<?php
/**
 * Applies field changes to products and variations through WooCommerce's product objects,
 * reporting each item's values before and after so the app can show results and undo them.
 */

defined( 'ABSPATH' ) || exit;

class Storeloom_Batch {

	const BATCH_SIZE_OPTION  = 'storeloom_batch_size';
	const DEFAULT_BATCH_SIZE = 50;

	/** Fields the app may change, and how each is applied. */
	const FIELDS = array(
		'name',
		'sku',
		'status',
		'regular_price',
		'sale_price',
		'manage_stock',
		'stock_quantity',
		'stock_status',
		'backorders',
		'weight',
		'length',
		'width',
		'height',
		'shipping_class_id',
		'catalog_visibility',
		'featured',
		'category_ids',
		'tag_ids',
		'sale_from_date',
		'sale_to_date',
		'description',
		'short_description',
	);

	public static function max_items() {
		return max( 1, (int) get_option( self::BATCH_SIZE_OPTION, self::DEFAULT_BATCH_SIZE ) );
	}

	/**
	 * @param array $items [{ id, expected_modified?: int (Unix seconds), expected_fingerprint?: string, changes: { field: value } }]
	 * @return array One result per item: { id, status: ok|conflict|not_found|error, message?, before?, after? }
	 */
	public static function apply( array $items ) {
		$results = array();
		foreach ( $items as $item ) {
			$results[] = self::apply_item( $item );
		}

		// Parents edited in this batch whose variations were edited too: report them as synced.
		$synced = Storeloom_Catalog::run_deferred_syncs();
		foreach ( $results as &$result ) {
			if ( 'ok' === $result['status'] && in_array( $result['id'], $synced, true ) ) {
				$product = wc_get_product( $result['id'] );
				if ( $product ) {
					$result['after'] = self::row( $product, isset( $result['after']['description'] ) );
				}
			}
		}
		unset( $result );
		return $results;
	}

	private static function apply_item( $item ) {
		$id      = isset( $item['id'] ) ? (int) $item['id'] : 0;
		$changes = isset( $item['changes'] ) && is_array( $item['changes'] ) ? $item['changes'] : array();
		$product = $id > 0 ? wc_get_product( $id ) : false;

		if ( ! $product || 'trash' === $product->get_status() ) {
			return array(
				'id'      => $id,
				'status'  => 'not_found',
				'message' => 'This item no longer exists on the store.',
			);
		}

		// Description changes report the texts too, so the app can show them and undo them.
		$with_text = isset( $changes['description'] ) || isset( $changes['short_description'] );
		$before    = self::row( $product, $with_text );

		// Changed on the store since the app read it: hold it back instead of overwriting. The fingerprint catches
		// edits made within the same second as the app's read, which leave the modified date as it was.
		$date_changed    = isset( $item['expected_modified'] ) && null !== $item['expected_modified'] && (int) $item['expected_modified'] !== (int) $before['date_modified'];
		$content_changed = ! empty( $item['expected_fingerprint'] ) && $item['expected_fingerprint'] !== $before['fingerprint'];
		if ( $date_changed || $content_changed ) {
			return array(
				'id'      => $id,
				'status'  => 'conflict',
				'message' => 'This item was changed on the store after Storeloom loaded it.',
				'before'  => $before,
			);
		}

		try {
			foreach ( $changes as $field => $value ) {
				self::set_field( $product, $field, $value );
			}
			$product->save();
		} catch ( Exception $e ) {
			return array(
				'id'      => $id,
				'status'  => 'error',
				'message' => wp_strip_all_tags( $e->getMessage() ),
				'before'  => $before,
			);
		}

		$saved = wc_get_product( $id );
		return array(
			'id'     => $id,
			'status' => 'ok',
			'before' => $before,
			'after'  => self::row( $saved ? $saved : $product, $with_text ),
		);
	}

	private static function row( WC_Product $product, $with_text ) {
		$row = Storeloom_Catalog::row( $product );
		if ( $with_text ) {
			$texts                    = Storeloom_Catalog::texts( $product );
			$row['description']       = $texts['description'];
			$row['short_description'] = $texts['short_description'];
		}
		return $row;
	}

