<?php

namespace app\api\logic\tcm;

use app\common\service\FileService;
use think\facade\Db;
use think\facade\Log;

/**
 * 控糖消消乐平台能力：真实用户、每周7人同行榜、幂等成绩上报和微信分享。
 */
class GamePlatformLogic
{
    private const GROUP_SIZE = 7;
    private const MAX_SESSION_LEARNED = 20000;
    private const MAX_SCORE = 100000000;

    protected static string $error = '';

    public static function getError(): string
    {
        return self::$error;
    }

    protected static function fail(string $message): bool
    {
        self::$error = $message;
        return false;
    }

    /**
     * 获取当前用户所在的真实周榜；首次进入会分配到当周同性别7人组。
     */
    public static function leaderboard(int $userId): array|false
    {
        self::$error = '';
        if ($userId <= 0) {
            return self::fail('请先登录');
        }

        try {
            Db::startTrans();
            $score = self::ensureWeeklyScore($userId, self::weekStart());
            $inviteCode = self::ensureShareInvite($userId, self::weekStart());
            Db::commit();
            return self::buildLeaderboard((int) $score['group_id'], $userId, $inviteCode);
        } catch (\Throwable $e) {
            Db::rollback();
            self::logException('leaderboard', $e);
            return self::fail('同行榜暂时不可用，请稍后再试');
        }
    }

    /**
     * 上报每局绝对进度。session_key + learned_count 共同保证网络重试不会重复计分。
     *
     * @param array{session_key:string,learned_count:int,score:int,ended:int|bool} $params
     */
    public static function submitProgress(int $userId, array $params): array|false
    {
        self::$error = '';
        if ($userId <= 0) {
            return self::fail('请先登录');
        }

        $sessionKey = trim((string) ($params['session_key'] ?? ''));
        if (!preg_match('/^[A-Za-z0-9_-]{16,64}$/', $sessionKey)) {
            return self::fail('游戏局标识无效');
        }
        $learned = max(0, min(self::MAX_SESSION_LEARNED, (int) ($params['learned_count'] ?? 0)));
        $scoreValue = max(0, min(self::MAX_SCORE, (int) ($params['score'] ?? 0)));
        $ended = !empty($params['ended']) ? 1 : 0;
        $weekStart = self::weekStart();

        try {
            Db::startTrans();
            $weeklyScore = self::ensureWeeklyScore($userId, $weekStart);
            $session = Db::name('tcm_game_session')
                ->where('session_key', $sessionKey)
                ->lock(true)
                ->find();

            $now = time();
            if ($session && (int) $session['user_id'] !== $userId) {
                Db::rollback();
                return self::fail('游戏局标识已被使用');
            }

            if (!$session) {
                $sessionId = Db::name('tcm_game_session')->insertGetId([
                    'session_key'   => $sessionKey,
                    'user_id'       => $userId,
                    'week_start'    => $weekStart,
                    'learned_count' => 0,
                    'last_score'    => 0,
                    'ended'         => 0,
                    'create_time'   => $now,
                    'update_time'   => $now,
                ]);
                $session = [
                    'id'            => $sessionId,
                    'week_start'    => $weekStart,
                    'learned_count' => 0,
                    'last_score'    => 0,
                    'ended'         => 0,
                ];
            }

            $sessionWeek = (string) $session['week_start'];
            if ($sessionWeek !== $weekStart) {
                $weeklyScore = self::ensureWeeklyScore($userId, $sessionWeek);
            }

            $confirmedLearned = (int) $session['learned_count'];
            $nextLearned = max($confirmedLearned, $learned);
            $delta = $nextLearned - $confirmedLearned;
            $wasEnded = (int) $session['ended'] === 1;
            $markEnded = $wasEnded || $ended === 1;

            Db::name('tcm_game_session')->where('id', (int) $session['id'])->update([
                'learned_count' => $nextLearned,
                'last_score'    => max((int) $session['last_score'], $scoreValue),
                'ended'         => $markEnded ? 1 : 0,
                'update_time'   => $now,
            ]);

            $weeklyLearned = (int) $weeklyScore['learned_count'] + $delta;
            $weeklyBest = max((int) $weeklyScore['best_score'], $scoreValue);
            $gamesPlayed = (int) $weeklyScore['games_played'] + (!$wasEnded && $ended === 1 ? 1 : 0);
            Db::name('tcm_game_weekly_score')->where('id', (int) $weeklyScore['id'])->update([
                'learned_count' => $weeklyLearned,
                'best_score'    => $weeklyBest,
                'games_played'  => $gamesPlayed,
                'update_time'   => $now,
            ]);

