<?php

namespace App\Services;

use App\Exceptions\RepositoryException;
use App\Models\StatementItemModel;
use App\Models\StatementModel;
use App\Models\StoreModel;
use App\Models\StoreOrderItemModel;
use App\Models\StoreOrderModel;
use Illuminate\Support\Carbon;
use Illuminate\Support\Facades\DB;

/**
 * 门店对账单生成（小程序端自助生成）
 *
 * 流程（事务内）：
 * 1. 拉取门店周期内的订单明细（排除已取消订单，按 order_item 去重防止重复入账）
 * 2. 快照当前 payment_cycle_days，settlement_date = period_end + cycle 天
 * 3. 明细快照商品名/单价/数量/重量/金额，statement_no = ST…
 */
class StatementGenerateService
{
    public function __construct(private readonly BillNumberService $billNumberService)
    {
    }

    /**
     * @param StoreModel $store 门店（回款周期从此快照）
     * @param string $periodStart 周期开始（Y-m-d）
     * @param string $periodEnd 周期结束（Y-m-d）
     */
    public function generate(StoreModel $store, string $periodStart, string $periodEnd): StatementModel
    {
        return DB::transaction(function () use ($store, $periodStart, $periodEnd) {
            $orderItems = StoreOrderItemModel::query()
                ->join('store_order', 'store_order.id', '=', 'store_order_item.order_id')
                ->where('store_order_item.store_id', $store->id)
                ->whereDate('store_order.order_date', '>=', $periodStart)
                ->whereDate('store_order.order_date', '<=', $periodEnd)
                ->where('store_order.status', '<>', StoreOrderModel::STATUS_CANCELLED)
                ->select('store_order_item.*')
                ->get();

            if ($orderItems->isEmpty()) {
                throw new RepositoryException('周期内本店无订单数据，无法生成对账单');
            }

            // 防重复入账：剔除已计入过对账单的订单明细
            $usedItemIds = StatementItemModel::query()
                ->whereIn('statement_id', StatementModel::where('store_id', $store->id)->pluck('id'))
                ->pluck('order_item_id');
            $orderItems = $orderItems->reject(fn ($item) => $usedItemIds->contains($item->id));
            if ($orderItems->isEmpty()) {
                throw new RepositoryException('周期内的订单明细均已生成过对账单');
            }

            // 快照回款周期 → 应结算日期
            $cycleDays = (int) $store->payment_cycle_days;
            $totalAmount = $orderItems->reduce(
                static fn (string $carry, $item): string => bcadd($carry, (string) $item->amount, 2),
                '0'
            );

            $statement = StatementModel::create([
                'statement_no' => $this->billNumberService->make('ST'),
                'store_id' => $store->id,
                'period_start' => $periodStart,
                'period_end' => $periodEnd,
                'total_amount' => $totalAmount,
                'payment_cycle_days' => $cycleDays,
                'settlement_date' => Carbon::parse($periodEnd)->addDays($cycleDays)->toDateString(),
                'status' => StatementModel::STATUS_PENDING,
            ]);

            $rows = [];
            $now = now();
            foreach ($orderItems as $item) {
                $rows[] = [
                    'statement_id' => $statement->id,
                    'order_id' => $item->order_id,
                    'order_item_id' => $item->id,
                    'product_id' => $item->product_id,
                    'product_name' => $item->product_name,
                    'price' => $item->price,
                    'quantity' => $item->quantity,
                    'weight' => $item->weight,
                    'amount' => $item->amount,
                    'is_reconciled' => StatementItemModel::NOT_RECONCILED,
                    'store_remark' => '',
                    'created_at' => $now,
                    'updated_at' => $now,
                ];
            }
            StatementItemModel::insert($rows);

            return $statement;
        });
    }
}