<?php

namespace App\Services;

use App\Models\CartModel;
use App\Models\CustomerLevelModel;
use App\Models\ProductModel;
use App\Models\StoreModel;

/**
 * 购物车共享服务：商品列表/详情附加购物车数量、悬浮球汇总（种数/总数量/总金额）
 *
 * 汇总口径（与 Mini/CartController::index 一致，勿偏离）：
 * - total_count = 购物车全部行数（含已下架等不可购项）
 * - total_quantity / total_amount = 仅统计可购项（商品在上架且门店已设等级），
 *   金额 = Σ 数量 × 等级上浮价（CustomerLevelModel::calcLevelPrice）
 */
class CartService
{
    /**
     * 门店购物车行映射：product_id => ['id' => 购物车行ID, 'quantity' => 数量字符串]
     * （商品列表/详情附加 cart_id/cart_quantity 用；行ID供直接加减/删除操作）
     *
     * @return array<int, array{id: int, quantity: string}>
     */
    public function cartRowMap(int $storeId): array
    {
        return CartModel::query()
            ->where('store_id', $storeId)
            ->get(['id', 'product_id', 'quantity'])
            ->keyBy('product_id')
            ->map(static fn (CartModel $row): array => [
                'id' => (int) $row->id,
                'quantity' => (string) $row->quantity,
            ])
            ->all();
    }

    /**
     * 购物车悬浮球汇总：种数/总数量/总金额（未登录或空购物车返回零值结构）
     *
     * @return array{total_count: int, total_quantity: string, total_amount: string}
     */
    public function summary(?StoreModel $store): array
    {
        $empty = ['total_count' => 0, 'total_quantity' => '0.00', 'total_amount' => '0.00'];
        if ($store === null) {
            return $empty;
        }

        $rows = CartModel::query()
            ->where('store_id', $store->id)
            ->get(['id', 'product_id', 'quantity']);
        if ($rows->isEmpty()) {
            return $empty;
        }

        $products = ProductModel::query()
            ->where('status', ProductModel::STATUS_ON)
            ->whereIn('id', $rows->pluck('product_id')->all())
            ->get(['id', 'cost_price'])
            ->keyBy('id');
        $level = $store->level_id > 0 ? $store->level : null;

        $totalQuantity = '0.00';
        $totalAmount = '0.00';
        foreach ($rows as $row) {
            $product = $products->get($row->product_id);
            if ($product === null || $level === null) {
                continue;
            }
            $price = CustomerLevelModel::calcLevelPrice($product->cost_price, $level->percent);
            $totalQuantity = bcadd($totalQuantity, (string) $row->quantity, 2);
            $totalAmount = bcadd($totalAmount, bcmul($price, (string) $row->quantity, 2), 2);
        }

        return [
            'total_count' => $rows->count(),
            'total_quantity' => $totalQuantity,
            'total_amount' => $totalAmount,
        ];
    }
}