<?php
/**
 * WooCommerce's native Cost of Goods Sold field.
 *
 * @package MadeCost
 */

namespace MadeCost;

defined( 'ABSPATH' ) || exit;

/**
 * Checks and writes the Cost of Goods Sold value (WooCommerce 10.3 and later).
 *
 * WooCommerce stores the value you set as the product's "defined" cost. For a variation, the cost is
 * inherited from the parent unless the variation has its own value; the "additive" flag adds the two
 * together. MadeCost always writes the full cost on the variation and turns the additive flag off, so
 * the cost WooCommerce uses on orders is exactly the cost MadeCost computed.
 */
final class Cogs {

	const FEATURE_ID = 'cost_of_goods_sold';

	/**
	 * Whether this WooCommerce version has the Cost of Goods Sold API at all.
	 */
	public static function supported(): bool {
		return class_exists( '\WC_Product' ) && method_exists( '\WC_Product', 'set_cogs_value' );
	}

	/**
	 * Whether the merchant turned the feature on (WooCommerce > Settings > Advanced > Features).
	 */
	public static function enabled(): bool {
		return self::supported()
			&& class_exists( '\Automattic\WooCommerce\Utilities\FeaturesUtil' )
			&& \Automattic\WooCommerce\Utilities\FeaturesUtil::feature_is_enabled( self::FEATURE_ID );
	}

	/**
	 * Where the merchant turns the feature on.
	 */
	public static function settings_url(): string {
		return admin_url( 'admin.php?page=wc-settings&tab=advanced&section=features' );
	}

	/**
	 * Write costs.
	 *
	 * @param array[] $items Each: productId, variantId, costCents.
	 * @return array[] One result per item: variantId, ok, and either previousCents/newCents or code/message.
	 */
	public function write( array $items ): array {
		$results = array();
		foreach ( $items as $item ) {
			$results[] = $this->write_one( is_array( $item ) ? $item : array() );
		}

		/**
		 * Fires after a batch of costs was written, so an add-on can keep a history.
		 *
		 * @param array[] $results One entry per item: productId, variantId, ok, and previousCents/newCents when ok.
		 */
		do_action( 'madecost_costs_written', $results );

		return $results;
	}

	/**
	 * Write one cost.
	 *
	 * @param array $item productId, variantId, costCents.
	 * @return array
	 */
	private function write_one( array $item ): array {
		$product_id = $item['productId'] ?? null;
		$variant_id = $item['variantId'] ?? null;
		$cents      = $item['costCents'] ?? null;
		$result     = array(
			'productId' => is_scalar( $product_id ) ? (string) $product_id : '',
			'variantId' => is_scalar( $variant_id ) ? (string) $variant_id : '',
			'ok'        => false,
		);

		if ( ! self::enabled() ) {
			return $result + array(
				'code'    => 'cogs_disabled',
				'message' => __( 'Turn on Cost of Goods Sold in WooCommerce first (Settings > Advanced > Features).', 'madecost' ),
			);
		}
		if ( ! Validator::is_int_in( $cents, 1, Validator::MAX_CENTS ) || ! ctype_digit( (string) $product_id ) || ! ctype_digit( (string) $variant_id ) ) {
			return $result + array(
				'code'    => 'invalid',
				'message' => __( 'This cost cannot be written: it is empty or out of range.', 'madecost' ),
			);
		}

		$product = wc_get_product( (int) $variant_id );
		// A variation must belong to the product the recipe is attached to.
		$belongs = $product && (
			( $product instanceof \WC_Product_Variation && (int) $product->get_parent_id() === (int) $product_id )
			|| ( $product->is_type( 'simple' ) && (int) $product->get_id() === (int) $product_id )
		);
		if ( ! $belongs || 'trash' === $product->get_status() ) {
			return $result + array(
				'code'    => 'not_found',
				'message' => __( 'This product or variation no longer exists.', 'madecost' ),
			);
		}
		if ( ! current_user_can( 'edit_post', (int) $product_id ) ) {
			return $result + array(
				'code'    => 'forbidden',
				'message' => __( 'You are not allowed to edit this product.', 'madecost' ),
			);
		}

		$previous = Catalog::to_cents( $product->get_cogs_total_value() );
		$product->set_cogs_value( round( ( (int) $cents ) / 100, 2 ) );
		if ( $product instanceof \WC_Product_Variation ) {
			$product->set_cogs_value_is_additive( false );
		}
		$product->save();

		// Read it back from the database: the cost WooCommerce will use must be the one we meant.
		$stored = wc_get_product( (int) $variant_id );
		if ( ! $stored || Catalog::to_cents( $stored->get_cogs_total_value() ) !== (int) $cents ) {
			return $result + array(
				'code'    => 'not_saved',
				'message' => __( 'WooCommerce did not keep the cost. Another plugin may be changing it.', 'madecost' ),
			);
		}

		return array(
			'productId'     => (string) $product_id,
			'variantId'     => (string) $variant_id,
			'ok'            => true,
			'previousCents' => ( null === $previous || $previous <= 0 ) ? null : $previous,
			'newCents'      => (int) $cents,
		);
	}
}