require 'openssl'
require "base64"

module AuthingRuby
  class Utils
    # 参照 JS SDK 的 encrypt 函数
    # https://github.com/Authing/authing.js/blob/cf4757d09de3b44c3c3f4509ae8c8715c9f302a2/src/lib/utils.ts#L12
    # 用途：传入一个明文，传入一个公钥
    # 用这个公钥对明文进行 RSA 加密，
    # 然后返回 base64 编码后的结果
    def self.encrypt(plainText, publicKey)
      key = OpenSSL::PKey::RSA.new(publicKey)
      result = key.public_encrypt(plainText)
      return Base64.encode64(result)
    end

    # 生成随机字符串，参照 JS SDK 里的 src/lib/utils.ts
    def self.generateRandomString(length = 30)
      result = ""
      chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'
      for i in 0..length-1
        random_index = rand(0..chars.length-1)
        result += chars[random_index]
      end
      return result
    end

    # 生成一个纯数字的随机字符串
    def self.randomNumberString(length = 8)
      result = ""
      chars = '0123456789'
      for i in 0..length-1
        random_index = rand(0..chars.length-1)
        result += chars[random_index]
      end
      return result
    end

  end
end