<?php
/**
 * Settings class.
 *
 * @package SpeedNest
 */

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

/**
 * Class WPSCO_Settings
 *
 * Handles options registration, sanitization, presets, import/export, and safe mode.
 */
class WPSCO_Settings {

    /**
     * Option name.
     */
    const OPTION_NAME = 'wpsco_settings';

    /**
     * Constructor.
     */
    public function __construct() {
        add_action( 'admin_init', array( $this, 'register_settings' ) );
    }

    /**
     * Register settings in WordPress.
     */
    public function register_settings() {
        register_setting(
            'wpsco_settings_group',
            self::OPTION_NAME,
            array(
                'type'              => 'array',
                'sanitize_callback' => array( $this, 'sanitize_settings' ),
                'default'           => wpsco_get_default_settings(),
            )
        );
    }

    /**
     * Sanitize settings on save.
     *
     * @param array $input Raw input.
     * @return array
     */
    public function sanitize_settings( $input ) {
        if ( ! is_array( $input ) ) {
            return wpsco_get_default_settings();
        }

        $defaults = wpsco_get_default_settings();
        $clean    = array();

        foreach ( $defaults as $key => $default_val ) {
            if ( ! isset( $input[ $key ] ) ) {
                if ( is_bool( $default_val ) ) {
                    // Checkboxes not sent in POST are false.
                    $clean[ $key ] = false;
                } else {
                    $clean[ $key ] = $default_val;
                }
                continue;
            }

            $val = $input[ $key ];

            if ( is_bool( $default_val ) ) {
                $clean[ $key ] = (bool) $val;
            } elseif ( is_int( $default_val ) ) {
                $clean[ $key ] = (int) $val;
            } elseif ( is_float( $default_val ) ) {
                $clean[ $key ] = (float) $val;
            } elseif ( is_array( $default_val ) ) {
                if ( is_array( $val ) ) {
                    $clean[ $key ] = array_map( 'sanitize_text_field', $val );
                } elseif ( is_string( $val ) ) {
                    // Line-separated textarea.
                    $lines = explode( "\n", str_replace( "\r", '', $val ) );
                    $clean[ $key ] = array_values( array_filter( array_map( 'sanitize_text_field', array_map( 'trim', $lines ) ) ) );
                } else {
                    $clean[ $key ] = $default_val;
                }
            } else {
                $clean[ $key ] = sanitize_text_field( $val );
            }
        }

        // Increment cache version whenever settings change.
        wpsco_increment_cache_version();

        // Trigger cache purge for generated CSS/JS/HTML.
        $plugin = WPSCO_Plugin::get_instance();
        $purger = $plugin ? $plugin->get_module( 'cache_purger' ) : null;
        if ( $purger ) {
            $purger->purge_all();
        }

        wpsco_log( 'Settings saved and caches invalidated.' );

        return $clean;
    }

    /**
     * Apply Safe Mode preset.
     *
     * @return bool
     */
    public static function apply_safe_mode() {
        $settings = wpsco_get_setting();

        // Safe mode configuration:
        $settings['safe_mode']               = true;
        $settings['page_cache_enabled']      = true;
        $settings['css_minify']              = true;
        $settings['css_combine']             = false; // Keep false to avoid breaking layouts
        $settings['css_critical']            = false;
        $settings['css_remove_unused']       = false; // Never automatically remove selectors
        $settings['js_minify']               = false; // Keep false / safe in-memory
        $settings['js_combine']              = false; // Avoid JS ordering conflicts
        $settings['js_defer']                = false;
        $settings['js_delay']                = false;
        $settings['html_minify']             = true;
        $settings['lazy_load_images']        = true;
        $settings['lazy_load_iframes']       = true;
        $settings['add_missing_dimensions']  = true;
        $settings['font_display_swap']       = true;
        $settings['google_fonts_local']      = false; // Strictly opt-in to prevent external calls (Guideline 7)
        $settings['disable_emojis']          = true;
        $settings['remove_wp_version']       = true;

