# joyce


* [Homepage](https://rubygems.org/gems/joyce)
* [Documentation](http://rubydoc.info/gems/joyce/frames)
* [Email](mailto:jweissman1986 at gmail.com)

[![Code Climate GPA](https://codeclimate.com/github//joyce/badges/gpa.svg)](https://codeclimate.com/github//joyce)

## Description

Joyce is a multiplayer game server framework built on top of Metacosm

## What is the big idea?

The idea is to build 'isomorphic' Ruby games: to target both a Gosu game client as well as a game server running in the cloud. Both are running the same code, but the responsibilities are split:

  - The game server runs game business logic, and publishes events that the clients consume to hydrate their local views
  - Clients publish commands the the server validates and handles, updating game state and generating events

One upshot of this is that all game processing is kept on the server, and clients are doing nothing but rendering views and when necessary figuring out what commands to publish (when the user interacts).

## Features

## Examples

Below is the source for a toy app that displays a list of other connected players and how long they've been connected. The server uses a ping command from clients to determine if players have disconnected.

    require 'joyce'
    module Example
      class SampleAppView < Joyce::ApplicationView
        def render
          game_view.render(window, font)
        end

        def game_view
          GameView.find_by active_player_id: application.player_id
        end
      end

      class SampleServer < Joyce::Server
        def setup
          Game.create
        end

        def tick
          Game.all.each(&:iterate!)
        end
      end

      class Application < Joyce::Application
        viewed_with Example::SampleAppView

        def setup
          GameView.create(active_player_id: player_id)
          sim.params[:active_player_id] = player_id
        end

        def tick
          @ticks ||= 0
          @ticks += 1
          # p [ :sample_app_tick ]
          if (@ticks % 30 == 0)
            fire(PingCommand.create(player_id: player_id, player_name: player_name))
          end
        end

        def player_id
          @player_id ||= SecureRandom.uuid
        end

        def player_name
          @player_name ||= %w[ Alice Bob Cardiff Danielle Echo Fargo ].sample
        end
      end

      class BulletPointAtom
        def render(color: 0xf0f0f0f0, location:,size: 10,window:)
          x,y = location
          window.draw_quad(x,y,color,
                           x,y+size,color,
                           x+size,y,color,
                           x+size,y+size,color)
        end
      end

      class TextBoxAtom
        def render(message:, location:, font:)
          x,y = *location
          font.draw(message, x, y, 1)
        end
      end

      class ListMolecule
        def render(title: '', elements:, location:, font:, window:)
          x0,y0 = location
          font.draw(title, x0, y0, 1)
          elements.each_with_index do |element, index|
            x, y = x0, y0 + ((index+1)*20)

            bullet_point = BulletPointAtom.new
            bullet_point.render(location: [x-10,y], window: window)

            text_box = TextBoxAtom.new
            text_box.render(message: element, location: [x,y], font: font)
          end
        end
      end

      class PlayerView < Metacosm::View
        belongs_to :game_view
        attr_accessor :name, :joined_at, :player_id
      end

      class GameView < Metacosm::View
        has_many :player_views

        attr_accessor :active_player_id, :game_id
        # attr_accessor :player_names

        def render(window, font)
          # p [ :render_game_view, pinged_at: pinged_at ]
          window.draw_quad(10,10, 0xf0f0f0f0,
                           10,20, 0xf0f0f0f0,
                           20,10, 0xf0f0f0f0,
                           20,20, 0xf0f0f0f0)

          if player_names && player_names.any?
            ListMolecule.new.render(
              title: "Connected Users:",
              elements: player_names,
              location: [40,40],
              font: font,
              window: window
            )
          end
        end

        private
        def player_names
          self.player_views.map { |p| "#{p.name} (#{time_ago_in_words(p.joined_at)})" }
        end
      end

      class PingCommand < Metacosm::Command
        attr_accessor :player_id, :player_name
      end

      class PingCommandHandler
        def handle(player_id:, player_name:)
          game = Game.find_by(players: { id: player_id })
          if game.nil?
            game = Game.first || Game.create
            game.admit_player(player_id: player_id, player_name: player_name)
          end

          game.ping(player_id: player_id)
        end
      end

      class ApplicationEventListener < Metacosm::EventListener
        def game_view
          GameView.find_by(active_player_id: active_player_id)
        end

        def active_player_id
          self.simulation.params[:active_player_id]
        end
      end

      class PlayerAdmittedEvent < Metacosm::Event
        attr_accessor :player_id, :player_name, :connected_player_list
      end

      class PlayerAdmittedEventListener < ApplicationEventListener
        def receive(player_id:, player_name:, connected_player_list:)
          if game_view
            connected_player_list.each do |id:, name:, joined_at:|
              player_view = game_view.player_views.where(player_id: id).first_or_create
              player_view.update(name: name, joined_at: joined_at)
            end
          end
        end
      end

      class PlayerDroppedEvent < Metacosm::Event
        attr_accessor :player_id, :connected_player_list
      end

      class PlayerDroppedEventListener < ApplicationEventListener
        def receive(player_id:, connected_player_list:)
          if game_view
            game_view.player_views.map(&:destroy)
            connected_player_list.each do |id:, name:, joined_at:|
              player_view = game_view.player_views.where(player_id: id).first_or_create
              player_view.update(name: name, joined_at: joined_at)
            end
          end
        end
      end
    end

## Requirements

## Install

    $ gem install joyce

## Synopsis

    $ joyce

## Copyright

Copyright (c) 2016 Joseph Weissman

See {file:LICENSE.txt} for details.