<?php

namespace AchlaAI;

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

final class Runtime_Diagnostics {
	const COOLDOWN            = 60;
	const TRANSITION_COOLDOWN = 5;

	/** @var Storage */
	private $storage;

	/** @var callable */
	private $clock;

	public function __construct( Storage $storage, $clock = null ) {
		$this->storage = $storage;
		$this->clock   = null === $clock ? 'time' : $clock;
	}

	/** @return true|\WP_Error */
	public function record( $code, $origin ) {
		if ( ! in_array( $code, array( 'attach_target_missing', 'attach_target_restored' ), true ) ) {
			return $this->error();
		}
		$current = Protocol::canonical_site( home_url( '/' ) );
		$source  = Protocol::canonical_site( $origin );
		if ( ! $current || ! $source || ! Crypto::safe_equal( $current['site_origin'], $source['site_origin'] ) ) {
			return $this->error();
		}
		$settings = $this->storage->get();
		$selector = $settings['placement']['attach_selector'];
		if ( ! $this->storage->has_management_binding( $settings ) || 'attach' !== $settings['placement']['mode'] || ! is_string( $selector ) || '' === $selector ) {
			return $this->error();
		}
		$now       = call_user_func( $this->clock );
		$last_at   = (int) $settings['placement']['fallback_observed_at'];
		$last_code = $settings['placement']['fallback_observed_code'];
		if ( 'attach_target_restored' === $code && 'attach_target_missing_runtime' !== $settings['placement']['fallback_warning'] ) {
			return true;
		}
		if ( ( $last_code === $code && $last_at > $now - self::COOLDOWN )
			|| ( '' !== $last_code && $last_code !== $code && $last_at > $now - self::TRANSITION_COOLDOWN ) ) {
			return true;
		}
		$settings['placement']['fallback_observed_at']   = $now;
		$settings['placement']['fallback_observed_code'] = $code;
		if ( 'attach_target_missing' === $code ) {
			$settings['placement']['fallback_warning'] = 'attach_target_missing_runtime';
		} elseif ( 'attach_target_missing_runtime' === $settings['placement']['fallback_warning'] ) {
			$settings['placement']['fallback_warning'] = '';
		}
		$this->storage->save( $settings );
		return true;
	}

	/** @return \WP_Error */
	private function error() {
		return new \WP_Error( 'invalid_runtime_diagnostic', 'Runtime diagnostic rejected.', array( 'status' => 403 ) );
	}
}