<?php
/**
 * E-commerce line item value object.
 *
 * @package AdPix\Analytics
 */

declare( strict_types = 1 );

namespace AdPix\Analytics\Model;

defined( 'ABSPATH' ) || exit;

/**
 * One product line on a commerce event.
 *
 * Ingest expands these into per-item rows, which is what makes "which campaign sells which product"
 * answerable. The field names are the collector's, not WooCommerce's, and the translation belongs
 * here rather than in the WooCommerce controller so the same shape is reachable from any other
 * commerce plugin an integration is later written for.
 */
final class LineItem {

	/**
	 * @var array<string,mixed>
	 */
	private $values;

	/**
	 * @param array<string,mixed> $values Normalised values.
	 */
	private function __construct( array $values ) {
		$this->values = $values;
	}

	/**
	 * Build a line item.
	 *
	 * @param string $item_id   Product or SKU id.
	 * @param string $item_name Product name.
	 * @param float  $price     Unit price, excluding the line discount.
	 * @param float  $quantity  Units ordered.
	 * @param array  $extra     Optional category, brand, variant, discount.
	 * @return self
	 */
	public static function create( string $item_id, string $item_name, float $price, float $quantity, array $extra = array() ): self {
		$values = array(
			'item_id'   => sanitize_text_field( $item_id ),
			'item_name' => sanitize_text_field( $item_name ),
			'price'     => round( $price, 4 ),
			// A zero quantity would make the line's revenue zero; ingest already defaults it to one, and
			// matching that here keeps the payload and the stored row telling the same story.
			'quantity'  => $quantity > 0 ? round( $quantity, 4 ) : 1.0,
		);

		foreach ( array( 'category', 'brand', 'variant' ) as $key ) {
			if ( isset( $extra[ $key ] ) && is_scalar( $extra[ $key ] ) ) {
				$text = sanitize_text_field( (string) $extra[ $key ] );
				if ( '' !== $text ) {
					$values[ $key ] = $text;
				}
			}
		}

		if ( isset( $extra['discount'] ) && is_numeric( $extra['discount'] ) ) {
			$discount = round( (float) $extra['discount'], 4 );
			if ( $discount > 0 ) {
				$values['discount'] = $discount;
			}
		}

		return new self( $values );
	}

	/**
	 * The contract shape.
	 *
	 * @return array<string,mixed>
	 */
	public function to_array(): array {
		return $this->values;
	}
}