require 'faraday'
require 'json'
module Rsbe
  module Client
    class Base
      def self.find(id)
        o = find_and_instantiate(id)
        raise Rsbe::Client::RecordNotFound.new("#{self.name} with #{id} not found") if o.nil?
        o
      end

      # returns an array of Partner objects
      def self.all
        conn = Rsbe::Client::Connection.new
        local_response = conn.get base_path
        raise "Error retrieving partners" unless local_response.status == 200
        JSON.parse(local_response.body).collect { |json_hash| new(json_hash) }
      end

      def self.find_and_instantiate(id)
        p = self.new(id: id)
        if p.send(:get)
          p.send(:update_hash_from_response)
        else
          p = nil
        end
        p
      end
      private_class_method :find_and_instantiate

      def initialize
        @conn = Rsbe::Client::Connection.new
      end
      def self.base_path
        '/api/v0'
      end
      def save
        (has_id? && exists?) ? update : create
      end

      private
      # N.B. intentionally not updating hash here
      def get(id = @hash[:id])
        @response = @conn.get item_path(id)
        @response.status == 200
      end

      def get_children(path_segment)
        path = item_path(id) + '/' + path_segment
        @response = @conn.get path
        @response.status == 200
      end

      def create
        @response = @conn.post do |req|
          req.url coll_path
          req.headers['Content-Type'] = 'application/json'
          req.body = @hash.to_json
        end
        return false unless @response.status == 201

        update_hash_from_response
        true
      end

      def update_hash_from_response
        raise "@response not initialized" if @response.nil?

        # update attributes with those from server
        response_hash = JSON.parse(@response.body)
        raise "unable to parse response to hash" unless response_hash.is_a?(Hash)
        update_hash(response_hash)
      end

      def update_hash_nils_from_response
        raise "@response not initialized" if @response.nil?

        # update attributes with those from server
        response_hash = JSON.parse(@response.body)
        raise "unable to parse response to hash" unless response_hash.is_a?(Hash)
        update_hash_nils(response_hash)
      end

      def update_hash(arg)
        # update object state
        self.class.all_attrs.each { |k| (@hash[k] = arg[k.to_s]) if arg.has_key?(k.to_s) }
      end

      def update_hash_nils(arg)
        # update object state
        self.class.all_attrs.each do |k|
          (@hash[k] = arg[k.to_s]) if @hash[k].nil?
        end
      end

      def update
        @response = @conn.put do |req|
          req.url item_path(@hash[:id])
          req.headers['Content-Type'] = 'application/json'
          req.body = @hash.to_json
        end

        success = @response.status == 204
        if success
          get
          update_hash_from_response
        end
        success
      end

      def has_id?
        !@hash[:id].nil?
      end

      def exists?
        get
      end

      def coll_path
        self.class.base_path
      end

      def item_path(id)
        coll_path + "/#{id}"
      end

      def self.rw_attrs
        []
      end

      def self.ro_attrs
        []
      end

      def self.all_attrs
        self.rw_attrs + self.ro_attrs
      end
    end
  end
end