<?php
/**
 * Local installation identity, independent of hosted credentials and consent.
 * No automatic registration, collection or network calls.
 *
 * @package abtestkit
 */

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

final class ABTestKit_Connected_Installation {
    const OPTION = 'abtestkit_connected_installation';

    /** Preserve installation paths; two WordPress installs can share an origin. */
    private static function context() {
        $parts = wp_parse_url( home_url( '/' ) );
        $environment = wp_get_environment_type();
        if (
            ! is_array( $parts ) || empty( $parts['host'] ) ||
            ! in_array( $parts['scheme'] ?? '', array( 'https', 'http' ), true ) ||
            isset( $parts['user'] ) || isset( $parts['pass'] ) || isset( $parts['query'] ) || isset( $parts['fragment'] ) ||
            ! in_array( $environment, array( 'production', 'staging', 'development', 'local' ), true )
        ) {
            return new WP_Error( 'abtestkit_connected_invalid_context' );
        }
        $url = $parts['scheme'] . '://' . strtolower( rtrim( $parts['host'], '.' ) );
        $port = (int) ( $parts['port'] ?? 0 );
        if ( $port && ! ( ( 'https' === $parts['scheme'] && 443 === $port ) || ( 'http' === $parts['scheme'] && 80 === $port ) ) ) {
            $url .= ':' . $port;
        }
        $url .= rtrim( (string) ( $parts['path'] ?? '' ), '/' );
        return array( 'home_url' => $url, 'environment' => $environment );
    }

    /**
     * Atomically initialise on an explicit caller action. Never silently replace
     * an existing identity after a clone, domain change or damaged option.
     */
    public static function get_or_create() {
        $context = self::context();
        if ( is_wp_error( $context ) ) {
            return $context;
        }
        $stored = get_option( self::OPTION, null );
        if ( null === $stored ) {
            $id = ABTestKit_Connected_Event::new_id();
            if ( is_wp_error( $id ) ) {
                return $id;
            }
            $candidate = array_merge( $context, array( 'schema_version' => 1, 'installation_id' => $id, 'created_at' => time() ) );
            // Unique option_name selects one winner if setup requests overlap.
            add_option( self::OPTION, $candidate, '', 'no' );
            $stored = get_option( self::OPTION, null );
        }
        if (
            ! is_array( $stored ) || 1 !== ( $stored['schema_version'] ?? null ) ||
            ! ABTestKit_Connected_Event::valid_id( $stored['installation_id'] ?? null ) ||
            ! is_int( $stored['created_at'] ?? null ) || $stored['created_at'] <= 0
        ) {
            return new WP_Error( 'abtestkit_connected_identity_unavailable' );
        }
        if ( $context['home_url'] !== ( $stored['home_url'] ?? null ) || $context['environment'] !== ( $stored['environment'] ?? null ) ) {
            return new WP_Error( 'abtestkit_connected_identity_mismatch' );
        }
        return $stored;
    }
}