<?php
/**
 * Scan result storage.
 *
 * Results live in a single autoloaded-off option rather than a custom table.
 * A site scans a handful of representative pages, not thousands, so a table
 * would be a schema to migrate for no benefit — and uninstall stays a one-liner.
 *
 * @package AccessVane
 */

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

/**
 * Persists and summarises scan results.
 */
class AccessVane_Storage {

	const OPTION = 'accessvane_results';

	/**
	 * Hard cap on stored scans, oldest dropped first. Keeps the option small
	 * enough that reading it never becomes a performance problem.
	 */
	const MAX_RESULTS = 60;

	/**
	 * All stored results, newest first.
	 *
	 * @return array
	 */
	public static function all() {
		$stored = get_option( self::OPTION, array() );

		return is_array( $stored ) ? $stored : array();
	}

	/**
	 * Store one page's result, replacing any previous result for that URL.
	 *
	 * @param array $result Sanitised result payload.
	 * @return void
	 */
	public static function save( array $result ) {
		$results = self::all();
		$key     = self::key_for( $result['url'] );

		$results[ $key ] = $result;

		uasort(
			$results,
			static function ( $a, $b ) {
				$left  = isset( $a['scanned_at'] ) ? (int) $a['scanned_at'] : 0;
				$right = isset( $b['scanned_at'] ) ? (int) $b['scanned_at'] : 0;

				return $right <=> $left;
			}
		);

		if ( count( $results ) > self::MAX_RESULTS ) {
			$results = array_slice( $results, 0, self::MAX_RESULTS, true );
		}

		// Explicitly non-autoloaded: this can reach a few hundred kilobytes and
		// has no business being loaded on every front-end request.
		update_option( self::OPTION, $results, false );
	}

	/**
	 * Fetch one stored result.
	 *
	 * @param string $url Page URL.
	 * @return array|null
	 */
	public static function get( $url ) {
		$results = self::all();
		$key     = self::key_for( $url );

		return isset( $results[ $key ] ) ? $results[ $key ] : null;
	}

	/**
	 * Remove one stored result.
	 *
	 * @param string $url Page URL.
	 * @return void
	 */
	public static function forget( $url ) {
		$results = self::all();
		$key     = self::key_for( $url );

		if ( isset( $results[ $key ] ) ) {
			unset( $results[ $key ] );
			update_option( self::OPTION, $results, false );
		}
	}

	/**
	 * Drop every stored result.
	 *
	 * @return void
	 */
	public static function clear() {
		delete_option( self::OPTION );
	}

	/**
	 * Site-wide roll-up across every scanned page.
	 *
	 * @return array
	 */
	public static function summary() {
		$results = self::all();

		$summary = array(
			'pages'            => count( $results ),
			'critical'         => 0,
			'serious'          => 0,
			'moderate'         => 0,
			'minor'            => 0,
			'elements'         => 0,
			'average_score'    => null,
			'worst_page'       => null,
			'last_scanned_at'  => 0,
			'fixable_rules'    => array(),
			'top_issues'       => array(),
		);

		if ( ! $results ) {
			return $summary;
		}

		$scores      = array();
		$issue_tally = array();
		$worst       = null;

		foreach ( $results as $result ) {
			$counts = isset( $result['counts'] ) ? $result['counts'] : array();

			foreach ( array( 'critical', 'serious', 'moderate', 'minor' ) as $level ) {
				$summary[ $level ] += isset( $counts[ $level ] ) ? (int) $counts[ $level ] : 0;
			}

			$summary['elements'] += isset( $result['elements'] ) ? (int) $result['elements'] : 0;
			$scores[]             = isset( $result['score'] ) ? (int) $result['score'] : 100;

			if ( isset( $result['scanned_at'] ) && $result['scanned_at'] > $summary['last_scanned_at'] ) {
				$summary['last_scanned_at'] = (int) $result['scanned_at'];
			}

			if ( null === $worst || $result['score'] < $worst['score'] ) {
				$worst = $result;
			}

			if ( ! empty( $result['issues'] ) && is_array( $result['issues'] ) ) {
				foreach ( $result['issues'] as $issue ) {
					$rule = isset( $issue['id'] ) ? $issue['id'] : '';

					if ( '' === $rule ) {
						continue;
					}

					if ( ! isset( $issue_tally[ $rule ] ) ) {
						$issue_tally[ $rule ] = array(
							'id'          => $rule,
							'impact'      => isset( $issue['impact'] ) ? $issue['impact'] : 'moderate',
							'pages'       => 0,
							'elements'    => 0,
							'autoFixable' => ! empty( $issue['autoFixable'] ),
						);
					}

					$issue_tally[ $rule ]['pages']++;
					$issue_tally[ $rule ]['elements'] += isset( $issue['count'] ) ? (int) $issue['count'] : 0;

					if ( ! empty( $issue['autoFixable'] ) ) {
						$summary['fixable_rules'][ $rule ] = true;
					}
				}
			}
		}

		$summary['average_score'] = (int) round( array_sum( $scores ) / count( $scores ) );
		$summary['worst_page']    = $worst;
		$summary['fixable_rules'] = array_keys( $summary['fixable_rules'] );

		$order = array(
			'critical' => 0,
			'serious'  => 1,
			'moderate' => 2,
			'minor'    => 3,
		);

		uasort(
			$issue_tally,
			static function ( $a, $b ) use ( $order ) {
				$left  = isset( $order[ $a['impact'] ] ) ? $order[ $a['impact'] ] : 4;
				$right = isset( $order[ $b['impact'] ] ) ? $order[ $b['impact'] ] : 4;

				if ( $left !== $right ) {
					return $left <=> $right;
				}

				return $b['elements'] <=> $a['elements'];
			}
		);

		$summary['top_issues'] = array_values( $issue_tally );

		return $summary;
	}

	/**
	 * Stable storage key for a URL.
	 *
	 * @param string $url Page URL.
	 * @return string
	 */
	private static function key_for( $url ) {
		return md5( untrailingslashit( (string) $url ) );
	}
}