<?php
/**
 * Catalog sync: tells Thridify which products this store sells so each one
 * resolves to its 3D experience.
 *
 * Only identifiers leave the site — product ID, SKU, slug and title. Never
 * prices, stock or customer data.
 *
 * @package Thridify
 */

namespace Thridify\Catalog;

use Thridify\Connect\Api;
use Thridify\Connect\Connection;
use Thridify\Support\Env;

defined( 'ABSPATH' ) || exit;

/**
 * Paged full-catalog push (POST /v1/platform/link/catalog) run by WooCommerce's
 * Action Scheduler: one page per action, chained, so large catalogs never hit
 * a request time limit. Runs on connect, on match-field change, a couple of
 * minutes after products change, daily, and on demand.
 */
class CatalogSync {

	const GROUP       = 'thridify';
	const ACTION_PAGE = 'thridify_catalog_page';
	const ACTION_SYNC = 'thridify_catalog_sync';
	const ACTION_DAY  = 'thridify_catalog_daily';
	const PAGE_SIZE   = 500;
	const MAX_PAGES   = 40; // Thridify accepts up to 20,000 products per sweep.
	const STATUS      = 'thridify_catalog_status';
	const SWEEP       = 'thridify_catalog_sweep';

	/**
	 * Register hooks.
	 *
	 * @return void
	 */
	public function register() {
		add_action( self::ACTION_SYNC, array( $this, 'start_sweep' ) );
		add_action( self::ACTION_DAY, array( $this, 'start_sweep' ) );
		add_action( self::ACTION_PAGE, array( $this, 'run_page' ), 10, 1 );

		add_action( 'woocommerce_new_product', array( $this, 'product_changed' ) );
		add_action( 'woocommerce_update_product', array( $this, 'product_changed' ) );
		add_action( 'woocommerce_delete_product', array( $this, 'product_changed' ) );
		add_action( 'woocommerce_trash_product', array( $this, 'product_changed' ) );
		add_action( 'untrashed_post', array( $this, 'maybe_product_untrashed' ) );

		add_action( 'init', array( $this, 'ensure_daily' ) );
	}

	/**
	 * The context schema registered with Thridify: what identifies a product here.
	 *
	 * @return array<string,mixed>
	 */
	public static function schema() {
		$samples = array();
		foreach ( self::products_page( 1, 20 )['products'] as $product ) {
			$samples[] = self::entity( $product );
		}
		return array(
			'entity'         => 'product',
			'fields'         => array(
				array(
					'key'   => 'productId',
					'label' => 'Product ID',
				),
				array(
					'key'   => 'sku',
					'label' => 'SKU',
				),
				array(
					'key'   => 'slug',
					'label' => 'Slug',
				),
				array(
					'key'   => 'title',
					'label' => 'Title',
				),
			),
			'sampleEntities' => $samples,
		);
	}

	/**
	 * Queue a sync soon (debounced: one pending sync at a time).
	 *
	 * @param string $reason Why (connect, settings, product, manual).
	 * @param int    $delay  Seconds from now.
	 * @return void
	 */
	public static function queue( $reason, $delay = 0 ) {
		if ( ! function_exists( 'as_schedule_single_action' ) || null === Connection::token() ) {
			return;
		}
		if ( as_has_scheduled_action( self::ACTION_SYNC, array(), self::GROUP ) ) {
			return;
		}
		as_schedule_single_action( time() + max( 0, (int) $delay ), self::ACTION_SYNC, array(), self::GROUP );
		self::set_status(
			array(
				'state'       => 'queued',
				'reason'      => sanitize_key( $reason ),
				'requestedAt' => time(),
			)
		);
	}

	/**
	 * A product changed: re-sync in two minutes (bulk edits coalesce).
	 *
	 * @return void
	 */
	public function product_changed() {
		self::queue( 'product', 2 * MINUTE_IN_SECONDS );
	}

	/**
	 * A trashed product came back.
	 *
	 * @param int $post_id Post ID.
	 * @return void
	 */
	public function maybe_product_untrashed( $post_id ) {
		if ( 'product' === get_post_type( $post_id ) ) {
			$this->product_changed();
		}
	}

	/**
	 * Keep one daily safety-net sync scheduled while connected.
	 *
	 * @return void
	 */
	public function ensure_daily() {
		if ( ! function_exists( 'as_has_scheduled_action' ) || null === Connection::token() ) {
			return;
		}
		if ( ! as_has_scheduled_action( self::ACTION_DAY, array(), self::GROUP ) ) {
			as_schedule_recurring_action( strtotime( 'tomorrow 03:00' ), DAY_IN_SECONDS, self::ACTION_DAY, array(), self::GROUP );
		}
	}

	/**
	 * Begin a sweep at page 1.
	 *
	 * @return void
	 */
	public function start_sweep() {
		delete_option( self::SWEEP );
		self::set_status(
			array(
				'state'     => 'running',
				'startedAt' => time(),
				'error'     => '',
			)
		);
		$this->run_page( 1 );
	}

