04-base-filter-1.rb

# app/filters/base_filter.rb
class BaseFilter
  include ActiveModel::Model
  include ActiveModel::Attributes

  def initialize(session)
    @_session = session
    super(@_session.fetch(:filters, {})[filter_resource_class])
  end

  def apply!(_chain)
    raise NotImplementedError
  end

  def active_for?(attribute, value=true)
    filter_attribute = send(attribute)

    return filter_attribute.include?(value) if filter_attribute.is_a?(Enumerable)
    filter_attribute == value
  end

  def filter_resource_class
    @filter_resource_class || self.class.name.match(/\A(?<resource>.*)Filter\Z/)[:resource]
  end
end

04-base-filter-2.rb

# app/filters/base_filter.rb
class BaseFilter
  # ...

  def merge!(_attribute, _value)
    @_session[:filters] ||= {}
    @_session[:filters][filter_resource_class] ||= {}
  end
end

# app/filters/embed_filter.rb
class EmbedFilter < BaseFilter
  # ...

  def merge!(attribute, value)
    super

    if send(attribute).is_a? Array
      if send(attribute).include? value
        send(attribute).delete value
      else
        send(attribute) << value
      end
    end

    @_session[:filters]["Embed"].merge!(attribute => send(attribute))
  end
end

04-board-history-entry-filter.rb

# app/filters/board_filter.rb
class BoardFilter < BaseFilter
  attribute :query, :string, default: ""

  def apply!(chain)
    chain = chain.search(query) if query.present?
    chain
  end

  def merge!(attribute, value)
    super

    send(:"#{attribute}=", value)

    @_session[:filters]["Board"].merge!(attribute => send(attribute))
  end
end

# app/filters/history_entry_filter.rb
class HistoryEntryFilter < BaseFilter
  attribute :show_all, :boolean, default: false

  def apply!(chain)
    chain = chain.with_reactions unless show_all
    chain
  end

  def merge!(attribute, value)
    super

    send(:"#{attribute}=", !send(attribute))

    @_session[:filters]["HistoryEntry"].merge!(attribute => send(attribute))
  end
end

04-boards-controller.rb

# app/controllers/boards_controller.rb
class BoardsController
  # ...

  def show
    @embed = @board.embeds.build
    @embed_import = EmbedImport.new(board: @board)
    @embeds = filter_for("Embed").apply!(@board.embeds)
  end

  # ...
end

04-controllers.rb

# app/controllers/boards_controller.rb
class BoardsController < ApplicationController
  include Filterable

  def index
    set_filter_for!("Board", "query", "")
    @boards = current_user.boards.order(:created_at)
    @boards = @boards.search(filter_for("Board", "query")) if filter_for("Board", "query").present?
  end

  def show
    set_filter_for!("Embed", "embeddable_type", %w[MediaAsset OEmbedLink])
    @embed = @board.embeds.build
    @embed_import = EmbedImport.new(board: @board)
    @embeds = @board.embeds.where(session[:filters]["Embed"])
  end

  # ...
end

# app/controllers/embed_controller.rb
class EmbedsController < ApplicationController
  include Filterable

  # ...

  def show
    set_filter_for!("HistoryEntry", "show_all", false)
    @comment ||= Comment.new(user: current_user)
    @comment.build_history_entry(embed: @embed)

    @history_entries = @embed.history_entries.includes(:entryable)
    @history_entries = @history_entries.with_reactions unless filter_for("HistoryEntry", "show_all")
  end

  # ...
end

# app/reflexes/filter_reflex.rb
class FilterReflex < ApplicationReflex
  include Filterable

  def filter
    resource, param = element.dataset.to_h.fetch_values(:resource, :param)
    value = element.dataset.value || element.value

    if element["role"] == "checkbox"
      if filter_for(resource, param).is_a? Array
        if filter_for(resource, param).include? value
          filter_for(resource, param).delete value
        else
          filter_for(resource, param) << value
        end
      else
        set_filter_for!(resource, param, !filter_for(resource, param))
      end
    else
      set_filter_for!(resource, param, value)
    end
  end
end

04-embed-filter-1.rb

# app/filters/embed_filter.rb
class EmbedFilter < BaseFilter
  attribute :embeddable_type, default: %w[MediaAsset OEmbedLink] # cannot use type: :array here :-(

  def apply!(chain)
    chain.where(embeddable_type: embeddable_type) if embeddable_type.present?
    chain
  end
end

04-filter-active-for.rb

def filter_active_for?(resource, param, value=true)
  filter = session.fetch(:filters, {}).fetch(resource, {}).fetch(param, [])

  return filter.include?(value) if filter.is_a?(Enumerable)
  filter == value 
end

04-filter-boards-view.erb

<!-- app/views/boards/index.html.erb -->

<%= text_field_tag "Search",
     session[:filters]["Board"]["title"],
     placeholder: "Search for a board",
     data: {reflex: "debounced:input->Filter#filter", resource: "Board", param: "query"},
     %>

04-filter-comments-view.erb

<button type="button"
            role="checkbox"
            data-reflex="click->Filter#filter"
            data-resource="HistoryEntry"
            data-param="show_all"
            >
    <span class="sr-only">Use setting</span>
    <span aria-hidden="true" class="<%= filter_active_for?("HistoryEntry", "show_all") ? "translate-x-5" : "translate-x-0" %> ..."></span>
</button>

