// ========================================
// ULTRA FAST CACHE + IMAGE OPTIMIZER
// ========================================

$cacheDir = __DIR__ . '/cache/service/';
$imageCacheDir = __DIR__ . '/cache/images/';

if (!is_dir($cacheDir)) {
    mkdir($cacheDir, 0777, true);
}

if (!is_dir($imageCacheDir)) {
    mkdir($imageCacheDir, 0777, true);
}

$slugCache = $_GET['slug'] ?? 'default';

$cacheFile =
    $cacheDir .
    md5($slugCache) .
    '.html';

// 7 дни кеш
$cacheLife = 604800;

// ако има кеш
if (
    file_exists($cacheFile)
    &&
    (
        time() -
        filemtime($cacheFile)
    ) < $cacheLife
) {
    readfile($cacheFile);
    exit;
}

// старт на HTML cache
ob_start();


// ========================================
// IMAGE OPTIMIZER
// ========================================

function optimizeImage($imagePath)
{
    if (!$imagePath) {
        return '';
    }

    $root = __DIR__;

    $fullPath =
        $root .
        '/' .
        ltrim($imagePath, '/');

    if (!file_exists($fullPath)) {
        return $imagePath;
    }

    $cacheDir =
        $root .
        '/cache/images/';

    $ext =
        strtolower(
            pathinfo(
                $fullPath,
                PATHINFO_EXTENSION
            )
        );

    $hash =
        md5(
            $fullPath .
            filemtime($fullPath)
        );

    $webpFile =
        $cacheDir .
        $hash .
        '.webp';

    $webpUrl =
        '/cache/images/' .
        $hash .
        '.webp';

    // вече кеширана
    if (
        file_exists(
            $webpFile
        )
    ) {
        return $webpUrl;
    }

    switch ($ext) {

        case 'jpg':
        case 'jpeg':

            $img =
                imagecreatefromjpeg(
                    $fullPath
                );

        break;

        case 'png':

            $img =
                imagecreatefrompng(
                    $fullPath
                );

        break;

        case 'webp':
            return $imagePath;

        default:
            return $imagePath;
    }

    $width =
        imagesx($img);

    $height =
        imagesy($img);

    // resize huge images
    $maxWidth = 1200;

    if (
        $width >
        $maxWidth
    ) {

        $newHeight =
            intval(
                (
                    $height /
                    $width
                )
                *
                $maxWidth
            );

        $tmp =
            imagecreatetruecolor(
                $maxWidth,
                $newHeight
            );

        imagecopyresampled(
            $tmp,
            $img,
            0,
            0,
            0,
            0,
            $maxWidth,
            $newHeight,
            $width,
            $height
        );

        imagedestroy($img);

        $img = $tmp;
    }

    imagewebp(
        $img,
        $webpFile,
        80
    );

    imagedestroy($img);

    return $webpUrl;
}

Slug не е подаден!