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

class AccessMate_RestApi {

    private static string $ns = 'accessmate/v1';

    private const FREE_PAGE_LIMIT = 25;

    /**
     * True when the Freemius SDK is present and the active licence allows premium features.
     * Safe to call from the free build — acc_fs() won't exist there so it returns false.
     */
    private static function is_premium(): bool {
        return function_exists( 'acc_fs' ) && acc_fs()->can_use_premium_code();
    }

    /**
     * Sanitize axe-core issue text (title/description) without stripping HTML tag names.
     * axe-core titles often reference element names literally, e.g. "<ul> must only contain <li>".
     * sanitize_text_field() would strip those angle-bracketed tokens, garbling the title.
     * This helper validates UTF-8 and removes control characters but preserves all printable text.
     */
    private static function sanitize_issue_text( string $text ): string {
        $text = wp_check_invalid_utf8( $text );
        // Remove ASCII control characters (except tab/newline/carriage-return).
        $text = preg_replace( '/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]/', '', $text );
        return substr( trim( $text ), 0, 1000 );
    }

    public static function register(): void {
        add_action( 'rest_api_init', [ self::class, 'register_routes' ] );
    }

    public static function register_routes(): void {
        // GET /wp-json/accessmate/v1/settings
        register_rest_route( self::$ns, '/settings', [
            'methods'             => WP_REST_Server::READABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_get_settings' ],
        ]);

        // POST /wp-json/accessmate/v1/settings
        register_rest_route( self::$ns, '/settings', [
            'methods'             => WP_REST_Server::CREATABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_save_settings' ],
            'args'                => [
                'ai_provider'   => [ 'type' => 'string', 'sanitize_callback' => 'sanitize_text_field', 'default' => 'none' ],
                'ai_key'        => [ 'type' => 'string', 'sanitize_callback' => 'sanitize_text_field', 'default' => '' ],
                'ai_model'      => [ 'type' => 'string', 'sanitize_callback' => 'sanitize_text_field', 'default' => '' ],
                'scan_schedule' => [ 'type' => 'string', 'sanitize_callback' => 'sanitize_text_field', 'default' => 'weekly' ],
                'default_rulesets' => [
                    'type'    => 'array',
                    'items'   => [ 'type' => 'string' ],
                    'default' => [ 'wcag22aa' ],
                ],
            ],
        ]);

        // POST /wp-json/accessmate/v1/ai/test — test connection with current form values (unsaved)
        register_rest_route( self::$ns, '/ai/test', [
            'methods'             => WP_REST_Server::CREATABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_ai_test' ],
            'args'                => [
                'ai_provider' => [ 'type' => 'string', 'sanitize_callback' => 'sanitize_text_field', 'required' => true ],
                'ai_key'      => [ 'type' => 'string', 'sanitize_callback' => 'sanitize_text_field', 'default' => '' ],
                'ai_model'    => [ 'type' => 'string', 'sanitize_callback' => 'sanitize_text_field', 'default' => '' ],
            ],
        ]);

        // POST /wp-json/accessmate/v1/ai/proxy
        register_rest_route( self::$ns, '/ai/proxy', [
            'methods'             => WP_REST_Server::CREATABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_ai_proxy' ],
            'args'                => [
                'task'   => [ 'type' => 'string', 'sanitize_callback' => 'sanitize_text_field', 'required' => true ],
                'params' => [ 'type' => 'object', 'default' => [] ],
            ],
        ]);

        // GET /wp-json/accessmate/v1/scan-history
        register_rest_route( self::$ns, '/scan-history', [
            'methods'             => WP_REST_Server::READABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_scan_history' ],
        ]);

        // GET /wp-json/accessmate/v1/widget-config
        register_rest_route( self::$ns, '/widget-config', [
            'methods'             => WP_REST_Server::READABLE,
            'permission_callback' => '__return_true',   // public — widget reads this on front end
            'callback'            => [ self::class, 'handle_get_widget_config' ],
        ]);

