require "concurrent"

module Clerk
  class JWKSCache
    def initialize(lifetime)
      @lifetime = lifetime
      @jwks = nil
      @last_update = nil
      @lock = Concurrent::ReadWriteLock.new
    end

    def fetch(sdk, force_refresh: false, kid_not_found: false)
      should_refresh = @lock.with_read_lock do
        now = Time.now.to_i

        @jwks.nil? || @last_update.nil? || force_refresh ||
          (now - @last_update > @lifetime) ||
          (kid_not_found && now - @last_update > 300)
      end

      if should_refresh
        @lock.with_write_lock do
          @last_update = Time.now.to_i
          @jwks = begin
            sdk.jwks.get_jwks.keys.map(&:to_hash)
          rescue Clerk::Error, ClerkHttpClient::ApiError
            nil
          end
        end
      end

      @lock.with_read_lock do
        @jwks
      end
    end
  end
end