import { ForbiddenException, HttpStatus, Injectable } from '@nestjs/common';
import { PrismaService } from '../prisma/prisma.service.js';
import { RedisService } from '../common/redis/redis.service.js';
import { getRequestContext } from '../common/context/request-context.js';
import { RESERVED_ROLE_CODES, sessionRevokedKey } from '../common/constants.js';
import { BusinessException } from '../common/business-exception.js';
import { ErrorCodes } from '../common/error-codes.js';
import { ListSessionQuery } from './dto.js';

/** 与 auth.service 的 access token 有效时长对齐（黑名单 TTL）。 */
const ACCESS_TTL = Number(process.env.JWT_ACCESS_TTL ?? 7200);

interface SessionRow {
  sid: string | null;
  userId: string;
  ip: string | null;
  userAgent: string | null;
  loginAt: Date;
  expireAt: Date;
}

@Injectable()
export class SessionsService {
  constructor(
    private readonly prisma: PrismaService,
    private readonly redis: RedisService,
  ) {}

  /** 活跃会话分页：数据权限过滤可见用户 + 用户名/IP 筛选。 */
  async listSessions(q: ListSessionQuery) {
    const ctx = getRequestContext()!;

    // 1. 数据权限 → 允许的 userId 集合（null=不限）
    let userIds: string[] | null = null;
    if (ctx.dataScope === 'self') {
      userIds = [ctx.userId];
    } else if (ctx.orgCodes.length > 0) {
      const users = await this.prisma.client.user.findMany({
        where: { orgCode: { in: ctx.orgCodes } },
        select: { id: true },
      });
      userIds = users.map((u) => u.id);
      if (userIds.length === 0) return { list: [], total: 0, page: q.page, pageSize: q.pageSize };
    }

    // 2. 用户名筛选 → 进一步收窄 userId 集合
    if (q.username) {
      const where: Record<string, unknown> = { username: { contains: q.username } };
      if (userIds) where.id = { in: userIds };
      const users = await this.prisma.client.user.findMany({ where, select: { id: true } });
      userIds = users.map((u) => u.id);
      if (userIds.length === 0) return { list: [], total: 0, page: q.page, pageSize: q.pageSize };
    }

    // 3. refresh token 查询（tenantCode 由 Prisma 扩展自动注入）
    const where: Record<string, unknown> = { revokedAt: null, expireAt: { gt: new Date() } };
    if (userIds) where.userId = { in: userIds };
    if (q.ip) where.ip = { contains: q.ip };

    const [rows, total] = await Promise.all([
      this.prisma.client.refreshToken.findMany({
        where,
        skip: (q.page - 1) * q.pageSize,
        take: q.pageSize,
        orderBy: { loginAt: 'desc' },
        select: { sid: true, userId: true, ip: true, userAgent: true, loginAt: true, expireAt: true },
      }),
      this.prisma.client.refreshToken.count({ where }),
    ]);

    // 4. 补用户名/昵称
    const ids = [...new Set((rows as SessionRow[]).map((r) => r.userId))];
    const users = ids.length
      ? await this.prisma.client.user.findMany({ where: { id: { in: ids } }, select: { id: true, username: true, nickname: true } })
      : [];
    const userMap = new Map(users.map((u) => [u.id, u]));
    const list = (rows as SessionRow[]).map((r) => {
      const u = userMap.get(r.userId);
      return {
        sid: r.sid,
        userId: r.userId,
        username: u?.username ?? '',
        nickname: u?.nickname ?? null,
        ip: r.ip,
        userAgent: r.userAgent,
        loginAt: r.loginAt,
        expireAt: r.expireAt,
      };
    });
    return { list, total, page: q.page, pageSize: q.pageSize };
  }

  /** 单会话强退：吊销该 sid 的 refresh token + 写黑名单使在飞 access token 失效。 */
  async kickSession(sid: string): Promise<null> {
    const ctx = getRequestContext()!;
    const session = await this.prisma.client.refreshToken.findFirst({
      where: { sid, revokedAt: null },
      select: { userId: true },
    });
    if (!session) throw new BusinessException(ErrorCodes.SESSION_NOT_FOUND, '会话不存在或已下线', HttpStatus.NOT_FOUND);
    const roles = await this.prisma.client.userRole.findMany({
      where: { tenantCode: ctx.tenantCode, userId: session.userId },
      select: { roleCode: true },
    });
    if (roles.some((r) => RESERVED_ROLE_CODES.includes(r.roleCode))) {
      throw new ForbiddenException('保留角色账号的会话不可强退');
    }
    const result = await this.prisma.client.refreshToken.updateMany({
      where: { sid, revokedAt: null },
      data: { revokedAt: new Date() },
    });
    if (result.count === 0) throw new BusinessException(ErrorCodes.SESSION_NOT_FOUND, '会话不存在或已下线', HttpStatus.NOT_FOUND);
    await this.redis.setJson(sessionRevokedKey(sid), 1, ACCESS_TTL);
    return null;
  }
}