        // POST /wp-json/accessmate/v1/widget-config
        register_rest_route( self::$ns, '/widget-config', [
            'methods'             => WP_REST_Server::CREATABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_save_widget_config' ],
            'args'                => [
                'enabled'     => [ 'type' => 'boolean', 'default' => true ],
                'color'       => [ 'type' => 'string',  'sanitize_callback' => 'sanitize_hex_color', 'default' => '#3858e9' ],
                'position'    => [
                    'type'              => 'string',
                    'sanitize_callback' => 'sanitize_text_field',
                    'default'           => 'bottom-right',
                    'enum'              => [ 'top-left', 'top-right', 'bottom-left', 'bottom-right' ],
                ],
                'button_size' => [
                    'type'              => 'string',
                    'sanitize_callback' => 'sanitize_text_field',
                    'default'           => 'medium',
                    'enum'              => [ 'small', 'medium', 'large' ],
                ],
                'features'    => [ 'type' => 'array', 'default' => [] ],
            ],
        ]);

        // POST /wp-json/accessmate/v1/scan
        register_rest_route( self::$ns, '/scan', [
            'methods'             => WP_REST_Server::CREATABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_scan' ],
            'args'                => [
                'url' => [
                    'type'              => 'string',
                    'sanitize_callback' => 'esc_url_raw',
                    'default'           => '',
                ],
            ],
        ]);

        // GET /wp-json/accessmate/v1/issues
        register_rest_route( self::$ns, '/issues', [
            'methods'             => WP_REST_Server::READABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_issues' ],
        ]);

        // GET /wp-json/accessmate/v1/report
        register_rest_route( self::$ns, '/report', [
            'methods'             => WP_REST_Server::READABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_report' ],
        ]);

        // POST /wp-json/accessmate/v1/axe-scan  — store browser-computed axe-core results
        register_rest_route( self::$ns, '/axe-scan', [
            'methods'             => WP_REST_Server::CREATABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_axe_scan' ],
            'args'                => [
                'url'    => [ 'type' => 'string',  'sanitize_callback' => 'esc_url_raw', 'required' => true ],
                'score'  => [ 'type' => 'integer', 'default' => 0 ],
                'grade'  => [ 'type' => 'string',  'sanitize_callback' => 'sanitize_text_field', 'default' => 'F' ],
                'passed' => [ 'type' => 'integer', 'default' => 0 ],
                'failed' => [ 'type' => 'integer', 'default' => 0 ],
                'issues' => [ 'type' => 'array',   'default' => [] ],
                'rulesets' => [ 'type' => 'array', 'items' => [ 'type' => 'string' ], 'default' => [] ],
                'passed_checks' => [ 'type' => 'array', 'default' => [] ],
            ],
        ]);

        // GET /wp-json/accessmate/v1/scannable-urls
        register_rest_route( self::$ns, '/scannable-urls', [
            'methods'             => WP_REST_Server::READABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_scannable_urls' ],
        ]);

        // POST /wp-json/accessmate/v1/scan-page
        register_rest_route( self::$ns, '/scan-page', [
            'methods'             => WP_REST_Server::CREATABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_scan_page' ],
            'args'                => [
                'url' => [
                    'type'              => 'string',
                    'sanitize_callback' => 'esc_url_raw',
                    'required'          => true,
                ],
            ],
        ]);

        // GET /wp-json/accessmate/v1/page-scans
        register_rest_route( self::$ns, '/page-scans', [
            'methods'             => WP_REST_Server::READABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_page_scans' ],
        ]);

        // GET /wp-json/accessmate/v1/statement
        register_rest_route( self::$ns, '/statement', [
            'methods'             => WP_REST_Server::READABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_get_statement' ],
        ]);

        // POST /wp-json/accessmate/v1/statement
        register_rest_route( self::$ns, '/statement', [
            'methods'             => WP_REST_Server::CREATABLE,
            'permission_callback' => fn() => current_user_can( 'manage_options' ),
            'callback'            => [ self::class, 'handle_save_statement' ],
        ]);
    }

    public static function handle_scan( WP_REST_Request $request ): WP_REST_Response {
        $url = $request->get_param( 'url' );
        if ( empty( $url ) ) {
            $url = get_site_url();
        }

        if ( ! filter_var( $url, FILTER_VALIDATE_URL ) ) {
            return new WP_REST_Response( [ 'error' => __( 'Invalid URL provided.', 'accessmate' ) ], 400 );
        }

        if ( wp_parse_url( $url, PHP_URL_HOST ) !== wp_parse_url( home_url(), PHP_URL_HOST ) ) {
            return new WP_REST_Response( [ 'error' => __( 'URL must belong to this site.', 'accessmate' ) ], 400 );
        }

