#!/usr/local/bin/perl
use strict;
use Image::Magick;
use Image::Magick::Tiler;

# ディレクトリを指定して、その直下にある画像ファイルをリサイズする（出力はjpg固定、変更時はソースを修正すること）
# このplファイルと指定するディレクトリは同一階層にあること
my @DIRS = ();

# リサイズ後の画像サイズ
my $RESIZE_X = 480;
my $RESIZE_Y = 854;

# 見開きのページの際に、左ページ→右ページの順で読む場合は0、右ページ→左ページの順で読む場合は1
my $READ_DIRECTION = 0;

# 横のサイズが縦のサイズの何倍以上になったら縦に2分割する対象であると解釈するか
my $WIDTH_PER_HEIGHT = 1.3;

foreach my $dir(@DIRS) {
    my ($SEC, $MIN, $HOUR, $DAY, $MONTH, $YEAR) = localtime();
    $YEAR += 1900;
    $MONTH++;

    my $dir_time_name = sprintf("%04d%02d%02d_%02d%02d%02d", $YEAR, $MONTH, $DAY, $HOUR, $MIN, $SEC);
    my @files = ();

    opendir(CURRENT, "$dir");
    while (defined(my $file = readdir(CURRENT))) {
        if ($file =~ /(.*)\.jpg|(.*)\.gif|(.*)\.png/i) {
            push(@files, "$dir/$file");
        }
    }
    closedir(CURRENT);

    my $output_dir = "${dir}_$dir_time_name";
    mkdir("$output_dir");

    foreach my $jpg(@files) {
        my $image = Image::Magick->new;
        $image->Read($jpg);
        my ($x, $y) = $image->Get('width', 'height');
        if ($x >= $y * $WIDTH_PER_HEIGHT) {
            my $result_ref=Image::Magick::Tiler->new(
                input_file=>"$jpg",
                geometry=>'2x1',
                output_dir=>"$output_dir",
                output_type=>'jpg',
                verbose=>0,
                write=>1,
                return=>1)->tile();
            my @ref = @$result_ref;
            my @new_files = ();
            foreach (@ref) {
                my %obj = %$_;
                my $created = $obj{'file_name'};
                push(@new_files, $created);
            }
            if ($READ_DIRECTION) {
                @new_files = reverse(@new_files);
            }
            my @file_path = split(/\//, $jpg);
            my @file_name = split(/\./, $file_path[1]);
            my $counter = 1;
            foreach my $new_file(@new_files) {
                my $new_image = Image::Magick->new;
                $new_image->Read("$new_file");
                my ($new_x, $new_y) = $new_image->Get('width', 'height');
                my $new_magni_x = $RESIZE_X / $new_x;
                my $new_magni_y = $RESIZE_Y / $new_y;
                my $new_magnification;
                if ($new_magni_x < 1 || $new_magni_y < 1) {
                    if ($new_magni_x > $new_magni_y) {
                        $new_magnification = $new_magni_y;
                    } else {
                        $new_magnification = $new_magni_x;
                    }
                } else {
                    $new_magnification = 1;
                }
                $new_image->Resize(width=>$new_x * $new_magnification, height=>$new_y * $new_magnification);
                binmode(STDOUT);
                $new_image->Write("$output_dir/$file_name[0]" . '-' . $counter . '.jpg');
                unlink("$new_file");
                undef $new_image;
                $counter++;
            }
        } else {
            my $magni_x = $RESIZE_X / $x;
            my $magni_y = $RESIZE_Y / $y;
            my $magnification;
            if ($magni_x < 1 || $magni_y < 1) {
                if ($magni_x > $magni_y) {
                    $magnification = $magni_y;
                } else {
                    $magnification = $magni_x;
                }
            } else {
                $magnification = 1;
            }
            $image->Resize(width=>$x * $magnification, height=>$y * $magnification);
            my @file_path = split(/\//, $jpg);
            my @file_name = split(/\./, $file_path[1]);
            binmode(STDOUT);
            $image->Write("$output_dir/$file_name[0]" . '.jpg');
        }
        undef $image;
    }
}