            $inviteCode = self::ensureShareInvite($userId, $sessionWeek);
            Db::commit();

            $result = self::buildLeaderboard((int) $weeklyScore['group_id'], $userId, $inviteCode, $sessionWeek);
            $result['confirmed_session_learned'] = $nextLearned;
            return $result;
        } catch (\Throwable $e) {
            Db::rollback();
            self::logException('submitProgress', $e);
            return self::fail('成绩保存失败，请稍后再试');
        }
    }

    /** 记录用户发起一次微信分享，并返回当前分享码。 */
    public static function recordShare(int $userId): array|false
    {
        self::$error = '';
        if ($userId <= 0) {
            return self::fail('请先登录');
        }
        try {
            Db::startTrans();
            $score = self::ensureWeeklyScore($userId, self::weekStart());
            Db::name('tcm_game_weekly_score')->where('id', (int) $score['id'])->inc('share_count')->update([
                'update_time' => time(),
            ]);
            $inviteCode = self::ensureShareInvite($userId, self::weekStart());
            Db::commit();
            return ['invite_code' => $inviteCode];
        } catch (\Throwable $e) {
            Db::rollback();
            self::logException('recordShare', $e);
            return self::fail('分享记录失败');
        }
    }

    /**
     * 记录从分享卡片进入。仅记录一次轻量同行关系，不做家庭/好友强绑定。
     */
    public static function acceptShare(int $userId, string $inviteCode): array|false
    {
        self::$error = '';
        $inviteCode = strtoupper(trim($inviteCode));
        if ($userId <= 0) {
            return self::fail('请先登录');
        }
        if (!preg_match('/^[A-F0-9]{12}$/', $inviteCode)) {
            return self::fail('分享码无效');
        }

        try {
            $invite = Db::name('tcm_game_share_invite')->where('invite_code', $inviteCode)->find();
            if (!$invite) {
                return self::fail('分享已失效');
            }
            $inviterUserId = (int) $invite['user_id'];
            if ($inviterUserId === $userId) {
                return ['accepted' => false, 'message' => '这是您自己的分享'];
            }

            Db::startTrans();
            $inserted = Db::name('tcm_game_share_visit')->duplicate([
                'invite_code',
            ])->insert([
                'invite_code'     => $inviteCode,
                'inviter_user_id' => $inviterUserId,
                'visitor_user_id' => $userId,
                'create_time'     => time(),
            ]);
            $accepted = $inserted === 1;
            if ($accepted) {
                Db::name('tcm_game_share_invite')->where('id', (int) $invite['id'])->inc('open_count')->update([
                    'update_time' => time(),
                ]);
            }
            Db::commit();

            $inviter = Db::name('user')->where('id', $inviterUserId)->field('nickname')->find();
            return [
                'accepted' => $accepted,
                'message'  => '已加入控糖消消乐',
                'inviter'  => self::displayName((string) ($inviter['nickname'] ?? ''), $inviterUserId),
            ];
        } catch (\Throwable $e) {
            Db::rollback();
            self::logException('acceptShare', $e);
            return self::fail('分享关系记录失败');
        }
    }

    private static function ensureWeeklyScore(int $userId, string $weekStart): array
    {
        $profile = self::userProfile($userId);
        $now = time();
        $existing = Db::name('tcm_game_weekly_score')
            ->where('week_start', $weekStart)
            ->where('user_id', $userId)
            ->find();

        if ($existing) {
            $existing = Db::name('tcm_game_weekly_score')
                ->where('id', (int) $existing['id'])
                ->lock(true)
                ->find();
            $profileChanged = (string) $existing['nickname'] !== $profile['nickname']
                || (string) $existing['avatar'] !== $profile['avatar'];
            if ($profileChanged) {
                Db::name('tcm_game_weekly_score')->where('id', (int) $existing['id'])->update([
                    'nickname'   => $profile['nickname'],
                    'avatar'     => $profile['avatar'],
                    'update_time'=> $now,
                ]);
                $existing['nickname'] = $profile['nickname'];
                $existing['avatar'] = $profile['avatar'];
            }
            return $existing;
        }

        // 每周、每个性别使用一行分配锁串行化首次入组。直接 upsert 锁行，
        // 避免空分组上的间隙锁导致首批并发请求互相等待或偶发死锁。
        Db::name('tcm_game_weekly_allocator')->duplicate([
            'update_time',
        ])->insert([
            'week_start' => $weekStart,
            'sex'        => $profile['sex'],
            'create_time'=> $now,
            'update_time'=> $now,
        ]);
        $allocator = Db::name('tcm_game_weekly_allocator')
            ->where('week_start', $weekStart)
            ->where('sex', $profile['sex'])
            ->lock(true)
            ->find();
        if (!$allocator) {
            throw new \RuntimeException('同行分配锁创建失败');
        }

