import { User } from '@prisma/client';
import { cookies } from 'next/headers';
import { prisma } from '@/lib/db';
import jwt from 'jsonwebtoken';

export interface AdminUser {
  id: string;
  email: string;
  name: string | null;
  role: string;
  permissions: string[];
}

export enum AdminPermission {
  VIEW_USERS = 'users:read',
  MANAGE_USERS = 'users:write',
  MODERATE_CONTENT = 'content:moderate',
  VIEW_ANALYTICS = 'analytics:read',
  MANAGE_SYSTEM = 'system:manage'
}

export function hasPermission(user: AdminUser, permission: AdminPermission): boolean {
  if (user.role === 'admin') return true; // Super admin has all permissions
  return user.permissions.includes(permission);
}

export function getAdminPermissions(role: string): AdminPermission[] {
  switch (role) {
    case 'admin':
      return Object.values(AdminPermission); // All permissions
    case 'moderator':
      return [
        AdminPermission.VIEW_USERS,
        AdminPermission.MODERATE_CONTENT,
        AdminPermission.VIEW_ANALYTICS
      ];
    default:
      return [];
  }
}

export async function verifyAdminToken(token: string): Promise<AdminUser | null> {
  try {
    const decoded = jwt.verify(token, process.env.JWT_SECRET!) as any;

    if (!decoded.userId) return null;

    const user = await prisma.user.findUnique({
      where: { id: decoded.userId },
      select: {
        id: true,
        email: true,
        name: true,
        role: true
      }
    });

    if (!user || !['admin', 'moderator'].includes(user.role)) {
      return null;
    }

    return {
      id: user.id,
      email: user.email,
      name: user.name,
      role: user.role,
      permissions: getAdminPermissions(user.role)
    };
  } catch (error) {
    return null;
  }
}

export async function getCurrentAdmin(): Promise<AdminUser | null> {
  const cookieStore = await cookies();
  const token = cookieStore.get('adminToken')?.value;

  if (!token) return null;

  return verifyAdminToken(token);
}

export function generateAdminToken(user: User): string {
  if (!['admin', 'moderator'].includes(user.role)) {
    throw new Error('User is not an admin');
  }

  const payload = {
    userId: user.id,
    role: user.role,
    type: 'admin'
  };

  return jwt.sign(payload, process.env.JWT_SECRET!, {
    expiresIn: '8h' // Admin sessions expire after 8 hours
  });
}