<?php

/**
 * 文件功能：聊天室礼包（红包）控制器
 *
 * 提供两个核心接口：
 *  - send()  ：superlevel 站长凭空发出 888 数量 10 份礼包（金币 or 经验）
 *  - claim() ：在线用户抢礼包（先到先得，每人一份）
 *
 * 接入 UserCurrencyService 记录所有货币变动流水。
 *
 * @author  ChatRoom Laravel
 * @version 1.0.0
 */

namespace App\Http\Controllers;

use App\Enums\CurrencySource;
use App\Events\MessageSent;
use App\Events\RedPacketClaimed;
use App\Events\RedPacketSent;
use App\Jobs\SaveMessageJob;
use App\Models\RedPacketClaim;
use App\Models\RedPacketEnvelope;
use App\Models\Sysparam;
use App\Services\ChatStateService;
use App\Services\UserCurrencyService;
use Illuminate\Database\UniqueConstraintViolationException;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\DB;

class RedPacketController extends Controller
{
    /** 礼包固定总数量 */
    private const TOTAL_AMOUNT = 888;

    /** 礼包固定份数 */
    private const TOTAL_COUNT = 10;

    /** 礼包有效期（秒） */
    private const EXPIRE_SECONDS = 120;

    /**
     * 构造函数：注入依赖服务
     */
    public function __construct(
        private readonly ChatStateService $chatState,
        private readonly UserCurrencyService $currencyService,
    ) {}

    /**
     * superlevel 站长凭空发出礼包。
     *
     * 不扣发包人自身货币，888 数量凭空发出分 10 份。
     * type 参数决定本次发出的是金币（gold）还是经验（exp）。
     *
     * @param  Request  $request  需包含 room_id 和 type（gold / exp）
     */
    public function send(Request $request): JsonResponse
    {
        $request->validate([
            'room_id' => 'required|integer',
            'type'    => 'required|in:gold,exp',
        ]);

        $user   = Auth::user();
        $roomId = (int) $request->input('room_id');
        $type   = $request->input('type'); // 'gold' 或 'exp'

        // 权限校验：仅 superlevel 可发礼包
        $superLevel = (int) Sysparam::getValue('superlevel', '100');
        if ($user->user_level < $superLevel) {
            return response()->json(['status' => 'error', 'message' => '仅站长可发礼包红包'], 403);
        }

        // 检查该用户在此房间是否有进行中的红包（防止刷包）
        $activeExists = RedPacketEnvelope::query()
            ->where('sender_id', $user->id)
            ->where('room_id', $roomId)
            ->where('status', 'active')
            ->where('expires_at', '>', now())
            ->exists();

        if ($activeExists) {
            return response()->json(['status' => 'error', 'message' => '您有一个礼包尚未领完，请稍后再发！'], 422);
        }

        // 随机拆分数量（二倍均值法，保证每份至少 1，总额精确等于 TOTAL_AMOUNT）
        $amounts = $this->splitAmount(self::TOTAL_AMOUNT, self::TOTAL_COUNT);

        // 货币展示文案
        $typeLabel = $type === 'exp' ? '经验' : '金币';
        $typeIcon  = $type === 'exp' ? '✨' : '🪙';
        $btnBg     = $type === 'exp'
            ? 'linear-gradient(135deg,#7c3aed,#4f46e5)'
            : 'linear-gradient(135deg,#dc2626,#ea580c)';

        // 事务：创建红包记录 + Redis 写入分额
        $envelope = DB::transaction(function () use ($user, $roomId, $type, $amounts): RedPacketEnvelope {
            // 创建红包主记录（凭空发出，不扣发包人货币）
            $envelope = RedPacketEnvelope::create([
                'sender_id'       => $user->id,
                'sender_username' => $user->username,
                'room_id'         => $roomId,
                'type'            => $type,
                'total_amount'    => self::TOTAL_AMOUNT,
                'total_count'     => self::TOTAL_COUNT,
                'claimed_count'   => 0,
                'claimed_amount'  => 0,
                'status'          => 'active',
                'expires_at'      => now()->addSeconds(self::EXPIRE_SECONDS),
            ]);

            // 将拆分好的数量序列存入 Redis（List，LPOP 抢红包）
            $key = "red_packet:{$envelope->id}:amounts";
            foreach ($amounts as $amt) {
                \Illuminate\Support\Facades\Redis::rpush($key, $amt);
            }
            // 多留 60s，确保领完后仍可回查
            \Illuminate\Support\Facades\Redis::expire($key, self::EXPIRE_SECONDS + 60);

            return $envelope;
        });

