<?php
if (!defined('ABSPATH')) { exit; }

/** Local, privacy-conscious request activity for AEOHelper endpoints. */
final class Zire_AI_Activity {
    const CLEANUP_HOOK = 'zire_ai_cleanup_activity';
    const DB_VERSION = '1';

    public static function table(): string {
        global $wpdb;
        return $wpdb->prefix . 'zire_ai_requests';
    }

    public static function install(): void {
        global $wpdb;
        require_once ABSPATH . 'wp-admin/includes/upgrade.php';
        $table = self::table();
        $charset = $wpdb->get_charset_collate();
        dbDelta("CREATE TABLE {$table} (
            id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
            requested_at datetime NOT NULL,
            endpoint varchar(20) NOT NULL,
            post_id bigint(20) unsigned NOT NULL DEFAULT 0,
            request_method varchar(8) NOT NULL,
            response_status smallint(5) unsigned NOT NULL,
            agent_label varchar(40) NOT NULL,
            PRIMARY KEY  (id),
            KEY requested_at (requested_at),
            KEY post_id (post_id),
            KEY endpoint (endpoint),
            KEY agent_label (agent_label)
        ) {$charset};");
        if (!wp_next_scheduled(self::CLEANUP_HOOK)) {
            wp_schedule_event(time() + HOUR_IN_SECONDS, 'daily', self::CLEANUP_HOOK);
        }
        update_option('zire_ai_activity_db_version', self::DB_VERSION, false);
    }

    public static function boot(): void {
        add_action('plugins_loaded', [__CLASS__, 'maybe_install'], 20);
        add_action(self::CLEANUP_HOOK, [__CLASS__, 'cleanup']);
    }

    public static function maybe_install(): void {
        if (get_option('zire_ai_activity_db_version') !== self::DB_VERSION) { self::install(); }
    }

    public static function log(string $endpoint, int $post_id, string $method, int $status): void {
        $settings = Zire_AI_Plugin::settings();
        if (empty($settings['logging']) || is_user_logged_in() || isset($_GET['zire_ai_download'])) { return; }
        if (!in_array($endpoint, ['markdown', 'llms.txt'], true)) { return; }
        // Do not let arbitrary query-string IDs create rows. The log is an
        // operational signal, not a record of hostile endpoint enumeration.
        if ($endpoint === 'markdown' && ($post_id < 1 || !get_post($post_id))) { return; }
        $method = strtoupper($method);
        $method = in_array($method, ['GET', 'HEAD'], true) ? $method : 'OTHER';
        $agent = self::agent_label( sanitize_text_field( wp_unslash( (string) ( $_SERVER['HTTP_USER_AGENT'] ?? '' ) ) ) );
        // Collapse identical activity into 15-minute observations. This keeps
        // a public endpoint from growing the database on every repeat request
        // without storing an IP address or raw user-agent.
        $bucket = (int) floor(time() / (15 * MINUTE_IN_SECONDS));
        $key = 'zire_ai_seen_' . md5(implode('|', [$endpoint, $post_id, $method, $status, $agent, $bucket]));
        if (get_transient($key)) { return; }
        set_transient($key, 1, 16 * MINUTE_IN_SECONDS);
        global $wpdb;
        $wpdb->insert(self::table(), [
            'requested_at' => current_time('mysql', true),
            'endpoint' => $endpoint,
            'post_id' => max(0, $post_id),
            'request_method' => $method,
            'response_status' => max(100, min(599, $status)),
            'agent_label' => $agent,
        ], ['%s', '%s', '%d', '%s', '%d', '%s']);
        self::maintain_size();
    }

    public static function agent_label(string $user_agent): string {
        $agents = [
            'OAI-SearchBot' => 'OAI-SearchBot',
            'ChatGPT-User' => 'ChatGPT-User',
            'GPTBot' => 'GPTBot',
            'Claude-SearchBot' => 'Claude-SearchBot',
            'Claude-User' => 'Claude-User',
            'ClaudeBot' => 'ClaudeBot',
            'PerplexityBot' => 'PerplexityBot',
            'Google-Extended' => 'Google-Extended',
            'Googlebot' => 'Googlebot',
            'Bingbot' => 'Bingbot',
            'Applebot-Extended' => 'Applebot-Extended',
            'Applebot' => 'Applebot',
            'Amazonbot' => 'Amazonbot',
            'Bytespider' => 'Bytespider',
            'CCBot' => 'CCBot',
        ];
        foreach ($agents as $needle => $label) {
            if (stripos($user_agent, $needle) !== false) { return $label; }
        }
        return preg_match('/bot|crawler|spider|slurp|fetch/i', $user_agent) ? 'Other crawler' : 'Browser / other';
    }

