<?php
/**
 * Template variables: every SEO plugin's dialect, translated into ours.
 *
 * @package AiRankSuite
 */

declare(strict_types=1);

namespace AiRankSuite\Modules\ImportExport\Services;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Four dialects are in circulation: Yoast's `%%var%%`, Rank Math's and
 * SEOPress's `%var%`, All in One SEO's `#var`, and The SEO Framework's and
 * Genesis's mixture of the two. They also disagree on names for the same
 * thing — `%%excerpt%%`, `%excerpt%`, `#post_excerpt` and `%seo_description%`
 * all mean "the excerpt".
 *
 * The rule this class implements is exact, and it is the rule a customer can
 * check on their own site: a variable this plugin resolves passes through
 * unchanged, a foreign variable with an equivalent becomes that equivalent,
 * and a variable nothing here can resolve is dropped — dropped rather than
 * kept, because a template that ships `%%ct_custom_field%%` to a live page
 * prints those characters into the search results.
 */
final class Variables {

	/**
	 * Foreign variable => ours. strtr() prefers the longest key, which is what
	 * keeps `%%category%%` from being read as `%` + `%category%` + `%`.
	 *
	 * @return array<string, string>
	 */
	public static function map(): array {
		return array(
			// Yoast (%%var%%), also used by SEOPress in its templates.
			'%%title%%'            => '%title%',
			'%%page_title%%'       => '%title%',
			'%%post_title%%'       => '%title%',
			'%%sitename%%'         => '%sitename%',
			'%%sitedesc%%'         => '%tagline%',
			'%%sep%%'              => '%sep%',
			'%%excerpt%%'          => '%excerpt%',
			'%%excerpt_only%%'     => '%excerpt%',
			'%%category%%'         => '%category%',
			'%%primary_category%%' => '%category%',
			'%%category_title%%'   => '%term%',
			'%%tag%%'              => '%tags%',
			'%%name%%'             => '%author%',
			'%%user_description%%' => '%term_description%',
			'%%date%%'             => '%date%',
			'%%modified%%'         => '%modified%',
			'%%currentyear%%'      => '%currentyear%',
			'%%currentdate%%'      => '%currentdate%',
			'%%currentmonth%%'     => '%currentdate%',
			'%%currentday%%'       => '%currentdate%',
			'%%page%%'             => '%page%',
			'%%pagenumber%%'       => '%page%',
			'%%pagetotal%%'        => '%page%',
			'%%term_title%%'       => '%term%',
			'%%tax_title%%'        => '%term%',
			'%%term_description%%' => '%term_description%',
			'%%tag_description%%'  => '%term_description%',
			'%%category_description%%' => '%term_description%',
			'%%pt_single%%'        => '%post_type%',
			'%%pt_plural%%'        => '%post_type%',
			'%%searchphrase%%'     => '%search_query%',
			'%%parent_title%%'     => '%parent_title%',
			// Rank Math / SEOPress / AIOSEO (%var%).
			'%title%'              => '%title%',
			'%post_title%'         => '%title%',
			'%seo_title%'          => '%title%',
			'%page_title%'         => '%title%',
			'%sitename%'           => '%sitename%',
			'%site_title%'         => '%sitename%',
			'%sep%'                => '%sep%',
			'%separator%'          => '%sep%',
			'%sitedesc%'           => '%tagline%',
			'%tagline%'            => '%tagline%',
			'%site_description%'   => '%tagline%',
			'%excerpt%'            => '%excerpt%',
			'%excerpt_only%'       => '%excerpt%',
			'%post_excerpt%'       => '%excerpt%',
			'%seo_description%'    => '%excerpt%',
			'%wc_shortdesc%'       => '%excerpt%',
			'%category%'           => '%category%',
			'%categories%'         => '%category%',
			'%primary_category%'   => '%category%',
			'%category_title%'     => '%term%',
			'%tags%'               => '%tags%',
			'%tag%'                => '%tags%',
			'%author%'             => '%author%',
			'%post_author%'        => '%author%',
			'%name%'               => '%author%',
			'%date%'               => '%date%',
			'%post_date%'          => '%date%',
			'%modified%'           => '%modified%',
			'%post_modified%'      => '%modified%',
			'%currentyear%'        => '%currentyear%',
			'%current_year%'       => '%currentyear%',
			'%currentdate%'        => '%currentdate%',
			'%current_date%'       => '%currentdate%',
			'%currentmonth%'       => '%currentdate%',
			'%currentday%'         => '%currentdate%',
			'%page%'               => '%page%',
			'%pagenumber%'         => '%page%',
			'%page_number%'        => '%page%',
			'%term%'               => '%term%',
			'%term_title%'         => '%term%',
			'%tax_title%'          => '%term%',
			'%taxonomy_title%'     => '%term%',
			'%term_description%'   => '%term_description%',
			'%taxonomy_description%' => '%term_description%',
			'%pt_single%'          => '%post_type%',
			'%pt_plural%'          => '%post_type%',
			'%post_type_name%'     => '%post_type%',
			'%search_query%'       => '%search_query%',
			'%search_term%'        => '%search_query%',
			'%count%'              => '%count%',
			'%parent_title%'       => '%parent_title%',
			// All in One SEO (#var) and The SEO Framework / Genesis.
			'#post_title'          => '%title%',
			'#page_title'          => '%title%',
			'#site_title'          => '%sitename%',
			'#blog_title'          => '%sitename%',
			'#site_description'    => '%tagline%',
			'#tagline'             => '%tagline%',
			'#separator_sa'        => '%sep%',
			'#separator'           => '%sep%',
			'#post_excerpt'        => '%excerpt%',
			'#post_content'        => '%excerpt%',
			'#current_year'        => '%currentyear%',
			'#current_date'        => '%currentdate%',
			'#author_name'         => '%author%',
			'#post_date'           => '%date%',
			'#taxonomy_title'      => '%term%',
			'#taxonomy_description' => '%term_description%',
			'#archive_title'       => '%term%',
			'#search_term'         => '%search_query%',
			'#page_number'         => '%page%',
			'#categories'          => '%category%',
			'#tags'                => '%tags%',
		);
	}

