatPDLTOTFTensor {
    my ($p) = @_;
    return AI::TensorFlow::Libtensorflow::Tensor->New(
        FLOAT, [ reverse $p->dims ], $p->get_dataref, sub { undef $p }
    );
}

sub FloatTFTensorToPDL {
    my ($t) = @_;

    my $pdl = zeros(float,reverse( map $t->Dim($_), 0..$t->NumDims-1 ) );

    memcpy scalar_to_pointer( ${$pdl->get_dataref} ),
        scalar_to_pointer( ${$t->Data} ),
        $t->ByteSize;
    $pdl->upd_data;

    $pdl;
}

sub Uint8PDLTOTFTensor {
    my ($p) = @_;
    return AI::TensorFlow::Libtensorflow::Tensor->New(
        UINT8, [ reverse $p->dims ], $p->get_dataref, sub { undef $p }
    );
}

sub Uint8TFTensorToPDL {
    my ($t) = @_;

    my $pdl = zeros(byte,reverse( map $t->Dim($_), 0..$t->NumDims-1 ) );

    memcpy scalar_to_pointer( ${$pdl->get_dataref} ),
        scalar_to_pointer( ${$t->Data} ),
        $t->ByteSize;
    $pdl->upd_data;

    $pdl;
}

# image_size => [width, height] (but usually square images)
my %model_name_to_params = (
    centernet_hourglass_512x512 => {
        handle => 'https://tfhub.dev/tensorflow/centernet/hourglass_512x512/1',
        image_size => [ 512, 512 ],
    },
);

my $model_name = 'centernet_hourglass_512x512';

say "Selected model: $model_name : $model_name_to_params{$model_name}{handle}";

my $model_uri = URI->new( $model_name_to_params{$model_name}{handle} );
$model_uri->query_form( 'tf-hub-format' => 'compressed' );
my $model_base = substr( $model_uri->path, 1 ) =~ s,/,_,gr;
my $model_archive_path = "${model_base}.tar.gz";

my $http = HTTP::Tiny->new;

for my $download ( [ $model_uri  => $model_archive_path ],) {
    my ($uri, $path) = @$download;
    say "Downloading $uri to $path";
    next if -e $path;
    $http->mirror( $uri, $path );
}

use Archive::Extract;
my $ae = Archive::Extract->new( archive => $model_archive_path );
die "Could not extract archive" unless $ae->extract( to => $model_base );

my $saved_model = path($model_base)->child('saved_model.pb');
say "Saved model is in $saved_model" if -f $saved_model;

# Get the labels
my $response = $http->get('https://raw.githubusercontent.com/tensorflow/models/a4944a57ad2811e1f6a7a87589a9fc8a776e8d3c/object_detection/data/mscoco_label_map.pbtxt');

my %labels_map = $response->{content} =~ m<
(?:item \s+ \{  \s+
  \Qname:\E \s+ "[^"]+" \s+
  \Qid:\E   \s+ (\d+) \s+
  \Qdisplay_name:\E \s+ "([^"]+)" \s+
})+
>sgx;

my $label_count = List::Util::max keys %labels_map;

say "We have a label count of $label_count. These labels include: ",
    join ", ", List::Util::head( 5, @labels_map{ sort keys %labels_map } );

my @tags = ( 'serve' );

if( File::Which::which('saved_model_cli')) {
    local $ENV{TF_CPP_MIN_LOG_LEVEL} = 3; # quiet the TensorFlow logger for the following command
    system(qw(saved_model_cli show),
        qw(--dir)           => $model_base,
        qw(--tag_set)       => join(',', @tags),
        qw(--signature_def) => 'serving_default'
    ) == 0 or die "Could not run saved_model_cli";
} else {
    say "Install the tensorflow Python package to get the `saved_model_cli` command.";
}

my $opt = AI::TensorFlow::Libtensorflow::SessionOptions->New;

my $graph = AI::TensorFlow::Libtensorflow::Graph->New;
my $session = AI::TensorFlow::Libtensorflow::Session->LoadFromSavedModel(
    $opt, undef, $model_base, \@tags, $graph, undef, $s
);
AssertOK($s);

my %ops = (
    in  => {
        op   =>  $graph->OperationByName('serving_default_input_tensor'),
        dict => {
            input_tensor => 0,
        }
    },
    out => {
        op => $graph->OperationByName('StatefulPartitionedCall'),
        dict => {
            detection_boxes   => 0,
            detection_classes => 1,
            detection_scores  => 2,
            num_detections    => 3,
        }
    },
);

my %outputs;

%outputs = map {
    my $put_type = $_;
    my $op = $ops{$put_type}{op};
    my $port_dict = $ops{$put_type}{dict};