	/**
	 * Push one page; chain the next.
	 *
	 * @param int $page 1-based page.
	 * @return void
	 */
	public function run_page( $page ) {
		$page  = max( 1, (int) $page );
		$sweep = get_option( self::SWEEP, array() );
		$sweep = is_array( $sweep ) ? $sweep : array();

		$batch    = self::products_page( $page, self::PAGE_SIZE );
		$entities = array_map( array( __CLASS__, 'entity' ), $batch['products'] );
		$final    = $page >= $batch['pages'] || $page >= self::MAX_PAGES;

		$body = array(
			'entities' => $entities,
			'final'    => $final,
		);
		if ( $page > 1 && ! empty( $sweep['id'] ) ) {
			$body['sweepId'] = (string) $sweep['id'];
		}

		$result = Api::request( 'POST', '/catalog', $body, null, 60 );
		if ( ! Api::ok( $result ) ) {
			delete_option( self::SWEEP );
			self::set_status(
				array(
					'state'      => 'error',
					'error'      => Api::error_message( $result ),
					'finishedAt' => time(),
				)
			);
			if ( ! is_wp_error( $result ) && 409 === $result['status'] ) {
				self::queue( 'retry', 10 * MINUTE_IN_SECONDS ); // Another sweep held the lock.
			}
			return;
		}

		$response   = $result['body'];
		$unresolved = isset( $response['page']['unresolvedValues'] ) && is_array( $response['page']['unresolvedValues'] ) ? $response['page']['unresolvedValues'] : array();
		$sample     = array_slice( array_merge( (array) ( $sweep['sample'] ?? array() ), array_map( 'strval', $unresolved ) ), 0, 20 );
		$products   = (int) ( $sweep['products'] ?? 0 ) + count( $entities );

		if ( ! $final ) {
			update_option(
				self::SWEEP,
				array(
					'id'       => isset( $response['sweepId'] ) ? sanitize_text_field( (string) $response['sweepId'] ) : '',
					'products' => $products,
					'sample'   => $sample,
				),
				false
			);
			as_enqueue_async_action( self::ACTION_PAGE, array( $page + 1 ), self::GROUP );
			return;
		}

		delete_option( self::SWEEP );
		$totals = isset( $response['totals'] ) && is_array( $response['totals'] ) ? $response['totals'] : array();
		self::set_status(
			array(
				'state'            => 'ok',
				'finishedAt'       => time(),
				'products'         => $products,
				'compiled'         => (int) ( $totals['compiled'] ?? 0 ),
				'unresolved'       => (int) ( $totals['unresolved'] ?? 0 ),
				'deleted'          => (int) ( $totals['deleted'] ?? 0 ),
				'unresolvedSample' => $sample,
				'error'            => '',
			)
		);
	}

	/**
	 * One page of published products.
	 *
	 * @param int $page  1-based page.
	 * @param int $limit Page size.
	 * @return array{products:\WC_Product[],pages:int}
	 */
	private static function products_page( $page, $limit ) {
		$result = wc_get_products(
			array(
				'status'   => 'publish',
				'limit'    => $limit,
				'page'     => $page,
				'orderby'  => 'ID',
				'order'    => 'ASC',
				'paginate' => true,
			)
		);
		return array(
			'products' => is_object( $result ) ? (array) $result->products : array(),
			'pages'    => is_object( $result ) ? max( 1, (int) $result->max_num_pages ) : 1,
		);
	}

	/**
	 * A product as Thridify context (identifiers only; empty fields omitted).
	 *
	 * @param \WC_Product $product Product.
	 * @return array<string,string>
	 */
	public static function entity( $product ) {
		$entity = array(
			'productId' => (string) $product->get_id(),
			'sku'       => (string) $product->get_sku(),
			'slug'      => (string) $product->get_slug(),
			'title'     => wp_strip_all_tags( (string) $product->get_name() ),
		);
		return array_filter( $entity, 'strlen' );
	}

	/**
	 * Last sync outcome.
	 *
	 * @return array<string,mixed>
	 */
	public static function status() {
		$status = get_option( self::STATUS, array() );
		return is_array( $status ) ? $status : array();
	}

	/**
	 * Merge into the status record.
	 *
	 * @param array<string,mixed> $fields Fields.
	 * @return void
	 */
	private static function set_status( array $fields ) {
		update_option( self::STATUS, array_merge( self::status(), $fields ), false );
	}

	/**
	 * Clear the status (after disconnect).
	 *
	 * @return void
	 */
	public static function reset_status() {
		delete_option( self::STATUS );
		delete_option( self::SWEEP );
		self::unschedule();
	}

	/**
	 * Cancel every scheduled sync.
	 *
	 * @return void
	 */
	public static function unschedule() {
		if ( function_exists( 'as_unschedule_all_actions' ) ) {
			as_unschedule_all_actions( self::ACTION_SYNC, array(), self::GROUP );
			as_unschedule_all_actions( self::ACTION_DAY, array(), self::GROUP );
			as_unschedule_all_actions( self::ACTION_PAGE, null, self::GROUP );
		}
	}
}