import { NextRequest, NextResponse } from 'next/server';
import { getServerSession } from 'next-auth';
import { authOptions } from '@/lib/auth';
import { prisma } from '@/lib/prisma';

/**
 * 更新用户部门
 * POST /api/admin/users/update-department
 */
export async function POST(request: NextRequest) {
  try {
    // 验证管理员权限
    const session = await getServerSession(authOptions);
    if (!session || !session.user || (session.user as any).role !== 'ADMIN') {
      return NextResponse.json(
        { error: '权限不足' },
        { status: 403 }
      );
    }

    const { userId, department } = await request.json();

    console.log('[Update Department] Request:', { userId, department });

    if (!userId) {
      return NextResponse.json(
        { error: '缺少用户ID' },
        { status: 400 }
      );
    }

    // 双写：同时更新 department（旧字段）和 departmentId（新字段）
    let updateData: any = {
      department: department || ''  // 旧字段（向后兼容）
    };

    // 如果提供了部门名称，查找对应的部门ID
    if (department && department.trim() !== '') {
      const dept = await prisma.department.findUnique({
        where: { name: department.trim() }
      });

      if (dept) {
        updateData.departmentId = dept.id;  // 新字段（阶段二新增）
      } else {
        // 部门不存在，清除 departmentId
        updateData.departmentId = null;
      }
    } else {
      // 部门为空，清除 departmentId
      updateData.departmentId = null;
    }

    // 更新用户部门
    const user = await prisma.user.update({
      where: { id: userId },
      data: updateData,
      include: {
        departmentRef: true  // 包含部门关联信息
      }
    });

    console.log('[Update Department] Success:', {
      userId: user.id,
      username: user.username,
      department: user.department
    });

    return NextResponse.json(user);
  } catch (error) {
    console.error('[Update Department] Error:', error);
    return NextResponse.json(
      { error: '更新部门失败' },
      { status: 500 }
    );
  }
}