<?php
namespace Clusterlane\Core;

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

/**
 * Multisite
 *
 * Network lifecycle + URL scoping for WordPress multisite.
 *
 * Lifecycle
 *   - Network activation installs tables + capabilities on existing sites
 *     (up to NETWORK_ACTIVATE_LIMIT immediately; the rest self-install on
 *     their first request via Installer::maybe_upgrade() /
 *     Capabilities::maybe_install(), which run on every boot).
 *   - New sites get tables + caps as soon as they're created, if Clusterlane
 *     is network-active.
 *   - Deleting a site drops that site's Clusterlane tables.
 *
 * URL scoping
 *   On a subdirectory network every site shares one host, so
 *   https://example.com/site-b/post looked "internal" from the main site
 *   (it starts with home_url()) and the slug fallback could map it onto an
 *   unrelated local post with the same slug. is_internal_url() excludes
 *   URLs that belong to another site on the same domain.
 *
 * On single-site installs every method behaves exactly as before.
 */
final class Multisite {

    /** Sites installed synchronously on network activation. */
    const NETWORK_ACTIVATE_LIMIT = 100;

    /** Table names without prefix — must match Installer / uninstall.php. */
    const TABLES = [
        'clusterlane_links', 'clusterlane_clusters', 'clusterlane_post_metrics', 'clusterlane_ai_cache',
        'clusterlane_custom_members', 'clusterlane_tms_skipped', 'clusterlane_cluster_post_class',
        'clusterlane_snapshots', 'clusterlane_activity',
    ];

    /* ------------------------------------------------------------------
       Lifecycle
    ------------------------------------------------------------------ */

    public static function register_hooks(): void {
        if ( ! is_multisite() ) return;
        // Priority 900: after core has created the site's tables and roles.
        add_action( 'wp_initialize_site', [ self::class, 'on_new_site' ], 900 );
        add_filter( 'wpmu_drop_tables',   [ self::class, 'drop_tables' ], 10, 2 );
    }

    public static function is_network_active(): bool {
        if ( ! is_multisite() ) return false;
        $plugins = (array) get_site_option( 'active_sitewide_plugins', [] );
        return isset( $plugins[ plugin_basename( CLUSTERLANE_FILE ) ] );
    }

    /** Activation hook handler — $network_wide comes from WordPress. */
    public static function activate( bool $network_wide ): void {
        require_once __DIR__ . '/class-installer.php';

        if ( ! is_multisite() || ! $network_wide ) {
            Installer::activate();
            return;
        }

        $site_ids = get_sites( [
            'fields'   => 'ids',
            'number'   => self::NETWORK_ACTIVATE_LIMIT,
            'archived' => 0,
            'deleted'  => 0,
            'spam'     => 0,
        ] );
        foreach ( $site_ids as $site_id ) {
            switch_to_blog( (int) $site_id );
            Installer::activate();
            restore_current_blog();
        }
    }

    /**
     * Deactivation hook handler. Network deactivation used to unschedule the
     * daily snapshot on the main site only — the other sites kept the event
     * until uninstall (0.98.175). Data is kept either way.
     */
    public static function deactivate( bool $network_wide ): void {
        require_once __DIR__ . '/class-installer.php';

        if ( ! is_multisite() || ! $network_wide ) {
            Installer::deactivate();
            return;
        }

        foreach ( get_sites( [ 'fields' => 'ids', 'number' => 0 ] ) as $site_id ) {
            switch_to_blog( (int) $site_id );
            Installer::deactivate();
            restore_current_blog();
        }
    }

    public static function on_new_site( \WP_Site $site ): void {
        if ( ! self::is_network_active() ) return;
        require_once __DIR__ . '/class-installer.php';
        switch_to_blog( (int) $site->blog_id );
        Installer::activate();
        restore_current_blog();
    }

    /**
     * @param string[] $tables
     * @return string[]
     */
    public static function drop_tables( array $tables, int $site_id ): array {
        global $wpdb;
        $prefix = $wpdb->get_blog_prefix( $site_id );
        foreach ( self::TABLES as $bare ) {
            $tables[] = $prefix . $bare;
        }
        return $tables;
    }