        $result = AccessMate_Scanner::run( $url );

        $status = isset( $result['error'] ) ? 422 : 200;
        return new WP_REST_Response( $result, $status );
    }

    public static function handle_issues( WP_REST_Request $request ): WP_REST_Response {
        $scan = get_option( 'accessmate_last_scan', [] );

        // Always return an array — never null.
        $issues = $scan['issues'] ?? [];

        return new WP_REST_Response( $issues, 200 );
    }

    public static function handle_report( WP_REST_Request $request ): WP_REST_Response {
        $report = AccessMate_Report::get();
        return new WP_REST_Response( $report, 200 );
    }

    public static function handle_get_settings( WP_REST_Request $request ): WP_REST_Response {
        return new WP_REST_Response( AccessMate_Settings::get(), 200 );
    }

    public static function handle_save_settings( WP_REST_Request $request ): WP_REST_Response {
        $provider       = $request->get_param( 'ai_provider' );
        $raw_key        = $request->get_param( 'ai_key' );
        $model          = $request->get_param( 'ai_model' );
        $schedule       = $request->get_param( 'scan_schedule' );
        $default_rulesets = array_map( 'sanitize_text_field', (array) $request->get_param( 'default_rulesets' ) );

        $valid_providers  = array_merge( [ 'none' ], array_keys( AccessMate_Providers::all() ) );
        $valid_schedules  = [ 'daily', 'weekly', 'monthly' ];

        if ( ! in_array( $provider, $valid_providers, true ) ) {
            return new WP_REST_Response( [ 'error' => __( 'Invalid provider.', 'accessmate' ) ], 400 );
        }
        if ( ! in_array( $schedule, $valid_schedules, true ) ) {
            return new WP_REST_Response( [ 'error' => __( 'Invalid schedule.', 'accessmate' ) ], 400 );
        }

        // Reject if a key-requiring provider is selected but no key is provided or stored.
        if ( $provider !== 'none' ) {
            $provider_def = AccessMate_Providers::get( $provider );
            if ( $provider_def && $provider_def['auth'] !== null ) {
                $current = get_option( 'accessmate_settings', [] );
                if ( empty( $raw_key ) && empty( $current['ai_key'] ) ) {
                    return new WP_REST_Response(
                        [ 'error' => __( 'An API key is required for the selected provider.', 'accessmate' ) ],
                        400
                    );
                }
            }
        }

        $old_schedule = AccessMate_Settings::get()['scan_schedule'] ?? 'weekly';
        AccessMate_Settings::save( $provider, $raw_key, $model, $schedule, $default_rulesets );

        // Reschedule cron if the scan frequency changed.
        if ( $schedule !== $old_schedule ) {
            AccessMate_Scheduler::reschedule( $schedule );
        }

        return new WP_REST_Response( [ 'saved' => true ], 200 );
    }

    public static function handle_scan_history( WP_REST_Request $request ): WP_REST_Response {
        return new WP_REST_Response( AccessMate_Report::get_history(), 200 );
    }

    public static function handle_get_widget_config( WP_REST_Request $request ): WP_REST_Response {
        $defaults = AccessMate_Widget_Injector::defaults();
        $config   = get_option( 'accessmate_widget_config', $defaults );
        return new WP_REST_Response( array_merge( $defaults, (array) $config ), 200 );
    }

    public static function handle_save_widget_config( WP_REST_Request $request ): WP_REST_Response {
        $allowed_features = [ 'font', 'contrast', 'dyslexia', 'grayscale', 'reading-guide', 'animations', 'line-height', 'cursor', 'links', 'screen-mask' ];

        $features = array_values( array_filter(
            array_map( 'sanitize_text_field', (array) $request->get_param( 'features' ) ),
            fn( $f ) => in_array( $f, $allowed_features, true )
        ));