    public static function cleanup(): void {
        global $wpdb;
        $days = self::retention_days();
        $cutoff = gmdate('Y-m-d H:i:s', time() - ($days * DAY_IN_SECONDS));
        $wpdb->query(
            $wpdb->prepare(
                'DELETE FROM %i WHERE requested_at < %s',
                self::table(),
                $cutoff
            )
        );
    }

    public static function clear(): void {
        global $wpdb;
        $wpdb->query(
            $wpdb->prepare(
                'DELETE FROM %i',
                self::table()
            )
        );
    }

    private static function maintain_size(): void {
        if (get_transient('zire_ai_activity_maintenance')) { return; }
        set_transient('zire_ai_activity_maintenance', 1, HOUR_IN_SECONDS);
        self::cleanup();
        global $wpdb;
        $table = self::table();
        $cutoff_id = (int) $wpdb->get_var(
            $wpdb->prepare(
                'SELECT id FROM %i ORDER BY id DESC LIMIT 1 OFFSET 10000',
                $table
            )
        );
        if ($cutoff_id > 0) {
            $wpdb->query(
                $wpdb->prepare(
                    'DELETE FROM %i WHERE id <= %d',
                    $table,
                    $cutoff_id
                )
            );
        }
    }

    public static function retention_days(): int {
        $days = (int) (Zire_AI_Plugin::settings()['retention'] ?? 30);
        return in_array($days, [7, 30, 90], true) ? $days : 30;
    }

    public static function count_since(int $days): int {
        global $wpdb;
        $cutoff = gmdate('Y-m-d H:i:s', time() - ($days * DAY_IN_SECONDS));
        return (int) $wpdb->get_var(
            $wpdb->prepare(
                'SELECT COUNT(*) FROM %i WHERE requested_at >= %s',
                self::table(),
                $cutoff
            )
        );
    }

    public static function last_request(): string {
        global $wpdb;
        return (string) $wpdb->get_var(
            $wpdb->prepare(
                'SELECT MAX(requested_at) FROM %i',
                self::table()
            )
        );
    }

    public static function last_for_page(int $post_id): string {
        global $wpdb;
        return (string) $wpdb->get_var(
            $wpdb->prepare(
                'SELECT MAX(requested_at) FROM %i WHERE post_id = %d AND endpoint = %s',
                self::table(),
                $post_id,
                'markdown'
            )
        );
    }

    public static function recent(int $limit = 100, string $endpoint = '', string $agent = ''): array {
        global $wpdb;
        $limit = max(1, min(250, $limit));
        $table = self::table();
        if (in_array($endpoint, ['markdown', 'llms.txt'], true) && $agent !== '') {
            return (array) $wpdb->get_results(
                $wpdb->prepare(
                    'SELECT * FROM %i WHERE endpoint = %s AND agent_label = %s ORDER BY requested_at DESC, id DESC LIMIT %d',
                    $table,
                    $endpoint,
                    substr($agent, 0, 40),
                    $limit
                ),
                ARRAY_A
            );
        }
        if (in_array($endpoint, ['markdown', 'llms.txt'], true)) {
            return (array) $wpdb->get_results(
                $wpdb->prepare(
                    'SELECT * FROM %i WHERE endpoint = %s ORDER BY requested_at DESC, id DESC LIMIT %d',
                    $table,
                    $endpoint,
                    $limit
                ),
                ARRAY_A
            );
        }
        if ($agent !== '') {
            return (array) $wpdb->get_results(
                $wpdb->prepare(
                    'SELECT * FROM %i WHERE agent_label = %s ORDER BY requested_at DESC, id DESC LIMIT %d',
                    $table,
                    substr($agent, 0, 40),
                    $limit
                ),
                ARRAY_A
            );
        }
        return (array) $wpdb->get_results(
            $wpdb->prepare(
                'SELECT * FROM %i ORDER BY requested_at DESC, id DESC LIMIT %d',
                $table,
                $limit
            ),
            ARRAY_A
        );
    }

    public static function top_pages(int $days = 30, int $limit = 5): array {
        global $wpdb;
        $cutoff = gmdate('Y-m-d H:i:s', time() - ($days * DAY_IN_SECONDS));
        $limit = max(1, min(20, $limit));
        return (array) $wpdb->get_results(
            $wpdb->prepare(
                'SELECT post_id, COUNT(*) AS requests, MAX(requested_at) AS last_request FROM %i WHERE endpoint = %s AND post_id > 0 AND requested_at >= %s GROUP BY post_id ORDER BY requests DESC, last_request DESC LIMIT %d',
                self::table(),
                'markdown',
                $cutoff,
                $limit
            ),
            ARRAY_A
        );
    }
}