require 'active_support/concern'

module Taggable

  extend ActiveSupport::Concern

  included do

    validate :tags_exist

  end

  class_methods do

    def tagged_with_all(*tags)

      where(tags_column.contains(normalize_tags(tags)))

    end

    alias_method :tagged_with, :tagged_with_all

    def tagged_with_any(*tags)

      where(tags_column.overlaps(normalize_tags(tags)))

    end

    def tagged

      where(tags_column.not_eq([]))

    end

    def untagged

      where(tags_column.eq([]))

    end

    def tags_column

      arel_table[:tags]

    end

    def normalize_tags(tags)

      Array(tags).flatten.map(&:to_i).compact.reject(&:zero?)

    end

  end

  def normalize_tags(tags)

    self.class.normalize_tags(tags)

  end

  def tags=(tags)

    super(normalize_tags(tags))

  end

  def tag_names

    Tag.where(id: tags).pluck(:name)

  end

  def tags_exist

    unless tags.all? { |tag| Tag.exists?(tag) }

      errors.add :tags, :invalid

    end

  end

end