discourse-chat-integration/app/models/rule.rb

class DiscourseChat::Rule < DiscourseChat::PluginModel
  KEY_PREFIX = 'rule:'

  # Setup ActiveRecord::Store to use the JSON field to read/write these values
  store :value, accessors: [ :channel_id, :group_id, :category_id, :tags, :filter ], coder: JSON

  after_initialize :init_filter

  def init_filter
    self.filter  ||= 'watch'
  end

  validates :filter, :inclusion => { :in => %w(watch follow mute),
    :message => "%{value} is not a valid filter" }

  validate :channel_valid?, :category_and_group_valid?, :tags_valid?

  def channel_valid?
    # Validate channel
    if not (DiscourseChat::Channel.where(id: channel_id).exists?)
      errors.add(:channel_id, "#{channel_id} is not a valid channel id")
    end
  end

  def category_and_group_valid?
    if category_id and group_id
      errors.add(:category_id, "cannot be specified in addition to group_id")
      return
    end

    if group_id
      # Validate group
      if not Group.where(id: group_id).exists?
        errors.add(:group_id, "#{group_id} is not a valid group id")
      end
      return
    end

    # Validate category
    if not (category_id.nil? or Category.where(id: category_id).exists?)
      errors.add(:category_id, "#{category_id} is not a valid category id")
    end
  end

  def tags_valid?
    # Validate tags
    return if tags.nil?
    tags.each do |tag|
      if not Tag.where(name: tag).exists?
        errors.add(:tags, "#{tag} is not a valid tag")
      end
    end
  end

  # We never want an empty array, set it to nil instead
  def tags=(array)
    if array.nil? or array.empty?
      super(nil)
    else
      super(array)
    end
  end

  # These are only allowed to be integers
  %w(channel_id category_id group_id).each do |name|
    define_method "#{name}=" do |val|
      if val.nil? or val.blank?
        super(nil)
      else
        super(val.to_i)
      end
    end
  end

  # Mock foreign key
  # Could return nil
  def channel
    DiscourseChat::Channel.find_by(id:channel_id)
  end
  def channel=(val)
    self.channel_id = val.id
  end

  scope :with_channel, ->(channel) { with_channel_id(channel.id) } 
  scope :with_channel_id, ->(channel_id) { where("value::json->>'channel_id'=?", channel_id.to_s)} 

  scope :with_category_id, ->(category_id) { category_id.nil? ? where("(value::json->'category_id') IS NULL OR json_typeof(value::json->'category_id')='null'") : where("value::json->>'category_id'=?", category_id.to_s)}
  scope :with_group_ids, ->(group_id) { where("value::json->>'group_id' IN (?)", group_id.map(&:to_s))}

  scope :order_by_precedence, ->{ order("CASE
                                          WHEN value::json->>'filter' = 'mute' THEN 1
                                          WHEN value::json->>'filter' = 'watch' THEN 2
                                          WHEN value::json->>'filter' = 'follow' THEN 3
                                         END") }

end