	private static function set_field( WC_Product $product, $field, $value ) {
		$is_variation = $product->is_type( 'variation' );
		switch ( $field ) {
			case 'name':
				if ( $is_variation ) {
					throw new Exception( 'Variation names come from their attributes and cannot be changed.' );
				}
				$product->set_name( sanitize_text_field( $value ) );
				break;
			case 'sku':
				$product->set_sku( wc_clean( $value ) ); // Throws WC_Data_Exception for invalid or duplicate SKUs.
				break;
			case 'status':
				$allowed = $is_variation ? array( 'publish', 'private' ) : array( 'publish', 'draft', 'pending', 'private' );
				if ( ! in_array( $value, $allowed, true ) ) {
					throw new Exception( 'Unknown status.' );
				}
				$product->set_status( $value );
				break;
			case 'regular_price':
				$product->set_regular_price( wc_format_decimal( $value ) );
				break;
			case 'sale_price':
				$product->set_sale_price( wc_format_decimal( $value ) );
				break;
			case 'manage_stock':
				$product->set_manage_stock( 'yes' === $value || true === $value );
				break;
			case 'stock_quantity':
				$product->set_stock_quantity( null === $value || '' === $value ? null : wc_stock_amount( $value ) );
				break;
			case 'stock_status':
				$product->set_stock_status( wc_clean( $value ) );
				break;
			case 'backorders':
				$product->set_backorders( wc_clean( $value ) );
				break;
			case 'weight':
				$product->set_weight( wc_format_decimal( $value ) );
				break;
			case 'length':
				$product->set_length( wc_format_decimal( $value ) );
				break;
			case 'width':
				$product->set_width( wc_format_decimal( $value ) );
				break;
			case 'height':
				$product->set_height( wc_format_decimal( $value ) );
				break;
			case 'shipping_class_id':
				$product->set_shipping_class_id( absint( $value ) );
				break;
			case 'tax_class':
				// WooCommerce quietly turns unknown classes into Standard; refuse them instead.
				$class = sanitize_title( (string) $value );
				$valid = array_merge( array( '' ), WC_Tax::get_tax_class_slugs(), $is_variation ? array( 'parent' ) : array() );
				if ( ! in_array( $class, $valid, true ) ) {
					throw new Exception( sprintf( 'The store has no tax class "%s".', esc_html( (string) $value ) ) );
				}
				$product->set_tax_class( $class );
				break;
			case 'catalog_visibility':
				if ( $is_variation ) {
					throw new Exception( 'Variations have no catalog visibility.' );
				}
				$product->set_catalog_visibility( wc_clean( $value ) ); // Throws for unknown values.
				break;
			case 'featured':
				if ( $is_variation ) {
					throw new Exception( 'Variations cannot be featured.' );
				}
				$product->set_featured( true === $value || 'yes' === $value || 1 === $value );
				break;
			case 'description':
			case 'short_description':
				if ( $is_variation && 'short_description' === $field ) {
					throw new Exception( 'Variations have no short description.' );
				}
				// Same filtering as post content: safe HTML only.
				$text = wp_kses_post( (string) $value );
				if ( 'description' === $field ) {
					$product->set_description( $text );
				} else {
					$product->set_short_description( $text );
				}
				break;
			case 'sale_from_date':
			case 'sale_to_date':
				// Like WooCommerce's product screen: a sale starts at the beginning and ends at the end of the day,
				// in the store's timezone.
				if ( '' !== $value && ! preg_match( '/^\d{4}-\d{2}-\d{2}$/', (string) $value ) ) {
					throw new Exception( 'Sale dates must look like 2026-11-01.' );
				}
				if ( 'sale_from_date' === $field ) {
					$product->set_date_on_sale_from( '' === $value ? '' : $value . ' 00:00:00' );
				} else {
					$product->set_date_on_sale_to( '' === $value ? '' : $value . ' 23:59:59' );
				}
				break;
			case 'category_ids':
			case 'tag_ids':
				if ( $is_variation ) {
					throw new Exception( 'Variations take their categories and tags from their product.' );
				}
				$taxonomy = 'category_ids' === $field ? 'product_cat' : 'product_tag';
				$ids      = array_map( 'absint', is_array( $value ) ? $value : array() );
				foreach ( $ids as $term_id ) {
					if ( ! term_exists( $term_id, $taxonomy ) ) {
						throw new Exception( sprintf( 'Term %d no longer exists on the store.', (int) $term_id ) );
					}
				}
				if ( 'category_ids' === $field ) {
					$product->set_category_ids( $ids );
				} else {
					$product->set_tag_ids( $ids );
				}
				break;
			default:
				throw new Exception( sprintf( 'Unknown field: %s', esc_html( (string) $field ) ) );
		}
	}
}