        // 等待分配锁期间，同一用户的另一个请求可能已经完成分配。
        $existing = Db::name('tcm_game_weekly_score')
            ->where('week_start', $weekStart)
            ->where('user_id', $userId)
            ->lock(true)
            ->find();
        if ($existing) {
            return $existing;
        }

        $group = Db::name('tcm_game_weekly_group')
            ->where('week_start', $weekStart)
            ->where('sex', $profile['sex'])
            ->where('member_count', '<', self::GROUP_SIZE)
            ->order('group_no', 'asc')
            ->lock(true)
            ->find();

        if (!$group) {
            $maxGroupNo = (int) Db::name('tcm_game_weekly_group')
                ->where('week_start', $weekStart)
                ->where('sex', $profile['sex'])
                ->max('group_no');
            $groupNo = $maxGroupNo + 1;
            // 首批用户并发进入时可能同时算出相同 group_no。利用唯一键 upsert，
            // 让请求汇合到同一组，再锁定该组继续分配，避免偶发 1062/死锁。
            Db::name('tcm_game_weekly_group')->duplicate([
                'update_time',
            ])->insert([
                'week_start'  => $weekStart,
                'sex'         => $profile['sex'],
                'group_no'    => $groupNo,
                'member_count'=> 0,
                'create_time' => $now,
                'update_time' => $now,
            ]);
            $group = Db::name('tcm_game_weekly_group')
                ->where('week_start', $weekStart)
                ->where('sex', $profile['sex'])
                ->where('group_no', $groupNo)
                ->lock(true)
                ->find();
            if (!$group) {
                throw new \RuntimeException('同行分组创建失败');
            }
        }

        $scoreRow = [
            'group_id'      => (int) $group['id'],
            'week_start'    => $weekStart,
            'user_id'       => $userId,
            'learned_count' => 0,
            'best_score'    => 0,
            'games_played'  => 0,
            'share_count'   => 0,
            'nickname'      => $profile['nickname'],
            'avatar'        => $profile['avatar'],
            'sex'           => $profile['sex'],
            'create_time'   => $now,
            'update_time'   => $now,
        ];
        $inserted = Db::name('tcm_game_weekly_score')->duplicate([
            'nickname',
            'avatar',
            'sex',
            'update_time',
        ])->insert($scoreRow);
        $score = Db::name('tcm_game_weekly_score')
            ->where('week_start', $weekStart)
            ->where('user_id', $userId)
            ->lock(true)
            ->find();
        if (!$score) {
            throw new \RuntimeException('同行成绩创建失败');
        }

        // 仅新插入时刷新人数；使用实际成绩行数纠正历史并发造成的计数漂移。
        if ($inserted === 1) {
            $memberCount = (int) Db::name('tcm_game_weekly_score')
                ->where('group_id', (int) $group['id'])
                ->count();
            Db::name('tcm_game_weekly_group')->where('id', (int) $group['id'])->update([
                'member_count' => min(self::GROUP_SIZE, $memberCount),
                'update_time'  => $now,
            ]);
        }

        return $score;
    }

    private static function buildLeaderboard(
        int $groupId,
        int $userId,
        string $inviteCode,
        ?string $weekStart = null
    ): array {
        $weekStart = $weekStart ?: self::weekStart();
        $rows = Db::name('tcm_game_weekly_score')
            ->where('group_id', $groupId)
            ->where('week_start', $weekStart)
            ->order('learned_count', 'desc')
            ->order('best_score', 'desc')
            ->order('create_time', 'asc')
            ->limit(self::GROUP_SIZE)
            ->select()
            ->toArray();

        $players = [];
        $myIndex = 0;
        foreach ($rows as $index => $row) {
            $isMe = (int) $row['user_id'] === $userId;
            if ($isMe) {
                $myIndex = $index;
            }
            $players[] = [
                // 前端只需要稳定列表键，不暴露平台内部 user_id。
                'id'         => (int) $row['id'],
                'name'       => self::displayName((string) $row['nickname'], (int) $row['user_id']),
                'avatar'     => self::avatarUrl((string) $row['avatar']),
                'count'      => (int) $row['learned_count'],
                'best_score' => (int) $row['best_score'],
                'rank'       => $index + 1,
                'is_me'      => $isMe,
            ];
        }