   $put_type => +{
        map {
            my $dict_key = $_;
            my $index = $port_dict->{$_};
            $dict_key => AI::TensorFlow::Libtensorflow::Output->New( {
                oper => $op,
                index => $index,
            });
        } keys %$port_dict
     }
} keys %ops;

p %outputs;

use HTML::Tiny;

my %images_for_test_to_uri = (
    "beach_scene" => 'https://github.com/tensorflow/models/blob/master/research/object_detection/test_images/image2.jpg?raw=true',
);

my @image_names = sort keys %images_for_test_to_uri;
my $h = HTML::Tiny->new;

my $image_name = 'beach_scene';
if( IN_IPERL ) {
    IPerl->html(
        $h->a( { href => $images_for_test_to_uri{$image_name} },
            $h->img({
                src => $images_for_test_to_uri{$image_name},
                alt => $image_name,
                width => '100%',
            })
        ),
    );
}

sub load_image_to_pdl {
    my ($uri, $image_size) = @_;

    my $http = HTTP::Tiny->new;
    my $response = $http->get( $uri );
    die "Could not fetch image from $uri" unless $response->{success};
    say "Downloaded $uri";

    my $img = Imager->new;
    $img->read( data => $response->{content} );

    # Create PDL ndarray from Imager data in-memory.
    my $data;
    $img->write( data => \$data, type => 'raw' )
        or die "could not write ". $img->errstr;

    die "Image does not have 3 channels, it has @{[ $img->getchannels ]} channels"
        if $img->getchannels != 3;

    # $data is packed as PDL->dims == [w,h] with RGB pixels
    my $pdl_raw = zeros(byte, $img->getchannels, $img->getwidth, $img->getheight);
    ${ $pdl_raw->get_dataref } = $data;
    $pdl_raw->upd_data;

    $pdl_raw;
}

my @pdl_images = map {
    load_image_to_pdl(
        $images_for_test_to_uri{$_},
        $model_name_to_params{$model_name}{image_size}
    );
} ($image_names[0]);

my $pdl_image_batched = cat(@pdl_images);
my $t = Uint8PDLTOTFTensor($pdl_image_batched);

die "There should be 4 dimensions" unless $pdl_image_batched->ndims == 4;

die "With the final dimension of length 1" unless $pdl_image_batched->dim(3) == 1;

p $pdl_image_batched;
p $t;

my $RunSession = sub {
    my ($session, $t) = @_;
    my @outputs_t;

    my @keys = keys %{ $outputs{out} };
    my @values = $outputs{out}->@{ @keys };
    $session->Run(
        undef,
        [ values %{$outputs{in} } ], [$t],
        \@values, \@outputs_t,
        undef,
        undef,
        $s
    );
    AssertOK($s);

    return { mesh \@keys, \@outputs_t };
};

undef;

my $tftensor_output_by_name = $RunSession->($session, $t);

my %pdl_output_by_name = map {
    $_ => FloatTFTensorToPDL( $tftensor_output_by_name->{$_} )
} keys $tftensor_output_by_name->%*;

undef;

my $min_score_thresh = 0.30;

my $which_detect = which( $pdl_output_by_name{detection_scores} > $min_score_thresh );

my %subset;

$subset{detection_boxes}   = $pdl_output_by_name{detection_boxes}->dice('X', $which_detect);
$subset{detection_classes} = $pdl_output_by_name{detection_classes}->dice($which_detect);
$subset{detection_scores}  = $pdl_output_by_name{detection_scores}->dice($which_detect);

$subset{detection_class_labels}->@* = map { $labels_map{$_} } $subset{detection_classes}->list;

p %subset;

use PDL::Graphics::Gnuplot;

my $plot_output_path = 'objects-detected.png';
my $gp = gpwin('pngcairo', font => ",12", output => $plot_output_path, aa => 2, size => [10] );

my @qual_cmap = ('#a6cee3','#1f78b4','#b2df8a','#33a02c','#fb9a99','#e31a1c','#fdbf6f','#ff7f00','#cab2d6');

$gp->options(
    map {
        my $idx = $_;
        my $lc_rgb = $qual_cmap[ $subset{detection_classes}->slice("($idx)")->squeeze % @qual_cmap ];

        my $box_corners_yx_norm = $subset{detection_boxes}->slice([],$idx,[0,0,0]);
        $box_corners_yx_norm->reshape(2,2);

        my $box_corners_yx_img = $box_corners_yx_norm * $pdl_images[0]->shape->slice('-1:-2');

        my $from_xy = join ",", $box_corners_yx_img->slice('-1:0,(0)')->list;
        my $to_xy   = join ",", $box_corners_yx_img->slice('-1:0,(1)')->list;
        my $label_xy = join ",", $box_corners_yx_img->at(1,1), $box_corners_yx_img->at(0,1);

        (
            [ object => [ "rect" =>
                from => $from_xy, to => $to_xy,
                qq{front fs empty border lc rgb "$lc_rgb" lw 5} ], ],
            [ label => [
                sprintf("%s: %.1f",
                    $subset{detection_class_labels}[$idx],
                    100*$subset{detection_scores}->at($idx,0) ) =>
                at => $label_xy, 'left',
                offset => 'character 0,-0.25',
                qq{font ",12" boxed front tc rgb "#ffffff"} ], ],
        )
    } 0..$subset{detection_boxes}->dim(1)-1
);

$gp->plot(
    topcmds => q{set style textbox opaque fc "#505050f0" noborder},
    square => 1,
    yrange => [$pdl_images[0]->dim(2),0],
    with => 'image', $pdl_images[0],
);

$gp->close;

IPerl->png( bytestream => path($plot_output_path)->slurp_raw ) if IN_IPERL;

use Filesys::DiskUsage qw/du/;

my $total = du( { 'human-readable' => 1, dereference => 1 },
    $model_archive_path, $model_base );

say "Disk space usage: $total"; undef;