<?php

namespace addons\shopro\library\commission;

use think\Db;

/**
 * 复购立减服务类
 * 针对指定商品（开启复购规则）且买家历史买过的商品，在付款时直接减免
 */
class RepurchaseService
{
    /**
     * 获取全局复购立减配置
     *
     * @return array
     */
    public static function getConfig()
    {
        $config = [];
        try {
            $configModel = new Config();
            $config = [
                'enable' => $configModel->isRepurchaseEnable(),
                'self_enable' => $configModel->isRepurchaseSelfEnable(),
                'self_type' => $configModel->getRepurchaseSelfType(),
                'self_amount' => $configModel->getRepurchaseSelfAmount(),
                'self_rate' => $configModel->getRepurchaseSelfRate(),
            ];
        } catch (\Throwable $e) {
            $config = [
                'enable' => false,
                'self_enable' => false,
                'self_type' => 'fixed',
                'self_amount' => 0.0,
                'self_rate' => 0.0,
            ];
        }

        return $config;
    }

    /**
     * 检查商品是否开启复购规则
     *
     * @param int $goodsId
     * @return bool
     */
    public static function isGoodsRepurchaseEnable($goodsId)
    {
        if (!$goodsId) {
            return false;
        }

        try {
            $row = Db::name('shopro_commission_goods')
                ->where('goods_id', $goodsId)
                ->where('status', 1)
                ->field('repurchase_enable')
                ->find();
            return !empty($row['repurchase_enable']);
        } catch (\Throwable $e) {
            return false;
        }
    }

    /**
     * 检查用户是否曾购买过该指定商品（有效付款订单）
     *
     * @param int $userId
     * @param int $goodsId
     * @return bool
     */
    public static function isUserRepurchasedGoods($userId, $goodsId)
    {
        if (!$userId || !$goodsId) {
            return false;
        }

        try {
            $count = Db::name('shopro_order_item')
                ->alias('oi')
                ->join('shopro_order o', 'o.id = oi.order_id')
                ->where('o.user_id', $userId)
                ->where('o.status', 'in', [1, 2])
                ->where('oi.goods_id', $goodsId)
                ->where('oi.refund_status', '<=', 0)
                ->count();

            return $count > 0;
        } catch (\Throwable $e) {
            return false;
        }
    }

    /**
     * 计算单项商品的复购立减金额
     *
     * @param array $item 商品信息 (goods_id, goods_num, goods_price, goods_amount)
     * @param array $config 复购配置
     * @param bool $isGoodsEnable 该商品是否开启复购
     * @param bool $isUserRepurchase 该用户是否复购该商品
     * @return float
     */
    public static function calculateItemDiscount($item, $config, $isGoodsEnable, $isUserRepurchase)
    {
        if (empty($config['enable']) || empty($config['self_enable'])) {
            return 0.0;
        }

        if (!$isGoodsEnable || !$isUserRepurchase) {
            return 0.0;
        }

        $goodsNum = isset($item['goods_num']) ? intval($item['goods_num']) : 1;
        $goodsAmount = isset($item['goods_amount']) ? floatval($item['goods_amount']) : 0.0;
        $goodsPrice = isset($item['goods_price']) ? floatval($item['goods_price']) : ($goodsNum > 0 ? $goodsAmount / $goodsNum : 0.0);

        if ($goodsAmount <= 0) {
            return 0.0;
        }

        $discount = 0.0;
        $selfType = $config['self_type'] ?? 'fixed';

        if ($selfType === 'rate') {
            $rate = floatval($config['self_rate'] ?? 0);
            if ($rate > 0) {
                $discount = round($goodsAmount * $rate * 0.01, 2);
            }
        } else {
            // 固定金额模式：按件数累加立减
            $unitAmount = floatval($config['self_amount'] ?? 0);
            if ($unitAmount > 0) {
                // 单件立减不可超过单件售价
                $validUnitDiscount = min($unitAmount, $goodsPrice);
                $discount = round($validUnitDiscount * $goodsNum, 2);
            }
        }

        // 兜底保护：总立减金额不可超过商品总额
        if ($discount > $goodsAmount) {
            $discount = $goodsAmount;
        }

        return max(0.0, $discount);
    }

    /**
     * 批量计算订单中各商品的复购立减金额
     *
     * @param array $goodsList 商品列表
     * @param int $userId 用户ID
     * @param array|null $config 配置
     * @param callable|null $goodsRuleChecker 自定义商品规则检查器 (用于单测或依赖注入)
     * @param callable|null $historyChecker 自定义历史购买检查器 (用于单测或依赖注入)
     * @return array ['goods_list' => ..., 'total_repurchase_discount' => float]
     */
    public static function calculateOrderRepurchaseDiscounts(
        $goodsList,
        $userId,
        $config = null,
        $goodsRuleChecker = null,
        $historyChecker = null
    ) {
        if ($config === null) {
            $config = self::getConfig();
        }

        $totalDiscount = 0.0;

        foreach ($goodsList as $key => $item) {
            $goodsId = $item['goods_id'] ?? 0;

            // 检查商品是否参与复购
            $isGoodsEnable = false;
            if ($goodsRuleChecker !== null) {
                $isGoodsEnable = (bool) call_user_func($goodsRuleChecker, $goodsId);
            } else {
                $isGoodsEnable = self::isGoodsRepurchaseEnable($goodsId);
            }

            // 检查用户是否复购该商品
            $isUserRepurchase = false;
            if ($isGoodsEnable) {
                if ($historyChecker !== null) {
                    $isUserRepurchase = (bool) call_user_func($historyChecker, $userId, $goodsId);
                } else {
                    $isUserRepurchase = self::isUserRepurchasedGoods($userId, $goodsId);
                }
            }

            $discount = self::calculateItemDiscount($item, $config, $isGoodsEnable, $isUserRepurchase);

            $goodsList[$key]['repurchase_discount_money'] = $discount;
            $goodsList[$key]['is_repurchase'] = ($isGoodsEnable && $isUserRepurchase && $discount > 0) ? 1 : 0;

            $totalDiscount = bcadd((string) $totalDiscount, (string) $discount, 2);
        }

        return [
            'goods_list' => $goodsList,
            'total_repurchase_discount' => floatval($totalDiscount)
        ];
    }
}