<?php
/**
 * The A11yMate score. See docs/SCORING.md.
 *
 * @package A11yMate
 */

namespace A11yMate\Store;

use A11yMate\Schema;

defined( 'ABSPATH' ) || exit;

/**
 * Score formulae.
 */
class Score {

	const SITE_SCALE = 250;
	const PAGE_SCALE = 60;

	/**
	 * Severity weights.
	 *
	 * @return array
	 */
	public static function weights() {
		return array(
			'critical' => 10,
			'serious'  => 6,
			'moderate' => 3,
			'minor'    => 1,
		);
	}

	/**
	 * Penalty of one grouped issue.
	 *
	 * @param string $severity Severity.
	 * @param int    $pages    Pages affected.
	 * @return float
	 */
	public static function issue_penalty( $severity, $pages ) {
		$w = self::weights();
		$w = isset( $w[ $severity ] ) ? $w[ $severity ] : 1;
		return $w * ( 1 + 0.5 * log( max( 1, (int) $pages ) ) );
	}

	/**
	 * Turn a penalty into 0-100.
	 *
	 * @param float $penalty Penalty.
	 * @param float $scale   Scale.
	 * @return int
	 */
	public static function to_score( $penalty, $scale = self::SITE_SCALE ) {
		if ( $penalty <= 0 ) {
			return 100;
		}
		$s = (int) round( 100 * exp( -$penalty / $scale ) );
		return max( 0, min( 99, $s ) );
	}

	/**
	 * Current site score and breakdown from the open, automated issues.
	 *
	 * @return array{score:int,categories:array,penalty:float,counts:array}
	 */
	public static function site() {
		global $wpdb;
		$t     = Schema::table( 'issues' );
		$rows  = $wpdb->get_results( $wpdb->prepare( "SELECT severity, category, page_count FROM %i WHERE state = 'open' AND mode = 'automated'", $t ), ARRAY_A ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery
		$total = 0.0;
		$cats  = array();
		foreach ( (array) $rows as $r ) {
			$p                      = self::issue_penalty( $r['severity'], $r['page_count'] );
			$total                 += $p;
			$cats[ $r['category'] ] = ( isset( $cats[ $r['category'] ] ) ? $cats[ $r['category'] ] : 0 ) + $p;
		}
		$cat_scores = array();
		foreach ( \A11yMate\Rules\Registry::categories() as $c ) {
			$pen                    = isset( $cats[ $c['id'] ] ) ? $cats[ $c['id'] ] : 0;
			$cat_scores[ $c['id'] ] = self::to_score( $pen, self::SITE_SCALE / 2 );
		}
		return array(
			'score'      => self::to_score( $total ),
			'categories' => $cat_scores,
			'penalty'    => round( $total, 2 ),
		);
	}

	/**
	 * Score a page from its list of [rule, severity, count] entries.
	 *
	 * @param array $entries Entries with severity and n keys.
	 * @return int
	 */
	public static function page( array $entries ) {
		$w   = self::weights();
		$pen = 0;
		foreach ( $entries as $e ) {
			$weight = isset( $w[ $e['severity'] ] ) ? $w[ $e['severity'] ] : 1;
			$pen   += $weight * ( 1 + 0.5 * log( max( 1, (int) $e['n'] ) ) );
		}
		return self::to_score( $pen, self::PAGE_SCALE );
	}

	/**
	 * Per-post editor score (used by the block editor assistant, mirrored in JS).
	 *
	 * @param array $severities List of severities.
	 * @return int
	 */
	public static function editor( array $severities ) {
		$w   = self::weights();
		$pen = 0;
		foreach ( $severities as $s ) {
			$pen += isset( $w[ $s ] ) ? $w[ $s ] : 1;
		}
		return self::to_score( $pen, 20 );
	}
}