        $updated = update_option( self::OPTION_NAME, $settings );
        wpsco_increment_cache_version();

        return $updated;
    }

    /**
     * Apply One-Click Safe Optimization Wizard preset.
     *
     * @return bool
     */
    public static function apply_one_click_safe_optimization() {
        $settings = wpsco_get_setting();

        $settings['safe_mode']               = true;
        $settings['page_cache_enabled']      = true;
        $settings['page_cache_ttl']          = 3600;
        $settings['css_minify']              = true;
        $settings['css_combine']             = false;
        $settings['css_async']               = true; // Asynchronous non-blocking CSS delivery
        $settings['js_minify']               = false; // Safe in-memory optimization only when explicitly toggled
        $settings['js_defer']                = true;
        $settings['js_delay']                = true; // Eliminates TBT on mobile
        $settings['js_delay_timeout']        = 3;
        $settings['js_delay_trigger']        = 'interaction';
        $settings['html_minify']             = true;
        $settings['lazy_load_images']        = true;
        $settings['lazy_load_iframes']       = true;
        $settings['lazy_load_youtube']       = true;
        $settings['add_missing_dimensions']  = true; // Eliminates CLS
        $settings['lcp_image_preload']       = true; // Optimizes LCP
        $settings['webp_conversion']         = true; // Next-gen image format
        $settings['image_compression']       = true; // Lossless compression
        $settings['font_display_swap']       = true; // Eliminates FOIT
        $settings['google_fonts_local']      = false; // Disabled by default to prevent automatic external requests (Guideline 7)
        $settings['disable_emojis']          = true;
        $settings['disable_embeds']          = true;
        $settings['remove_wp_version']       = true;
        $settings['delay_analytics']         = true;
        $settings['delay_gtm']               = true;
        $settings['delay_facebook_pixel']    = true;
        $settings['delay_clarity']           = true;
        $settings['browser_cache_htaccess']  = true;
        $settings['compression_htaccess']    = true;

        $updated = update_option( self::OPTION_NAME, $settings );
        wpsco_increment_cache_version();

        return $updated;
    }

    /**
     * Reset settings to default.
     *
     * @return bool
     */
    public static function reset_to_defaults() {
        $defaults = wpsco_get_default_settings();
        $updated  = update_option( self::OPTION_NAME, $defaults );
        wpsco_increment_cache_version();

        $plugin = WPSCO_Plugin::get_instance();
        $purger = $plugin ? $plugin->get_module( 'cache_purger' ) : null;
        if ( $purger ) {
            $purger->purge_everything();
        }

        return $updated;
    }

    /**
     * Export settings as JSON string.
     *
     * @return string
     */
    public static function export_json() {
        $settings = wpsco_get_setting();
        // Redact secret API keys on export.
        $export = $settings;
        $export['cloudflare_api_token'] = '';
        $export['cdn_api_key']          = '';
        $export['export_version']       = WPSCO_VERSION;
        $export['exported_at']          = gmdate( 'Y-m-d H:i:s' );

        return wp_json_encode( $export, JSON_PRETTY_PRINT );
    }

    /**
     * Import settings from JSON string.
     *
     * @param string $json JSON payload.
     * @return bool|WP_Error
     */
    public static function import_json( $json ) {
        $data = json_decode( $json, true );
        if ( ! is_array( $data ) ) {
            return new WP_Error( 'invalid_json', __( 'Invalid JSON format for settings import.', 'speednest' ) );
        }

        unset( $data['export_version'], $data['exported_at'] );

        $defaults = wpsco_get_default_settings();
        $merged   = wp_parse_args( $data, $defaults );

        // Sanitize before saving.
        $sanitizer = new self();
        $clean     = $sanitizer->sanitize_settings( $merged );

        update_option( self::OPTION_NAME, $clean );
        wpsco_increment_cache_version();

        return true;
    }
}