require "async/http/internet"
require "base64"
require "uri"
require "fileutils"

module Terminalwire
  module Client
    class ServerLicenseVerification
      include Logging

      def initialize(url:)
        @url = URI(url)
        @internet = Async::HTTP::Internet.new
        @cache_store = Terminalwire::Cache::File::Store.new(path: "~/.terminalwire/cache/licenses/verifications")
      end

      def key
        Base64.urlsafe_encode64 @url
      end

      def cache = @cache_store.entry key

      def payload
        if cache.miss?
          logger.debug "Stale verification. Requesting new verification."
          request do |response|
            # Set the expiry on the file cache for the header.
            if max_age = response.headers["cache-control"].max_age
              logger.debug "Caching for #{max_age}"
              cache.expires = Time.now + max_age
            end

            # Process based on the response code.
            case response.status
            in 200
              logger.debug "License for #{@url} found."
              data = self.class.unpack response.read
              cache.value = data
              return data
            in 404
              logger.debug "License for #{@url} not found."
              return self.class.unpack response.read
            end
          end
        else
          return cache.value
        end
      end

      def message
        payload.dig(:shell, :output)
      end

      protected

      def verification_url
        Terminalwire.url
          .path("/licenses/verifications", key)
      end

      def request(&)
        logger.debug "Requesting license verification from #{verification_url}."
        response = @internet.get verification_url, {
          "Accept" => "application/x-msgpack",
          "User-Agent" => "Terminalwire/#{Terminalwire::VERSION} Ruby/#{RUBY_VERSION} (#{RUBY_PLATFORM})",
        }, &
      end

      def self.unpack(pack)
        MessagePack.unpack(pack, symbolize_keys: true)
      end
    end
  end
end