<?php

namespace App\Services;

use App\Exceptions\RepositoryException;
use App\Models\ProductCategoryModel;
use App\Models\ProductModel;
use App\Models\ReconciliationItemModel;
use App\Models\ReconciliationModel;
use App\Models\StoreOrderItemModel;
use App\Models\StoreOrderModel;
use Illuminate\Support\Facades\DB;

/**
 * 对账明细构建（D1 品类 / D2 供应商筛选）
 *
 * 流程（事务内，可重复 build：先清后建）：
 * 1. 按周期 + 品类（含子孙分类）+ 供应商拉取「已完成」门店订单的订货明细
 * 2. 每条订货明细 → 一条对账明细：
 *    publish_amount = 订货金额（order_item.amount = 每包等级价×数量）
 *    actual_amount  = 采购成本（数量 × 每包成本价；单价/包规不参与金额计算）
 *    diff = publish − actual，冗余 product_name / store_id
 * 3. 汇总写回头的 publish/actual/diff_amount，status → 对账中
 */
class ReconciliationBuildService
{
    /**
     * @return int 生成的对账明细数
     */
    public function build(ReconciliationModel $recon): int
    {
        return DB::transaction(function () use ($recon) {
            // 1. 按周期 + 品类 + 供应商拉取已完成订单的订货明细
            $itemQuery = StoreOrderItemModel::query()
                ->join('store_order', 'store_order.id', '=', 'store_order_item.order_id')
                ->where('store_order.status', StoreOrderModel::STATUS_COMPLETED)
                ->whereNull('store_order.deleted_at')
                ->whereDate('store_order.order_date', '>=', $recon->period_start)
                ->whereDate('store_order.order_date', '<=', $recon->period_end)
                ->select('store_order_item.*');

            if ((int) $recon->supplier_id > 0) {
                $itemQuery->where('store_order_item.supplier_id', $recon->supplier_id);
            }
            if ((int) $recon->category_id > 0) {
                $itemQuery->whereIn(
                    'store_order_item.category_id',
                    $this->descendantCategoryIds((int) $recon->category_id)
                );
            }

            $orderItems = $itemQuery->get()->makeVisible('cost_price');
            if ($orderItems->isEmpty()) {
                throw new RepositoryException('周期内无符合筛选条件的已完成订单数据，无法生成对账明细');
            }

            // 2. 先清后建（幂等）
            ReconciliationItemModel::where('recon_id', $recon->id)->delete();

            $publishTotal = '0';
            $actualTotal = '0';
            $rows = [];
            $sort = 1;
            $now = now();
            foreach ($orderItems as $orderItem) {
                $publish = (string) $orderItem->amount;
                $actual = bcmul((string) $orderItem->quantity, (string) ($orderItem->cost_price ?? '0'), 2);
                $publishTotal = bcadd($publishTotal, $publish, 2);
                $actualTotal = bcadd($actualTotal, $actual, 2);

                $rows[] = [
                    'recon_id' => $recon->id,
                    'store_id' => $orderItem->store_id,
                    'order_item_id' => $orderItem->id,
                    'product_id' => $orderItem->product_id,
                    'product_name' => $orderItem->product_name,
                    'quantity' => $orderItem->quantity,
                    'weight' => $orderItem->weight,
                    'publish_amount' => $publish,
                    'actual_amount' => $actual,
                    'diff_amount' => bcsub($publish, $actual, 2),
                    'is_reconciled' => ReconciliationItemModel::NOT_RECONCILED,
                    'store_remark' => '',
                    'sort' => $sort++,
                    'created_at' => $now,
                    'updated_at' => $now,
                ];
            }
            ReconciliationItemModel::insert($rows);

            // 3. 汇总写回头 + 状态流转
            $recon->publish_amount = $publishTotal;
            $recon->actual_amount = $actualTotal;
            $recon->diff_amount = bcsub($publishTotal, $actualTotal, 2);
            $recon->status = ReconciliationModel::STATUS_WORKING;
            $recon->save();

            return count($rows);
        });
    }

    /**
     * 分类自身 + 全部子孙分类ID（多级分类下按顶级分类筛选）
     *
     * @return array<int, int>
     */
    private function descendantCategoryIds(int $categoryId): array
    {
        $parentMap = ProductCategoryModel::pluck('parent_id', 'id');
        $ids = [$categoryId];
        $queue = [$categoryId];
        while ($queue !== []) {
            $current = array_shift($queue);
            foreach ($parentMap as $id => $parentId) {
                if ((int) $parentId === $current && ! in_array((int) $id, $ids, true)) {
                    $ids[] = (int) $id;
                    $queue[] = (int) $id;
                }
            }
        }

        return $ids;
    }
}