Wordpress Custom Meta Description based on Faceted Categories

gistfile1.txt

function add_meta_tags() {
    global $post;
    if ( is_archive() || is_home()) {
    	/*
    	 * CONTEXT CLASS
    	 * Here we go, need to create a context for the library pages and its facets
    	 */
        class Context
        {
            public $isContentType = false;
            public $isTopic = false;
            public $isIndustry = false;
            public $isPromoUse = false;
            public $contentType = false;
            public $topic = false;
            public $industry = false;
            public $promoUse = false;

            function __construct() {
                $this->isContentType = (func_get_arg(0) == '-1') ? false : true;
                $this->isTopic = (func_get_arg(1) == '-1') ? false : true;
                $this->isIndustry = (func_get_arg(2) == '-1') ? false : true;
                $this->isPromoUse = (func_get_arg(3) == '-1') ? false : true;

                $this->contentType = (func_get_arg(0) == '-1') ? false : func_get_arg(0);
                $this->topic = (func_get_arg(1) == '-1') ? false : func_get_arg(1);
                $this->industry = (func_get_arg(2) == '-1') ? false : func_get_arg(2);
                $this->promoUse = (func_get_arg(3) == '-1') ? false : func_get_arg(3);
            }

            /*
            Content Types:
            4Ideas Friday
            Blog
            Blue Paper
            eBook
            eNewsletter
            Infographic
            Podcast
            Press Release
            Staff Favorites
            Success Stories
            Video
            */
			
            function setContentType($name) {
                $this->contentType = $name;
                $this->isContentType = true;
            }

            function setTopic($name) {
                $this->topic = $name;
                $this->isTopic = true;
            }

            function setIndustry($name) {
                $this->industry = $name;
                $this->isIndustry = true;
            }

            function setPromoUse($name) {
                $this->promoUse = $name;
                $this->isPromoUse = true;
            }

            function getPluralContentType($ct) {
                if ($ct == '4Ideas Friday') {
                    return '4Ideas Friday content';
                }
                $plurals = array("Blue Paper", "eBook", "eNewsletter", "Infographic", "Podcast", "Press Release", "Video");

                if (in_array($ct, $plurals)) {
                    //var_dump($ct);
                    return $ct . 's';
                }

                return $ct;
            }
            
            function printMetaDescription() {
                $metaContent = "Discover ways to use your promotional products in our Learning Center.";

                if ($this->isContentType && $this->isTopic && $this->isIndustry && $this->isPromoUse) { //Correct
					$metaContent = sprintf("Want to use promotional products for %s? We have examples for %s %s in our %s.", $this->promoUse, $this->industry, $this->topic, $this->getPluralContentType($this->contentType));
                } elseif ($this->isContentType && $this->isTopic && $this->isIndustry) { //Correct
					$metaContent = sprintf("Stay up-to-date on marketing, branding, human resources and more with %s %s in info.4imprint.com’s %s.", $this->industry, $this->topic, $this->getPluralContentType($this->contentType));
                } elseif ($this->isContentType && $this->isIndustry && $this->isPromoUse) { //Correct
                    $industry_fix = ($this->industry == 'General' ? 'General industry' : $this->industry);
                    $industry_fix = ($this->industry == 'Nonprofit' ? 'Nonprofits' : $industry_fix);
                    $nonprofit_verb_fix = ($this->industry == 'Nonprofit' ? 'use' : 'uses');
					$metaContent = sprintf("Check out our %s to learn how %s %s promotional products for %s.", $this->getPluralContentType($this->contentType), $industry_fix, $nonprofit_verb_fix, $this->promoUse);
                } elseif ($this->isTopic && $this->isIndustry && $this->isPromoUse) { //Correct
					$metaContent = sprintf("From %s %s to %s or promotional products, visit our learning center.", $this->industry, $this->topic, $this->promoUse);
                } elseif ($this->isContentType && $this->isTopic) { //Correct
					$metaContent = sprintf("When you want to know more about %s, check out the %s at info.4imprint.com.", $this->topic, $this->getPluralContentType($this->contentType));
                } elseif ($this->isContentType && $this->isIndustry) { //Correct
					$metaContent = sprintf("Find answers to your marketing, branding, team-building, business gifts questions and more in our %s %s.", $this->industry, $this->getPluralContentType($this->contentType));
                } elseif ($this->isContentType && $this->isPromoUse) { //Correct
					$metaContent = sprintf("For ideas on using promotional products for %s, check out the %s in the 4imprint Learning Center.", $this->promoUse, $this->getPluralContentType($this->contentType));
                } elseif ($this->isTopic && $this->isIndustry) { //Correct
                    $industry_fix = ($this->industry == 'General' ? '' : ' '.$this->industry);
					$metaContent = sprintf("Promotional products are just the beginning! Enhance your %s with tips from our%s Learning Center.", $this->topic, $industry_fix);
                } elseif ($this->isTopic && $this->isPromoUse) { //Correct
					$metaContent = sprintf("Learn how to use promotional products for %s or %s in our Learning Center.", $this->promoUse, $this->topic);
                } elseif ($this->isIndustry && $this->isPromoUse) { //Correct
					$metaContent = sprintf("If you’re looking for tips on using promotional products for %s in %s, check out our Learning Center.", $this->promoUse, $this->industry);
                } elseif ($this->isContentType) { //Correct
                	$metaContent = sprintf("Generate ideas and expand your knowledge on marketing, branding, team-building, business gifts and more with info.4imprint.com %s content.", $this->contentType);
                } elseif ($this->isTopic) { //Correct
                	$metaContent = sprintf("Find helpful tips on %s – and a wide range of other marketing, HR and promotional products topics - in our Learning Center.", $this->topic);
                } elseif ($this->isIndustry) { //Correct
                	$metaContent = sprintf("Explore the latest marketing, HR and digital tools – including promotional products – in our %s content.", $this->industry);
                } elseif ($this->isPromoUse) { //Correct
                	$metaContent = sprintf("Discover a variety of ways to use promotional products for %s in our Learning Center.", $this->promoUse);
                }
                
