module LazyGoogleAnalytics
  class Client

    CLIENT_OPTIONS = %w(api_method parameters ids start_date end_date dimensions metrics sort filters)
    attr_accessor :options, :auth

    def initialize(opts = {})

      @auth ||= LazyGoogleAnalytics::Auth.new
      @auth.authorize # check expiration and cache ?

      self.tap do |client|
        client.options    ||= {}
        client.defaults_options(opts)
        client.options ||= opts
        yield client if block_given?
      end
    end

    def defaults_options(opts)

      api_method = opts[:api_method] ||= @auth.analytics.data.ga.get
      start_date = opts[:start_date] ||= DateTime.now.prev_month.strftime("%Y-%m-%d")
      end_date   = opts[:end_date]   ||= DateTime.now.strftime("%Y-%m-%d")
      ids        = opts[:ids]        ||= "ga:#{LazyGoogleAnalytics::Config.profile_id}"
      dimensions = opts[:dimensions] ||= "ga:day,ga:month"
      metrics    = opts[:metrics]    ||= "ga:visits"
      sort       = opts[:sort]       ||= "ga:month,ga:day"

      self.api_method(api_method)
      self.parameters({'ids' => ids,
                      'start-date' => start_date,
                      'end-date' => end_date,
                      'dimensions' => dimensions,
                      'metrics' => metrics,
                      'sort' => sort })
    end


    def results
      @results = @auth.client.execute(@options)
      raise_detected_errors if @results.status > 200
      @results
    end

    def formatted_columns
      (@results || self.results).data.column_headers.map { |c|
        c.name
      }.join("\t")
    end

    def formatted_rows
      (@results || self.results).data.rows.each do |r|
        print r.join("\t"), "\n"
      end
    end

    def method_missing(meth, opts = {})
      merge_options meth, opts
    end

  private

    def merge_options(name, opts)
      @options.merge!  name => opts
    end

    def raise_detected_errors
      body = JSON.parse(@results.body)
      raise body["error"]["errors"].collect{|e| "#{e["reason"]}: #{e["message"]}" }.join(", ") if body.keys.include?("error")
    end

  end
end