discourse-chat-integration/lib/discourse_chat/provider.rb

module DiscourseChat
  class ProviderError < StandardError
    attr_accessor :info

    def initialize(message = nil, info: nil)
      super(message)
      self.info = info.nil? ? {} : info
    end
  end

  module Provider
    def self.providers
      constants.select do |constant|
        constant.to_s =~ /Provider$/
      end.map(&method(:const_get))
    end

    def self.enabled_providers
      self.providers.select do |provider|
        self.is_enabled(provider)
      end
    end

    def self.provider_names
      self.providers.map {|x| x::PROVIDER_NAME}
    end

    def self.enabled_provider_names
      self.enabled_providers.map {|x| x::PROVIDER_NAME}
    end

    def self.get_by_name(name)
      self.providers.find{|p| p::PROVIDER_NAME == name}
    end

    def self.is_enabled(provider)
      if defined? provider::PROVIDER_ENABLED_SETTING 
        SiteSetting.send(provider::PROVIDER_ENABLED_SETTING)
      else
        false
      end
    end

    class HookEngine < ::Rails::Engine
      engine_name DiscourseChat::PLUGIN_NAME+"-hooks"
      isolate_namespace DiscourseChat::Provider
    end

    class HookController < ::ApplicationController
      requires_plugin DiscourseChat::PLUGIN_NAME

      class ProviderDisabled < StandardError; end

      rescue_from ProviderDisabled  do
        rescue_discourse_actions(:not_found, 404)
      end

      def self.requires_provider(provider_name)
        before_filter do
          raise ProviderDisabled.new unless Provider.enabled_provider_names.include?(provider_name)
        end
      end

      def respond
        render 
      end
    end

    # Automatically mount each provider's engine inside the HookEngine
    def self.mount_engines
      engines = []
      DiscourseChat::Provider.providers.each do |provider|
        engine = provider.constants.select do |constant|
          constant.to_s =~ /Engine$/ and not constant.to_s == "HookEngine"
        end.map(&provider.method(:const_get)).first

        if engine
          engines.push({engine: engine, name: provider::PROVIDER_NAME})
        end  
      end

      DiscourseChat::Provider::HookEngine.routes.draw do
        engines.each do |engine|
          mount engine[:engine], at: engine[:name]
        end
      end
    end

  end
end

require_relative "provider/slack/slack_provider.rb"
require_relative "provider/telegram/telegram_provider.rb"