<?php
/**
 * Recent Orders Preview (FR-056 / PRD 13.7).
 *
 * @package Kayvandra\MarginBeacon
 */

declare(strict_types=1);

namespace Kayvandra\MarginBeacon\Application\OrderRisk;

use Kayvandra\MarginBeacon\Infrastructure\Scheduler\SchedulerInterface;
use Kayvandra\MarginBeacon\Infrastructure\Scheduler\SchedulerResult;
use Kayvandra\MarginBeacon\Application\MaterialChange\OrderMaterialHasher;
use Kayvandra\MarginBeacon\Support\Constants;

/**
 * Opt-in bounded preview of recent promoted orders.
 */
final class RecentOrdersPreviewService {

	const MAX_DAYS   = 30;
	const MAX_ORDERS = 100;

	/**
	 * @var SchedulerInterface|null
	 */
	private $scheduler;

	/**
	 * @param SchedulerInterface|null $scheduler Scheduler.
	 */
	public function __construct( $scheduler = null ) {
		$this->scheduler = $scheduler;
	}

	/**
	 * Estimate eligible orders before enqueue.
	 *
	 * @return array{count:int,order_ids:int[],window_days:int,cap:int}
	 */
	public function estimate() {
		$ids = $this->find_eligible_order_ids();
		return array(
			'count'       => count( $ids ),
			'order_ids'   => $ids,
			'window_days' => self::MAX_DAYS,
			'cap'         => self::MAX_ORDERS,
		);
	}

	/**
	 * Enqueue preview evaluations (opt-in only).
	 *
	 * @return array{success:bool,enqueued:int,skipped:int,message?:string}
	 */
	public function start() {
		$pressure = ( new QueuePressureGuard( $this->scheduler ) )->assess();
		if ( ! empty( $pressure['blocked'] ) ) {
			return array(
				'success'  => false,
				'enqueued' => 0,
				'skipped'  => 0,
				'message'  => isset( $pressure['reason'] ) ? (string) $pressure['reason'] : __( 'Queue is under pressure. Try again later.', 'marginbeacon' ),
			);
		}

		$estimate = $this->estimate();
		$ids      = $estimate['order_ids'];

		if ( empty( $ids ) ) {
			return array(
				'success'  => true,
				'enqueued' => 0,
				'skipped'  => 0,
				'message'  => __( 'No eligible promoted orders in the last 30 days (max 100).', 'marginbeacon' ),
			);
		}

		$detector = new PromotionSignalDetector();
		$enqueued = 0;
		$skipped  = 0;

		foreach ( $ids as $order_id ) {
			$order = wc_get_order( $order_id );
			if ( ! $order ) {
				++$skipped;
				continue;
			}

			$signal = $detector->detect( $order );
			if ( 'none' === $signal['signal'] ) {
				++$skipped;
				continue;
			}

			// Prefer async when scheduler healthy; otherwise evaluate inline for local/dev reliability.
			$queued = false;
			if ( $this->scheduler ) {
				$revision = OrderMaterialHasher::hash_order( $order );
				$id       = $this->scheduler->enqueue(
					Constants::ACTION_EVALUATE_ORDER,
					array(
						'order_id' => (int) $order_id,
						'revision' => $revision,
						'origin'   => 'recent_preview',
					),
					Constants::SCHEDULER_GROUP,
					null,
					'preview_' . $order_id . '_' . substr( $revision, 0, 12 )
				);
				$queued   = SchedulerResult::is_enqueued( $id );
			}

			if ( $queued ) {
				++$enqueued;
			} else {
				++$skipped;
			}
		}

		$state = array(
			'last_run_gmt'  => gmdate( 'Y-m-d H:i:s' ),
			'last_enqueued' => $enqueued,
			'last_estimate' => $estimate['count'],
			'ever_run'      => true,
		);
		update_option( Constants::OPTION_RECENT_PREVIEW_STATE, $state, false );

		if ( 0 === $enqueued && $skipped > 0 && ! $this->scheduler ) {
			return array(
				'success'  => false,
				'enqueued' => 0,
				'skipped'  => $skipped,
				'message'  => __( 'Scheduler not ready. Recent Orders Preview requires Action Scheduler.', 'marginbeacon' ),
			);
		}

		return array(
			'success'  => $enqueued > 0 || 0 === $skipped,
			'enqueued' => $enqueued,
			'skipped'  => $skipped,
			'message'  => sprintf(
				/* translators: %d: enqueued count */
				__( 'Recent Orders Preview started for %d order(s). Badges update as jobs complete.', 'marginbeacon' ),
				$enqueued
			),
		);
	}

	/**
	 * Preview run state.
	 *
	 * @return array
	 */
	public function state() {
		$state = get_option( Constants::OPTION_RECENT_PREVIEW_STATE, array() );
		return is_array( $state ) ? $state : array();
	}

	/**
	 * @return int[]
	 */
	private function find_eligible_order_ids() {
		if ( ! function_exists( 'wc_get_orders' ) ) {
			return array();
		}

		$after  = gmdate( 'Y-m-d H:i:s', time() - ( self::MAX_DAYS * DAY_IN_SECONDS ) );
		$orders = wc_get_orders(
			array(
				'limit'        => self::MAX_ORDERS,
				'orderby'      => 'date',
				'order'        => 'DESC',
				'status'       => array( 'processing', 'completed', 'on-hold' ),
				'date_created' => '>=' . $after,
				'return'       => 'ids',
			)
		);

		if ( ! is_array( $orders ) ) {
			return array();
		}

		$detector = new PromotionSignalDetector();
		$eligible = array();
		foreach ( $orders as $order_id ) {
			$order = wc_get_order( $order_id );
			if ( ! $order ) {
				continue;
			}
			$signal = $detector->detect( $order );
			if ( 'none' === $signal['signal'] ) {
				continue;
			}
			$eligible[] = (int) $order_id;
			if ( count( $eligible ) >= self::MAX_ORDERS ) {
				break;
			}
		}

		return $eligible;
	}
}