04-filter-embeds-view.erb

<div class="flex items-center">
  <button type="button"
          role="checkbox"
          data-reflex="click->Filter#filter"
          data-resource="Embed"
          data-param="embeddable_type"
          data-value="OEmbedLink"
          >
    <span class="sr-only">Use setting</span>
    <span aria-hidden="true" class="<%= filter_active_for?("Embed", "embeddable_type", "OEmbedLink") ? "translate-x-5" : "translate-x-0" %> ..."></span>
  </button>
  <span class="ml-3" id="annual-billing-label">
    <span class="text-sm font-medium text-gray-900">Show Links</span>
  </span>
</div>
<div class="flex items-center">
  <button type="button"
          role="checkbox"
          data-reflex="click->Filter#filter"
          data-resource="Embed"
          data-param="embeddable_type"
          data-value="MediaAsset"
          >
    <span class="sr-only">Use setting</span>
    <span aria-hidden="true" class="<%= filter_active_for?("Embed", "embeddable_type", "MediaAsset") ? "translate-x-5" : "translate-x-0" %> ..."></span>
  </button>
  <span class="ml-3" id="annual-billing-label">
    <span class="text-sm font-medium text-gray-900">Show Uploads</span>
  </span>
</div>

04-filter-reflex-2.rb

# app/reflexes/filter_reflex.rb
class FilterReflex < ApplicationReflex
  include Filterable

  def filter
    resource, param = element.dataset.to_h.fetch_values(:resource, :param)
    value = element.dataset.value || element.value

    set_filter_for!(resource, param, value)
  end
end

04-filter-reflex.rb

# app/reflexes/filter_reflex.rb
class FilterReflex < ApplicationReflex
  def filter
    resource, param = element.dataset.to_h.fetch_values(:resource, :param)
    value = element.dataset.value || element.value

    if element["role"] == "checkbox"
      # checkbox toggles elements in an array on and off
      # %w[OEmbedLink MediaAsset]
      if session[:filters][resource][param].is_a? Array
        if session[:filters][resource][param].include? value
          session[:filters][resource][param].delete value
        else
          session[:filters][resource][param] << value
        end
      # checkbox toggles a single value on and off 
      else
        session[:filters][resource][param] = !session[:filters][resource][param]
      end
    else
      session[:filters][resource][param] = value
    end
  end
end

04-filterable-concern-2.rb

# app/controllers/concerns/filterable.rb
module Filterable
  # ...

  def filter_active_for?(resource, attribute, value=true)
    filter = filter_for(resource)

    filter.active_for?(attribute, value)
  end

  private

  def filter_for(resource)
    "#{resource}Filter".constantize.new(session)
  end

  # ...
end

04-filterable.rb

module Filterable
  extend ActiveSupport::Concern

  private

  def filter_for(resource, param)
    session.fetch(:filters, {}).fetch(resource, {}).fetch(param, [])
  end

  def set_filter_for!(resource, param, value)
    session[:filters] ||= {}
    session[:filters][resource] ||= {}
    session[:filters][resource][param] = value if (self.class.ancestors.include? StimulusReflex::Reflex || filter_for(resource, param).blank?)
  end
end

04-filtered-controller-actions.rb

# app/controllers/boards_controller.rb
class BoardsController < ApplicationController

  # ...

  def index
    session[:filters] ||= {}
    session[:filters]["Board"] ||= {"query" => ""}
    query = session[:filters]["Board"]["query"]
    @boards = current_user.boards.order(:created_at)
    @boards = @boards.search(query) if query.present?
  end

  def show
    session[:filters] ||= {}
    session[:filters]["Embed"] ||= {"embeddable_type" => %w[MediaAsset OEmbedLink]}
    @embed = @board.embeds.build
    @embed_import = EmbedImport.new(board: @board)
    @embeds = @board.embeds.where(session[:filters]["Embed"])
  end

  # ...

end

# app/controllers/embed_controller.rb
class EmbedsController < ApplicationController

  # ...

  def show
    session[:filters] ||= {}
    session[:filters]["HistoryEntry"] ||= {"show_all" => false}
    @comment ||= Comment.new(user: current_user)
    @comment.build_history_entry(embed: @embed)

    @history_entries = @embed.history_entries.includes(:entryable)
    @history_entries = @history_entries.with_reactions unless filter_for("HistoryEntry", "show_all")
  end

  # ...

end

04-media-asset.rb

# db/migrate/20210208120653_create_media_assets.rb
class CreateMediaAssets < ActiveRecord::Migration[6.1]
  def change
    create_table :media_assets do |t|
      t.string :title

      t.timestamps
    end
  end
end

# app/models/media_asset.rb
class MediaAsset < ApplicationRecord
  include Embeddable

  validates :title, presence: true

  has_one_attached :media_file

  def embed_code
    "<audio controls><source src=\"#{Rails.application.routes.url_helpers.rails_blob_path(media_file, only_path: true)}\" type=\"audio/mp3\"></audio>".html_safe
  end
end

# app/models/embed.rb
class Embed < ApplicationRecord

  # ...

  # 👇 add MediaAsset to the list of embeddable types
  delegated_type :embeddable, types: %w(OEmbedLink MediaAsset) 

  # 👇 initialize MediaAsset correctly
  after_initialize do
    next if persisted?

    if input&.start_with? "http"
      self.embeddable = OEmbedLink.new(url: input)
    else
      self.embeddable = MediaAsset.new(title: input)
    end
  end

  def title
    self[:title] || embeddable.title
  end
end