        $me = $players[$myIndex] ?? [
            'count' => 0,
            'rank' => 1,
            'best_score' => 0,
        ];
        $distance = $myIndex > 0
            ? max(1, (int) $players[$myIndex - 1]['count'] - (int) $me['count'] + 1)
            : 0;
        $group = Db::name('tcm_game_weekly_group')->where('id', $groupId)->find();
        $sex = (int) ($group['sex'] ?? 0);

        return [
            'week_start'  => $weekStart,
            'week_end'    => date('Y-m-d', strtotime($weekStart . ' +6 days')),
            'sex'         => $sex,
            'sex_label'   => $sex === 1 ? '男士同行' : ($sex === 2 ? '女士同行' : '同行'),
            'group_size'  => self::GROUP_SIZE,
            'member_count'=> count($players),
            'players'     => $players,
            'me'          => [
                'count'       => (int) ($me['count'] ?? 0),
                'rank'        => (int) ($me['rank'] ?? 1),
                'best_score'  => (int) ($me['best_score'] ?? 0),
                'distance'    => $distance,
                'is_first'    => $myIndex === 0,
            ],
            'invite_code' => $inviteCode,
        ];
    }

    /** @return array{nickname:string,avatar:string,sex:int} */
    private static function userProfile(int $userId): array
    {
        $user = Db::name('user')
            ->where('id', $userId)
            ->whereNull('delete_time')
            ->field('id,sn,nickname,avatar,sex')
            ->find();
        if (!$user) {
            throw new \RuntimeException('用户不存在');
        }

        $sex = (int) ($user['sex'] ?? 0);
        if ($sex !== 1 && $sex !== 2) {
            $gender = Db::name('diagnosis_view_records')->alias('v')
                ->join('tcm_diagnosis d', 'd.id = v.diagnosis_id')
                ->where('v.user_id', $userId)
                ->whereNull('v.delete_time')
                ->whereNull('d.delete_time')
                ->order('v.id', 'desc')
                ->value('d.gender');
            if ($gender !== null && $gender !== '') {
                $sex = (int) $gender === 1 ? 1 : 2;
            }
        }

        return [
            'nickname' => self::displayName((string) ($user['nickname'] ?? ''), $userId),
            'avatar'   => (string) ($user['avatar'] ?? ''),
            'sex'      => in_array($sex, [1, 2], true) ? $sex : 0,
        ];
    }

    private static function displayName(string $nickname, int $userId): string
    {
        $nickname = trim(strip_tags($nickname));
        if ($nickname === '') {
            return '控糖好友' . substr((string) $userId, -2);
        }
        return mb_substr($nickname, 0, 12);
    }

    private static function avatarUrl(string $avatar): string
    {
        return $avatar === '' ? '' : FileService::getFileUrl($avatar);
    }

    private static function ensureShareInvite(int $userId, string $weekStart): string
    {
        $existing = Db::name('tcm_game_share_invite')
            ->where('week_start', $weekStart)
            ->where('user_id', $userId)
            ->find();
        if ($existing) {
            return (string) $existing['invite_code'];
        }

        for ($attempt = 0; $attempt < 5; $attempt++) {
            $code = strtoupper(bin2hex(random_bytes(6)));
            $now = time();
            // 同一用户并发打开榜单时，以 week_start + user_id 唯一键汇合；
            // 极小概率随机码撞车时，查询不到本人的记录就继续生成新码。
            Db::name('tcm_game_share_invite')->duplicate([
                'update_time',
            ])->insert([
                'invite_code' => $code,
                'user_id'     => $userId,
                'week_start'  => $weekStart,
                'open_count'  => 0,
                'create_time' => $now,
                'update_time' => $now,
            ]);
            $invite = Db::name('tcm_game_share_invite')
                ->where('week_start', $weekStart)
                ->where('user_id', $userId)
                ->find();
            if ($invite) {
                return (string) $invite['invite_code'];
            }
        }
        throw new \RuntimeException('分享码生成失败');
    }

    private static function weekStart(?int $timestamp = null): string
    {
        $timestamp = $timestamp ?: time();
        $day = (int) date('N', $timestamp);
        return date('Y-m-d', strtotime('-' . ($day - 1) . ' days', $timestamp));
    }

    private static function logException(string $action, \Throwable $e): void
    {
        Log::error(sprintf(
            'tcm endless game %s failed: %s at %s:%d',
            $action,
            $e->getMessage(),
            $e->getFile(),
            $e->getLine()
        ));
    }
}