module Picky
  class Categories
    attr_reader :categories, :category_hash

    forward :each,
            :first,
            :map,
            :map!,
            :include?,
            :empty?,
            to: :categories

    each_forward :cache,
                 :dump,
                 :empty,
                 :inject,
                 :reindex,
                 :reset_backend,
                 to: :categories

    # A list of indexed categories.
    #
    def initialize(_options = {})
      clear_categories
    end

    # Clears both the array of categories and the hash of categories.
    #
    def clear_categories
      @categories    = []
      @category_hash = {}
    end

    # Updates the qualifier ("qualifier:searchterm") mapping.
    #
    # Example:
    #   You dynamically add a new category to an index.
    #   To add the qualifiers to a search, you call this
    #   method.
    #
    def qualifier_mapper
      @qualifier_mapper ||= QualifierMapper.new self
    end

    # Resets the qualifier mapper used.
    #
    def reset_qualifier_mapper
      @qualifier_mapper = nil
    end

    # Add the given category to the list of categories.
    #
    def <<(category)
      reset_qualifier_mapper # TODO: Have an add method on QualifierMapper?
      # TODO: This is wrong, and needs to be handled in index.rb
      categories << category unless categories.include? category
      category_hash[category.name] = category
    end

    # Find a given category in the categories.
    #
    def [](category_name)
      category_name = category_name.intern
      category_hash[category_name] || raise_not_found(category_name)
    end

    def raise_not_found(category_name)
      raise %(Index category "#{category_name}" not found. Possible categories: "#{categories.map(&:name).join('", "')}".)
    end

    def to_stats
      map(&:name).join(', ')
    end

    def to_tree_s(indent = 0)
      ([' ' * indent] * categories.size).zip(categories.map(&:to_tree_s)).map(&:join).join "\n"
    end

    def to_s
      "#{self.class}(#{categories.join(', ')})"
    end
  end
end
