# frozen_string_literal: true

require_relative '../helpers/jwt_helper'

module Alula
  # Helper class to generate OAuth access tokens (core API) and JWT tokens (VSP API)
  class TokenExchange
    class << self
      def token_for_user(user_id, opts = {}, scope: nil)
        url = '/rest/v1/oauth/accesstokens'
        payload = { data: { attributes: { userId: user_id } } }
        payload[:data][:attributes][:scope] = scope if scope

        response = Alula::Client.request(:post, url, payload, opts)

        if response.ok?
          ImpersonatedToken.new(response.data['data']['attributes'])
        else
          error_class = AlulaError.for_response(response)
          raise error_class
        end
      end

      def fetch_video_token(payload)
        cache_key = generate_cache_key(payload)
        cached_token, expiry = retrieve_cached_token(cache_key)

        if cached_token && Time.now.to_i < expiry
          jwt_token = cached_token
        else
          jwt_token = build_jwt_token(payload)
          expiry = Time.now.to_i + JwtHelper::ONE_HOUR # 1 hour expiry
          store_token_in_cache(cache_key, jwt_token, expiry)
        end

        jwt_token
      end

      private

      def build_jwt_token(payload)
        JwtHelper.build_jwt_token(payload)
      end

      def store_token_in_cache(cache_key, jwt_token, expiry)
        @token_cache ||= {}
        @token_cache[cache_key] = [jwt_token, expiry]
      end

      def retrieve_cached_token(cache_key)
        @token_cache ||= {}
        @token_cache[cache_key]
      end

      def generate_cache_key(payload)
        if payload[:internal]
          'jwt_token_internal'
        elsif payload[:customerId]
          "jwt_token_customer_#{payload[:customerId]}"
        else
          raise ArgumentError, 'Invalid payload'
        end
      end
    end

    class ImpersonatedToken
      # Simple Oauth::Response reader object
      attr_reader :date_created, :access_token, :expires_in, :expires_at, :refresh_token, :scope, :impersonated_by

      def initialize(attributes)
        @raw_response = attributes

        @date_created = Time.parse(attributes['dateCreated'])
        @access_token = attributes['accessToken']
        @expires_at = Time.parse(attributes['expires'])
        @expires_in = (@expires_at - Time.now.utc).to_i
        @refresh_token = attributes['refresh_token']
        @scope = attributes['scope']
        @impersonated_by = attributes['impersonatedBy']
      end
    end
  end
end