<?php

namespace App\Services;

use App\Models\Activity;
use App\Models\Coupon;
use App\Models\ProductPart;
use App\Models\ReceivePartCouponLog;
use App\Models\User;
use App\Models\UserCoupon;
use Illuminate\Database\QueryException;

class CouponService
{
    /**
     * 根据SKU商品获取可用优惠券
     *
     * @param User $user
     * @param array $products 至少包含以下内容
     *  [
     *      ['sku' => 商品SKU, 'quantity' => 10]
     *  ]
     * @return array
     */
    public function getAvailableCoupons(User $user, array $products): array
    {
        $coupons = $user->coupons()->onlyAvailable()->get();

        $coupons->load(['ranges' => function ($query) {
            $query->isEnable();
        }]);

        $availableCoupons = [];

        foreach ($coupons as $coupon) {
            // 是否满足券使用规则
            $passes = false;

            // 可用优惠券的商品的总额
            $amount = 0;

            foreach ($products as $product) {
                $sku = $product['sku'];

                if ($coupon->isSupport($sku)) {
                    $passes = true;

                    $amount += $sku->getRealPrice($user) * $product['quantity'];
                }
            }

            if ($passes && $amount >= $coupon->coupon_threshold) {
                $availableCoupons[] = $coupon;
            }
        }

        return $availableCoupons;
    }

    /**
     * 根据分区，领取优惠券
     */
    public function receivePartCoupon(ProductPart $part, User $user)
    {
        //如果分区不显示，直接退出；
        if (!$part->is_show) {
            return;
        }
        //如果用户已领取过该分区设置的券，直接退出；
        if (ReceivePartCouponLog::where(['user_id'=>$user->id, 'part_id'=>$part->id])->exists()) {
            return;
        }

        //取出需要发放的券
        $coupons = Coupon::whereIn('id', $part->coupons->pluck('coupon_id')->toArray())->get();
        $coupons = $coupons->keyBy('id');
        $someCoupons = [];
        foreach ($part->coupons as $coupon) {
            $someCoupons[] = [
                'coupon'=>$coupons[$coupon->coupon_id],
                'num'=>$coupon->num,
            ];
        }
        $this->receiveSomeCoupons($user, $someCoupons);

        ReceivePartCouponLog::create(['user_id'=>$user->id, 'part_id'=>$part->id]);
    }

    /**
     * 根据活动领取优惠券
     *
     * @return void
     */
    public function receiveActivityCoupons(Activity $activity, User $user)
    {
        $someCoupons = [];
        foreach ($activity->coupons as $coupon) {
            $someCoupons[] = [
                'coupon'=>$coupon,
                'num'=>$coupon->pivot->qty,
            ];
        }
        $this->receiveSomeCoupons($user, $someCoupons, $activity->id);
    }

    /**
     * 领取一批券
     *
     * @param User $user
     * @param array $coupons
     * @return void
     */
    protected function receiveSomeCoupons(User $user, array $coupons, ?int $activityId = null)
    {
        $userCoupons = [];
        foreach ($coupons as $key=> $coupon) {
            //更新对应券发送量，余量;
            try {
                $canSent = true;
                if ($coupon['coupon']->limit > 0) {//限量才减少余量
                    $coupon['coupon']->decrement('stock', $coupon['num']);
                }
            } catch (QueryException $e) {
                if (strpos($e->getMessage(), 'Numeric value out of range') !== false) {
                    $canSent = false;
                } else {
                    throw new $e();
                }
            }
            if ($canSent) {
                for ($i = 0; $i < $coupon['num']; $i++) {
                    $userCoupons[] = self::createUserCouponData($user->id, $coupon['coupon'], $activityId ?? null);
                }
                $coupon['coupon']->increment('sent', $coupon['num']);
            }
        }
        UserCoupon::insert($userCoupons);
    }

    /**
     * todo-领取指定券
     *
     * @param User $user
     * @param Coupon $coupon
     * @param int $num
     * @return void
     */
    public function receiveCoupon(User $user, Coupon $coupon, int $num = 1)
    {
        return;
    }

    /**
     * 创建用户券数据
     *
     * @return array
     */
    public static function createUserCouponData(int $userId, Coupon $coupon, ?int $activityId = null)
    {
        //如果userId小于等于0，直接退出
        if ($userId <= 0) {
            return [];
        }
        if ($coupon->use_start_at && $coupon->use_end_at) {
            $useStartAt = $coupon->use_start_at;
            $useEndAt = $coupon->use_end_at;
        } else {
            $useStartAt = now();
            $useEndAt = now()->addDays($coupon->use_day);
        }
        return [
            'user_id'       => $userId,
            'coupon_id'     => $coupon->id,
            'coupon_name'   => $coupon->name,
            'coupon_type'   => $coupon->type,
            'coupon_amount' => (int) bcmul($coupon->amount, 100),
            'coupon_threshold'=> (int) bcmul($coupon->threshold, 100),
            'use_start_at'  => $useStartAt,
            'use_end_at'    => $useEndAt,
            'created_at'    => now(),
            'updated_at'    => now(),
            'activity_id'   => $activityId ?? null,
        ];
    }
}