<?php
/**
 * Smart reorder dashboard + bulk PO creation.
 *
 * @package ProfitEngine
 */

declare( strict_types=1 );

namespace ProfitEngine\Forecasting;

use ProfitEngine\Purchasing\ProductSettingsRepository;
use ProfitEngine\Purchasing\SupplierProductRepository;
use ProfitEngine\PurchaseOrders\POService;
use ProfitEngine\Support\Money;
use ProfitEngine\Support\ProductResolver;
use WP_Error;

defined( 'ABSPATH' ) || exit;

/**
 * Turns cached forecasts into an actionable reorder list and creates purchase
 * orders from selected items, automatically grouped by supplier.
 */
class ReorderService {

	private ForecastRepository $forecasts;

	private ProductSettingsRepository $settings;

	private SupplierProductRepository $supplier_products;

	private ProductResolver $resolver;

	private POService $po_service;

	/**
	 * Constructor.
	 *
	 * @param ForecastRepository        $forecasts         Forecast repo.
	 * @param ProductSettingsRepository $settings          Settings repo.
	 * @param SupplierProductRepository $supplier_products Supplier-product repo.
	 * @param ProductResolver           $resolver          Product resolver.
	 * @param POService                 $po_service        PO service.
	 */
	public function __construct(
		ForecastRepository $forecasts,
		ProductSettingsRepository $settings,
		SupplierProductRepository $supplier_products,
		ProductResolver $resolver,
		POService $po_service
	) {
		$this->forecasts         = $forecasts;
		$this->settings          = $settings;
		$this->supplier_products = $supplier_products;
		$this->resolver          = $resolver;
		$this->po_service        = $po_service;
	}

	/**
	 * The reorder list.
	 *
	 * @param array<string,mixed> $args Filters (severity, supplier).
	 * @return array{items:array<int,array<string,mixed>>,counts:array<string,int>,meta:array<string,mixed>}
	 */
	public function list( array $args ): array {
		$severities = ! empty( $args['severity'] )
			? array( (string) $args['severity'] )
			: array( 'critical', 'warning', 'recommended' );

		$rows            = $this->forecasts->by_severity( $severities );
		$supplier_filter = (int) ( $args['supplier'] ?? 0 );
		$items           = array();

		foreach ( $rows as $f ) {
			$item = $this->enrich( $f );
			if ( $supplier_filter > 0 && $item['supplier_id'] !== $supplier_filter ) {
				continue;
			}
			$items[] = $item;
		}

		return array(
			'items'  => $items,
			'counts' => $this->forecasts->severity_counts(),
			'meta'   => array(
				'configured_products'    => $this->settings->count_enabled(),
				'forecasted_products'    => $this->forecasts->count_all(),
				'products_with_velocity' => $this->forecasts->count_with_velocity(),
				'severity_filter'        => (string) ( $args['severity'] ?? '' ),
			),
		);
	}

	/**
	 * Create draft purchase orders from selected reorder lines, grouped by supplier.
	 *
	 * @param array<int,array{product_id:int,qty:float}> $selections Selections.
	 * @return array{created:array<int,array<string,mixed>>,skipped:int[]}|WP_Error
	 */
	public function create_pos( array $selections ) {
		if ( empty( $selections ) ) {
			return new WP_Error( 'profit_engine_reorder_empty', __( 'Nothing selected.', 'profit-engine' ), array( 'status' => 400 ) );
		}

		$groups  = array();
		$skipped = array();

		foreach ( $selections as $sel ) {
			$product_id = (int) ( $sel['product_id'] ?? 0 );
			$qty        = (float) ( $sel['qty'] ?? 0 );
			if ( $product_id <= 0 || $qty <= 0 ) {
				continue;
			}

			$primary = $this->supplier_products->primary_for_product( $product_id );
			if ( ! $primary ) {
				$skipped[] = $product_id;
				continue;
			}

			$supplier_id              = (int) $primary['supplier_id'];
			$groups[ $supplier_id ][] = array(
				'product_id'   => $product_id,
				'supplier_sku' => (string) $primary['supplier_sku'],
				'qty_ordered'  => $qty,
				'unit_cost'    => Money::to_float( $primary['purchase_cost'] ),
			);
		}

		$created = array();
		foreach ( $groups as $supplier_id => $items ) {
			$po = $this->po_service->create(
				array(
					'supplier_id' => $supplier_id,
					'items'       => $items,
				)
			);
			if ( ! is_wp_error( $po ) ) {
				$created[] = array(
					'id'            => $po['id'],
					'po_number'     => $po['po_number'],
					'supplier_name' => $po['supplier_name'],
					'item_count'    => count( $po['items'] ),
					'grand_total'   => $po['grand_total'],
				);
			}
		}

		return array(
			'created' => $created,
			'skipped' => array_values( array_unique( $skipped ) ),
		);
	}

	/**
	 * Enrich a forecast row with product/supplier/cost info for the UI.
	 *
	 * @param array<string,mixed> $f Forecast row.
	 * @return array<string,mixed>
	 */
	private function enrich( array $f ): array {
		$pid      = (int) $f['product_id'];
		$primary  = $this->supplier_products->primary_for_product( $pid );
		$settings = $this->settings->get( $pid );

		$unit_cost = 0.0;
		if ( $primary ) {
			$unit_cost = Money::to_float( $primary['purchase_cost'] );
		} elseif ( $settings ) {
			$unit_cost = Money::to_float( $settings['current_cost'] );
		}

		$suggested = (int) $f['suggested_qty'];

		return array(
			'product_id'      => $pid,
			'label'           => $this->resolver->unit_label( $pid ),
			'sku'             => $this->resolver->sku( $pid ),
			'severity'        => (string) $f['severity'],
			'confidence'      => (string) $f['confidence'],
			'current_stock'   => Money::to_float( $f['current_stock'] ),
			'avg_daily_sales' => Money::to_float( $f['avg_daily_sales'] ),
			'days_remaining'  => Money::to_float( $f['days_remaining'] ),
			'qty_on_open_pos' => Money::to_float( $f['qty_on_open_pos'] ),
			'suggested_qty'   => $suggested,
			'unit_cost'       => $unit_cost,
			'estimated_cost'  => $suggested * $unit_cost,
			'supplier_id'     => $primary ? (int) $primary['supplier_id'] : 0,
			'supplier_name'   => $primary ? (string) $primary['supplier_name'] : '',
		);
	}
}