<?php
/**
 * @package AccessMate
 * @license GPL-2.0-or-later
 */
defined( 'ABSPATH' ) || exit;

class AccessMate_Report {

    /**
     * Build a structured report from the last scan stored in wp_options.
     */
    public static function get(): array {
        $scan = get_option( 'accessmate_last_scan', [] );

        // If the scanned URL belongs to a post/page that's since been trashed or
        // deleted, don't surface its stale issues — treat this as no data, same
        // as AccessMate_Site_Scanner::get_page_scans() already does for the
        // per-page scan list.
        if ( ! empty( $scan['url'] ) ) {
            $post_id = url_to_postid( $scan['url'] );
            if ( $post_id > 0 && get_post_status( $post_id ) !== 'publish' ) {
                $scan = [];
            }
        }

        if ( empty( $scan ) ) {
            return [
                'has_data'   => false,
                'score'      => 0,
                'grade'      => 'F',
                'scanned_at' => null,
                'url'        => null,
                'issues'     => [],
                'groups'     => [],
                'summary'    => self::empty_summary(),
            ];
        }

        $issues = $scan['issues'] ?? [];

        return [
            'has_data'   => true,
            'score'      => $scan['score']      ?? 0,
            'grade'      => $scan['grade']       ?? 'F',
            'scanned_at' => $scan['scanned_at']  ?? null,
            'url'        => $scan['url']          ?? null,
            'passed'     => $scan['passed']       ?? 0,
            'failed'     => $scan['failed']       ?? 0,
            'issues'     => $issues,
            'groups'     => self::group_by_severity( $issues ),
            'pour'       => self::pour_breakdown( $issues ),
            'summary'    => self::summary_stats( $issues ),
        ];
    }

    /**
     * Group issues by severity for the report view.
     */
    private static function group_by_severity( array $issues ): array {
        $groups = [
            'critical' => [],
            'serious'  => [],
            'warning'  => [],
            'notice'   => [],
        ];
        foreach ( $issues as $issue ) {
            $sev = $issue['severity'] ?? 'notice';
            if ( isset( $groups[ $sev ] ) ) {
                $groups[ $sev ][] = $issue;
            }
        }
        return $groups;
    }

    /**
     * Map issues to WCAG POUR principles (Perceivable, Operable, Understandable, Robust).
     */
    private static function pour_breakdown( array $issues ): array {
        $pour = [
            'perceivable'    => [ 'score' => 100, 'issues' => [] ],
            'operable'       => [ 'score' => 100, 'issues' => [] ],
            'understandable' => [ 'score' => 100, 'issues' => [] ],
            'robust'         => [ 'score' => 100, 'issues' => [] ],
        ];

        $wcag_map = [
            // Perceivable
            '1.1.1' => 'perceivable',
            '1.3.1' => 'perceivable',
            '1.3.6' => 'perceivable',
            '1.4.3' => 'perceivable',
            // Operable
            '2.1.1' => 'operable',
            '2.3.3' => 'operable',
            '2.4.4' => 'operable',
            '2.4.6' => 'operable',
            '2.4.7' => 'operable',
            // Understandable
            '3.1.1' => 'understandable',
            // Robust
            '4.1.2' => 'robust',
        ];

        // POUR principle lookup by WCAG criterion leading digit — covers all WCAG 2.x criteria.
        $pour_by_digit = [ '1' => 'perceivable', '2' => 'operable', '3' => 'understandable', '4' => 'robust' ];

        foreach ( $issues as $issue ) {
            // Best-practice issues are not part of WCAG POUR and should not affect POUR scores.
            if ( ( $issue['category'] ?? 'wcag' ) === 'best-practice' ) continue;

            $wcag = $issue['wcag'] ?? '';
            if ( isset( $wcag_map[ $wcag ] ) ) {
                $principle = $wcag_map[ $wcag ];
            } else {
                // Derive from leading digit (e.g. 1.x.x → perceivable, 2.x.x → operable).
                $principle = $pour_by_digit[ $wcag[0] ?? '' ] ?? 'perceivable';
            }
            $pour[ $principle ]['issues'][] = $issue;

            $weight = $issue['severity'] === 'critical' ? 20 : ( $issue['severity'] === 'serious' ? 15 : 10 );
            $pour[ $principle ]['score'] = max( 0, $pour[ $principle ]['score'] - $weight );
        }

        return $pour;
    }

    private static function summary_stats( array $issues ): array {
        $critical = 0;
        $serious  = 0;
        $warnings = 0;
        $notices  = 0;
        foreach ( $issues as $issue ) {
            switch ( $issue['severity'] ?? '' ) {
                case 'critical': $critical++; break;
                case 'serious':  $serious++;  break;
                case 'warning':  $warnings++; break;
                default:         $notices++;  break;
            }
        }
        return compact( 'critical', 'serious', 'warnings', 'notices' );
    }

    private static function empty_summary(): array {
        return [ 'critical' => 0, 'serious' => 0, 'warnings' => 0, 'notices' => 0 ];
    }

    /**
     * Return the rolling scan history (last 10 entries).
     */
    public static function get_history(): array {
        return get_option( 'accessmate_scan_history', [] );
    }
}