                echo "\n" . "<meta name='description' content='{$metaContent}' />" . "\n";
            }
        }
        /*
    	 * END CONTEXT CLASS
    	 */

		/*
		 * INITIAL CONTEXT 
		 * Get arguments from url and set the context
		 */
        if (isset($_GET['content_type']) && ($_GET['content_type'] != '-1')) {
        	$category = get_term_by('id', $_GET['content_type'], 'category');
            $category_name = $category->name;
        	$content_type_get = $category_name;
        } else {
        	$content_type_get = '-1';
        }
        if (isset($_GET['topic']) && ($_GET['topic'] != '-1')) {
        	$category = get_term_by('id', $_GET['topic'], 'category');
            $category_name = $category->name;
        	$topic_get = $category_name;
        } else {
        	$topic_get = '-1';
        }
        if (isset($_GET['industry']) && ($_GET['industry'] != '-1')) {
        	$category = get_term_by('id', $_GET['industry'], 'category');
            $category_name = $category->name;
        	$industry_get = $category_name;
        } else {
        	$industry_get = '-1';
        }
        if (isset($_GET['promo_use']) && ($_GET['promo_use'] != '-1')) {
        	$category = get_term_by('id', $_GET['promo_use'], 'category');
            $category_name = $category->name;
        	$promo_use_get = $category_name;
        } else {
        	$promo_use_get = '-1';
        }
		
        $current_context = new Context($content_type_get, $topic_get, $industry_get, $promo_use_get);

        $cat_id = get_query_var('cat');
        /*
		 * END INITIAL CONTEXT 
		 */

        /*
         * SINGLE CATEGORY CONTEXT
         * Arguments are not always set in url, but a single category can still be set
         * Let's check for those
         */
        
        if ('' != $cat_id) {
            $category = get_term_by('id', $cat_id, 'category');
            $content_type = get_term_by('name', 'Content Type', 'category');
            $topic = get_term_by('name', 'Topic', 'category');
            $industry = get_term_by('name', 'Industry', 'category');
            $promo_use = get_term_by('name', 'Promotional Products Use', 'category');

            if ($category->parent == $content_type->term_id) {
                $current_context->setContentType($category->name);
            } elseif ($category->parent == $topic->term_id) {
                $current_context->setTopic($category->name);
            } elseif ($category->parent == $industry->term_id) {
                $current_context->setIndustry($category->name);
            } elseif ($category->parent == $promo_use->term_id) {
                $current_context->setPromoUse($category->name);
            } elseif (cat_is_ancestor_of(get_cat_id('Topic'), $cat_id)) {
            	$current_context->setTopic($category->name);
            }
        }
        /*
         * END SINGLE CATEGORY CONTEXT
         */

		//Let's print this stuff
        $current_context->printMetaDescription();
    }
}
add_action( 'wp_head', 'add_meta_tags' , 2 );