	/**
	 * Every variable some resolver in this plugin fills: post templates
	 * (SeoModule::fill) plus archive templates (Archives). One list, so an
	 * importer cannot keep a variable the front end then prints literally.
	 *
	 * @return array<string, true>
	 */
	public static function known(): array {
		return array_fill_keys(
			array( '%title%', '%sitename%', '%sep%', '%tagline%', '%excerpt%', '%category%', '%author%', '%date%', '%modified%', '%currentyear%', '%currentdate%', '%page%', '%tags%', '%term%', '%term_description%', '%taxonomy%', '%post_type%', '%search_query%', '%count%', '%pagenumber%', '%parent_title%' ),
			true
		);
	}

	/**
	 * Translate one template string. Idempotent: running it over a value this
	 * plugin already produced changes nothing.
	 */
	public static function translate( string $value ): string {
		if ( '' === trim( $value ) ) {
			return '';
		}
		$value = strtr( $value, self::map() );
		$known = self::known();
		$value = (string) preg_replace_callback(
			'/%%?[a-z_0-9\-]+(?:\([^)]*\))?%%?|#[a-z_]+/i',
			static fn( array $m ): string => isset( $known[ $m[0] ] ) ? $m[0] : '',
			$value
		);
		return trim( (string) preg_replace( '/\s{2,}/', ' ', $value ) );
	}

	/**
	 * A separator constant into the character it stands for. Yoast and Rank
	 * Math both store a key ('sc-pipe', 'sep-pipe') rather than the glyph.
	 */
	public static function separator( string $value ): string {
		$map = array(
			'sc-dash'    => '-',
			'sc-ndash'   => '–',
			'sc-mdash'   => '—',
			'sc-middot'  => '·',
			'sc-bull'    => '•',
			'sc-star'    => '*',
			'sc-smstar'  => '⋆',
			'sc-pipe'    => '|',
			'sc-tilde'   => '~',
			'sc-laquo'   => '«',
			'sc-raquo'   => '»',
			'sc-lt'      => '<',
			'sc-gt'      => '>',
			'sep-hyphen' => '-',
			'sep-dash'   => '–',
			'sep-emdash' => '—',
			'sep-pipe'   => '|',
			'sep-bullet' => '•',
			'sep-raquo'  => '»',
			'sep-laquo'  => '«',
			'sep-mid'    => '·',
			'sep-colon'  => ':',
			'sep-tilde'  => '~',
			'sep-star'   => '*',
			'sep-gt'     => '>',
		);
		$value = trim( $value );
		if ( isset( $map[ $value ] ) ) {
			return $map[ $value ];
		}
		// An unknown key ('sc-something') is not a separator glyph — better no
		// separator than three letters in every title on the site.
		return preg_match( '/^(sc|sep)-/', $value ) ? '' : mb_substr( $value, 0, 3 );
	}
}