<?php
/**
 * Cache Manager class.
 *
 * @package SpeedNest
 */

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

/**
 * Class WPSCO_Cache_Manager
 *
 * Manages all cache operations and provides cache status information.
 */
class WPSCO_Cache_Manager {

    /**
     * Constructor.
     */
    public function __construct() {
        // No hooks needed — this is a utility class.
    }

    /**
     * Get cache status for all layers.
     *
     * @return array
     */
    public function get_cache_status() {
        $status = array();

        $base_dir = function_exists( 'wpsco_get_cache_dir' ) ? wpsco_get_cache_dir() : ( defined( 'WPSCO_CACHE_DIR' ) ? WPSCO_CACHE_DIR : '' );

        // Plugin generated cache.
        $status['plugin_cache'] = array(
            'name'      => __( 'WP Speed Cache', 'speednest' ),
            'enabled'   => true,
            'size'      => wpsco_get_dir_size( $base_dir ),
            'size_text' => wpsco_format_size( wpsco_get_dir_size( $base_dir ) ),
            'clearable' => true,
        );

        // CSS cache.
        $css_dir = $base_dir . 'css/';
        $status['css_cache'] = array(
            'name'      => __( 'CSS Cache', 'speednest' ),
            'enabled'   => wpsco_get_setting( 'css_minify', false ) || wpsco_get_setting( 'css_combine', false ),
            'size'      => wpsco_get_dir_size( $css_dir ),
            'size_text' => wpsco_format_size( wpsco_get_dir_size( $css_dir ) ),
            'clearable' => true,
        );

        // JS cache.
        $js_dir = $base_dir . 'js/';
        $status['js_cache'] = array(
            'name'      => __( 'JS Cache', 'speednest' ),
            'enabled'   => wpsco_get_setting( 'js_minify', false ) || wpsco_get_setting( 'js_combine', false ),
            'size'      => wpsco_get_dir_size( $js_dir ),
            'size_text' => wpsco_format_size( wpsco_get_dir_size( $js_dir ) ),
            'clearable' => true,
        );

        // HTML cache.
        $html_dir = $base_dir . 'html/';
        $status['html_cache'] = array(
            'name'      => __( 'HTML Cache', 'speednest' ),
            'enabled'   => wpsco_get_setting( 'page_cache_enabled', false ),
            'size'      => wpsco_get_dir_size( $html_dir ),
            'size_text' => wpsco_format_size( wpsco_get_dir_size( $html_dir ) ),
            'clearable' => true,
        );

        // Critical CSS.
        $ccss_dir = $base_dir . 'critical-css/';
        $status['critical_css'] = array(
            'name'      => __( 'Critical CSS', 'speednest' ),
            'enabled'   => wpsco_get_setting( 'css_critical', false ),
            'size'      => wpsco_get_dir_size( $ccss_dir ),
            'size_text' => wpsco_format_size( wpsco_get_dir_size( $ccss_dir ) ),
            'clearable' => true,
        );

        // WordPress Object Cache.
        $status['object_cache'] = array(
            'name'      => __( 'WordPress Object Cache', 'speednest' ),
            'enabled'   => wp_using_ext_object_cache(),
            'type'      => $this->detect_object_cache_type(),
            'clearable' => true,
        );

        // Transients.
        $status['transients'] = array(
            'name'      => __( 'Transients', 'speednest' ),
            'enabled'   => true,
            'count'     => $this->count_transients(),
            'clearable' => true,
        );

        // OPcache.
        $opcache             = wpsco_get_opcache_status();
        $status['opcache']   = array(
            'name'      => __( 'PHP OPcache', 'speednest' ),
            'enabled'   => $opcache['enabled'],
            'available' => $opcache['available'],
            'can_reset' => $opcache['can_reset'],
            'memory'    => $opcache['memory_usage'],
            'reason'    => $opcache['reason'],
            'clearable' => $opcache['can_reset'],
        );

        // Server cache.
        $server_type                = wpsco_get_server_type();
        $status['server_cache']     = array(
            'name'      => __( 'Server Cache', 'speednest' ),
            'server'    => $server_type,
            'clearable' => in_array( $server_type, array( 'litespeed', 'openlitespeed' ), true ),
            'reason'    => $this->get_server_cache_reason( $server_type ),
        );

        // Cloudflare.
        $status['cloudflare'] = array(
            'name'       => __( 'Cloudflare', 'speednest' ),
            'enabled'    => wpsco_get_setting( 'cloudflare_enabled', false ),
            'configured' => ! empty( wpsco_get_setting( 'cloudflare_api_token', '' ) ) && ! empty( wpsco_get_setting( 'cloudflare_zone_id', '' ) ),
            'clearable'  => wpsco_get_setting( 'cloudflare_enabled', false ),
        );

        // CDN.
        $status['cdn'] = array(
            'name'       => __( 'CDN', 'speednest' ),
            'enabled'    => wpsco_get_setting( 'cdn_enabled', false ),
            'url'        => wpsco_get_setting( 'cdn_url', '' ),
            'clearable'  => ! empty( wpsco_get_setting( 'cdn_purge_endpoint', '' ) ),
        );

