<?php

return function($site) {
    $files = $site->slideshow()->toFiles();
    $count = $files->count();

    $units = [];
    $i     = 0;

    while ($i < $count) {
        $file     = $files->nth($i);
        $nextFile = $files->nth($i + 1);

        $isPortrait     = $file->type() === 'image' && $file->orientation() === 'portrait';
        $nextIsPortrait = $nextFile && $nextFile->type() === 'image' && $nextFile->orientation() === 'portrait';

        if ($isPortrait && $nextIsPortrait) {
            $units[] = ['pair' => true, 'a' => $file, 'b' => $nextFile];
            $i += 2;
        } else {
            $units[] = ['pair' => false, 'file' => $file, 'isHiddenOnMobile' => (bool) $file->isHiddenOnMobile()->isTrue()];
            $i++;
        }
    }

    if ($site->areSlidesShuffled()->isTrue()) {
        shuffle($units);
    }

    return [
        'slides' => $units,
    ];
};