<?php

namespace App\Module\Game\Logics;

use App\Module\Game\Dtos\RewardGroupDto;
use App\Module\Game\Dtos\RewardItemDto;
use App\Module\Game\Logics\Reward\Item;
use App\Module\Game\Services\PityService;
use App\Module\Game\Models\GameRewardItem;
use Illuminate\Support\Facades\Log;
use UCore\Exception\LogicException;

/**
 * 权重选择模式奖励处理
 */
class WeightSelectionReward
{

    /**
     * 处理权重选择模式奖励
     *
     * @param RewardGroupDto $groupDto 奖励组DTO
     * @param int|null $userId 用户ID（用于保底机制）
     * @return RewardItemDto[] 要发放的奖励项
     */
    public static function process(RewardGroupDto $groupDto, ?int $userId = null,$multiplier = 1): array
    {
        $items = $groupDto->items;
        if($multiplier > 1){
            $userId = null;
        }
        // 应用保底机制调整（如果有用户ID）
        if ($userId !== null) {
            $items = self::applyPityAdjustments($userId, $items);
        }

        // 如果不是随机发放，返回所有奖励项
        if (!$groupDto->isRandom) {
            $selectedItems =[];
            foreach ($items as $item){
                $selectedItems[] = Item::processQuantity($item,$multiplier);
            }
            return $selectedItems;


        }
        if($multiplier > 1){
            throw new LogicException('倍率下，错误的进入了随机发放！');
        }

        // 随机发放：按权重选择指定数量的奖励项
        return self::processRandomSelection($groupDto, $items);
    }

    /**
     * 处理随机选择
     */
    private static function processRandomSelection(RewardGroupDto $groupDto, array $items): array
    {
        $randomCount = $groupDto->randomCount;

        // 分离必中项和普通项
        $guaranteedItems = [];
        $normalItems     = [];

        foreach ($items as $item) {
            if ($item->isGuaranteed) {
                $guaranteedItems[] = $item;
            } else {
                $normalItems[] = $item;
            }
        }

        // 先选择必中项
        $selectedItems = array_map([ self::class, 'processQuantity' ], $guaranteedItems);

        // 如果必中项数量已经达到或超过随机数量，直接返回必中项
        if (count($selectedItems) >= $randomCount) {
            return array_slice($selectedItems, 0, $randomCount);
        }

        // 计算剩余需要选择的数量
        $remainingCount = $randomCount - count($selectedItems);

        // 如果没有普通项，直接返回必中项
        if (empty($normalItems)) {
            return $selectedItems;
        }

        // 按权重随机选择普通项
        $selectedNormalItems = self::selectByWeight($normalItems, $remainingCount);

        // 合并必中项和选中的普通项
        return array_merge($selectedItems, $selectedNormalItems);
    }

    /**
     * 按权重随机选择奖励项
     */
    private static function selectByWeight(array $items, int $count): array
    {
        $selectedItems  = [];
        $availableItems = $items;

        for ($i = 0; $i < $count; $i++) {
            if (empty($availableItems)) {
                break;
            }

            // 计算总权重
            $totalWeight = array_sum(array_map(function ($item) {
                return $item->weight;
            }, $availableItems));

            if ($totalWeight <= 0) {
                // 如果总权重为0，随机选择
                shuffle($availableItems);
                $selectedItems[] = self::processQuantity(array_shift($availableItems));
                continue;
            }

            // 生成随机权重
            $randomWeight  = mt_rand(1, $totalWeight * 100) / 100;
            $currentWeight = 0;

            // 选择奖励项
            foreach ($availableItems as $index => $item) {
                $currentWeight += $item->weight;
                if ($randomWeight <= $currentWeight) {
                    $selectedItems[] = self::processQuantity($item);
                    unset($availableItems[$index]);
                    $availableItems = array_values($availableItems);
                    break;
                }
            }
        }

        return $selectedItems;
    }

    /**
     * 处理奖励项数量（支持随机数量）
     * @deprecated
     */
    private static function processQuantity(RewardItemDto $item): RewardItemDto
    {
        return Item::processQuantity($item);
    }

    /**
     * 应用保底机制调整
     */
    private static function applyPityAdjustments(int $userId, array $items): array
    {
        try {
            // 将DTO转换为模型集合以便保底服务处理
            $rewardItemModels = collect($items)->map(function ($itemDto) {
                return GameRewardItem::find($itemDto->id);
            })->filter();

            // 应用保底机制调整权重
            $adjustedItems = PityService::applyPityAdjustments($userId, $rewardItemModels);

            // 将调整后的模型转换回DTO
            return $adjustedItems->map(function ($model) {
                return RewardItemDto::fromModel($model);
            })->toArray();
        } catch (\Exception $e) {
            Log::warning("权重选择模式：保底机制调整失败", [
                'userId' => $userId,
                'error'  => $e->getMessage()
            ]);

            return $items; // 返回原始项目
        }
    }

}