        // Browser cache.
        $status['browser_cache'] = array(
            'name'      => __( 'Browser Cache', 'speednest' ),
            'enabled'   => true,
            'note'      => __( 'Browser cache cannot be cleared from the server. Asset versioning and cache-busting URLs ensure visitors receive the latest files.', 'speednest' ),
            'clearable' => false,
        );

        return $status;
    }

    /**
     * Detect object cache type.
     *
     * @return string
     */
    public function detect_object_cache_type() {
        if ( ! wp_using_ext_object_cache() ) {
            return 'default';
        }

        // Check for Redis.
        if ( class_exists( 'Redis' ) || class_exists( 'Predis\\Client' ) || defined( 'WP_REDIS_DISABLED' ) ) {
            return 'redis';
        }

        // Check for Memcached.
        if ( class_exists( 'Memcached' ) || class_exists( 'Memcache' ) ) {
            return 'memcached';
        }

        return 'external';
    }

    /**
     * Count transients.
     *
     * @return array
     */
    public function count_transients() {
        global $wpdb;

        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Direct database query required to count total transients in options table.
        $total = (int) $wpdb->get_var(
            "SELECT COUNT(*) FROM {$wpdb->options} WHERE option_name LIKE '_transient_%' AND option_name NOT LIKE '_transient_timeout_%'"
        );

        // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Direct database query required to count expired transients in options table.
        $expired = (int) $wpdb->get_var(
            $wpdb->prepare(
                "SELECT COUNT(*) FROM {$wpdb->options} a
                INNER JOIN {$wpdb->options} b ON b.option_name = CONCAT('_transient_timeout_', SUBSTRING(a.option_name, 12))
                WHERE a.option_name LIKE %s AND a.option_name NOT LIKE %s AND b.option_value < %d",
                $wpdb->esc_like( '_transient_' ) . '%',
                $wpdb->esc_like( '_transient_timeout_' ) . '%',
                time()
            )
        );

        return array(
            'total'   => $total,
            'expired' => $expired,
        );
    }

    /**
     * Get server cache reason.
     *
     * @param string $server_type Server type.
     * @return string
     */
    private function get_server_cache_reason( $server_type ) {
        switch ( $server_type ) {
            case 'litespeed':
            case 'openlitespeed':
                return __( 'LiteSpeed server cache can be purged via server headers.', 'speednest' );
            case 'nginx':
                return __( 'NGINX FastCGI cache cannot be purged from WordPress. Please purge from your server or hosting control panel.', 'speednest' );
            case 'apache':
                return __( 'Apache does not provide a server-level page cache purge API.', 'speednest' );
            default:
                return __( 'Server type could not be determined.', 'speednest' );
        }
    }

    /**
     * Get cache layer visualization data.
     *
     * @return array
     */
    public function get_cache_layers() {
        return array(
            array(
                'name'   => __( 'Visitor Browser', 'speednest' ),
                'icon'   => 'dashicons-desktop',
                'status' => __( 'Asset versioning active', 'speednest' ),
                'type'   => 'browser',
            ),
            array(
                'name'   => __( 'Cloudflare / CDN', 'speednest' ),
                'icon'   => 'dashicons-cloud',
                'status' => wpsco_get_setting( 'cloudflare_enabled', false )
                    ? __( 'Connected', 'speednest' )
                    : __( 'Not configured', 'speednest' ),
                'type'   => 'cdn',
            ),
            array(
                'name'   => __( 'Server Cache', 'speednest' ),
                'icon'   => 'dashicons-admin-generic',
                'status' => ucfirst( wpsco_get_server_type() ),
                'type'   => 'server',
            ),
            array(
                'name'   => __( 'WordPress Page Cache', 'speednest' ),
                'icon'   => 'dashicons-media-document',
                'status' => wpsco_get_setting( 'page_cache_enabled', false )
                    ? __( 'Active', 'speednest' )
                    : __( 'Disabled', 'speednest' ),
                'type'   => 'page',
            ),
            array(
                'name'   => __( 'Object Cache', 'speednest' ),
                'icon'   => 'dashicons-database',
                'status' => wp_using_ext_object_cache()
                    ? sprintf( '%s (%s)', __( 'Active', 'speednest' ), $this->detect_object_cache_type() )
                    : __( 'Default', 'speednest' ),
                'type'   => 'object',
            ),
            array(
                'name'   => __( 'PHP OPcache', 'speednest' ),
                'icon'   => 'dashicons-editor-code',
                'status' => wpsco_get_opcache_status()['enabled']
                    ? __( 'Enabled', 'speednest' )
                    : __( 'Disabled', 'speednest' ),
                'type'   => 'opcache',
            ),
            array(
                'name'   => __( 'WordPress', 'speednest' ),
                'icon'   => 'dashicons-wordpress-alt',
                'status' => __( 'Application', 'speednest' ),
                'type'   => 'wordpress',
            ),
        );
    }
}