require 'get_fitter/error'

module GetFitter
  # Wrap request attrs
  class Request
    FORMAT = 'application/json'

    # The format of the HTTP request
    # @return [String]
    # @api private
    attr_accessor :as

    # The http method for the request
    # @return [Symbol]
    # @api private
    attr_accessor :method

    # The resouce object that we going to call to fetch the data
    # @return [Booking, Event, Organisation, User, Venue]
    # @api private
    attr_accessor :resource

    # The remote url for the resource that we want to fetch
    # @return [String]
    # @api private
    attr_accessor :uri

    # Extra params we want to send with the http request
    # @return [Hash]
    # @api private
    attr_accessor :params

    # Initializer
    # @param [Hash] attrs request attributes
    # @option attrs [GetFitter::] :resource
    # @option attrs [Symbol] :method
    # @option attrs [String] :uri
    # @option attrs [Hash] :params
    # @option attrs [String] :as
    # @return [GetFitter::Request]
    # @example
    #   data = Request.new(resource: Event.new(id: 1), uri: "/something")
    # @api public
    def initialize(attrs)
      self.resource = attrs.fetch(:resource)
      self.method = attrs.fetch(:method) { :get }
      self.uri = attrs.fetch(:uri)
      self.as = attrs.fetch(:as) { FORMAT }
      self.params = attrs.fetch(:params) { {} }
    end

    #
    # Delegate to the Roar client to fetch data from api
    # @return [Booking, Event, Organisation, User, Venue]
    # @example
    #   request.perform_request
    # @raise [GetFitter::Error]
    # @api public
    def fetch
      params[:page] = 1
      full_resource = resource.send(method, uri: build_uri, as: as).dup
      
      while (resource.entries && !resource.entries.empty?) do
        params[:page] += 1

        full_resource.entries.concat(
          resource.send(method, uri: build_uri, as: as).entries)
      end
        
      full_resource

      rescue Roar::Transport::Error => e
        raise_http_errors(e.response.code.to_i, e.response.msg)
    end

    def first
      fetch.entries.first
    end

    def first_or_create
      first || create
    end

    def create
      #  Response will be single entry not collection
      klass_name = /(.+)s$/.match(resource.class.name)[1].split('::').last
      new_resource = GetFitter.const_get("#{klass_name}").new(params)

      new_resource.post(uri: uri, as: as) do |req|
        req.add_field('Authorization', 'Bearer ' + params[:token])
      end

      rescue Roar::Transport::Error => e
        raise_http_errors(e.response.code.to_i, e.response.msg)
    end

    private

    #
    # Check the response code and raise exceptions if needed
    # @param status [Integer]
    # @param message [String]
    # @return [void]
    # @api private
    def raise_http_errors(status, message)
      error_class = GetFitter::Error.errors[status]
      fail(error_class.new(message, status)) if error_class
    end

    def build_uri
      path = URI(uri)
      path.query = URI.encode_www_form(params)

      path
    end
  end
end