        $valid_sizes = [ 'small', 'medium', 'large' ];
        $button_size = sanitize_text_field( $request->get_param( 'button_size' ) ?? 'medium' );
        if ( ! in_array( $button_size, $valid_sizes, true ) ) {
            $button_size = 'medium';
        }

        update_option( 'accessmate_widget_config', [
            'enabled'          => (bool) $request->get_param( 'enabled' ),
            'color'            => sanitize_hex_color( $request->get_param( 'color' ) ) ?? '#3858e9',
            'position'         => sanitize_text_field( $request->get_param( 'position' ) ),
            'button_size'      => $button_size,
            'features'         => $features,
            'hide_powered_by'  => (bool) $request->get_param( 'hide_powered_by' ),
        ]);

        return new WP_REST_Response( [ 'saved' => true ], 200 );
    }

    public static function handle_axe_scan( WP_REST_Request $request ): WP_REST_Response {
        $url        = $request->get_param( 'url' );
        $page_title = sanitize_text_field( (string) ( $request->get_param( 'page_title' ) ?? '' ) );
        $score      = (int) $request->get_param( 'score' );
        $grade      = $request->get_param( 'grade' );
        $passed     = (int) $request->get_param( 'passed' );
        $failed     = (int) $request->get_param( 'failed' );

        $rulesets = array_map( 'sanitize_text_field', (array) $request->get_param( 'rulesets' ) );
        $rulesets = array_values( array_unique( array_intersect( $rulesets, AccessMate_Settings::VALID_RULESETS ) ) );

        // Sanitise the issues array coming from the browser.
        $clean_issues = [];
        $allowed_severities = [ 'critical', 'serious', 'warning', 'notice' ];
        $allowed_categories = [ 'wcag', 'best-practice' ];
        foreach ( (array) $request->get_param( 'issues' ) as $iss ) {
            if ( ! is_array( $iss ) ) continue;
            $sev = sanitize_text_field( $iss['severity'] ?? 'notice' );
            $cat = sanitize_text_field( $iss['category'] ?? 'wcag' );
            // Validate help_url: must be a Deque University or W3C URL.
            $raw_help_url  = $iss['help_url'] ?? '';
            $allowed_hosts = [ 'dequeuniversity.com', 'www.w3.org', 'www.dequeuniversity.com' ];
            $parsed_host   = wp_parse_url( $raw_help_url, PHP_URL_HOST );
            $safe_help_url = in_array( $parsed_host, $allowed_hosts, true )
                ? esc_url_raw( $raw_help_url )
                : '';

            $clean_nodes = [];
            foreach ( (array) ( $iss['nodes'] ?? [] ) as $node ) {
                if ( ! is_array( $node ) ) continue;
                $clean_nodes[] = [
                    'element'  => self::sanitize_issue_text( $node['element']  ?? '' ),
                    'selector' => sanitize_text_field( $node['selector'] ?? '' ),
                ];
            }

            $clean_issues[] = [
                'id'            => sanitize_text_field( $iss['id']            ?? '' ),
                'rule'          => sanitize_text_field( $iss['rule']          ?? '' ),
                'wcag'          => sanitize_text_field( $iss['wcag']          ?? '' ),
                'wcag_level'    => sanitize_text_field( $iss['wcag_level']    ?? '' ),
                'wcag_standard' => sanitize_text_field( $iss['wcag_standard'] ?? '' ),
                'severity'      => in_array( $sev, $allowed_severities, true ) ? $sev : 'notice',
                'category'      => in_array( $cat, $allowed_categories, true ) ? $cat : 'wcag',
                'title'         => self::sanitize_issue_text( $iss['title']       ?? '' ),
                'description'   => self::sanitize_issue_text( $iss['description'] ?? '' ),
                'element'       => self::sanitize_issue_text( $iss['element']  ?? '' ),
                'selector'      => sanitize_text_field( $iss['selector']    ?? '' ),
                'nodes'         => $clean_nodes,
                'count'         => (int) ( $iss['count'] ?? 1 ),
                'fixed'         => false,
                'ai_fixable'    => (bool) ( $iss['ai_fixable'] ?? false ),
                'help_url'      => $safe_help_url,
            ];
        }

