base_client.rb

class BaseClient
  class APINotFound < StandardError; end

  attr_reader :auth_strategy

  def initialize(auth_strategy: :headers, headers: {})
    @auth_strategy = auth_strategy
    @headers = headers
  end

  private

  def get_response(endpoint)
    response = HTTParty.get(endpoint_url(endpoint), request_options(endpoint))
    handle_response(response, endpoint)
  end

  def delete_response(endpoint)
    response = HTTParty.delete(endpoint_url(endpoint), request_options(endpoint))
    handle_response(response, endpoint)
  end
  
  def post_response(endpoint, body)
    response = HTTParty.post(endpoint_url(endpoint), request_options(endpoint, body))
    handle_response(response, endpoint)
  end

  def put_response(endpoint, body)
    response = HTTParty.put(endpoint_url(endpoint), request_options(endpoint, body))
    handle_response(response, endpoint)
  end

  def get_response_with_params(endpoint, params)
    query = URI.encode_www_form(params)
    get_response("#{endpoint}?#{query}")
  end

  def request_options(endpoint, body = nil)
    options = {
      headers: headers
    }
    options[:body] = body.to_json if body

    options.deep_merge(auth_options)
  end

  def auth_options
    case auth_strategy
    when :headers
      {headers: api_auth}
    when :basic_auth
      {basic_auth: api_auth}
    else
      {}
    end
  end

  def handle_response(response, endpoint)
    case response.code
    when 200, 201
      response
    when 404
      raise BaseClient::APINotFound, "Endpoint #{endpoint} not found."
    else
      raise "Unable to connect to #{endpoint}: #{response.code} \n#{response.body}"
    end
  end

  def endpoint_url(endpoint)
    URI.join(base_url, endpoint).to_s
  end

  def base_url
    raise NotImplementedError, "Subclasses must define `base_url`"
  end

  def api_auth
    raise NotImplementedError, "Subclasses must define `api_auth`"
  end

  def headers
    @headers.merge(default_headers)
  end 

  def default_headers
    { "content-type" => "application/json", "accept" => "application/json" }
  end
end