    /* ------------------------------------------------------------------
       URL scoping
    ------------------------------------------------------------------ */

    /**
     * True if $url points at the current site.
     * Single-site / subdomain networks: unchanged behaviour (starts with
     * home_url(), or is root-relative).
     */
    public static function is_internal_url( string $url ): bool {
        $url      = self::normalize_url( $url );
        if ( strpos( $url, '//' ) === 0 ) return false; // protocol-relative to another host (ours was rewritten above)
        $internal = strpos( $url, home_url() ) === 0 || strpos( $url, '/' ) === 0;
        if ( ! $internal ) return false;
        if ( ! is_multisite() || is_subdomain_install() ) return true;

        $path = strpos( $url, '/' ) === 0 ? $url : (string) wp_parse_url( $url, PHP_URL_PATH );
        $path = trailingslashit( '/' . ltrim( (string) strtok( $path, '?#' ), '/' ) );
        $own  = self::current_site_path();

        // Root-relative link on a sub-site that doesn't include our own path
        // points at the main site (or another sub-site), not at us.
        if ( $own !== '/' && strpos( $path, $own ) !== 0 ) return false;

        // Deeper path owned by another site on this domain (e.g. /site-b/).
        foreach ( self::other_site_paths() as $other ) {
            if ( strlen( $other ) > strlen( $own ) && strpos( $path, $other ) === 0 ) {
                return false;
            }
        }
        return true;
    }

    /**
     * A link to this site written another way — http instead of https, with or
     * without "www.", protocol-relative "//host/…", host in capitals — rewritten
     * to home_url()'s own scheme and host, so it counts as the internal link it is
     * (0.98.167; such links used to be skipped, making their targets look unlinked).
     * Links to other hosts come back unchanged.
     */
    public static function normalize_url( string $url ): string {
        $url = trim( $url );
        if ( ! preg_match( '#^(?:https?:)?//([^/?\#:]+)(:\d+)?(.*)$#i', $url, $m ) ) return $url;
        static $home = null;
        if ( $home === null ) {
            $h    = wp_parse_url( home_url() );
            $home = [
                'host' => strtolower( (string) ( $h['host'] ?? '' ) ),
                'base' => ( $h['scheme'] ?? 'https' ) . '://' . ( $h['host'] ?? '' ) . ( isset( $h['port'] ) ? ':' . $h['port'] : '' ),
            ];
        }
        $bare = fn( string $host ) => preg_replace( '/^www\./', '', strtolower( $host ) );
        if ( $home['host'] === '' || $bare( $m[1] ) !== $bare( $home['host'] ) ) return $url;
        return $home['base'] . $m[3];
    }

    /**
     * Root-relative "/foo" → "https://host/foo". Root-relative URLs are
     * relative to the domain, not to home_url() — prefixing home_url()
     * doubled the path on sub-sites and subdirectory installs.
     */
    public static function absolutize( string $url ): string {
        if ( strpos( $url, '//' ) === 0 ) return set_url_scheme( $url );
        if ( strpos( $url, '/' ) !== 0 ) return $url;
        $parts = wp_parse_url( home_url() );
        $base  = ( $parts['scheme'] ?? 'https' ) . '://' . ( $parts['host'] ?? '' )
               . ( isset( $parts['port'] ) ? ':' . $parts['port'] : '' );
        return $base . $url;
    }

    private static function current_site_path(): string {
        $details = get_site( get_current_blog_id() );
        return $details ? trailingslashit( $details->path ) : '/';
    }

    /** @return string[] paths of the other sites on the current domain */
    private static function other_site_paths(): array {
        static $cache = [];
        $blog_id = get_current_blog_id();
        if ( isset( $cache[ $blog_id ] ) ) return $cache[ $blog_id ];

        $current = get_site( $blog_id );
        $paths   = [];
        if ( $current ) {
            $sites = get_sites( [
                'domain'         => $current->domain,
                'site__not_in'   => [ $blog_id ],
                'number'         => 0,
                'fields'         => '',
                'update_site_meta_cache' => false,
            ] );
            foreach ( $sites as $site ) {
                $paths[] = trailingslashit( $site->path );
            }
        }
        return $cache[ $blog_id ] = $paths;
    }
}