import { Injectable, CanActivate, ExecutionContext, ForbiddenException } from '@nestjs/common';
import { Reflector } from '@nestjs/core';
import { ROLES_KEY } from '../decorators/roles.decorator';
import { UserRole } from '../enums';
import { ErrorCode, ErrorMessage } from '../interfaces/response.interface';

/**
 * 角色守卫
 * 检查用户是否拥有所需的角色
 */
@Injectable()
export class RolesGuard implements CanActivate {
  constructor(private reflector: Reflector) {}

  canActivate(context: ExecutionContext): boolean {
    const requiredRoles = this.reflector.getAllAndOverride<UserRole[]>(
      ROLES_KEY,
      [context.getHandler(), context.getClass()],
    );

    if (!requiredRoles) {
      return true;
    }

    const { user } = context.switchToHttp().getRequest();

    if (!user) {
      throw new ForbiddenException({
        code: ErrorCode.UNAUTHORIZED,
        message: ErrorMessage[ErrorCode.UNAUTHORIZED],
      });
    }

    const hasRole = requiredRoles.some((role) => user.role === role);

    if (!hasRole) {
      throw new ForbiddenException({
        code: ErrorCode.NO_PERMISSION,
        message: ErrorMessage[ErrorCode.NO_PERMISSION],
      });
    }

    return true;
  }
}