        // Sanitise the passed-check summaries coming from the browser.
        $allowed_help_hosts = [ 'dequeuniversity.com', 'www.w3.org', 'www.dequeuniversity.com' ];
        $clean_passed_checks = [];
        foreach ( (array) $request->get_param( 'passed_checks' ) as $chk ) {
            if ( ! is_array( $chk ) ) continue;
            $raw_help_url = $chk['help_url'] ?? '';
            $parsed_host  = wp_parse_url( $raw_help_url, PHP_URL_HOST );
            $clean_passed_checks[] = [
                'id'          => sanitize_text_field( $chk['id']          ?? '' ),
                'title'       => self::sanitize_issue_text( $chk['title']       ?? '' ),
                'description' => self::sanitize_issue_text( $chk['description'] ?? '' ),
                'help_url'    => in_array( $parsed_host, $allowed_help_hosts, true ) ? esc_url_raw( $raw_help_url ) : '',
                'count'       => (int) ( $chk['count'] ?? 0 ),
            ];
        }

        $result = [
            'url'           => $url,
            'page_title'    => $page_title,
            'scanned_at'    => current_time( 'c' ),
            'score'         => $score,
            'grade'         => $grade,
            'issues'        => $clean_issues,
            'passed'        => $passed,
            'failed'        => $failed,
            'rulesets'      => $rulesets,
            'passed_checks' => $clean_passed_checks,
        ];

        // Enforce free-tier page limit before persisting.
        if ( ! self::is_premium() ) {
            $existing      = AccessMate_Site_Scanner::get_page_scans();
            $scanned_urls  = array_column( array_values( $existing ), 'url' );
            $already_saved = in_array( $url, $scanned_urls, true );
            if ( ! $already_saved && count( $existing ) >= self::FREE_PAGE_LIMIT ) {
                return new WP_REST_Response(
                    [ 'error' => __( 'Free plan limit reached. Upgrade to Pro to scan unlimited pages.', 'accessmate' ), 'limit_reached' => true ],
                    403
                );
            }
        }

        // Persist as last scan (Dashboard) and per-page scan (PageScanner).
        update_option( 'accessmate_last_scan', $result );
        AccessMate_Site_Scanner::store_axe_scan( $url, $result );
        AccessMate_Scanner::append_history( $result );

        return new WP_REST_Response( [ 'saved' => true ], 200 );
    }

    public static function handle_scannable_urls( WP_REST_Request $request ): WP_REST_Response {
        $urls   = AccessMate_Site_Scanner::get_scannable_urls();
        $search = strtolower( trim( (string) $request->get_param( 'search' ) ) );
        if ( $search !== '' ) {
            $urls = array_values( array_filter( $urls, static function ( $item ) use ( $search ) {
                return strpos( strtolower( $item['label'] ), $search ) !== false
                    || strpos( strtolower( $item['url'] ),   $search ) !== false;
            } ) );
        }
        if ( ! self::is_premium() ) {
            $urls = array_slice( $urls, 0, self::FREE_PAGE_LIMIT );
        }
        return new WP_REST_Response( $urls, 200 );
    }

    public static function handle_scan_page( WP_REST_Request $request ): WP_REST_Response {
        $url = $request->get_param( 'url' );

        if ( ! filter_var( $url, FILTER_VALIDATE_URL ) ) {
            return new WP_REST_Response( [ 'error' => __( 'Invalid URL.', 'accessmate' ) ], 400 );
        }

        if ( wp_parse_url( $url, PHP_URL_HOST ) !== wp_parse_url( home_url(), PHP_URL_HOST ) ) {
            return new WP_REST_Response( [ 'error' => __( 'URL must belong to this site.', 'accessmate' ) ], 400 );
        }

        $result = AccessMate_Site_Scanner::scan_page( $url );
        $status = isset( $result['error'] ) ? 422 : 200;
        return new WP_REST_Response( $result, $status );
    }

    public static function handle_page_scans( WP_REST_Request $request ): WP_REST_Response {
        $scans  = AccessMate_Site_Scanner::get_page_scans(); // URL-keyed associative array
        $search = strtolower( trim( (string) $request->get_param( 'search' ) ) );
        if ( $search !== '' ) {
            $scans = array_filter( $scans, static function ( $scan ) use ( $search ) {
                return strpos( strtolower( $scan['url'] ?? '' ),   $search ) !== false
                    || strpos( strtolower( $scan['title'] ?? '' ), $search ) !== false;
            } );
        }
        // Sort by most issues first — preserve URL keys so response serialises as a JSON object.
        uasort( $scans, static fn( $a, $b ) => ( $b['failed'] ?? 0 ) <=> ( $a['failed'] ?? 0 ) );
        if ( ! self::is_premium() ) {
            $scans = array_slice( $scans, 0, self::FREE_PAGE_LIMIT, true ); // preserve_keys = true
        }
        return new WP_REST_Response( $scans, 200 );
    }

