<?php

namespace app\common\tools;

use app\ydyd_service\model\ShoppingCartModel;
use think\facade\Cache;

class Cart
{

    // 个人购物车标记前缀
    protected $cartName = 'USER_CART_INFO_';
    // 商品数据
    protected $goods = [];
    // 当前用户
    protected $user_id = 0;

    public function __construct()
    {
        $init_flag = false;
        $this->user_id = session('user_id');
        $this->cartName .= $this->user_id;
        $default_data = Cache::get($this->cartName)['goods_list']??[];//缓存数据索引：goods_list
        if (!$default_data){
            $_where[] = ['user_id',"=",$this->user_id];
            $_where[] = ['type',"=",''];//type为空：自营；否则如 hy：华源(目前统一标记为extend)
            //购物车数据--shopping_cart表
            $cart_data = ShoppingCartModel::field("batch_id as id,goods_number as num, unit_price as price")->where($_where)->select()->toArray();
            if ($cart_data){
                $init_flag = true;//true：shopping_cart表存在该用户的数据
                foreach ($cart_data as $item){
                    $this->add($item, true);//添加到购物车数据缓存,返回值(类型：布尔)未处理
                }

            }
        }
        if (!$init_flag){
            $this->setGoods($default_data);//缓存数据存在时，$this->goods = 缓存数据;
        }
    }

    public function getGoods()
    {
        return $this->goods;
    }

    public function setGoods($goods)
    {
        $this->goods = $goods;
    }

    /**
     * @todo 现有业务逻辑待厘清
     * 添加购物车 同时更新model
     * @access  public
     * @param array $data
     *      $data为数组包含以下几个值
     *      $Data= [
     *          "id"=>1,                        //批次ID
     *          "num"=>2,                       //商品数量
     *          "options"=>array()              //其他参数，如价格、颜色可以是数组或字符串|可以不添加
     *      ]
     *
     * @throws \Exception
     * @return void
     */
    public function add($data,$init_flag = false)
    {
        if (!is_array($data) || !isset($data['id']) || !isset($data['num']) || !isset($data['price']) || ($data['price'] <0)) {
            throw new \Exception('购物车ADD方法参数设置错误');//抛出异常，keys：捕获异常--异常处理
        }
        //添加商品支持多商品添加
        //$options = isset($data['options']) ? $data['options'] : '';
        //$sid     = md5($data['id']);
        $sid = $data['id'];//batch_id
        $_where[] = ['user_id',"=",$this->user_id];
        $_where[] = ["batch_id","=",$sid];
        //生成唯一ID用于处理相同商品有不同属性时
        if (isset($this->goods[$sid])) {//缓存已存在？
            //如果数量为0删除商品
            if ($data['num'] == 0) {
                unset($this->goods[$sid]);
                if (!$init_flag){//缓存发起删除shopping_cart记录？
                    //user_id+batch_id校验足矣？
                    ShoppingCartModel::where($_where)->delete();//模型delete？模型对象or数据表？软删除？
                }
            } else {//不为0 增加
                //已经存在相同商品时增加商品数量
                $this->goods[$sid]['num']   = $this->goods[$sid]['num'] + $data['num'];
                $this->goods[$sid]['total'] = $this->goods[$sid]['num'] * $this->goods[$sid]['price'];//两次添加，销售价格不一样未处理
                if (!$init_flag){
                    if ($this->goods[$sid]['num'] > 0){
                        $update_data['goods_number'] = $this->goods[$sid]['num'];
                        $update_data['unit_price'] = $this->goods[$sid]['price'];
                        ShoppingCartModel::where($_where)->update($update_data);
                    }else{
                        ShoppingCartModel::where($_where)->delete();
                    }
                }
            }
        } else {//不存在 写入
            if ($data['num'] > 0) {
                $this->goods[$sid]          = $data;//batch_id索引对应商品数据
                $this->goods[$sid]['total'] = $data['num'] * $data['price'];//金额

                if (!$init_flag) {
                    $add_data['user_id'] = $this->user_id;
                    $add_data['batch_id'] = $sid;
                    $add_data['unit_price'] = $data['price'];
                    $add_data['goods_number'] = $data['num'];
                    ShoppingCartModel::create($add_data);
                }
            }
        }
        //存在问题：每add一条数据即缓存一次。
        //修改方案：放到__construct方法内，所有数据add之后(foreach结束后)设置一次缓存
        return $this->store();
    }