        // 广播系统公告，含可点击「立即抢包」按钮
        $btnHtml = '<button onclick="showRedPacketModal('
            .$envelope->id
            .',\''.$user->username.'\','
            .self::TOTAL_AMOUNT.','
            .self::TOTAL_COUNT.','
            .self::EXPIRE_SECONDS
            .',\''.$type.'\''
            .')" style="margin-left:8px;padding:2px 10px;background:'.$btnBg.';'
            .'color:#fff;border:none;border-radius:10px;cursor:pointer;font-size:12px;font-weight:bold;'
            .'box-shadow:0 2px 6px rgba(0,0,0,0.3);">'.$typeIcon.' 立即抢包</button>';

        $msg = [
            'id'         => $this->chatState->nextMessageId($roomId),
            'room_id'    => $roomId,
            'from_user'  => '系统公告',
            'to_user'    => '',
            'content'    => "🧧 <b>{$user->username}</b> 发出了一个 <b>".self::TOTAL_AMOUNT."</b> {$typeLabel}的礼包！共 ".self::TOTAL_COUNT." 份，先到先得，快去抢！{$btnHtml}",
            'is_secret'  => false,
            'font_color' => $type === 'exp' ? '#6d28d9' : '#b91c1c',
            'action'     => '',
            'sent_at'    => now()->toDateTimeString(),
        ];
        $this->chatState->pushMessage($roomId, $msg);
        broadcast(new MessageSent($roomId, $msg));
        SaveMessageJob::dispatch($msg);

        // 广播红包事件（触发前端弹出红包卡片）
        broadcast(new RedPacketSent(
            roomId:         $roomId,
            envelopeId:     $envelope->id,
            senderUsername: $user->username,
            totalAmount:    self::TOTAL_AMOUNT,
            totalCount:     self::TOTAL_COUNT,
            expireSeconds:  self::EXPIRE_SECONDS,
            type:           $type,
        ));

        return response()->json([
            'status'  => 'success',
            'message' => "🧧 {$typeLabel}礼包已发出！".self::TOTAL_AMOUNT." {$typeLabel} · ".self::TOTAL_COUNT." 份",
        ]);
    }

    /**
     * 查询礼包当前状态（弹窗打开时实时刷新用）。
     *
     * 返回：剩余份数、是否已过期、当前用户是否已领取。
     *
     * @param  int  $envelopeId  红包 ID
     */
    public function status(int $envelopeId): JsonResponse
    {
        $envelope = RedPacketEnvelope::find($envelopeId);
        if (! $envelope) {
            return response()->json(['status' => 'error', 'message' => '红包不存在'], 404);
        }

        $user           = Auth::user();
        $isExpired      = $envelope->expires_at->isPast();
        $remainingCount = $envelope->remainingCount();
        $hasClaimed     = RedPacketClaim::where('envelope_id', $envelopeId)
            ->where('user_id', $user->id)
            ->exists();

        return response()->json([
            'status'          => 'success',
            'remaining_count' => $remainingCount,
            'total_count'     => $envelope->total_count,
            'envelope_status' => $envelope->status,
            'is_expired'      => $isExpired,
            'has_claimed'     => $hasClaimed,
            'type'            => $envelope->type ?? 'gold',
        ]);
    }

    /**
     * 用户抢礼包（先到先得）。
     *
     * 使用 Redis LPOP 原子操作获取数量，再写入数据库流水。
     * 重复领取通过 unique 约束保障幂等性。
     * 按红包 type 字段决定入账金币还是经验。
     *
     * @param  Request  $request     需包含 room_id
     * @param  int      $envelopeId  红包 ID
     */
    public function claim(Request $request, int $envelopeId): JsonResponse
    {
        $request->validate([
            'room_id' => 'required|integer',
        ]);

        $user   = Auth::user();
        $roomId = (int) $request->input('room_id');

        // 加载红包记录
        $envelope = RedPacketEnvelope::find($envelopeId);
        if (! $envelope) {
            return response()->json(['status' => 'error', 'message' => '红包不存在'], 404);
        }

        // 检查红包是否可领
        if (! $envelope->isClaimable()) {
            return response()->json(['status' => 'error', 'message' => '红包已抢完或已过期'], 422);
        }

        // 检查是否已领取过
        $alreadyClaimed = RedPacketClaim::where('envelope_id', $envelopeId)
            ->where('user_id', $user->id)
            ->exists();
        if ($alreadyClaimed) {
            return response()->json(['status' => 'error', 'message' => '您已经领过这个礼包了'], 422);
        }