    public static function handle_ai_test( WP_REST_Request $request ): WP_REST_Response {
        $provider = $request->get_param( 'ai_provider' );
        $raw_key  = $request->get_param( 'ai_key' );
        $model    = $request->get_param( 'ai_model' );

        if ( ! AccessMate_Providers::is_valid( $provider ) ) {
            return new WP_REST_Response( [ 'error' => __( 'Invalid provider.', 'accessmate' ) ], 400 );
        }

        $result = AccessMate_AI_Proxy::test( $provider, $raw_key, $model );
        $status = isset( $result['error'] ) ? 400 : 200;
        return new WP_REST_Response( $result, $status );
    }

    public static function handle_ai_proxy( WP_REST_Request $request ): WP_REST_Response {
        $task   = $request->get_param( 'task' );
        $params = (array) ( $request->get_param( 'params' ) ?? [] );

        // Sanitise each param value — preserve HTML for fields that carry element snippets.
        foreach ( $params as $k => $v ) {
            if ( is_string( $v ) ) {
                $params[ $k ] = in_array( $k, [ 'html', 'element' ], true )
                    ? wp_kses_post( $v )
                    : sanitize_text_field( $v );
            }
        }

        $result = AccessMate_AI_Proxy::call( $task, $params );
        $status = isset( $result['error'] ) ? 400 : 200;
        return new WP_REST_Response( $result, $status );
    }

    private static function statement_defaults(): array {
        return [
            'status'      => 'none',
            'page_id'     => 0,
            'page_url'    => '',
            'edit_url'    => '',
            'updated_at'  => '',
            'basic_info'  => [ 'org_name' => '', 'website' => '', 'website_name' => '' ],
            'efforts'     => [ 'selected' => [], 'additional' => [] ],
            'conformance' => [ 'standard' => 'wcag21-aa', 'custom_standard' => '', 'level' => 'partially-conformant', 'additional_notes' => '' ],
            'tech_specs'  => [ 'browsers' => [ 'Chrome', 'Firefox', 'Safari', 'Edge' ], 'operating_systems' => [ 'Windows', 'macOS' ], 'assistive_tech' => [], 'technology_reliance' => [ 'HTML', 'CSS', 'JavaScript' ] ],
            'feedback'    => [ 'phone' => '', 'email' => '', 'address' => '', 'response_duration' => '2 business days' ],
        ];
    }

    public static function handle_get_statement( WP_REST_Request $request ): WP_REST_Response {
        $stored = get_option( 'accessmate_statement', [] );
        $data   = array_merge( self::statement_defaults(), (array) $stored );
        return new WP_REST_Response( $data, 200 );
    }

    public static function handle_save_statement( WP_REST_Request $request ): WP_REST_Response {
        $body = $request->get_json_params();
        if ( ! is_array( $body ) ) {
            return new WP_REST_Response( [ 'error' => __( 'Invalid request body.', 'accessmate' ) ], 400 );
        }

        $stored  = (array) get_option( 'accessmate_statement', self::statement_defaults() );
        $publish = ! empty( $body['publish'] );

        // Sanitise basic_info.
        $basic = (array) ( $body['basic_info'] ?? [] );
        $stored['basic_info'] = [
            'org_name'     => sanitize_text_field( $basic['org_name']     ?? '' ),
            'website'      => esc_url_raw( $basic['website']              ?? '' ),
            'website_name' => sanitize_text_field( $basic['website_name'] ?? '' ),
        ];

        // Sanitise efforts.
        $efforts = (array) ( $body['efforts'] ?? [] );
        $stored['efforts'] = [
            'selected'   => array_map( 'sanitize_text_field', (array) ( $efforts['selected']   ?? [] ) ),
            'additional' => array_map( 'sanitize_text_field', (array) ( $efforts['additional'] ?? [] ) ),
        ];

