<?php
/**
 * Whether a post id's row in `wp_posts` is the thing an owner means by it.
 *
 * @package WPPilot
 */

namespace WPPilot;

defined( 'ABSPATH' ) || exit;

/**
 * Resolves the real kind of record behind a post id before a post-addressed
 * route reads it as a post or writes to it.
 *
 * Most content lives in its post row: a page, a product, an Elementor
 * template. Some does not. A WooCommerce order on a store using its own order
 * tables (HPOS) lives in `wc_orders`; its id also names a placeholder post
 * (`shop_order_placehold`) that WooCommerce keeps only to reserve the id, and
 * whose status, title and fields are not the order's. Writing that row
 * changes nothing the owner sees and reports a change that did not happen
 * (Phase A fixture gate, WooCommerce 10.3.8 with HPOS: `post_status.set` on
 * an order wrote the placeholder's status and said the order moved, while
 * `wc_orders.status` was untouched). Even where orders are still stored as
 * posts, their status is WooCommerce's state machine — stock, emails and
 * order notes move with it — and a bare post write skips all of it.
 *
 * So every post-addressed route asks this first, and a post whose storage
 * WingPilot does not own is refused, by name, before anything is read as the
 * object or written. The refusal is the same for both reasons:
 *
 * - **foreign storage**: a type another plugin keeps and changes through its
 *   own records — WooCommerce's order types (whatever `wc_get_order_types()`
 *   reports, plus the HPOS placeholder and subscriptions), and Easy Digital
 *   Downloads payments, which EDD 3 keeps in its own order tables;
 * - **unregistered type**: a post whose type nothing on the site registers
 *   (the plugin that owns it is inactive), so nothing can say where the record
 *   really lives or what writing it would mean.
 */
final class Post_Storage {

	/** The one refusal code, for the backend to report the refusal as a refusal. */
	public const REFUSAL_CODE = 'wppilot_storage_not_owned';

	/**
	 * Post types whose post row is not the record, or not the way to change it.
	 * Literal, so they are refused even while their plugin is inactive.
	 */
	private const FOREIGN_TYPES = array(
		'shop_order',
		'shop_order_refund',
		'shop_order_placehold',
		'shop_subscription',
		'edd_payment',
	);

	/**
	 * Why this post cannot be addressed as a post here, or null when it can.
	 *
	 * @param \WP_Post $post The post the request names.
	 * @return \WP_Error|null A 409 `wppilot_storage_not_owned` refusal, or null.
	 */
	public static function refusal( \WP_Post $post ): ?\WP_Error {
		$type = (string) $post->post_type;
		if ( in_array( $type, self::foreign_types(), true ) ) {
			return new \WP_Error(
				self::REFUSAL_CODE,
				sprintf(
					'Item %1$d is a %2$s, which another plugin keeps in its own records and changes through its own screens. WPPilot does not read or change it as a post. Nothing was changed.',
					(int) $post->ID,
					$type
				),
				array(
					'status'    => 409,
					'post_type' => $type,
					'reason'    => 'foreign_storage',
				)
			);
		}
		if ( ! get_post_type_object( $type ) instanceof \WP_Post_Type ) {
			return new \WP_Error(
				self::REFUSAL_CODE,
				sprintf(
					'Item %1$d is of the type %2$s, which nothing active on this site registers, so WPPilot cannot tell where it is really kept. Nothing was changed.',
					(int) $post->ID,
					$type
				),
				array(
					'status'    => 409,
					'post_type' => $type,
					'reason'    => 'unregistered_type',
				)
			);
		}
		return null;
	}

	/**
	 * The foreign-storage types: the literal list plus WooCommerce's own list
	 * of order types where WooCommerce is active (an extension's order type,
	 * registered through `wc_register_order_type`, is in it).
	 *
	 * @return string[]
	 */
	/**
	 * Core's own block content types: templates, template parts, synced
	 * patterns and navigation menus. Not public, yet each is ordinary page
	 * content the site editor writes as block markup.
	 */
	private const BLOCK_CONTENT_TYPES = array( 'wp_template', 'wp_template_part', 'wp_block', 'wp_navigation' );

	/**
	 * Why a post's body or status may not be written here, or null.
	 *
	 * Body and status writes are for content: a public type, or core's own
	 * block content. Anything else that keeps a post row (Additional CSS,
	 * global styles, another plugin's code snippets, internal records) is
	 * left to the screens that own it, since its body may be code or its
	 * status may switch code on.
	 *
	 * @param \WP_Post $post The addressed post, already past refusal().
	 */
	public static function write_refusal( \WP_Post $post ): ?\WP_Error {
		$type   = (string) $post->post_type;
		$object = get_post_type_object( $type );
		if ( ( $object instanceof \WP_Post_Type && ! empty( $object->public ) ) || in_array( $type, self::BLOCK_CONTENT_TYPES, true ) ) {
			return null;
		}
		return new \WP_Error(
			self::REFUSAL_CODE,
			sprintf(
				'Item %1$d is a %2$s, which is not site content WPPilot changes. Nothing was changed.',
				(int) $post->ID,
				$type
			),
			array(
				'status'    => 409,
				'post_type' => $type,
				'reason'    => 'not_content',
			)
		);
	}

	public static function foreign_types(): array {
		$types = self::FOREIGN_TYPES;
		if ( function_exists( 'wc_get_order_types' ) ) {
			$types = array_merge( $types, array_map( 'strval', (array) wc_get_order_types() ) );
		}
		return array_values( array_unique( $types ) );
	}
}