require 'securerandom'
require 'asciidoctor/attribute_list'

module AsciidoctorBibliography
  class Citation
    TEX_MACROS_NAMES = Formatters::TeX::MACROS.keys.map { |s| Regexp.escape s }.concat(['fullcite']).join('|')
    REGEXP = /\\?(#{TEX_MACROS_NAMES}):(?:(\S*?)?\[(|.*?[^\\])\])(?:\+(\S*?)?\[(|.*?[^\\])\])*/

    # No need for a fully fledged class right now.
    Cite = Struct.new(:key, :occurrence_index, :target, :positional_attributes, :named_attributes)

    attr_reader :macro, :cites

    def initialize(macro, *targets_and_attributes_list)
      @uuid = SecureRandom.uuid
      @macro = macro
      @cites = []
      targets_and_attributes_list.compact.each_slice(2).each do |target, attributes|
        positional_attributes, named_attributes = # true, false
          ::Asciidoctor::AttributeList.new(attributes).parse
            .group_by { |hash_key, _| hash_key.is_a? Integer }
            .values.map { |a| Hash[a] }
        positional_attributes = positional_attributes.values
        @cites << Cite.new(
          positional_attributes.first,
          nil,
          target,
          positional_attributes,
          named_attributes
        )
      end
    end

    def render(bibliographer)
      if macro == 'fullcite'
        # NOTE: we reinstantiate to avoid tracking used keys.
        formatter = Formatters::CSL.new(bibliographer.options['reference-style'])
        formatter.import bibliographer.database
        # TODO: as is, cites other than the first are simply ignored.
        '{empty}' + Helpers.html_to_asciidoc(formatter.render(:bibliography, id: cites.first.key).join)
      elsif Formatters::TeX::MACROS.keys.include? macro
        bibliographer.citation_formatter.render(self)
      end
    end

    def uuid
      ":#{@uuid}:"
    end

    def keys
      @cites.map { |h| h[:key] }
    end

    def xref(key, label)
      "xref:#{self.render_id(key)}[#{label.gsub(']','\]')}]"
    end

    def render_id(key)
      ['bibliography', key].compact.join('-')
    end

    private

    def render_label(formatter, key)
      formatter.render(:citation, id: key)
    end

    def render_xref(formatter, key)
      "xref:#{render_id(key)}[#{render_label(formatter, key)}]"
    end
  end
end