<?php
/**
 * Source, trigger and actor resolution. Only claims what evidence supports.
 *
 * @package Enrollment_Verifier_Logger
 */

defined( 'ABSPATH' ) || exit;

/**
 * Resolves who/what caused an event.
 *
 * Integrations extend this through filters: evlfl_resolve_source, evlfl_resolve_trigger,
 * evlfl_resolve_actor (each receives the baseline value, the event and the context).
 */
class EVLFL_Source_Detector {

	/**
	 * Resolve origin.
	 *
	 * @param array $event   Normalized event.
	 * @param array $context Context snapshot (may include expired_hook_fired).
	 * @return array source, event_trigger, actor_type, actor_id, confidence.
	 */
	public function resolve( array $event, array $context ) {
		$type    = isset( $context['request_type'] ) ? $context['request_type'] : 'frontend';
		$uid     = isset( $context['current_user_id'] ) ? absint( $context['current_user_id'] ) : 0;
		$priv    = ! empty( $context['privileged'] );
		$expired = ! empty( $context['expired_hook_fired'] ) && EVLFL_Event::ACTION_UNENROLLED === $event['action'];
		$wc_hook = isset( $context['woocommerce_hook'] ) && is_scalar( $context['woocommerce_hook'] ) ? (string) $context['woocommerce_hook'] : '';

		$r = array(
			'source'        => 'unknown',
			'event_trigger' => 'unknown',
			'actor_type'    => 'unknown',
			'actor_id'      => null,
			'confidence'    => 'unknown',
		);

		if ( $expired ) {
			$r = array(
				'source'        => 'learndash',
				'event_trigger' => 'course_access_expired',
				'actor_type'    => 'system',
				'actor_id'      => null,
				'confidence'    => 'confirmed',
			);
		} elseif ( '' !== $wc_hook ) {
			// The change ran inside a WooCommerce order hook, so WooCommerce drove it (also for block checkout, which is a REST request).
			$wc_trigger = 'unknown';
			if ( EVLFL_Event::ACTION_ENROLLED === $event['action'] ) {
				$wc_trigger = 'purchase';
			} elseif ( ! empty( $context['reenrolled_in_request'] ) ) {
				$wc_trigger = 'access_reset';
			} elseif ( false !== strpos( $wc_hook, 'refunded' ) ) {
				$wc_trigger = 'refund';
			}
			$r = array(
				'source'        => 'woocommerce',
				'event_trigger' => $wc_trigger,
				'actor_type'    => $uid > 0 ? ( $priv ? 'admin' : 'user' ) : 'unknown',
				'actor_id'      => $uid > 0 ? $uid : null,
				'confidence'    => 'detected',
			);
		} elseif ( 'cron' === $type ) {
			$r = array(
				'source'        => 'cron',
				'event_trigger' => 'unknown',
				'actor_type'    => 'cron',
				'actor_id'      => null,
				'confidence'    => 'detected',
			);
		} elseif ( 'wp_cli' === $type ) {
			$r = array(
				'source'        => 'wp_cli',
				'event_trigger' => 'unknown',
				'actor_type'    => 'system',
				'actor_id'      => null,
				'confidence'    => 'detected',
			);
		} elseif ( 'rest_api' === $type ) {
			$r = array(
				'source'        => 'rest_api',
				'event_trigger' => 'api',
				'actor_type'    => 'api',
				'actor_id'      => $uid > 0 ? $uid : null,
				'confidence'    => 'detected',
			);
		} elseif ( 'admin' === $type && $priv ) {
			$r = array(
				'source'        => 'admin',
				'event_trigger' => 'manual',
				'actor_type'    => 'admin',
				'actor_id'      => $uid,
				'confidence'    => 'detected',
			);
		} elseif ( 'ajax' === $type && $priv ) {
			// An admin-AJAX call by a privileged user: the actor is known, the exact feature is not.
			$r = array(
				'source'        => 'admin',
				'event_trigger' => 'unknown',
				'actor_type'    => 'admin',
				'actor_id'      => $uid,
				'confidence'    => 'inferred',
			);
		} elseif ( $uid > 0 ) {
			// A logged-in user acted, but the originating feature (LearnDash form, shop, ...) is not reliably known.
			$r['actor_type'] = $priv ? 'admin' : 'user';
			$r['actor_id']   = $uid;
			$r['confidence'] = 'inferred';
		}

		$source             = apply_filters( 'evlfl_resolve_source', $r['source'], $event, $context );
		$r['source']        = $this->allowed( $source, EVLFL_Event::get_sources(), $r['source'] );
		$trigger            = apply_filters( 'evlfl_resolve_trigger', $r['event_trigger'], $event, $context, $r['source'] );
		$r['event_trigger'] = $this->allowed( $trigger, EVLFL_Event::get_triggers(), $r['event_trigger'] );
		$actor              = apply_filters(
			'evlfl_resolve_actor',
			array(
				'actor_type' => $r['actor_type'],
				'actor_id'   => $r['actor_id'],
			),
			$event,
			$context
		);
		if ( is_array( $actor ) && isset( $actor['actor_type'] ) ) {
			$type_ok         = $this->allowed( $actor['actor_type'], EVLFL_Event::get_actor_types(), $r['actor_type'] );
			$r['actor_type'] = $type_ok;
			$r['actor_id']   = ( isset( $actor['actor_id'] ) && absint( $actor['actor_id'] ) > 0 ) ? absint( $actor['actor_id'] ) : null;
		}
		if ( 'unknown' !== $r['source'] && 'unknown' === $r['confidence'] ) {
			$r['confidence'] = 'detected'; // A filter supplied a source; it cannot be less than detected.
		}
		return $r;
	}

	/**
	 * Allowlist helper.
	 *
	 * @param mixed  $value    Candidate.
	 * @param array  $allow    Allowlist.
	 * @param string $fallback Fallback.
	 * @return string
	 */
	private function allowed( $value, array $allow, $fallback ) {
		$value = is_scalar( $value ) ? sanitize_key( (string) $value ) : '';
		return isset( $allow[ $value ] ) ? $value : $fallback;
	}
}