        // Sanitise conformance.
        $conformance = (array) ( $body['conformance'] ?? [] );
        $allowed_standards = [
            'wcag22-aa',
            'wcag21-aaa', 'wcag21-aa', 'wcag21-a',
            'wcag20-aaa', 'wcag20-aa', 'wcag20-a',
            'section508', 'other',
        ];
        $allowed_levels    = [ 'fully-conformant', 'partially-conformant', 'non-conformant', 'not-assessed' ];
        $std = sanitize_text_field( $conformance['standard'] ?? 'wcag21-aa' );
        $lvl = sanitize_text_field( $conformance['level']    ?? 'partially-conformant' );
        $stored['conformance'] = [
            'standard'         => in_array( $std, $allowed_standards, true ) ? $std : 'wcag21-aa',
            'custom_standard'  => sanitize_text_field( $conformance['custom_standard']  ?? '' ),
            'level'            => in_array( $lvl, $allowed_levels,    true ) ? $lvl : 'partially-conformant',
            'additional_notes' => sanitize_textarea_field( $conformance['additional_notes'] ?? '' ),
        ];

        // Sanitise tech_specs.
        $ts = (array) ( $body['tech_specs'] ?? [] );
        $stored['tech_specs'] = [
            'browsers'           => array_map( 'sanitize_text_field', (array) ( $ts['browsers']           ?? [] ) ),
            'operating_systems'  => array_map( 'sanitize_text_field', (array) ( $ts['operating_systems']  ?? [] ) ),
            'assistive_tech'     => array_map( 'sanitize_text_field', (array) ( $ts['assistive_tech']     ?? [] ) ),
            'technology_reliance'=> array_map( 'sanitize_text_field', (array) ( $ts['technology_reliance']?? [] ) ),
        ];

        // Sanitise feedback.
        $fb    = (array) ( $body['feedback'] ?? [] );
        $email = sanitize_email( $fb['email'] ?? '' );
        if ( empty( $email ) ) {
            return new WP_REST_Response(
                [ 'error' => __( 'A valid e-mail address is required in the Feedback section.', 'accessmate' ) ],
                400
            );
        }
        $stored['feedback'] = [
            'phone'             => preg_replace( '/[^0-9+\-() .]/', '', sanitize_text_field( $fb['phone'] ?? '' ) ),
            'email'             => $email,
            'address'           => sanitize_textarea_field( $fb['address']       ?? '' ),
            'response_duration' => sanitize_text_field( $fb['response_duration'] ?? '2 business days' ),
        ];

        if ( $publish ) {
            $page_content = self::generate_statement_html( $stored );
            $page_id      = (int) ( $stored['page_id'] ?? 0 );

            if ( $page_id > 0 && get_post( $page_id ) ) {
                wp_update_post( [
                    'ID'           => $page_id,
                    'post_content' => $page_content,
                    'post_status'  => 'publish',
                ] );
            } else {
                $page_id = wp_insert_post( [
                    'post_title'   => __( 'Accessibility Statement', 'accessmate' ),
                    'post_content' => $page_content,
                    'post_status'  => 'publish',
                    'post_type'    => 'page',
                ] );
            }

            if ( is_wp_error( $page_id ) ) {
                return new WP_REST_Response( [ 'error' => $page_id->get_error_message() ], 500 );
            }

            $stored['page_id']    = $page_id;
            $stored['page_url']   = get_permalink( $page_id );
            $stored['edit_url']   = get_edit_post_link( $page_id, 'raw' );
            $stored['status']     = 'published';
            $stored['updated_at'] = current_time( 'F j, Y' );
        }

        update_option( 'accessmate_statement', $stored );
        return new WP_REST_Response( $stored, 200 );
    }

    private static function generate_statement_html( array $data ): string {
        $org     = esc_html( $data['basic_info']['org_name']    ?? '' );
        $site    = esc_html( $data['basic_info']['website_name']?? '' );
        $website = esc_url( $data['basic_info']['website']      ?? '' );

        $std_labels = [
            'wcag22-aa'  => 'WCAG 2.2 Level AA',
            'wcag21-aaa' => 'WCAG 2.1 Level AAA',
            'wcag21-aa'  => 'WCAG 2.1 Level AA',
            'wcag21-a'   => 'WCAG 2.1 Level A',
            'wcag20-aaa' => 'WCAG 2.0 Level AAA',
            'wcag20-aa'  => 'WCAG 2.0 Level AA',
            'wcag20-a'   => 'WCAG 2.0 Level A',
            'section508' => 'Section 508',
        ];
        $conformance_standard = esc_html(
            $data['conformance']['standard'] === 'other'
                ? ( $data['conformance']['custom_standard'] ?? '' )
                : ( $std_labels[ $data['conformance']['standard'] ] ?? $data['conformance']['standard'] )
        );

