<?php

namespace App\Services;

use App\Exceptions\RepositoryException;
use App\Models\BillModel;
use App\Models\ContainerReturnModel;
use App\Models\PurchaseOrderModel;
use App\Models\StoreModel;
use App\Models\StoreOrderItemModel;
use App\Models\StoreOrderModel;
use Illuminate\Support\Facades\DB;
use Throwable;

/**
 * 门店账单生成（采购单完成后，按门店各生成一张账单）
 *
 * 流程（事务内）：
 * 1. 锁定采购单全部有效订单，按门店分组，校验提交门店完整覆盖
 * 2. 商品金额 = 门店订单商品金额汇总（快照，生成后不可修改）
 * 3. 附加金额 = 周转筐数量×筐单价 + 托盘数量×托盘单价（单价取站点配置快照）
 * 4. 总金额 = 商品金额 + 配送费 + 附加金额；回写门店订单 bill_id 完成关联
 */
readonly class BillGenerateService
{
    public function __construct(private BillNumberService $billNumberService)
    {
    }

    /**
     * @param PurchaseOrderModel $purchase 已完成采购单
     * @param array<int, array{store_id: int, delivery_fee: string, box_num: int, tray_num: int}> $stores 按门店提交的配送费/周转筐/托盘数量
     * @param int $operatorId 生成人（后台系统用户ID）
     * @return BillModel[] 生成的账单列表
     * @throws Throwable
     */
    public function generate(PurchaseOrderModel $purchase, array $stores, int $operatorId): array
    {
        return DB::transaction(function () use ($purchase, $stores, $operatorId) {
            // 1. 行锁采购单全部有效订单（并发防护），按门店分组
            $orders = StoreOrderModel::query()
                ->where('purchase_id', $purchase->id)
                ->whereNull('deleted_at')
                ->lockForUpdate()
                ->get();
            if ($orders->isEmpty()) {
                throw new RepositoryException('采购单下无门店订单，无法生成账单');
            }
            $ordersByStore = $orders->groupBy('store_id');

            // 提交的门店必须完整覆盖采购单门店，避免漏门店造成订单未入账
            $submitted = [];
            foreach ($stores as $row) {
                $submitted[(int) $row['store_id']] = $row;
            }
            $missing = array_diff(array_map('intval', $ordersByStore->keys()->all()), array_keys($submitted));
            if ($missing !== []) {
                throw new RepositoryException('提交不完整，缺少门店账单信息：' . implode('、', $missing));
            }
            if (array_diff(array_keys($submitted), array_map('intval', $ordersByStore->keys()->all())) !== []) {
                throw new RepositoryException('包含不属于该采购单的门店');
            }

            // 2. 防重复生成：任一门店已出账则整批拒绝
            $billedStoreIds = BillModel::query()
                ->where('purchase_id', $purchase->id)
                ->pluck('store_id')
                ->map(static fn ($id) => (int) $id)
                ->all();
            if ($billedStoreIds !== []) {
                $names = StoreModel::withTrashed()
                    ->whereIn('id', $billedStoreIds)
                    ->pluck('name')
                    ->implode('、');
                throw new RepositoryException('以下门店已生成账单，不允许重复生成：' . $names);
            }

            // 3. 逐门店生成账单并关联订单
            $boxPrice = (string) site_config('services.box_amount', 0);
            $trayPrice = (string) site_config('services.tray_amount', 0);
            $billDate = now()->toDateString();
            $bills = [];
            foreach ($ordersByStore as $storeId => $storeOrders) {
                $row = $submitted[(int) $storeId];

                $productAmount = $storeOrders->reduce(
                    static fn (string $carry, StoreOrderModel $order): string => bcadd($carry, (string) $order->total_amount, 2),
                    '0'
                );
                $deliveryFee = bcadd((string) $row['delivery_fee'], '0', 2);
                $addedAmount = bcadd(
                    bcmul((string) (int) $row['box_num'], $boxPrice, 2),
                    bcmul((string) (int) $row['tray_num'], $trayPrice, 2),
                    2
                );
                $totalAmount = bcadd(bcadd($productAmount, $deliveryFee, 2), $addedAmount, 2);

                $bill = BillModel::create([
                    'bill_no' => $this->billNumberService->make('ZD'),
                    'purchase_id' => $purchase->id,
                    'store_id' => (int) $storeId,
                    'bill_date' => $billDate,
                    'product_amount' => $productAmount,
                    'delivery_fee' => $deliveryFee,
                    'box_num' => (int) $row['box_num'],
                    'tray_num' => (int) $row['tray_num'],
                    'box_price' => bcadd($boxPrice, '0', 2),
                    'tray_price' => bcadd($trayPrice, '0', 2),
                    'added_amount' => $addedAmount,
                    'total_amount' => $totalAmount,
                    'operator_id' => $operatorId,
                ]);

                // 关联该门店在采购单中的全部订单与订单明细到账单
                StoreOrderModel::query()
                    ->whereIn('id', $storeOrders->pluck('id'))
                    ->update(['bill_id' => $bill->id]);
                StoreOrderItemModel::query()
                    ->whereIn('order_id', $storeOrders->pluck('id'))
                    ->update(['bill_id' => $bill->id]);

                // 压筐：累加门店待回筐/托盘（行锁防并发），并写入压筐记录
                $store = StoreModel::query()->lockForUpdate()->find((int) $storeId);
                if ($store !== null) {
                    $store->pending_box_num = (int) $store->pending_box_num + (int) $row['box_num'];
                    $store->pending_tray_num = (int) $store->pending_tray_num + (int) $row['tray_num'];
                    $store->save();
                }
                ContainerReturnModel::create([
                    'store_id' => (int) $storeId,
                    'bill_id' => $bill->id,
                    'type' => ContainerReturnModel::TYPE_PRESS,
                    'box_num' => (int) $row['box_num'],
                    'tray_num' => (int) $row['tray_num'],
                    'return_date' => $billDate,
                    'operator_id' => $operatorId,
                ]);

                $bills[] = $bill;
            }

            return $bills;
        });
    }
}