<?php

namespace Peidikeji\Goods;

use Peidikeji\Goods\Models\{Goods, GoodsSku};
use Illuminate\Support\Str;

class GoodsService
{
    public static function make(...$params)
    {
        return new static(...$params);
    }

    public function generateSn()
    {
        return (string)Str::uuid();
    }

    public function clearSku(Goods $goods)
    {
        GoodsSku::where('goods_id', $goods->id)->delete();
    }

    /**
     * 根据规格生成SKU
     *
     * @param Goods $goods 商品
     * @param array $options {spec: 指定规格, price: 基础价格, name: 基础名称, stock: 默认库存, name_add: 是否在名称上面追加属性值, price_add: 是否在价格上面追加属性的加价, force: 是否覆盖原有的货品}
     */
    public function generateSku(Goods $goods, $options = [])
    {
        $spec = data_get($options, 'spec', $goods->spec);
        $price = data_get($options, 'price', $goods->price);
        $name = data_get($options, 'name', $goods->name);
        $stock = data_get($options, 'stock', $goods->stock);
        $nameAdd = !!data_get($options, 'name_add', false);
        $priceAdd = !!data_get($options, 'price_add', false);
        $force = !!data_get($options, 'force', false);
        if ($spec) {
            $specList = [];
            foreach ($spec as $item) {
                $items = [];
                foreach($item['values'] as $value) {
                    array_push($items, [
                        'name' => $item['name'],
                        'value' => $value['value'],
                        'price' => floatval($value['price']),
                    ]);
                }
                array_push($specList, $items);
            }
            $cartesianList = $this->cartesianProduct($specList);
            foreach($cartesianList as $items) {
                $specPrice = $priceAdd ? $price + array_sum(array_column($items, 'price')) : $price;
                $specName = $nameAdd ? $name . ' ' . implode(' ', array_column($items, 'value')) : $name;
                $exists = $goods->skus()->jsonArray($items)->exists();
                $attributes = [
                    'name' => $specName,
                    'price' => $specPrice,
                    'stock' => $stock,
                    'spec' => $items,
                ];
                if ($exists) {
                    if ($force) {
                        $goods->skus()->jsonArray($items)->update($attributes);
                    }
                } else {
                    $attributes['sn'] = $this->generateSn();
                    $goods->skus()->create($attributes);
                }
            }
        }
    }

    protected function cartesianProduct($sets)
    {
        // 保存结果
        $result = [];
        if (count($sets) === 1) {
            // 保存临时数据
            $tmp = array();
            // 结果与下一个集合计算笛卡尔积
            foreach($sets[0] as $set) {
                $item = [];
                if (isset($set['value'])) {
                    array_push($item, $set);
                } else {
                    $item = $set;
                }
                array_push($item, $set);
                $tmp[] = $item;
            }
            // 将笛卡尔积写入结果
            $result = $tmp;
            return $result;
        }
        // 循环遍历集合数据
        for($i = 0; $i < count($sets) -1 ; $i++) {
            // 初始化
            if($i==0){
                $result = $sets[$i];
            }
            // 保存临时数据
            $tmp = array();
            // 结果与下一个集合计算笛卡尔积
            foreach($result as $res) {
                foreach($sets[$i+1] as $set) {
                    $item = [];
                    if (isset($res['value'])) {
                        array_push($item, $res);
                    } else {
                        $item = $res;
                    }
                    array_push($item, $set);
                    $tmp[] = $item;
                }
            }
            // 将笛卡尔积写入结果
            $result = $tmp;
        }
        return $result;
    }
}