#!/usr/bin/env ruby

begin
  require 'thor'
rescue LoadError => e
  puts "Thor is required. Please install the gem with development dependencies."
  exit 1
end

require 'open-uri'
require 'google/apis/discovery_v1'
require 'logger'

module Google
  class ApiGenerator < Thor

    def self.exit_on_failure?
      true
    end

    include Thor::Actions

    Google::Apis::ClientOptions.default.application_name = "generate-api"
    Google::Apis::ClientOptions.default.application_version = Google::Apis::VERSION

    Discovery = Google::Apis::DiscoveryV1

    desc 'gen OUTDIR', 'Generate ruby API from an API description'
    method_options url: :array, file: :array, from_discovery: :boolean, preferred_only: :boolean,
                   verbose: :boolean, names: :string, names_out: :string
    def gen(dir)
      ensure_active_support
      require 'google/apis/generator'

      self.destination_root = dir
      Google::Apis.logger.level = Logger::DEBUG if options[:verbose]
      generate_from_url(options[:url]) if options[:url]
      generate_from_file(options[:file]) if options[:file]
      generate_from_discovery(preferred_only: options[:preferred_only]) if options[:from_discovery]
      if options[:names_out]
        create_file(options[:names_out]) { |*| generator.dump_api_names } unless File.exist? options[:names_out]
      end
    end

    desc 'list', 'List public APIs'
    method_options verbose: :boolean, preferred_only: :boolean
    def list
      Google::Apis.logger.level = Logger::DEBUG if options[:verbose]
      discovery = Discovery::DiscoveryService.new
      apis = discovery.list_apis
      apis.items.each do |api|
        say sprintf('%s - %s', api.id, api.description).strip unless options[:preferred_only] && !api.preferred?
      end
    end

    no_commands do
      def generate_from_url(urls)
        Array(urls).each do |url|
          begin
            json = discovery.http(:get, url)
          rescue Google::Apis::ClientError
            warn sprintf('Failed request, skipping %s', url)
            next
          end
          generate_api(json)
        end
      end

      def generate_from_file(files)
        Array(files).each do |file|
          File.open(file) do |f|
            generate_api(f.read)
          end
        end
      end

      def generate_from_discovery(preferred_only: false)
        say 'Fetching API list'
        apis = discovery.list_apis
        apis.items.each do |api|
          if (preferred_only && !api.preferred?)
            say sprintf('Ignoring disoverable API %s', api.id)
          else
	    # The Discovery service may returned cached versions of a Discovery document that are
	    # not the most recent revision. That means that subsequent requests to the same
	    # Discovery document URL can return different documents. The
	    # `discovery-artifact-manager` repo always holds the most recent revision, so it's
	    # easier to use that document than to force revision checking against the URL returned
	    # by the Discovery index.
            discovery_rest_url = "https://raw.githubusercontent.com/googleapis/discovery-artifact-manager/master/discoveries/#{api.name}.#{api.version}.json"
            say sprintf('Loading %s, version %s from %s', api.name, api.version, discovery_rest_url)
            generate_from_url(discovery_rest_url)
          end
        end
      end

      def generate_api(json)
        files = generator.render(json)
        files.each do |file, content|
          create_file(file) { |*| content }
        end
      end

      def discovery
        @discovery ||= Discovery::DiscoveryService.new
      end

      def generator
        @generator ||= Google::Apis::Generator.new(api_names: options[:names], api_names_out: options[:names_out])
      end

      def ensure_active_support
        begin
          require 'active_support/inflector'
        rescue LoadError => e
          error 'ActiveSupport is required, please run:'
          error 'gem install activesupport'
          exit 1
        end
      end
    end
  end

end

Google::ApiGenerator.start(ARGV)