    /**
     * 保存到缓存
     *
     * 缓存数据结构
     * $cart =
     * [
     *      'goods_list'=>[
     *          'batch_id'=>['batch_id'=>$batch_id,'goods_num'=>$num,'price'=>$price],//新增shopping_cart_id 用于匹配shopping_cart表记录
     *          'batch_id'=>['batch_id'=>$batch_id,'goods_num'=>$num,'price'=>$price],
     *      ],
     *      'total_num' =>$num,//batch_id数量，相同batch_id合并处理
     *      'total_price'=>$total_price,//总金额
     * ]
     *
     * 重点 ： $goods 赋值逻辑！
     */
    private function store()
    {
        $cart = [
            'goods_list'       => $this->goods,
            'total_num'   => $this->getTotalNums(),
            'total_price' => $this->getTotalPrice(),
        ];
        return Cache::set($this->cartName,$cart,config('SYSTEM_CONSTANT')['USER_INFO_CACHE_TIME']);
    }

    /**
     * 统计购物车中商品分类数量
     */
    public function getTotalNums()
    {
        $rows = 0;
        foreach ($this->goods as $v) {
            //$rows += $v['num'];
            $rows ++;
        }
        return $rows;
    }

    /**
     * 获得商品汇总价格
     */
    public function getTotalPrice()
    {
        $total = 0;
        foreach ($this->goods as $v) {
            $total += $v['price'] * $v['num'];
        }
        return $total;
    }

    /**
     * 更新购物车数量(update+delete操作)
     * 适用场景：
     * 1.删除购物车数据，传值goods_number=0
     * 2.更新shopping_cart表中价格和数量信息
     *
     * @param $data
     *  $data=[
     *      "sid"=>'', //商品的唯一SID
     *      "num"=>2, //商品数量
     *  ]
     * @return bool
     * @throws \Exception
     */
    public function update($data)
    {
        if ( ! isset($data['sid']) || ! isset($data['num'])) {
            throw new \Exception('购物车update方法参数错误，缺少sid或num值');
        }
        $sid = $data['sid'];
        $_where[] = ['user_id',"=",$this->user_id];
        $_where[] = ["batch_id","=",$sid];
        if (isset($this->goods[$sid])) {
            if ($data['num'] == 0) {
                unset($this->goods[$sid]);
                ShoppingCartModel::where($_where)->delete();
            } else {
                $this->goods[$sid]['num'] = $data['num'];
                if (isset($data['price']) && is_numeric($data['price']) && $data['price'] > 0){
                    $this->goods[$sid]['price'] = $data['price'];
                }
                $this->goods[$sid]['total'] = $data['num'] * $this->goods[$sid]['price'];

                $update_data['goods_number'] = $this->goods[$sid]['num'];
                $update_data['unit_price'] = $this->goods[$sid]['price'];
                ShoppingCartModel::where($_where)->update($update_data);
            }
            return $this->store();
        }
        return false;
    }

    /**
     * 获得购物车中的所有数据(缓存中取出，初始状态为空)
     * @return mixed
     */
    public function getAllData()
    {
        $this->store();//缓存数据,此处已有返回值，下一行冗余，直接return 本行,方法体改为： return $this->store();
        return Cache::get($this->cartName);//cartName格式：前缀+user_id缓存值(session)
    }

    /**
     * 获取购物车内所有商品的ID信息(batch_id)
     * @return array
     */
    public function getAllId()
    {
        $id_arr = [];
        foreach ($this->goods as $k => $item) {
            $id_arr[] = $k;
        }
        return $id_arr;
    }

    /**
     * 删除购物车,同步删除数据库表记录
     * @param $sid 商品SID编号
     * @return bool
     * @throws \Exception
     */
    public function del($sid)
    {
        if (isset($this->goods[$sid])) {
            unset($this->goods[$sid]);
            $_where[] = ['user_id',"=",$this->user_id];
            $_where[] = ["batch_id","=",$sid];
            ShoppingCartModel::where($_where)->delete();
            $this->store();
            return true;
        }
        return false;
    }

    /**
     * 删除所有商品
     * @return bool
     * @throws \Exception
     */
    public function flush()
    {
        ShoppingCartModel::where("user_id",$this->user_id)->delete();
        $this->setGoods([]);
        $this->store();
        return true;
    }
}