        $level_labels = [
            'fully-conformant'     => 'Fully conformant',
            'partially-conformant' => 'Partially conformant',
            'non-conformant'       => 'Non conformant',
            'not-assessed'         => 'Not assessed',
        ];
        $conformance_level = esc_html( $level_labels[ $data['conformance']['level'] ] ?? $data['conformance']['level'] );

        // No leading heading here — the page template already renders the post title
        // (e.g. "Accessibility Statement"), so a duplicate heading here would repeat it.
        $html  = "<p>{$org} is committed to ensuring digital accessibility for people with disabilities. ";
        $html .= "We continually improve the user experience for everyone and apply the relevant accessibility standards.</p>\n";

        $html .= "<h3>Conformance Status</h3>\n";
        $html .= "<p>The Web Content Accessibility Guidelines (WCAG) define requirements for designers and developers to improve accessibility for people with disabilities. ";
        $html .= "It defines three levels of conformance: Level A, Level AA, and Level AAA. ";
        $html .= "<a href=\"{$website}\">{$site}</a> is <strong>{$conformance_level}</strong> with {$conformance_standard}.</p>\n";

        if ( ! empty( $data['conformance']['additional_notes'] ) ) {
            $html .= '<p>' . esc_html( $data['conformance']['additional_notes'] ) . "</p>\n";
        }

        $all_efforts = array_merge(
            (array) ( $data['efforts']['selected']   ?? [] ),
            (array) ( $data['efforts']['additional'] ?? [] )
        );
        if ( ! empty( $all_efforts ) ) {
            $html .= "<h3>Measures to Support Accessibility</h3>\n";
            $html .= "<p>{$org} takes the following measures to ensure accessibility:</p>\n<ul>\n";
            foreach ( $all_efforts as $effort ) {
                $html .= '<li>' . esc_html( $effort ) . "</li>\n";
            }
            $html .= "</ul>\n";
        }

        $ts = $data['tech_specs'] ?? [];
        $tech_sections = [
            'Compatible browsers'              => $ts['browsers']            ?? [],
            'Compatible operating systems'     => $ts['operating_systems']   ?? [],
            'Compatible assistive technologies'=> $ts['assistive_tech']      ?? [],
            'Technology reliance'              => $ts['technology_reliance'] ?? [],
        ];
        $has_tech = array_filter( $tech_sections );
        if ( ! empty( $has_tech ) ) {
            $html .= "<h3>Technical Specifications</h3>\n";
            $html .= "<p>Accessibility relies on the following technologies to work with the particular combination of web browser and any assistive technologies or plugins installed on your computer:</p>\n";
            foreach ( $tech_sections as $label => $items ) {
                if ( empty( $items ) ) continue;
                $html .= '<p><strong>' . esc_html( $label ) . ':</strong> ' . esc_html( implode( ', ', $items ) ) . "</p>\n";
            }
        }

        $fb = $data['feedback'] ?? [];
        $html .= "<h3>Feedback</h3>\n";
        $html .= "<p>We welcome your feedback on the accessibility of {$site}. Please let us know if you experience accessibility barriers.</p>\n";
        if ( ! empty( $fb['phone'] ) )   $html .= '<p>Phone: ' . esc_html( $fb['phone'] ) . "</p>\n";
        if ( ! empty( $fb['email'] ) )   $html .= '<p>E-mail: <a href="mailto:' . esc_attr( $fb['email'] ) . '">' . esc_html( $fb['email'] ) . "</a></p>\n";
        if ( ! empty( $fb['address'] ) ) $html .= '<p>Postal address: ' . nl2br( esc_html( $fb['address'] ) ) . "</p>\n";
        if ( ! empty( $fb['response_duration'] ) ) {
            $html .= '<p>We try to respond to feedback within ' . esc_html( $fb['response_duration'] ) . ".</p>\n";
        }

        return $html;
    }
}