<?php

namespace App\Services;

use App\Exceptions\RepositoryException;
use App\Models\ProductModel;
use App\Models\PurchaseOrderModel;
use App\Models\StoreOrderItemModel;
use App\Models\StoreOrderModel;
use Illuminate\Support\Facades\DB;
use Throwable;

/**
 * 采购单数据修改
 */
class PurchaseEditService
{

    /**
     * 商品行修改：品名/供应商/包规/单位/成本一键同步该商品全部订货明细；
     * syncProduct = true 时同步更新商品档案（product 表）
     *
     * @param PurchaseOrderModel $purchase
     * @param int $productId
     * @param array{product_name?: string, supplier_id?: int, product_spec?: string, unit?: string, cost_price?: float} $attrs 行属性（仅同步传入键）
     * @param bool $syncProduct
     * @return int
     * @throws Throwable
     */
    public function updateRow(PurchaseOrderModel $purchase, int $productId, array $attrs, bool $syncProduct = false): int
    {
        return DB::transaction(function () use ($purchase, $productId, $attrs, $syncProduct) {
            $items = StoreOrderItemModel::query()
                ->where('purchase_id', $purchase->id)
                ->where('product_id', $productId)
                ->lockForUpdate()
                ->get();
            if ($items->isEmpty()) {
                throw new RepositoryException('该采购单下无此商品的订货明细');
            }

            $sync = [];
            if (isset($attrs['product_name'])) {
                $sync['product_name'] = $attrs['product_name'];
            }
            if (isset($attrs['supplier_id'])) {
                $sync['supplier_id'] = (int) $attrs['supplier_id'];
            }
            if (isset($attrs['product_spec'])) {
                $sync['product_spec'] = $attrs['product_spec'];
            }
            if (isset($attrs['unit'])) {
                $sync['unit'] = $attrs['unit'];
            }
            if (isset($attrs['cost_price'])) {
                $sync['cost_price'] = bcadd((string) $attrs['cost_price'], '0', 2);
            }
            if ($sync !== []) {
                foreach ($items as $item) {
                    $item->fill($sync)->save();
                }

                // 同步至商品档案
                if ($syncProduct) {
                    $product = ProductModel::withTrashed()->find($productId);
                    if ($product === null || $product->trashed()) {
                        throw new RepositoryException('商品档案不存在或已删除，无法同步至商品');
                    }
                    $productAttrs = [];
                    if (isset($sync['product_name'])) {
                        $productAttrs['name'] = $sync['product_name'];
                    }
                    if (isset($sync['supplier_id'])) {
                        $productAttrs['supplier_id'] = $sync['supplier_id'];
                    }
                    if (isset($sync['product_spec'])) {
                        $productAttrs['spec'] = $sync['product_spec'];
                    }
                    if (isset($sync['unit'])) {
                        $productAttrs['unit'] = $sync['unit'];
                    }
                    if (isset($sync['cost_price'])) {
                        $productAttrs['cost_price'] = $sync['cost_price'];
                    }
                    $product->fill($productAttrs)->save();
                }
            }

            $this->recalculatePurchaseTotals($purchase);

            return $items->count();
        });
    }

    /**
     * 重算采购金额汇总
     */
    public function recalculatePurchaseTotals(PurchaseOrderModel $purchase): void
    {
        $items = StoreOrderItemModel::query()
            ->where('purchase_id', $purchase->id)
            ->get(['quantity', 'cost_price']);

        $totalQuantity = 0;
        $estimate = '0';
        foreach ($items as $item) {
            $totalQuantity += $item->quantity;
            $item_estimate = bcmul($item->cost_price, $item->quantity, 2);
            $estimate = bcadd($estimate, $item_estimate, 2);
        }

        $purchase->total_quantity = $totalQuantity;
        $purchase->estimate_amount = $estimate;
        $purchase->save();
    }

    /**
     * 采购成本金额：称重>0 按 称重×单价，否则按 数量×单价
     */
    public static function costAmount(string $quantity, string $weight, string $unitCost): string
    {
        return (float) $weight > 0
            ? bcmul($weight, $unitCost, 2)
            : bcmul($quantity, $unitCost, 2);
    }

    /**
     * 单价 = 成本 / 包规数值（spec 解析不出正数时按 1 处理，即单价=成本）
     */
    public static function unitCost(string $costPrice, string $spec): string
    {
        if (preg_match('/\d+(?:\.\d+)?/', $spec, $matches) === 1 && (float) $matches[0] > 0) {
            return bcdiv($costPrice, $matches[0], 2);
        }

        return bcadd($costPrice, '0', 2);
    }
}