        // 从 Redis 原子 POP 一份数量
        $redisKey = "red_packet:{$envelopeId}:amounts";
        $amount   = \Illuminate\Support\Facades\Redis::lpop($redisKey);
        if ($amount === null || $amount === false) {
            return response()->json(['status' => 'error', 'message' => '礼包已被抢完！'], 422);
        }
        $amount       = (int) $amount;
        // 兼容旧记录（type 字段可能为 null）
        $envelopeType = $envelope->type ?? 'gold';

        // 事务：写领取记录 + 更新统计 + 货币入账
        try {
            DB::transaction(function () use ($envelope, $user, $amount, $roomId, $envelopeType): void {
                // 写领取记录（unique 约束保障不重复）
                RedPacketClaim::create([
                    'envelope_id' => $envelope->id,
                    'user_id'     => $user->id,
                    'username'    => $user->username,
                    'amount'      => $amount,
                    'claimed_at'  => now(),
                ]);

                // 更新红包统计
                $envelope->increment('claimed_count');
                $envelope->increment('claimed_amount', $amount);

                // 若已全部领完，关闭红包
                $envelope->refresh();
                if ($envelope->claimed_count >= $envelope->total_count) {
                    $envelope->update(['status' => 'completed']);
                }

                // 按类型入账（金币或经验）
                if ($envelopeType === 'exp') {
                    $this->currencyService->change(
                        $user,
                        'exp',
                        $amount,
                        CurrencySource::RED_PACKET_RECV_EXP,
                        "抢到礼包 {$amount} 经验（红包#{$envelope->id}）",
                        $roomId,
                    );
                } else {
                    $this->currencyService->change(
                        $user,
                        'gold',
                        $amount,
                        CurrencySource::RED_PACKET_RECV,
                        "抢到礼包 {$amount} 金币（红包#{$envelope->id}）",
                        $roomId,
                    );
                }
            });
        } catch (UniqueConstraintViolationException) {
            // 并发重复领取：将数量放回 Redis（补偿）
            \Illuminate\Support\Facades\Redis::rpush($redisKey, $amount);

            return response()->json(['status' => 'error', 'message' => '您已经领过这个礼包了'], 422);
        }

        // 广播领取事件（给自己的私有频道，前端弹 Toast）
        broadcast(new RedPacketClaimed($user, $amount, $envelope->id));

        // 在聊天室发送领取播报（所有人可见）
        $typeLabel  = $envelopeType === 'exp' ? '经验' : '金币';
        $typeIcon   = $envelopeType === 'exp' ? '✨' : '🪙';
        $claimedMsg = [
            'id'         => $this->chatState->nextMessageId($roomId),
            'room_id'    => $roomId,
            'from_user'  => '系统传音',
            'to_user'    => '',
            'content'    => "🧧 <b>{$user->username}</b> 抢到了 <b>{$amount}</b> {$typeLabel}礼包！{$typeIcon}",
            'is_secret'  => false,
            'font_color' => $envelopeType === 'exp' ? '#6d28d9' : '#d97706',
            'action'     => '',
            'sent_at'    => now()->toDateTimeString(),
        ];
        $this->chatState->pushMessage($roomId, $claimedMsg);
        broadcast(new MessageSent($roomId, $claimedMsg));
        SaveMessageJob::dispatch($claimedMsg);

        $balanceField = $envelopeType === 'exp' ? 'exp_num' : 'jjb';
        $balanceNow   = $user->fresh()->$balanceField;

        return response()->json([
            'status'  => 'success',
            'amount'  => $amount,
            'type'    => $envelopeType,
            'message' => "🧧 恭喜！您抢到了 {$amount} {$typeLabel}！当前{$typeLabel}：{$balanceNow}。",
        ]);
    }

    /**
     * 随机拆分礼包数量。
     *
     * 使用「二倍均值法」：每次随机数量不超过剩余均值的 2 倍，
     * 保证每份至少 1 且总额精确等于 totalAmount。
     *
     * @param  int  $total  总数量
     * @param  int  $count  份数
     * @return int[]        每份数量数组
     */
    private function splitAmount(int $total, int $count): array
    {
        $amounts   = [];
        $remaining = $total;

        for ($i = 1; $i < $count; $i++) {
            $leftCount = $count - $i;
            $max       = min((int) floor($remaining / $leftCount * 2), $remaining - $leftCount);
            $max       = max(1, $max);
            $amount    = random_int(1, $max);
            $amounts[] = $amount;
            $remaining -= $amount;
        }

        // 最后一份为剩余全部
        $amounts[] = $remaining;

        // 打乱顺序，避免后来者必得少
        shuffle($amounts);

        return $amounts;
    }
}